Antioxidant Activity-Mediated Neuroprotective Effects of an Antagonist of AT1 Receptors, Candesartan, Against Cerebral Ischemia and Edema in Rats
We examined the effects of post-ischemic blockade of angiotensinAT1 receptors by candesartan
 on cerebral infarction and formation of edema. Male Sprague–Dawley rats were divided into
 three groups, sham, control ischemic, and candesartan-treated (0.3 mg/kg) ischemic. Transient&#...
Saved in:
| Published in: | Нейрофизиология |
|---|---|
| Date: | 2013 |
| Main Authors: | , , |
| Format: | Article |
| Language: | English |
| Published: |
Інститут фізіології ім. О.О. Богомольця НАН України
2013
|
| Online Access: | https://nasplib.isofts.kiev.ua/handle/123456789/148233 |
| Tags: |
Add Tag
No Tags, Be the first to tag this record!
|
| Journal Title: | Digital Library of Periodicals of National Academy of Sciences of Ukraine |
| Cite this: | Antioxidant Activity-Mediated Neuroprotective Effects of an Antagonist of AT1 Receptors, Candesartan, Against Cerebral Ischemia and Edema in Rats / H. Panahpour, Sh. Bohlooli, S.E. Motavallibashi // Нейрофизиология. — 2013. — Т. 45, № 5. — С. 469-475. — Бібліогр.: 37 назв. — англ. |
Institution
Digital Library of Periodicals of National Academy of Sciences of Ukraine| _version_ | 1860258229798305792 |
|---|---|
| author | Panahpour, H. Bohlooli, Sh. Motavallibashi, S.E. |
| author_facet | Panahpour, H. Bohlooli, Sh. Motavallibashi, S.E. |
| citation_txt | Antioxidant Activity-Mediated Neuroprotective Effects of an Antagonist of AT1 Receptors, Candesartan, Against Cerebral Ischemia and Edema in Rats / H. Panahpour, Sh. Bohlooli, S.E. Motavallibashi // Нейрофизиология. — 2013. — Т. 45, № 5. — С. 469-475. — Бібліогр.: 37 назв. — англ. |
| collection | DSpace DC |
| container_title | Нейрофизиология |
| description | We examined the effects of post-ischemic blockade of angiotensinAT1 receptors by candesartan
on cerebral infarction and formation of edema. Male Sprague–Dawley rats were divided into
three groups, sham, control ischemic, and candesartan-treated (0.3 mg/kg) ischemic. Transient
focal cerebral ischemia was induced by 90-min-long occlusion of the left middle cerebral
artery followed by 24-h-long reperfusion. Neurological deficit score was evaluated at the end
of the reperfusion period. Thereafter, the animals were randomly selected and used for three
projects: (i) Measurement of the infarct volumes, (ii) investigation of ischemic brain edema
formation using a wet/dry method, and (iii) assessment of the malondialdehyde (MDA) and
reduced glutathione (GSH) concentrations using a HPLC technique. Induction of cerebral
ischemia in the control group produced considerable infarctions in the cortex and striatum
in conjunction with severely impaired motor functions. Candesartan treatment significantly
reduced the infarct volumes and improved the above functions. The water content in the left
(lesioned) hemisphere was considerably elevated in the control ischemic group. Candesartan
treatment significantly lowered the water content in the ischemic lesioned hemisphere,
retained tissue GSH level, and led to a lower MDA production. AT1 receptor blockade by
candesartan treatment can noticeably decrease ischemic brain injury and attenuate edema
formation, likely via increasing the antioxidant activity.
Досліджували ефекти постішемічного блокування ангіотензивних рецепторів AT1 кандесартаном щодо зони церебрального інфаркту та формування набряку. Самці щурів лінії Спрейг–Доулі були розділені на три групи (інтактних
контрольних, контрольних з ішемією та ішемізованих, котрим уводили 0.3 мг/кг кандесартану). Епізод фокальної
ішемії мозку створювався за допомогою 90-хвилинної оклюзії лівої середньої церебральної артерії; оклюзія супроводжувалася 24-годинною реперфузією. Неврологічний дефіцит оцінювався в балах після закінчення періоду реперфузії.
Потім тварини рандомізовано відбиралися для вимірювань
трьох видів: об’єму зони інфаркту, ступеня набряку мозку з
використанням методу „суха/волога тканина” та концентрацій малонового діальдегіду (MDA) й відновленого глутатіону (GSH) з використанням методики HPLC. Індукція церебральної ішемії у відповідній контрольній групі призводила
до розвитку значних інфарктів у корі та стріатумі, спряженому з важкими порушеннями моторних функцій. Уведення
кандесартану забезпечувало істотне зменшення об’ємів інфарктів і послаблення порушень зазначених функцій. Вміст
води в лівій (ураженій) півкулі в контрольній групі з ішемією був значно підвищеним. Використання кандесартану
призводило до значного зменшення вмісту води в ішемізованій лівій півкулі, відновлення рівня GSH у тканині та зменшення продукції MDA. Отже, блокування AT1-рецепторів
кандесартаном може помітно зменшувати ступінь ішемічного пошкодження мозку та послаблювати формування набряку; ці ефекти опосередковуються підсиленням антиоксидантної активності
|
| first_indexed | 2025-12-07T18:51:39Z |
| format | Article |
| fulltext |
NEUROPHYSIOLOGY / НЕЙРОФИЗИОЛОГИЯ.—2013.—T. 45, № 5 469
UDC 616.831-005
H. PANAHPOUR1, SH. BOHLOOLI1, and S. E. MOTAVALLIBASHI1
ANTIOXIDANT ACTIVITY-MEDIATED NEUROPROTECTIVE EFFECTS
OF AN ANTAGONIST OF AT1 RECEPTORS, CANDESARTAN,
AGAINST CEREBRAL ISCHEMIA AND EDEMA IN RATS
Received February 22, 2013.
We examined the effects of post-ischemic blockade of angiotensin AT1 receptors by candesartan
on cerebral infarction and formation of edema. Male Sprague–Dawley rats were divided into
three groups, sham, control ischemic, and candesartan-treated (0.3 mg/kg) ischemic. Transient
focal cerebral ischemia was induced by 90-min-long occlusion of the left middle cerebral
artery followed by 24-h-long reperfusion. Neurological deficit score was evaluated at the end
of the reperfusion period. Thereafter, the animals were randomly selected and used for three
projects: (i) Measurement of the infarct volumes, (ii) investigation of ischemic brain edema
formation using a wet/dry method, and (iii) assessment of the malondialdehyde (MDA) and
reduced glutathione (GSH) concentrations using a HPLC technique. Induction of cerebral
ischemia in the control group produced considerable infarctions in the cortex and striatum
in conjunction with severely impaired motor functions. Candesartan treatment significantly
reduced the infarct volumes and improved the above functions. The water content in the left
(lesioned) hemisphere was considerably elevated in the control ischemic group. Candesartan
treatment significantly lowered the water content in the ischemic lesioned hemisphere,
retained tissue GSH level, and led to a lower MDA production. AT1 receptor blockade by
candesartan treatment can noticeably decrease ischemic brain injury and attenuate edema
formation, likely via increasing the antioxidant activity.
Keywords: focal cerebral ischemia, brain edema, candesartan, malondialdehyde,
glutathione.
1 Department of Physiology and Pharmacology, Medical School, Ardabil
University of Medical Sciences, Ardabil, Iran.
Correspondence should be addressed to H. Panahpour
(e-mail: h.panahpour@arums.ac.ir).
INTRODUCTION
With an around 30% mortality rate, stroke remains the
third leading cause of death in industrialized countries.
Ischemic brain injury results from a complex sequence
of pathophysiological events developing over time and
space [1]. The extent of the tissue damage depends on
both intensity and duration of focal cerebral ischemia
[2]. Ischemic brain edema is a life-threatening
complication of cerebral infarction that significantly
aggravates the primary ischemic injury of the brain
[3] via increased intracranial pressure and herniation
[1]. Therefore, prevention from the development of
brain edema may decrease cerebral injury and reduce
stroke-related mortality.
Experimental and cl inical s tudies al lowed
researchers to suggest that inhibition of the renin-
angiotensin system (RAS) by inactivation of ACE or
angiotensin 1 (AT1) receptors might be effective not
only in reducing the occurrence of stroke, but also
may attenuate neuronal injury [4]. Furthermore, long-
term pretreatment with ACE inhibitors or AT1 receptor
blockers was reported to prevent the occurrence of
cerebral ischemia in stroke-prone spontaneously
hypertensive rats [5-7]. Other reports also indicated
that inhibition of ACE [8] or AT1 receptors [9] prior
to the induction of ischemia improve neurological
recovery from cerebral ischemia. There are a few
studies of the effects of post-ischemic AT1 receptor
blockade on brain ischemic/reperfusion (I/R) injuries
and their mechanisms.
Oxygen free radicals may play a noticeable role in
brain I/R injuries. The amount of oxygen provided
during reperfusion exceeds the capabilities of
mitochondrial utilization. Therefore, a shift towards
high production of free radical-related compounds,
such as NO, superoxide, hydrogen peroxide, and
NEUROPHYSIOLOGY / НЕЙРОФИЗИОЛОГИЯ.—2013.—T. 45, № 5470
H. PANAHPOUR, SH. BOHLOOLI, and S. E. MOTAVALLIBASHI
hydroxyl, is formed [10]. These agents are constantly
scavenged by superoxide dismutase, glutathione
peroxidase, and catalase. Other antioxidants, including
reduced glutathione (GSH), ascorbic acid, and vitamin
E, are also likely to be involved in detoxification
of the free radicals. When endogenous antioxidant
mechanisms are suppressed or the production of free
radicals outweighs these mechanisms, a chain of
reactions (denaturation of proteins, inactivation of
enzymes, and breaking down of carbohydrates) starts.
This leads to intense lipid peroxidation in the inner
and outer mitochondrial and cell membranes [11].
As the RAS and inflammatory responses play
important roles in I/R injuries, our study was designed
to evaluate the neuroprotective effects of post-
ischemic treatment with candesartan, an AT1 receptor
antagonist, and the mechanisms of these effects.
METHODS
Fifty-four male Sprague-Dawley rats (280-320 g)
were obtained from the Central animal house facility
of the Ardabil University of Medical Sciences
(Ardabil, Iran). Anesthesia was made by i.p. injections
of chloral hydrate (400 mg/kg). Body temperature was
maintained at 37 ± 0.5°C with a heating feedback
control system.
Laser Doppler Flowmetery. Regional cerebral
blood flow (rCBF) was monitored in the cerebral
cortex of the left hemisphere within the territory
supplied by the middle cerebral artery (MCA) using
a laser Doppler flowmeter pencil probe (MNP100,
AD Instrument, Australia). Following dissection of
the left m. temporalis between the eye and the ear, a
burr hole was drilled 5 mm lateral and 1 mm posterior
to the bregma [12]. To prevent displacement of the
probe, rCBF was continuously measured from before
MCA occlusion, during such occlusion, and during
the first 10 min of reperfusion time. Baseline CBF
values measured before occlusion were defined as
100%. Occlusion of the MCA was documented by the
decrease in laser Doppler signals to lower than 20% of
the baseline.
Experimental Protocol . Effects of pos t -
ischemic candesartan treatment on brain injury and
neurological score were investigated in the following
randomly divided three groups of animals: group
1 (sham group, n = 6), rats underwent surgery at the
neck region with no occlusion of the MCA, group
2 (control ischemic group, n = 6), rats experienced
brain ischemia by 90-min-long MCA occlusion
followed by 24-h-long reperfusion and received the
vehicle (normal saline, 1 ml/kg) at the beginning
of the reperfusion period, and group 3 (candesartan
post-treated ischemic group, n = 6), rats experienced
ischemia and reperfusion similarly to group 2, but
received i.p. injections of candesartan (0.3 mg/kg, LKT
laboratories, USA) at the beginning of reperfusion.
Assessment of the effects of post-ischemic
candesartan treatment on the formation of brain
edema and measurement of the level of tissue
malondialdehyde (MDA) as a marker of lipid
peroxidation and that of tissue reduced glutathione
(GSH) as a marker of the antioxidant capacity were
done in another six parallel groups (n = 6 in each) of
animals under the same conditions as in groups 1-3.
Induction of Transient Focal Cerebral Ischemia.
Ninety-minute-long occlusion of the MCA and
24-h-long reperfusion of the left cerebral hemisphere
were carried out using an intraluminal filament
method described by Longa et al. [13] and modified by
Panahpour et al. [14]. Briefly, the left common carotid
artery was exposed through a midline neck incision.
Through this artery, a surgical nylon silicone-coated
thread (4-0 Ethilon) was placed into the internal
carotid artery and gently advanced up until seeing a
sharp decline in the blood flow trace is seen. Occlusion
was terminated by gently pulling out the thread. After
re-establishment of the blood flow, all the incisions
were sutured; the animals were allowed to recover
from anesthesia and returned to a warm cage for
recuperation during the 24-h-long reperfusion period.
Behavioral tests were performed by a blinded
observer 24 h after surgery in the sham group or
24 h after MCA occlusion in the ischemic groups.
As was described previously, the five-point scale
grading neurological deficit score (NDS) test was
carried out to evaluate the neurological outcome [14].
Rats with normal motor function were graded 1. Rats
with contralateral flexion of the body or forelimb
upon lifting by the tail were graded 2. Grade 3 was
assigned to dysfunctional rats circling to the side
contralateral with respect to occlusion. Grade 4 was
assigned to rats with loss of the righting reflex and
decreased resistance to lateral push; finally, grade
5 characterized rats having no spontaneous motor
activity. After the NDS test, animals were sacrificed
under deep anesthesia; the brain was removed,
cleaned, and solidified by immersion in cold saline
(4°C). Frontal 2-mm-thick slices were prepared using
a brain matrix and stained with triphenyltetrazolium
chloride (TTC), as was described previously
NEUROPHYSIOLOGY / НЕЙРОФИЗИОЛОГИЯ.—2013.—T. 45, № 5 471
ANTIOXIDANT ACTIVITY-MEDIATED NEUROPROTECTIVE EFFECTS
[14, 15]. After staining, the slice images were digitized
using a Cannon camera, and the cerebral infarction
areas were measured with computer-based NIH image
analyzer software [14, 15].
Ischemic brain edema was assessed using a dry/
wet method according to the technique presented
by Gerriets et al. [16]. The normalized brain water
content (WC) for each hemisphere was calculated by
measuring the wet weight (WW) and dry weight (DW)
of the ipsilateral (lesioned) and contralateral (non-
lesioned) hemispheres by the following equation:
WC (%) = [(WW – DW)/WW] ∙ 100%.
Preparation of Tissue Samples. Twenty-four
hours after the beginning of reperfusion, the animals
were decapitated. The brain was removed, and the
ischemic area (core and penumbra regions) of the
ipsilateral hemisphere was dissected according to
the well-known protocols for rodent models with
unilateral MCA occlusion [17, 18]. Briefly, the
brain was sectioned into three slices beginning
3 mm from the anterior tip of the frontal lobe.
In section 2 (4 mm thick), the ischemic area was
dissected with a longitudinal cut approximately
2 mm from the midline. The tissue was weighed and
homogenized in PBS with a weight-to-volume ratio
1:5. The homogenate was centrifuged (10,000g, 4°C)
for 30 min. The supernatants for each sample were
separated in Eppendorf tubes and kept at –80°C until
analysis.
Estimation of Lipid Peroxidation. Lipid
peroxidation was evaluated by measuring the
MDA concentration in brain samples. The MDA
levels were measured using a high-performance
liquid chromatography (HPLC) method [19] with
some modifications. Briefly, a 100 ml aliquot of
the supernatant was placed in a 1.5-ml Eppendorf
tube, and 50 ml of 6 M NaOH was added. Alkaline
hydrolysis of protein-bound MDA was achieved
by incubating this mixture in a 60°C water bath for
30 min. Then, protein was precipitated with 50 ml
of 35% (v/v) perchloric acid, and the mixture was
centrifuged at 2,800g for 10 min. A 100 ml volume
of the supernatant was transferred to an Eppendorf
tube and mixed with 10 ml 2,4-nitrophenylhydrazine
(DNPH) prepared as a 5 mM solution in 2 M
hydrochloric acid. Finally, this reaction mixture was
incubated for 30 min at room temperature (protected
from light). A 50 ml aliquot of the reaction mixture
was injected into the HPLC system equipped with a
C18 column (4.6´250 mm, 5 µm particle size). Results
were expressed in nanomoles per one milligram of wet
tissue weight.
Estimation of GSH. The concentration of reduced
GSH as an important biomarker of the antioxidant
defense capacity was also measured using the HPLC
method [20] with some modifications. Briefly, a 100
ml volume of the sample supernatant was placed in an
Eppendorf vial and diluted with an equal volume of
trichloroacetic acid (5% final concentration w/v) and
centrifuged at 10,000g for 15 min. A 100 ml volume
of the supernatant was transferred to a new Eppendorf
vial. After alkalization, the sample was reacted with
an equal volume of 2,4-dinintrofluorobenzene solution
(1.5% in ethanol v/v) for 1 h at room temperature in
the dark. After acidification with 10 ml HCl (37%
initial concentration v/v), 50 ml of the sample was
loaded onto the HPLC. Results were expressed in
millimoles per one milligram of wet tissue weight.
Statistical Analysis. Numerical values are
expressed as means ± s.e.m. The independent t-test and
one-way ANOVA with the post-hoc Holm-Sidak test
were used for comparisons. The statistical significance
was accepted at P < 0.05.
RESULTS
Cerebral Blood Flow Recording. The rCBF value
was reduced to less than 20% baseline in the control
and candesartan-treated ischemic groups after MCA
occlusion. There was no significant difference between
rCBF values in the groups during occlusion and the
first 10 min of reperfusion (Fig. 1).
Evaluation of NDS. The mean NDS of control
ischemic rats (4.3 ± 0.6) was dramatically higher than
that of sham-operated rats (1.00; P < 0.01). The NDS
of ischemic rats receiving 0.3 mg/kg candesartan post-
ischemically (1.67 ± 0.2) was significantly lower (less
than 40%) than that of control ischemic rats (P < 0.05).
Assessment of the Cerebral Infarct Volumes.
Sham-operated rats had no infarctions. The total
infarct volume in ischemic rats receiving 0.3 mg/kg
candesartan was significantly smaller than that in
control ischemic rats (P < 0.01). When compared
to control ischemic animals, candesartan-treated
ischemic rats had significantly smaller cortical and
striatal infarct volumes (P < 0.05; Fig. 2).
Assessment of Ischemic Brain Edema. There
was no statistically significant difference between
the right-side water content in the brains of animals
of the experimental groups. Moreover, there was
no significant difference between the left-side and
NEUROPHYSIOLOGY / НЕЙРОФИЗИОЛОГИЯ.—2013.—T. 45, № 5472
H. PANAHPOUR, SH. BOHLOOLI, and S. E. MOTAVALLIBASHI
F i g. 1. Normalized values of regional cerebral blood flow in control ischemic rats (filled columns, n = 5) and ischemic rats that
received 0.3 mg/kg candesartan (dashed columns, n = 5) during occlusion of the middle cerebral artery (MCAO) and at the beginning
of reperfusion (REP).
Р и с. 1. Нормовані величини місцевого кровотоку в контрольних щурів з ішемією (чорні стовпчики, n = 5) та ішемізованих тварин,
котрі отримували 0.3 мг/кг кандесартану (заштриховані стовпчики, n = 5), протягом оклюзії середньої церебральної артерії та на
початку реперфузії.
0
Baseline
0 min 15 30
MCAO
45 60 75 90 min 0 min
REP
5 10 min
10
20
30
40
50
60
70
80
90
100
%
Total
0
*
*
*100
200
300
400
500
600
mm3
Cortex Striatum
*
+
0
78
79
80
81
82
83
84
85
%
Sham Control Candesartan
F i g. 2. Total, cortical, and subcortical infarct volumes, mm3,
in control ischemic rats and ischemic rats that received candesartan
at the beginning of reperfusion (filled and dashed columns,
respectively). Asterisks indicate significant differences (P < 0.05)
from control rats.
Р и с. 2. Сумарні, кортикальні та субкортикальні об’єми зон
інфаркту (мм3) у контрольних щурів з ішемією та ішемізованих
тварин, котрі отримували кандесартан, на початку реперфузії
(чорні та заштриховані стовпчики відповідно).
F i g. 3. Normalized values of the brain water content in the left and
right hemispheres (filled/dashed and gray columns, respectively)
in sham-operated animals, control ischemic rats, and ischemic rats
that received candesartan (0.3 mg/kg). Asterisk indicates significant
difference (P < 0.05) from the control group; cross indicates
significant difference (P < 0.05) from the sham group.
Р и с. 3. Нормовані величини вмісту води в лівій та правій
півкулях мозку (чорні та заштриховані/сірі стовпчики
відповідно) в інтактних контрольних щурів, контрольних
тварин з ішемією та ішемізованих щурів, котрі отримували
кандесартан (0.3 мг/кг).
right-side water contents in the brains of sham-
operated rats. The left (ischemic)-side brain water
content of control ischemic rats (83.1 ± 0.46%) was
significantly greater than that in sham-operated rats
(P < 0.01). Post-ischemic treatment with candesartan
(0.3 mg/kg) was associated significantly with the
lower left-side brain water content (80.9 ± 0.81%)
than that in control ischemic rats (81.6 ± 0.45%,
P < 0.05; Fig. 3).
Assessment of MDA and GSH. Ninety-minute-
NEUROPHYSIOLOGY / НЕЙРОФИЗИОЛОГИЯ.—2013.—T. 45, № 5 473
ANTIOXIDANT ACTIVITY-MEDIATED NEUROPROTECTIVE EFFECTS
long ischemia and 24-h-long reperfusion in the control
ischemic group resulted in significantly reduced GSH
and increased MDA concentrations in the left side
of the brain tissue, as compared to the sham group
(P < 0.01). Post-ischemic candesartan treatment
provided a significantly increased GSH concentration
and a reduced MDA concentration, as compared to the
corresponding figures in the control ischemic group
(P < 0.05, Figs. 4 and 5).
DISCUSSION
The renin-angiotensin system has been shown
to significantly participate in the pathogenesis
of ischemic events, including stroke [4, 21, 22].
Most of the actions of Ang II are mediated through
AT1 receptors. Since these receptors contribute
to stroke-related pathophysiologic mechanisms,
such as hypertension, atherothrombosis, and
cardiac hypertrophy [23], it is possible that Ang II
aggravates I/R injuries through stimulation of AT1
receptors. Previous studies showed that pre-ischemic
RAS inhibition provides protective effects with respect
to ischemic brain injuries [14, 24, 25]. Our study was
carried out to evaluate the effects of post-ischemic
candesartan treatment on ischemic brain injuries
and edema formation. Candesartan freely crosses
the blood-brain barrier and produces an effective
and long-lasting blockade of cerebral AT1 receptors
[4, 26].
The results of our study demonstrate that blocking
of AT1 receptors significantly reduces the cortical and
striatal infarct volumes and improves neurological
motor deficits. This study also shows that transient
ischemia induces brain edema by increasing the
water content in the ischemic hemisphere, while
post-ischemic candesartan treatment significantly
reduces the water content in the above hemisphere
and prevents edema formation. These findings are
in agreement with reports of other investigators
demonstrating that blocking of AT1 receptors
with candesartan reduced the infarct size evoked
by transient cerebral ischemia in hypertensive
rats [27, 28].
Various mechanisms might be responsible for the
beneficial effects of the AT1 receptor blockade in brain
ischemia. Such effects might be partly attributed to
the stabilizing action on the impaired cerebrovascular
autoregulation within the penumbra [29-31]. In
addition, anti-apoptotic mechanisms may enhance
the protective effects of blocking of AT1 receptors
[32]. Furthermore, the beneficial effects of the AT1
blockade might also be attributed to a reduction in the
production of ROSs [33].
Cerebral ischemia is associated with excessive
0
5
10
15
20
25
*
+
nmol/mg
Sham Control Candesartan
+
*
100
200
300
400
500
600
700
800
nmol/mg
Sham Control Candesartan
F i g. 4. Concentration of malondialdehyde (nmol/mg brain
wet tissue) in sham-operated animals, control ischemic rats,
and ischemic rats that received candesartan at the beginning of
reperfusion. Asterisk indicates significant difference (P < 0.05)
from control ischemic rats; cross indicates significant difference
(P < 0.01) from sham-operated rats.
Р и с. 4. Концентрація малондіальдегіду (нмоль/мг вологої
тканини мозку) в інтактних контрольних щурів, контрольних
тварин з ішемією та ішемізованих щурів, котрі отримували
кандесартан на початку реперфузії.
F i g. 5. Concentration of reduced glutatione (mmol/mg brain
wet tissue) in sham-operated animals, control ischemic rats, and
ischemic rats that received candesartan. Other designations are the
same as in Fig. 4.
Р и с. 5. Концентрація відновленого глутатіону (нмоль/мг
вологої тканини мозку) в інтактних контрольних щурів,
контрольних тварин з ішемією та ішемізованих тварин, котрі
отримували кандесартан.
NEUROPHYSIOLOGY / НЕЙРОФИЗИОЛОГИЯ.—2013.—T. 45, № 5474
H. PANAHPOUR, SH. BOHLOOLI, and S. E. MOTAVALLIBASHI
production of ROSs, especially of superoxide [34].
The production of ROSs initiates chain reactions,
causing damage of cellular macromolecules and
promoting the mitochondrial apoptosis pathway, which
ultimately leads to cell death [35]. Our study showed
that candesartan inhibits ROS generation, increases
glutathione production, and reduces MDA production.
These findings are in agreement with other reports that
showed that activation of AT1 receptors results in the
intense production of superoxide, whereas blockade
of these receptors is associated with reductions in the
amounts of superoxide [33]and peroxynitrite [36].
The findings of our study also indicated that
inhibition of RAS by blocking AT1 receptors reduces
ischemic edema formation. Recent evidence suggests
that Ang II may be an important stimulus for the
production of superoxide and peroxynitrite in blood
vessels [36]. Oxygen-derived free radicals are known
to increase the permeability of the blood-brain
barrier [37]. Our results showed that candesartan
treatment suppresses lipid peroxidation and increases
the endogenous antioxidant defense capacity. Thus,
blocking of AT1 receptors may reduce ischemic
edema via protective effects on the blood-brain barrier
integrity by reduction of the ROS production.
Therefore, inhibition of RAS by the AT1 receptor
blocker candesartan noticeably reduces the cerebral
infarction volume and edema formation in rats
exposed to transient MCA occlusion. The respective
mechanisms may be attributed to inhibition of
lipid peroxidation and increase in the endogenous
antioxidant capacity.
All protocols of the study were approved by the Institutional
Animal Ethics Committee of the Ardabil University of Medical
Sciences, which follows the NIH guidelines for care and use of
experimental animals.
The authors, H. Panahpour, Sh. Bohlooli, and S. E. Mota-
vallibashi, have no conflict of interest.
Acknowledgments. This work was financially supported
(grant No. 88329) by the Vice Chancellor for Research of the
Ardabil University of Medical Sciences, Ardabil, Iran.
Х. Панахпур1, Ш. Бохлулі1, С. Е. Мотаваллібаші1
ОПОСЕРЕДКОВАНІ АНТИОКСИДАНТНОЮ АКТИВНІС-
ТЮ НЕЙРОЗАХИСНІ ЕФЕКТИ КАНДЕСАРТАНУ ПРИ
ІШЕМІЇ ТА НАБРЯКУ МОЗКУ У ЩУРІВ
1 Ардабильський медичний університет (Іран).
Р е з ю м е
Досліджували ефекти постішемічного блокування ангіо-
тензивних рецепторів AT1 кандесартаном щодо зони цереб-
рального інфаркту та формування набряку. Самці щурів лі-
нії Спрейг–Доулі були розділені на три групи (інтактних
контрольних, контрольних з ішемією та ішемізованих, ко-
трим уводили 0.3 мг/кг кандесартану). Епізод фокальної
ішемії мозку створювався за допомогою 90-хвилинної оклю-
зії лівої середньої церебральної артерії; оклюзія супрово-
джувалася 24-годинною реперфузією. Неврологічний дефі-
цит оцінювався в балах після закінчення періоду реперфузії.
Потім тварини рандомізовано відбиралися для вимірювань
трьох видів: об’єму зони інфаркту, ступеня набряку мозку з
використанням методу „суха/волога тканина” та концентра-
цій малонового діальдегіду (MDA) й відновленого глутаті-
ону (GSH) з використанням методики HPLC. Індукція цере-
бральної ішемії у відповідній контрольній групі призводила
до розвитку значних інфарктів у корі та стріатумі, спряже-
ному з важкими порушеннями моторних функцій. Уведення
кандесартану забезпечувало істотне зменшення об’ємів ін-
фарктів і послаблення порушень зазначених функцій. Вміст
води в лівій (ураженій) півкулі в контрольній групі з іше-
мією був значно підвищеним. Використання кандесартану
призводило до значного зменшення вмісту води в ішемізова-
ній лівій півкулі, відновлення рівня GSH у тканині та змен-
шення продукції MDA. Отже, блокування AT1-рецепторів
кандесартаном може помітно зменшувати ступінь ішеміч-
ного пошкодження мозку та послаблювати формування на-
бряку; ці ефекти опосередковуються підсиленням антиокси-
дантної активності.
REFFERENCES
1. U. Dirnagl, C. Iadecola, and M. A. Moskowitz, “Pathobiology
of ischemic stroke: an integrated view,” Trends Neurosci., 22,
No. 9, 391-397 (1999).
2. T. H. Jones, R. M. Crowell, F. W. Marcoux, et al., “Thresholds
of focal cerebral ischemia in awake monkeys,” J. Neurosurg.,
54, No. 773-782 (1981).
3. F. Schuier and K. Hossmann, “Experimental brain infarcts in
cats. II. Ischemic brain edema,” Stroke, 11, No. 6, 593-601
(1980).
4. J. Culman, A. Blume, P. Gohlke, and T. Unger, “The renin-
angiotensin system in the brain: possible therapeutic
implications for AT (1)-receptor blockers,” J. Human
Hypertens., 16, Suppl. 3, S64 -S70 (2002).
5. Y Inada, M. Ojima, K. Itoh, et al., “Effects of delapril on
stroke, kidney dysfunction and cardiac hypertrophy in stroke-
prone spontaneously hypertensive rats,” Drugs Exp. Clin. Res.,
21, No. 2, 41-49 (1995).
6. Y. Inada, M. Ojima, T. Sanada, et al., “Protective effects
of candesartan cilexetil (TCV-116) against stroke, kidney
dysfunction and cardiac hypertrophy in stroke-prone
spontaneously hypertensive rats,” Clin. Exp. Hypertens., 19,
1079-1099 (1997).
7. C. T. Stier, S. Levine, and P. N. Chander, “Stroke prevention
NEUROPHYSIOLOGY / НЕЙРОФИЗИОЛОГИЯ.—2013.—T. 45, № 5 475
ANTIOXIDANT ACTIVITY-MEDIATED NEUROPROTECTIVE EFFECTS
by losartan in stroke-prone spontaneously hypertensive rats,”
J. Hypertens., Suppl., 11, No. 3, S37-S42 (1993).
8. C. Werner, W. E. Hoffman, E. Kochs, et al., “Captopril
improves neurologic outcome from incomplete cerebral
ischemia in rats,” Stroke, 22, 910-914 (1991).
9. W. J. Dai, A. Funk, T. Herdegen, et al., “Blockade of central
angiotensin AT(1) receptors improves neurological outcome
and reduces expression of AP-1 transcription factors after focal
brain ischemia in rats,” Stroke, 30, No. 11, 2391-2399 (1999).
10. A. Boveris and B. Chance, “The mitochondria generation of
hydrogen peroxide,” Biochem. J., 134, 707-716 (1973).
11. G. Valen and J. Vaage, “Toxic oxygen metabolites and
leukocytes in reperfusion injury. A review,” Scand.
J. Thorac. Cardiovascul. Surg., Suppl., 41, 19-29 (1993).
12. E. Hungerhuber, S. Zausinger, T. Westermaier, et al.,
“Simultaneous bilateral laser Doppler fluxmetry and
electrophysiological recording during middle cerebral artery
occlusion in rats,” J. Neurosci. Methods, 154, Nos. 1/2, 109-
115 (2006).
13. E. Z. Longa, P. R. Weinstein, S. Carlson, et al., “Reversible
middle cerebral artery occlusion without craniectomy in rats,”
Stroke, 20, No. 1, 84-91 (1989).
14. H. Panahpour and G. A. Dehghani, “Inhibition of central
angiotensin-converting enzyme with enalapril protects the
brain from ischemia/reperfusion injury in normotensive rat,”
DARU J. Pharm. Sci., 18, No. 1, 35-40 (2010).
15. A. Vakili, F. Hosseinzadeh, and T. Sadogh, “Effect of
aminoguanidine on post-ischemic brain edema in transient
model of focal cerebral ischemia,” Brain Res., 1170, 97-102
(2007).
16. T. Gerriets, E. Stolz, M. Walberer, et al., “Middle cerebral
artery occlusion during MR-imaging: investigation of the
hyperacute phase of stroke using a new in-bore occlusion
model in rats,” Brain Res.-Brain Res. Protoc., 12, No. 3, 137-
143 (2004).
17. S. Ashwal, B. Tone, H. R. Tian, et al., “Core and pneumbral
nitric oxide synthase activity during cerebral ischemia and
reperfusion,” Stroke, 29, 1037-1047 (1998).
18. B. Lie, S. Popp, J. E. Cottrell, and I. S. Kass, “Lidocaine
attenuates apoptosis in the ischemic penumbra and reduces
infarct size after transient focal cerebral ischemia in rats,”
Neuroscience, 125, 691-701 (2004).
19. M. Raquel, E. Lecumberri, S. Ramos, et al., “Determination of
malondialdehyde by high-performance liquid chromatography
in serum and liver as a biomarker for oxidative stress
application to a rat model for hypercholesterolemia and
evaluation of the effect of diets rich in phenolic antioxidant
from fruits,” J. Chromatogr. B, 827, 76-82 (2005).
20. D. Giustarini, I. Dalle-Donne, R. Colombo, et al., “An
improved HPLC measurement for GSH and GSSG in human
blood,” Free Radical Biol. Med., 35, No. 11, 1365-1372
(2003).
21. R. Ferrari, A. Cargnoni, S. Curello, et al., “Protection
of the ischemic myocardium by the converting-enzyme
inhibitor zofenopril: insight into its mechanism of action,” J.
Cardiovascul. Pharmacol., 20, 694-704 (1992).
22. K. Kohara, H. Mikami, N. Okuda, et al., “Angiotensin
blockade and the progression of renal damage in the
spontaneously hypertensive rat ,” Hypertension , 21 ,
975-979 (1993).
23. C. Thone-Reineke, M. Zimmermann, C. Neumann, et al.,
“Are angiotensin receptor blockers neuroprotective?” Current
Hypertens. Rep., 6, 257-266 (2004).
24. H. Panahpour, A. A. Nekoueian, and G. A. Dehghani,
“Inhibition of angiotensin-converting enzyme reduces cerebral
infarction size in experimental-induced focal cerebral ischemia
in the rat,” Iran. J. Med. Sci. (IJMS), 32, No. 1, 12-17 (2007).
25. A. Ravati, V. Junker, M. Kouklei, et al., “Enalapril and
moexipril protect from free radical-induced neuronal damage
in vitro and reduce ischemic brain injury in mice and rats,”
Eur. J. Pharmacol., 373, 21-33 (1999).
26. W. Groth, A. Blume, P. Gohlke, et al., “Chronic pretreatment
with candesartan improves recovery from focal cerebral
ischaemia in rats,” J. Hypertens., 21, 2175-2182 (2003).
27. W. Kozak, A. Kozak, M. H. Johnson, et al., “Vascular
protection with candesartan after experimental acute
stroke in hypertensive rats: a dose-response study,”
J. Pharmacol. Exp. Ther., 326, No. 3, 773-782 (2008).
28. E. Omura-Matsuoka, Y. Yagita , T. Sasaki , e t a l . ,
“Postischemic administration of angiotensin II type 1
receptor blocker reduces cerebral infarction size in
hypertensive rats,” Hypertens. Res., 7, 548-553 (2009).
29. T. Vraamark, G. Waldemar, S. Strandgaard, and O.B. Paul-
son, “Angiotensin receptor antagonist CV-11974 and cerebral
blood flow autoregulation,” J. Hypertens., Suppl, 13, 755-761
(1995).
30. Y. Nishimura, T. Xu, O. Johren, et al., “The angiotensin AT1
receptor antagonist candesartan regulates cerebral blood flow
and brain angiotensin AT1 receptor expression,” Basic Res.
Cardiol., 93, 63-68 (1998).
31. Y. Nishimura, T. Ito, and J. M. Saavedra, “Angiotensin II
AT1 blockade normalizes cerebrovascular autoregulation and
reduces cerebral ischemia in spontaneously hypertensive rats,”
Stroke, 31, 2478-2486 (2000).
32. A. Blume, T. Herdegen, and T. Unger, “Angiotensin peptides
and inducible transcription factors,” J. Mol. Med., 77, 339-357
(1999).
33. T. Sugawara, H. Kinouchi, M. Oda, et al., “Candesartan
reduces superoxide production after global cerebral ischemia,”
NeuroReport, 16, 325-328 (2005).
34. P. H. Chan, J. W. Schmidley, R. A. Fishman, and
S. M. Longar, “Brain injury, edema, and vascular permeability
changes induced by oxygen-derived free radicals,” Neurology,
34, No. 3, 315-320 (1984).
35. H. Kinouchi, C. J. Epstein, T. Mizui, et al., “Attenuation
of focal cerebral ischemic injury in transgenic mice
overexpressing CuZn superoxide dismutase,” Proc. Natl. Acad.
Sci. USA, 88, No. 24, 11158-11162 (1991).
36. M. E. Pueyo, J. F. Arnal, J. Rami, and J. B. Michel,
“Angiotensin II stimulates the production of NO and
peroxynitrite in endothelial cells,” Am. J. Physiol., 274, Part
1, No. 1, C214-C220 (1998).
37. E. P. Wei, M. D. Ellison, H. A. Kontos, and J. T. Povli-
shock, “O2 radicals in arachidonate-induced increased
blood-brain barr ier permeabil i ty to proteins ,” Am.
J. Physiol., 251, Part 2, No. 4, H693-H699 (1986).
|
| id | nasplib_isofts_kiev_ua-123456789-148233 |
| institution | Digital Library of Periodicals of National Academy of Sciences of Ukraine |
| issn | 0028-2561 |
| language | English |
| last_indexed | 2025-12-07T18:51:39Z |
| publishDate | 2013 |
| publisher | Інститут фізіології ім. О.О. Богомольця НАН України |
| record_format | dspace |
| spelling | Panahpour, H. Bohlooli, Sh. Motavallibashi, S.E. 2019-02-17T18:32:10Z 2019-02-17T18:32:10Z 2013 Antioxidant Activity-Mediated Neuroprotective Effects of an Antagonist of AT1 Receptors, Candesartan, Against Cerebral Ischemia and Edema in Rats / H. Panahpour, Sh. Bohlooli, S.E. Motavallibashi // Нейрофизиология. — 2013. — Т. 45, № 5. — С. 469-475. — Бібліогр.: 37 назв. — англ. 0028-2561 https://nasplib.isofts.kiev.ua/handle/123456789/148233 616.831-005 We examined the effects of post-ischemic blockade of angiotensinAT1 receptors by candesartan
 on cerebral infarction and formation of edema. Male Sprague–Dawley rats were divided into
 three groups, sham, control ischemic, and candesartan-treated (0.3 mg/kg) ischemic. Transient
 focal cerebral ischemia was induced by 90-min-long occlusion of the left middle cerebral
 artery followed by 24-h-long reperfusion. Neurological deficit score was evaluated at the end
 of the reperfusion period. Thereafter, the animals were randomly selected and used for three
 projects: (i) Measurement of the infarct volumes, (ii) investigation of ischemic brain edema
 formation using a wet/dry method, and (iii) assessment of the malondialdehyde (MDA) and
 reduced glutathione (GSH) concentrations using a HPLC technique. Induction of cerebral
 ischemia in the control group produced considerable infarctions in the cortex and striatum
 in conjunction with severely impaired motor functions. Candesartan treatment significantly
 reduced the infarct volumes and improved the above functions. The water content in the left
 (lesioned) hemisphere was considerably elevated in the control ischemic group. Candesartan
 treatment significantly lowered the water content in the ischemic lesioned hemisphere,
 retained tissue GSH level, and led to a lower MDA production. AT1 receptor blockade by
 candesartan treatment can noticeably decrease ischemic brain injury and attenuate edema
 formation, likely via increasing the antioxidant activity. Досліджували ефекти постішемічного блокування ангіотензивних рецепторів AT1 кандесартаном щодо зони церебрального інфаркту та формування набряку. Самці щурів лінії Спрейг–Доулі були розділені на три групи (інтактних
 контрольних, контрольних з ішемією та ішемізованих, котрим уводили 0.3 мг/кг кандесартану). Епізод фокальної
 ішемії мозку створювався за допомогою 90-хвилинної оклюзії лівої середньої церебральної артерії; оклюзія супроводжувалася 24-годинною реперфузією. Неврологічний дефіцит оцінювався в балах після закінчення періоду реперфузії.
 Потім тварини рандомізовано відбиралися для вимірювань
 трьох видів: об’єму зони інфаркту, ступеня набряку мозку з
 використанням методу „суха/волога тканина” та концентрацій малонового діальдегіду (MDA) й відновленого глутатіону (GSH) з використанням методики HPLC. Індукція церебральної ішемії у відповідній контрольній групі призводила
 до розвитку значних інфарктів у корі та стріатумі, спряженому з важкими порушеннями моторних функцій. Уведення
 кандесартану забезпечувало істотне зменшення об’ємів інфарктів і послаблення порушень зазначених функцій. Вміст
 води в лівій (ураженій) півкулі в контрольній групі з ішемією був значно підвищеним. Використання кандесартану
 призводило до значного зменшення вмісту води в ішемізованій лівій півкулі, відновлення рівня GSH у тканині та зменшення продукції MDA. Отже, блокування AT1-рецепторів
 кандесартаном може помітно зменшувати ступінь ішемічного пошкодження мозку та послаблювати формування набряку; ці ефекти опосередковуються підсиленням антиоксидантної активності This work was financially supported
 (grant No. 88329) by the Vice Chancellor for Research of the
 Ardabil University of Medical Sciences, Ardabil, Iran. en Інститут фізіології ім. О.О. Богомольця НАН України Нейрофизиология Antioxidant Activity-Mediated Neuroprotective Effects of an Antagonist of AT1 Receptors, Candesartan, Against Cerebral Ischemia and Edema in Rats Опосередковані антиоксидантною активністю нейрозахисні ефекти кандесартану при ішемії та набряку мозку у щурів Article published earlier |
| spellingShingle | Antioxidant Activity-Mediated Neuroprotective Effects of an Antagonist of AT1 Receptors, Candesartan, Against Cerebral Ischemia and Edema in Rats Panahpour, H. Bohlooli, Sh. Motavallibashi, S.E. |
| title | Antioxidant Activity-Mediated Neuroprotective Effects of an Antagonist of AT1 Receptors, Candesartan, Against Cerebral Ischemia and Edema in Rats |
| title_alt | Опосередковані антиоксидантною активністю нейрозахисні ефекти кандесартану при ішемії та набряку мозку у щурів |
| title_full | Antioxidant Activity-Mediated Neuroprotective Effects of an Antagonist of AT1 Receptors, Candesartan, Against Cerebral Ischemia and Edema in Rats |
| title_fullStr | Antioxidant Activity-Mediated Neuroprotective Effects of an Antagonist of AT1 Receptors, Candesartan, Against Cerebral Ischemia and Edema in Rats |
| title_full_unstemmed | Antioxidant Activity-Mediated Neuroprotective Effects of an Antagonist of AT1 Receptors, Candesartan, Against Cerebral Ischemia and Edema in Rats |
| title_short | Antioxidant Activity-Mediated Neuroprotective Effects of an Antagonist of AT1 Receptors, Candesartan, Against Cerebral Ischemia and Edema in Rats |
| title_sort | antioxidant activity-mediated neuroprotective effects of an antagonist of at1 receptors, candesartan, against cerebral ischemia and edema in rats |
| url | https://nasplib.isofts.kiev.ua/handle/123456789/148233 |
| work_keys_str_mv | AT panahpourh antioxidantactivitymediatedneuroprotectiveeffectsofanantagonistofat1receptorscandesartanagainstcerebralischemiaandedemainrats AT bohloolish antioxidantactivitymediatedneuroprotectiveeffectsofanantagonistofat1receptorscandesartanagainstcerebralischemiaandedemainrats AT motavallibashise antioxidantactivitymediatedneuroprotectiveeffectsofanantagonistofat1receptorscandesartanagainstcerebralischemiaandedemainrats AT panahpourh oposeredkovaníantioksidantnoûaktivnístûneirozahisníefektikandesartanupriíšemíítanabrâkumozkuuŝurív AT bohloolish oposeredkovaníantioksidantnoûaktivnístûneirozahisníefektikandesartanupriíšemíítanabrâkumozkuuŝurív AT motavallibashise oposeredkovaníantioksidantnoûaktivnístûneirozahisníefektikandesartanupriíšemíítanabrâkumozkuuŝurív |