Cerebral Ischemia-reperfusion Model Research Articles

The effect of focal cerebral ischemia-reperfusion injury on TLR4 and NF-κB signaling pathway.

The present study analyzed the change of Toll-like receptor 4 (TLR4) and nuclear factor-κB (NF-κB) expression in focal cerebral ischemia-reperfusion injury model. A sample of 36 Sprague-Dawley rats were randomly selected and divided into sham operation group (group S), control group (group C) and Chrysanthemum ester group (NF-κB inhibitor, group CE), each group consisted of 12 rats. The rat model of focal cerebral ischemia-reperfusion was established. The physiological indexes and neurological severity score of rats was recorded by a double-blind method. The cerebral infarction area was evaluated by triphenyltetrazole oxide (TTC) staining on brain slices. Apoptosis was evaluated by TUNEL staining. Semi-quantitative PCR and western blot analysis was used to measure the expression of TLR4 and NF-κB. The neurological severity score of rats in group C and CE were found to be significantly lower than group S (P<0.01). The TTC staining results showed that group C and CE had different levels of cerebral infarction but the area of infarction in group CE was significantly lower than group C (P<0.01). In addition, the number of TUNEL positive cells in group CE was significantly lower than group C (P<0.01). Semi-quantitative PCR and westernblot analysis results showed that the expression of NF-κB and TLR4 of group S was significantly lower than that of group C and group CE (P<0.01), the relative expression of NF-κB and TLR4 of group CE was significantly lower than that of group C (P<0.01). Moreover, the expression of NF-κB p65/p50 of group CE and group C was significantly higher than that of group S (P<0.01). This study concludes that the focal cerebral ischemia-reperfusion injury in rats can cause brain damage and cell apoptosis. This effect might be associated to the increased expression of NF-κB and TLR4, and the activation of TLR4/NF-κB signaling pathway.

The protective role of verbenalin in rat model of focal cerebral ischemia reperfusion.

To investigate the protective mechanism of verbenalin on cerebral ischemia-reperfusion injury. Middle cerebral artery occlusion in the left hemisphere was induced in rats by filament insertion, and rat model of focal cerebral ischemia-reperfusion was established. The high, medium and low dose of verbenalin groups were injected in the tail vein of corresponding drugs 10 min before reperfusion, and submitted for 22 h of reperfusion after the operation. Mortality rate was then calculated, and neurological deficits of rats were scored. The serum of rats was got to determine the S-100β protein level, and the brain tissue was removed to determine the levels of Bax, Bcl-2, Caspase-3 and ATPase. TTC staining was performed on the brain tissue to calculate the percentage of cerebral infarct size. Changes in brain tissue morphology were observed. Rat model of focal cerebral ischemia-reperfusion was successfully replicated. In groups that have taken different doses of verbenalin, the mortality rate, neurological deficit score and the percentage of cerebral infarction size were significantly reduced, and the levels of Bax, Caspase-3, S-100β level of the serum in the brain tissue were also significantly reduced. Increases in the levels of Bcl-2 and ATPase in brain tissue and improvement of pathological damage of hippocampus and cortex were observed. Verbenalin can inhibit the expression of apoptosis genes, promote the expression of anti-apoptosis genes, improve brain microcirculation and energy metabolism, hence reducing cerebral ischemia-reperfusion injury.

Protective effects of notoginsenoside R1 on cerebral ischemia-reperfusion injury in rats.

The objective of this study was to investigate the protective effect of notoginsenoside R1 (NGR1) on cerebral ischemia-reperfusion injury (CIRI) in rats, and its molecular mechanism, to provide new insights into the diagnosis and treatment of CIRI. Sixty Sprague-Dawley rats were randomly divided into four groups including the sham-operation group (Sham), cerebral ischemia-reperfusion model group (CIR), NGR1 treatment group (NGR1), and nimodipine positive control group (NDC) with 15 rats each. Bilateral common carotid arteries occlusion was used to establish the rat CIRI model. The area of cerebral infarction at the end of reperfusion was calculated by triphenyl tetrazolium chloride staining. Apoptosis of hippocampal neurons in each group was detected by Annexin V/propidium iodide double staining. Hippocampal expression of brain-derived neurotrophic factor (BDNF) mRNA, and Bcl-2 and Bax protein at the end of reperfusion were measured by RT-qPCR and western blot analysis, respectively. Data were analyzed by SPSS software analysis to ensure statistical significance. At the end of reperfusion, the area of cerebral infarction in the NGR1 and NDC groups was significantly smaller than that of the CIR group. Apoptosis analysis showed that compared with the CIR group, the apoptosis rate of hippocampal neurons was significantly decreased in the NGR1 and NDC groups. RT-qPCR and western blot analysis showed that at the end of reperfusion, higher levels of BDNF mRNA and the anti-apoptotic factor, Bcl-2, and lower levels of the pro-apoptotic factor, Bax, in the hippocampus were found in the NGR1 and NDC groups compared with the CIR group. The protective effect of NGR1 on CIRI was significantly stronger than that of nimodipine. In conclusion, NGR1 can reduce the area of cerebral infarction, reduce apoptosis of hippocampal neurons, and protect rats from CIRI. Those effects were achieved by activating the expression of BDNF and Bcl-2, and by inhibiting the expression of Bax.

Study of Total Flavonoids from Mao Dongqing in Cerebral Ischemia Reperfusion Models

Objective Mao Dongqing (MDQ) is the dried root of Ilex pubescens Hook. et Arn. It is a renowned traditional Chinese medicine which has been used for the treatment of acute and chronic cardio-cerebrovascular diseases in the clinic for many years. The aim of this study was to further understand the effect of total flavonoids from MDQ on cerebral ischemia reperfusion injury. Methods Ginaton group (extract of ginkgo biloba leaves injection), the small, middle and large doses of total flavonoids from the MDQ group were given related drugs via intragastric administration before the operation. The sham operation group, ischaemic preconditioning model group and ischemia reperfusion group were given the same volume of 0.1% CMC daily for 10 days. After the last administration, animal models of cerebral ischemia reperfusion injury in mice were established using the method of blocking the bilateral common carotid artery for 10 min, restoring perfusion for 10 min, bilateral carotid artery occlusion for 10 min, and then reperfusion for 24 hours. Half of the brain was fixed in 10% formalin for HE staining. The other half of the brain was used to prepare brain homogenate, which was used to determine the content of ATPase, NO and NOS. Results We found that the models with cerebral ischemia reperfusion injury in mice were copied successfully. Large and medium doses of total flavonoids from MDQ could significantly reduce the content of NO, tNOS, iNOS and increase the activity of ATPase in brain tissue of mice. Total flavonoids from MDQ could also reduce the pathological changes of the hippocampus and cortical neuron cells in the hippocampus of mice. Conclusion The results of this study showed that the model of cerebral ischemia-reperfusion in mice was successful. The total flavonoids from MDQ could achieve the role of anti-cerebral ischemia injury by inhibition of the inflammatory cascade, improving the imbalance of oxygen supply and demand and the disorder of glucose metabolism, inhibiting the apoptosis of nerve cells during cerebral ischemia reperfusion injury. Acknowledgment National “Significant New Drug Creation” science and technology major special project (2009Z × 09103-324).

The role of histone deacetylase inhibitors in regulation of Akt/GSK-3β signaling pathway in mice following transient focal cerebral ischemia.

To investigate whether the neuroprotective effect of TSA on cerebral ischemia reperfusion injury is mediated by the activation of Akt/GSK-3β signaling pathway. Mice were randomly divided into four groups (n=15): sham group (S); ischemia reperfusion group (IR); ischemia reperfusion and pretreated with TSA group (IR+T); ischemia reperfusion and pretreated with TSA and LY294002 group (IR+T+L). The model of cerebral ischemia reperfusion was established by 1h of MCAO following 24h of reperfusion. TSA (5mg/kg) was intraperitoneally given for 3 days before MCAO, Akt inhibitor, LY294002 (15 nmol/kg) was injected by tail vein 30 min before the MCAO. TSA significantly increased the expression of p-Akt, p-GSK-3β proteins and the levels of SOD, Bcl-2, reduced the infarct volume and the levels of MDA, ROS, TNF-α, IL-1β, Bax, Caspase-3, TUNEL and attenuated neurological deficit in mice with transient MCAO, LY294002 weakened such effect of TSA dramatically. TSA could significantly decrease the neurological deficit and reduce the cerebral infarct volume, oxidative stress, inflammation, as well as apoptosis during cerebral ischemia reperfusion injury, which was achieved by activation of the Akt/GSK-3β signaling pathway.

The Synergic Effect of Tetramethylpyrazine Phosphate and Borneol for Protecting Against Ischemia Injury in Cortex and Hippocampus Regions by Modulating Apoptosis and Autophagy

This study aimed to investigate the synergic effects of tetramethylpyrazine phosphate (TMPP) and borneol (BO) for protecting against ischemia in the cortex and hippocampus. A rat model of global cerebral ischemia-reperfusion (GCIR) was induced by four-vessel occlusion. The results showed that TMPP (13.3mg/kg), BO (0.16g/kg), and their combination improved the ultrastructure of neurons, reduced the apoptosis index, and reduced the intracellular calcium content in both the cortex and hippocampus. TMPP and the combined treatment increased cortex autophagy by modulating phosphorylated adenosine monophosphate-activated protein kinase (pAMPK) in the pAMPK-mammalian target of rapamycin (mTOR)-Unc-51-like kinase 1 (ULK1) signaling pathway, whereas BO only regulated ULK1. Moreover, BO increased neuron autophagy in the hippocampus by modulating mTOR, whereas TMPP targeted both mTOR and Beclin1. Similarly, the combination targeted both pAMPK and Beclin1. All three treatments decreased the expression of p53 and caspase-3 in the two areas. Additionally, TMPP and the combined therapy regulated Bax and Bcl-2. These results demonstrated the synergic effects between TMPP and BO for treating ischemia-reperfusion injury in the cortex and hippocampus regions. Their neuroprotective effects could be partly attributed to switching from apoptosis to protective autophagy. Additionally, the potential mechanism triggering this switching could be ascribed to the reduction of intracellular calcium content.

Neuroprotective effect of Naomaitong extract following focal cerebral ischemia induced by middle cerebral artery occlusion in rats

ObjectiveTo examine the neuroprotective effect of extract from Naomaitong following focal cerebral ischemia reperfusion induced by occlusion of middle cerebral artery (MCA), and to determine the biochemical alterations in urine using proton nuclear magnetic resonance spectroscopy and principal component analysis. MethodsWistar rats were randomly assigned to three groups: sham-operated group, MCA focal cerebral ischemia reperfusion model group, and active extract of Naomaitong treatment group. The model was established by an improved MCA occlusion (MCAO) method. Sham-operated rats received the same surgical procedure, but without occlusion. The Naomaitong treatment group were treated with active extract from Naomaitong at a dose of 3.0 g·kg−1·d−1. Brain tissues and urine samples were collected from all groups for histopathological assessment and proton nuclear magnetic resonance spectroscopy-based metabonomics, respectively. ResultsHematoxylin-eosin and triphenyl tetrazolium chloride staining of brain tissues showed a significant decrease in cerebral infarction area in the Naomaitong group. In model rats, metabonomic analyses showed increased urinary levels of glutamate, taurine, trimetlylamine oxide, betaine, and glycine, and reduced levels of creatinine and creatine. Naomaitong regulated the metabolic changes by acting on multiple metabolic pathways, including glycine metabolism, glutaminolysis, transmethylation metabolism and creatinine metabolism. ConclusionThese data demonstrate that extract from Naomaitong is neuroprotective against focal cerebral ischemia induced by MCAO, and can alleviate biochemical changes in urinary metabolism. Metabonomics may be a useful approach for assessing the biochemical mechanisms underlying the neuroprotective actions of extract from Naomaitong.

Effects of the Rabdosia rubescens total flavonoids on focal cerebral ischemia reperfusion model in rats

The effect of the Rabdosia rubescens total flavonoids on focal cerebral ischemia reperfusion model in rats was observed. The model group, nimodipine group, cerebral collateral group, and large, medium and small dose group of the Rabdosia rubescens total flavonoids were administered with corresponding drugs but sham operation group and model group were administered the same volume of 0.5%CMC, 1 times a day, continuous administration of 7 d. After 1h at 7 d to medicine, left incision in the middle of the neck of rats after anesthesia, we can firstly expose and isolate the left common carotid artery (CCA), and then expose external carotid artery (ECA) and internal carotid artery (ICA). The common carotid artery and the external carotid artery are ligated. Then internal carotid artery with arterial clamp is temporarily clipped. Besides, cut the incision of 0.2mm from 5cm of the bifurcation of the common carotid artery. A thread Line bolt is inserted with more than 18–20mm from bifurcation of CCA into the internal carotid artery until there is resistance. Then the entrance of the middle cerebral artery is blocked and internal carotid artery is ligated (the blank group only exposed the left blood vessel without Plugging wire). Finally it is gently pulled out the plug line after 2h. Results: Compared with the model mice, Rabdosia rubescens total flavonoids can significantly relieve the injury of brain in hippocampus and cortex nerve cells; experimental rat focal cerebral ischemia was to improve again perfusion model of nerve function defect score mortality; significantly reduce brain homogenate NOS activity and no content, MDA, IL-1, TNF-a, ICAM-1 content; increase in brain homogenate SOD and ATPase activity (P<0.05, P<0.01); and reduce the serum S-100β protein content. Each dose group of the Rabdosia rubescens total flavonoids has a better Improvement effect on focal cerebral ischemia reperfusion model in rats.

Protective effect of chlorogenic acid on the focal cerebral ischemia reperfusion rat models

ObjectiveThe aim of the study was to investigate the protective characteristic of chlorogenic acid, a natural glucosyl xanthone found in Lonicera Japonica on the cerebral ischemia reperfusion injury and the underlying mechanism. MethodsFocal cerebral ischemia reperfusion model was built by blocking the left middle cerebral artery in rats by using the suture-occluded method. Before operation, the corresponding drugs were given for each group once a day for 7days. After 1h of final administration, the model was built, after operation, reperfusion was conducted for 22h, Before the reperfusion 10min tail vein injection of large, medium and small dose of chlorogenic acid and then mortality was calculated, and Neurological deficit score (NDS) was conducted, and serum was collected to measure the NSE level; a 2mm thick brain slice located at the intersection of optic nerves was collected for TTC staining, and the percentage of cerebral infarction area was calculated; brain homogenate was collected to measure the ICAM-1, VCAM-1, EPO and HIF-1α levels in brain tissue of cerebral ischemia reperfusion rat models; NGF was detected using immunohistochemical method; the morphological changes in brain tissue was observed with HE staining. ResultsAll focal cerebral ischemia reperfusion rat models were duplicated successfully. Every chlorogenic acid group with different dosage can significantly reduce the mortality, NDS and cerebral infarction area of rats, and significantly increase the EPO, HIF-1α and NGF levels in brain tissue; significantly improve the pathological lesions of hippocampus and cortex in brain tissue. ConclusionThe results showed that chlorogenic acid could protect the focal cerebral ischemia reperfusion injury rat models by adjusting the inflammatory factor, hypoxia factor and nerve growth factor.

Effect of PGE1 on the expression of Apaf-1 and TLR4 in rats with cerebral ischemia-reperfusion injury

Objective To explore the effects of prostaglandin E1(PGE1) on the expression of Apaf-1 and TLR4 in rats with cerebral ischemia-reperfusion(CIR) injury. Methods 32 healthy adult male Wistar rats were randomly divided into four groups, which were sham operated group(n=8), CIR model group(n=8) and PGE1 pretreated groups(low dose, 12 μg·kg-1; high dose, 24 μg·kg-1, n=8). Rat model of cerebral ischemia/reperfusion was established by bilateral common carotid artery ligation.The expression of Apaf-1 and TLR4 was detected with immunohistochemical staining method in hippocampus and epencephalon. Results After 20 min of ischemia and reperfusion for 24 h, compared with sham operated group(Apaf-1: hippocampus(0.87±0.78), epencephalon(0.67±0.43); TLR4: hippocampus(2.43±1.17), epencephalon(1.97±1.033)), the number of positive cells of Apaf-1(hippocampus(11.83±2.26); epencephalon(5.80±1.30) and TLR4 ( hippocampus(16.90±2.86); epencephalon(12.90±2.66)) was increased in CIR model group (P<0.05). Compared with CIR model group, the positive cell numbers of Apaf-1(hippocampus: low dose(9.83±2.12), high dose(5.50±1.17); epencephalon: low dose(4.87±1.38), high dose(2.73±1.172)) and TLR4(hippocampus: low dose(11.53±2.40), high dose(9.13±2.54); epencephalon: low dose(9.07±2.07), high dose(4.47±1.68)) were reduced dose-dependently in PGE1 pretreatment all group(all P<0.05). Conclusion PGE1 can inhibit the expression of Apaf-1 and TLR4 in hippocampus and epencephalon of rat with cerebral ischemia-reperfusion injury. Key words: Prostaglandin E1; Rat; Cerebral ischemia-reperfusion; Apoptotic protease activating factor-1; Toll-like receptor 4

The Effect of Dexmedetomidine on Oxidative Stress Response Following Cerebral Ischemia-Reperfusion in Rats and the Expression of Intracellular Adhesion Molecule-1 (ICAM-1) and S100B

BackgroundIschemia-reperfusion injury of whole brain involves a complicated pathophysiology mechanism. Dexmedetomidine (Dex) has been shown to have neuro protective functions. This study observed the effect of Dex on serum S100B and cerebral intracellular adhesion molecule-1 (ICAM-1) in a rat model of cerebral ischemia-reperfusion.Material/MethodsHealthy Sprague Dawley (SD) rats (males, 7 weeks old) were randomly divided into sham, model, and Dex groups (n=20 each). A cerebral ischemia-reperfusion model was prepared by clipping of the bilateral common carotid artery combined with hypotension. Dex (9 μg/kg) was infused intravenously immediately after reperfusion in the Dex group, while the other two groups received an equal volume of saline. Neural defect score (NDS) was measured at 6 hours, 24 hours, and 72 hours after surgery, with pathological observation of brain tissues. ELISA was then used to test serum S100B protein level. Malondialdehyde (MDA) and superoxide dismutase (SOD) were assayed by spectrometry. Nuclear factor-kappa B (NF-κB) and ICAM-1 levels were determined by real-time (RT)-PCR.ResultsModel rats had significant injury in the hippocampal CA1 region as shown by elevated NDS, S100B, and MDA levels, higher NF-κB and ICAM-1 mRNA expression, and lower SOD levels (p<0.05). Dex treatment improved pathological injury, decreased NDS, S100B, and MDA levels, decreased expression of mRNA of NF-κB and ICAM-1, and increased SOD levels.ConclusionsDex alleviated ischemia-reperfusion damage to rat brains, and inhibited NF-κB and ICAM-1 expression in brain tissues, possibly via inhibiting oxidative stress and inflammatory response.

MTOR/autophagy pathway in the hippocampus of rats suffering intermittent hypoxia preconditioning and global cerebral ischemia-reperfusion.

We explored the role of mTOR/autophagy pathway in the aggravation of cerebral ischemia-reperfusion nerve injury caused by intermittent hypoxia. Eighty male wistar rats were divided into four groups by the random number method: sham operation group (SO group, n=20), cerebral ischemia-reperfusion group (I/R group, n=20), intermittent hypoxia and cerebral ischemia-reperfusion group (IH+I/R group, n=20), intermittent hypoxia and cerebral ischemia-reperfusion group plus mTOR inhibitor group (inhibitor group, n=20). The results showed that compared with the SO group, HE staining showed structural damage of neurons at each time point, the immunohistochemical assay showed an increasing number of mTOR and beclin1 immune-positive cells (P<0.05) and RT-PCR showed enhanced expression of mTOR and beclin1 protein in the I/R group (P<0.05). Compared with the I/R group, HE staining showed exacerbating structural damage of neurons at each time point, the immunohistochemical assay showed an increasing number of mTOR and beclin1 immune-positive cells (P<0.05) and RT-PCR showed enhanced expression of mTOR and beclin1 protein in the IH+I/R group (P<0.05). Compared with the IH+I/R group, HE staining showed remissive structural damage of neurons at each time point, the immunohistochemical assay showed a decreasing number of mTOR immune-positive cells and a rising number of beclin1immune-positive cells (P<0.05) and RT-PCR showed weakened expression of mTOR protein and enhanced expression of beclin1 protein in the inhibitor group (P<0.05). Thence, the present study indicated that intermittent hypoxia preconditioning can aggravate the nerve injury of the global cerebral ischemia-reperfusion model, and the mechanism is associated with the activation of mTOR/autophagy pathway.

Effect of brain functional recovery decoction on expression of vascular endothelial growth factor and Ang-1 protein in a rat cerebral ischemia reperfusion model

OBJECTIVETo investigate the effect of brain functional recovery decoction (BFRD) on expression of vascular endothelial growth factor (VEGF) and angiopoietin-1 (Ang-1) protein in rats with cerebral ischemia reperfusion injury, and to explore the mechanism of action of BFRD. METHODSUsing the suture-occlusion method, a Wistar rat model of focal cerebral ischemia reperfusion was established. The rats were randomly divided into treatment group, model group, and sham operation group. The treatment group was administered BFRD. In situ hybridization was used to detect VEGF mRNA expression. Immunohistochemistry was used to observe expression of Ang-1 protein. RESULTSVEGF mRNA expression was greater in the model group compared with the sham operation group (P < 0.05); Ang-1 protein expression was more obvious in the treatment group than the model group (P< 0.05). CONCLUSIONBFRD promoted VEGF mRNA and Ang-1 protein expression in the brains of rats with cerebral ischemia, suggesting increased angiogenesis.

Effect of total flavonoids of Radix Ilicis pubescentis on cerebral ischemia reperfusion model.

This paper aims to observe the effects of total flavonoids of Radix Ilicis pubescentis on mouse model of cerebral ischemia reperfusion. Mice were orally given different doses of total flavonoids of Radix Ilicis pubescentis 10 d, and were administered once daily. On the tenth day after the administration of 1 h in mice after anesthesia, we used needle to hook the bilateral common carotid artery (CCA) for 10 min, with 10 min ischemia reperfusion, 10 min ischemia. Then we restored their blood supply, copy the model of cerebral ischemia reperfusion; We then had all mice reperfused for 24 h, and then took their orbital blood samples and measured blood rheology. We quickly removed the brain, with half of the brain having sagittal incision. Then we fixed the brains and sectioned them to observe the pathological changes of brain cells in the hippocampus and cortex. We also measured the other half sample which was made of brain homogenate of NO, NOS, Na+-K+-, ATP enzyme Mg2+-ATPase and Ca2+-ATPase. Acupuncture needle hook occlusion of bilateral common carotid arteries can successfully establish the model of cerebral ischemia reperfusion. After comparing with the model mice, we concluded that Ilex pubescens flavonoids not only reduce damage to the brain nerve cells in the hippocampus and cortex, but also significantly reduce the content of NO in brain homogenate, the activity of nitric oxide synthase (NOS) and increases ATP enzyme activity (P < 0.05, P < 0.01). In this way, cerebral ischemia reperfusion injury is improved. Different dosages of Ilex pubescens flavonoids on mouse cerebral ischemia reperfusion model have good effects.

The influence of stachydrine hydrochloride on the reperfusion model of mice with repetitive cerebral ischemia.

To study the influence of stachydrine hydrochloride on the inflammatory cytokines and tissue morphology of the re-perfusion model of mice with repetitive cerebral ischemia and probe into the protection mechanism of stachydrine hydrochloride for cerebral ischemia reperfusion impairment. Build a repetitive cerebral ischemia reperfusion model by first blocking the common carotid artery on both sides for 10 min, then resuming perfusion for 10 min and then blocking the common carotid artery on both sides again for 10 min. Before the operation, all the mice in the Nimodipine group, and the big, medium and small stachydrine hydrochloride dose groups were given corresponding gastric perfusion, the mice in the sham operation group and the modeled groups were at the same time given 0.5% sodium carboxymethyl cellulose for gastric perfusion of the same volume. The medicine was fed daily for 7 consecutive days. The model was built 1 h after the last feed and the perfusion continued for 24 h after the operation. Then the death rate of the mice was calculated. The mouse brains were taken out to test the ICAM-1 level and the TNF-α level, and the serum was taken out to test the NSE level and the MPO level. The tissue morphology changes were also observed. All the repetitive cerebral ischemia reperfusion models were successfully duplicated. The stachydrine hydrochloride in all the dose groups significantly reduced the death rates of big and small mice, reduced the level of ICAM-1 and the level of TNF-α in the brain tissues and the NSE level and the MPO level in the serum, significantly alleviating the pathological impairment in the hippocampus. Stachydrine hydrochloride can significantly reduce the death rate of mice, improve the pathological changes in the hippocampus, inhibit inflammatory reactions after ischemia, thus reducing the re-perfusion impairment after cerebral ischemia.

Huatuo Zaizao pill promotes functional recovery and neurogenesis after cerebral ischemia-reperfusion in rats

BackgroundIschemic stroke is the third leading cause of death in adults worldwide and is the first leading cause of long-term disability. Neurogenesis plays an important role in promoting behavioral recovery after stroke. Huatuo Zaizao pill (HT), a traditional Chinese medicine, has been used clinically in China to promote the rehabilitation after stroke, but the underlying mechanism of action was still unclear. This study is to investigate the effects of HT on the functional recovery in a rat model of cerebral ischemia-reperfusion (I/R) injury, and the potential molecular mechanisms.MethodsRats were randomly divided into sham, model with cerebral I/R injury, or HT-treated groups, then administered orally with vehicle (for the sham and model group) or HT (0.5, 1.0, or 2.0 mg/kg) respectively, for 3 or 7 days. Functional recovery was assessed by cylinder test, beam walking test, and adhesive test. Neurogenesis was investigated by double immunofluorescence staining for 5-ethynyl-2-deoxyuridine (EdU) and neuronal nuclear protein (NeuN). The proteins of kinase A (PKA), cAMP response element-binding protein (CREB), and brain-derived neurotrophic factor (BDNF) were assayed by western blotting. The level of BDNF mRNA was evaluated by RT-PCR.ResultsCompared with the model group, treatment with HT significantly promoted functional recovery in I/R injured rats (p < 0.05 or p < 0.01). The generation of new neurons was increased in the HT groups. HT treatment for 3 days increased the level of BDNF mRNA in I/R injured rats. Expression of PKA, phosphorylated CREB, and BDNF were significantly (p < 0.05) increased with the 7-day HT treatment.ConclusionsThese results indicated that HT treatment could promote functional recovery after stroke. HT enhanced the expression of BDNF and increased the level of neurogenesis in cerebral I/R animal, which might be associated with the functional recovery.

The mechanisms of neuroprotective action of p-tyrosol after the global cerebral ischemia in rats

Aim. The aim of our study is to explore the mechanisms of neuroprotective effects of p-tyrosol in acute global cerebral ischemia-reperfusion in rats. Material and methods. The study was performed on 30 male rats stock Wistar (250–300 g).Animals were divided into 3 groups of 10 rats. In the control and experimental groups we performed the new 3VO model of cerebral ischemia-reperfusion, and the sham-operated animals underwent the same surgical procedures, but without the ligature imposition. Animals in the experimental group received p-tyrosol for 5 days intravenously at a daily dose of 20 mg/kg in a 2% solution. The sham-operated rats and control animals received a isotonic solution of NaCl at the same scheme. We measured rheological blood parameters and the content of products of lipid peroxidation in the brain tissue on the 5th day after cerebral ischemia-reperfusion. Results. Acute ischemia-reperfusion of the brain in rats from the control group caused the significant hemorheological abnormalities, including the increased whole blood viscosity and plasma viscosity, decreased the erythrocyte aggregation half-time and decreased red blood cell deformability index. The increase blood viscosity caused the decrease of the oxygen delivery to the tissues. The content of diene and triene conjugates, fluorescent products and the lipid oxidation index increased in the brain tissue of the control group. These abnormalities induced the death of 50% animals from the control group. Given intravenously to animals of the experimental group, p-tyrosol reduced the whole blood viscosity by 19–31%, the plasma viscosity by 6% and increased the erythrocyte deformability by 31–40%, that led to the increase of oxygen availability for tissues by 21–31% in comparison with the control group. The contents of diene and p-triene conjugates and fluorescent products in the brain tissue under course administration of p-tyrosol decreased respectively by 37%, 49 and 45%, that reflected in the decreasing of lipids oxidation index by 38% in comparison with the control group. The number of survived animals in the experimental group was 1,4 times bigger than in the control group. Conclusion. Course administration of p-tyrosol to rats with acute cerebral ischemia-reperfusion reduces the blood viscosity and the intensity of oxidative stress in the brain tissue. The results of these effects are the reduction of negative outcomes of ischemia-reperfusion of the brain and the increasing of animal surviving, that confirms the neuroprotective action of p-tyrosol in these conditions.

Assessment of the MRI and Behavioral Test Results in a Focal Cerebral Ischemia-Reperfusion Model in the Rat after Separate and Combined Use of Mouse-Derived Neural Progenitor Cells, Human-Derived Neural Progenitor Cells and Atorvastatin.

To assess the efficacy of Neural progenitor cell (NPC) transplantation in ischemic stroke, and to investigate whether atorvastatin enhances therapeutic potency of NPC after stroke. The focal cerebral ischemia-reperfusion model was performed by transient occlusion of middle cerebral artery. Rats were assigned randomly to receive intracerebral transplantation of mouse NPC alone (mNPC), human NPC alone (hNPC), mouse NPC plus oral atorvastatin (mNPC+A), human NPC plus oral atorvastatin (hNPC+A), oral atorvastatin alone, or intracerebral Dulbecco"s Modified Eagle"s medium injection (control group). Adhesive removal, rotarod, cylinder tests, and magnetic resonance imaging (MRI) were used for assessment of rats during 4 weeks. After sacrification on 28th day, rats were investigated by immunofluorescent staining. The hNPC and mNPC groups showed significantly improved functional outcome and reduced infarct area ratio compared with the control group. The hNPC group had significantly better performance and lower infarct area ratio than the mNPC group. Addition of atorvastatin to stem cell therapy significantly improved functional outcome, although it did not affect the infarct area ratio on MRI. Anti-inflammatory response in the infarct area was higher in the mNPC group. NPC transplantation significantly reduced the amount of microglia and a significant increase in the amount of astrocytes. CD8a+ T lymphocyte and granzyme B activities were not detected in any of the subjects. Both hNPC and mNPC treatments significantly improved functional outcome, and reduced infarct area ratio after stroke. Atorvastatin enhanced the therapeutic potency of NPCs, including neurological improvement.

A neuroprotective action of carnosine in conditions of experimental focal cerebral ischemia-reperfusion

To assess neuroprotective properties of preventive injections of carnosine in experimental focal cerebral ischemia in rats. A focal ischemia in Wistar rats induced by the 60 min-occlusion of the middle cerebral artery with the following 24h-reperfusion was used. Animals received carnosine mixed with ration in daily dose of 150 mg/kg of body mass during 7 days before surgery. Carnosine decreased the size of the lesion by 20%, neurological deficit by 43% with a simultaneous increase in the antioxidant status of blood plasma and brain tissue compared to the animals of the control group. The authors showed for the first time the neuroprotective effect of low dose of carnosine (150 mg/kg of body mass) mixed with ration used in preventive treatment courses in the experimental focal cerebral ischemia-reperfusion model.

Effect of exercise preconditioning on nerve growth factor and learning-and-memory abilities in rats suffered from focal cerebral ischemia

Objective To investigate the effect of exercise preconditioning on the expression of nerve growth factor(NGF) and its receptor TrkA as well as learning-and-memory abilities in rats suffered from focal cerebral ischemia. Methods Thirty-six male SD rats were randomly divided into sham operation group (Sham-MCAO, n=12), focal cerebral ischemia-reperfusion group (MCAO, n=12) and exercise preconditioning + cerebral ischemia-reperfusion group (EX+ MCAO, n=12). Rats in EX+ MCAO group were placed in the treadmill device and accepted 4 weeks exercise training. Then method of middle cerebral artery occlusion was applied to prepare transient focal cerebral ischemia reperfusion model. Garcia’s method was used to assess the neural function in rats. Western blotting was applied to test the expression of NGF and TrkA protein in the successfully established experimental MCAO rats. Morris water maze experiment was utilized to test the learning-and-memory abilities of the rats. Results (1)Compared with Sham-MCAO group, the expression of NGF in rats’ brain tissue was lower in MCAO group (cerebral ischemia 1h reperfusion 24h) (P 0.05). Conclusion Exercise preconditioning can up-regulate the expressions of NGF and TrkA protein, which can also improve the learning-and-memory abilities in rats suffered from focal cerebral ischemia reperfusion injury. Key words: Exercise preconditioning; NFG; TrkA; Focal cerebral ischemia reperfusion; Learning and memory