Effect of naoluo xintong on expression of Fas,Fas L in hippocampus CA1 area and Fas mRNA in the cortex of frontal or parietal lobe after local cerebral ischemia/reperfusion in MCAO rats

AIM: To investigate the effets of naoluo xintong on the expression of Fas, FasL protein in hippocampus CA1 area and Fas mRNA in the cortex of frontal or parietal lobe after local cerebral ischemia/reperfusion in MCAO rats. METHODS: The local cerebral ischemia /reperfusion model was established by intraluminal thread occlusion of the middle cerebral arteries (MCAO), the middle cerebral arteries of rats were occluded for 2 hours and reperfused for 1, 3 and 7 days. The animals were divided into pseudo surgery group(sham group), model group, Yiqi group, Huoxue group and naoluo xintong group. Using the techniques of immuno-histochemical staining and in situ hybridization, the expression of Fas and FasL was observed in hippocampus CA1 area, the expression of Fas mRNA was also observed in the cortex of frontal and parietal lobe. RESULTS: A value of Fas and FasL protein expression or A value and positive unit of Fas mRNA expression in control group were higher than those in sham in hippocampus CA1 area, the cortex of frontal or parietal lobe after local cerebral ischemia/reperfusion in MCAO rats (P<0.01). A value and/or positive unit of their expression in naoluo xintong group were lower than those in control group (P<0.05 or P<0.01). A value and/or positive unit of their expression in Yiqi and Huoxue groups were higher than those in naoluo xintong group for 3 and/or 7 days (P<0.05 or P<0.01). CONCLUSION: naoluo xintong could resist neuron apoptosis, alleviate pathologic injury after local cerebral ischemia/reperfusion in MCAO rats by inhibiting the expression of Fas, FasL protein and Fas mRNA.     

Knockdown of Atg5 aggravates cerebral ischemia and reperfusion injury in mice

AIM: To study the role of autophagy-related gene 5 (Atg5) in cerebral ischemia and reperfusion injury in mice. METHODS: BALB/c male mice (weighing 18~22 g) were randomly divided into sham group, ischemia/reperfusion (I/R) group, Atg5 siRNA group and control siRNA group. Focal cerebral ischemia was performed using the method of middle cerebral artery occlusion (MCAO) for 60 min and reperfusion for 24 h. In siRNA group and control group, 5 μL Atg5 siRNA or scrambled siRNA was administered by intracerebroventricular injection 24 h before MCAO. The expression of Atg5 at mRNA and protein levels in ischemic cortex at 24 h after reperfusion was determined by real-time PCR and Western blot. The infarct volume and edema were evaluated by TTC staining, and motor deficits were evaluated by neurological scoring. RESULTS: The expression of Atg5 at mRNA and protein levels was significantly increased 24 h after reperfusion in I/R group compared with sham group. Atg5 siRNA obviously decreased the expression of Atg5 at mRNA and protein levels induced by I/R. Inhibition of Atg5 exacerbated the infarct volume and ameliorated the neurological symptoms. CONCLUSION: Atg5 has neuroprotective effect on focal cerebral ischemia and reperfusion injury.     

Inhibitive action of atorvastatin on NADPH oxidase-derived superoxide anion in ischemic brain tissue after reperfusion in rats

AIM: Reactive oxygen species, specifically superoxide anion formed during the early phase of reperfusion, augment neuronal injury. The present study tested the hypothesis that atorvastatin protects against cerebral infarction via inhibition of NADPH oxidase-derived superoxide anion in transient focal ischemia. METHODS: Transient focal ischemia was created in halothane-anesthetized adult male Sprague-Dawley rats by middle cerebral artery occlusion (MCAO). Atorvastatin (Liptor) was administrated subcutaneously 3 times before MCAO. Infarct volume was measured by triphenyltetrazolium chloride staining. NADPH oxidase enzymatic activity and superoxide anion levels were quantified in both ischemic core and penumbral regions by lucigenin (5 μmol/L)-enhanced chemiluminescence. The expression of NADPH oxidase membrane subunit gp91phox, membrane-translocated subunit p47phox and small GTPase Rac-1 were determined by Western blotting analyses. RESULTS: NADPH oxidase activity and superoxide anion levels increased following reperfusion and peaked within 2 h of reperfusion in the penumbra, but not in the ischemic core in MCAO rats. Atorvastatin pretreatment prevented this increases, blunted the expression of membrane subunit gp91phox and prevented the translocation of cytoplasmic subunit p47phox to the membrane in the penumbra 2 h after reperfusion. CONCLUSION: These results indicate that atorvastatin protects against cerebral infarction via inhibition of NADPH oxidase-derived superoxide anion in ischemic brain tissue after reperfusion partly.     

Combination of taurine and diazepam has neuroprotective effect on focal cerebral ischemia-reperfusion in rats

AIM: To observe the neuroprotective effect of combined treatment with taurine and diazepam against focal cerebral ischemia-reperfusion in rats. METHODS: Sixty male Sprague-Dawley rats were randomly divided into five groups: sham-operation group, vehicle group, taurine group (200 mg/kg, ip), diazepam group (10 mg/kg, ip) and combined treatment group (taurine 100 mg/kg+diazepam 5 mg/kg). Focal cerebral ischemia was induced by the method of middle cerebral artery occlusion (MCAO) in rats, and reperfusion was emerged by removing the thread 2 h later. The drugs were administered respectively at the time of reperfusion, and subsequently repeated once 12 h later. The animals in vehicle group were intraperitoneally injected with isodose normal saline. The neurological deficit score, the brain water content and cerebral infarction were measured 48 h after MCAO. Other 5 group animals of focal cerebral ischemia-reperfusion (n=16 in each group) were set up as mentioned above and accepted treatments 10 h after reperfusion, likewise repeated once 12 h later. Twelve animals in each group were adopted the same management as the previous 5 groups at 48 h after MCAO. The remained 4 animals in each group were sacrificed until two weeks after MCAO to observe the histopathological changes by nissl staining. RESULTS: Compared to vehicle group, the animals in combined treatment group at 2 h or 12 h after MCAO both decreased the neurological deficit score, reduced the brain water content and infarct volume (P<0.01 or P<0.05). The combined treatment significantly alleviated the neurological necrosis as well. The neuroprotective effect of the combined treatment was superior to that of using taurine or diazepam alone. CONCLUSION: These results suggest that combination of taurine and diazepam treatment has a coordinate neuroprotective effect on both the acute and chronic brain damage of focal cerebral ischemia-reperfusion.     

Effects of Salvia miltiorrhiza Bunge.f.alba. on mitochondrial damage and apoptosis induced by cerebral ischemia and reperfusion

AIM: To observe the effects of Salvia miltiorrhiza Bunge.f.alba. (Sal) on the mitochondrial ultra-structure, oxidative stress and apoptosis induced by ischemia injury in a rat model of focal cerebral ischemia and reperfusion.METHODS: The middle cerebral artery occlusion/reperfusion (MCAO/R) rat model was established by a modified Longa occlusion method. Adult male SD rats were randomly divided into control group, simple ischemia reperfusion group, Sal with ischemia reperfusion group and butylphthalide with ischemia reperfusion group. To study the protective effects of Sal and its mechanism, the intervention of Sal was given and the ultra-structure of mitochondria, functions of mitochondria under oxidative stress and the incidence of apoptosis of brain cells were determined.RESULTS: Many electron dense toxic granulation and vacuolus in mitochondria were observed in the rat brain of focal cerebral ischemia and reperfusion. Under the condition of ischemia and reperfusion, the mitochondria membrane was disaggregative, and the tubular cristae of mitochondrion disappeared. MDA content was obviously increased and the activity of glutathione peroxidase decreased significantly. The apoptosis of brain cells were observed in a great quantity. The changes of ultra-structure of mitochondria and the activity of GSH-Pxase were significantly improved by the treatment of Sal. Furthermore, treatment with Sal delayed the decrease of GSH-Pxase activity, and inhibited the increase in MDA content in brain tissue after ischemia and reperfusion. The incidence of apoptosis of brain cells was also decreased.CONCLUSION: Sal protects the brain tissue from ischemia injury.     

Effect of Chinese herbs 9602 on the alterations of evoking population spike and morphology in hippocampal CA1 region after ischemia/reperfusion in rats

AIM:To explore the relationship between dynamic changes of population spike (PS) and morphologic alterations in hippocampal CA1 region and morphology after transient ischemia/reperfusion and the improving effects of Chinese herbs 9602.METHODS:Changes of evoking population spike ware investigated by electrical stimulating Schaf er collateral in CA1 region of hippocampal slice after ischemia/reperfusion in vivo.Apoptosis and morphologic alterations at different time points after cerebral ischemia/reperfusion were detected by using TUNEL and Nissl staining.RESULTS:The threshold voltage of CA1 region in evoking population spike increased markedly as compared with sham control. The enhancement of wave amplitude was reduced significantly after tetanic stimulation. The duration of enhancement in amplitude decreased with the passage of reperfusion. Above all were observed from 8 h after ischemia/reperfusion. They became remarkable and got to its top at 7 day after ischemia/reperfusion treatment. TUNEL positive cells were observed in hippocampal CA1 region at 8 h, got to the top at 24 h and then gradually reduced after ischemia/reperfusion. A lot of abnormal cells in CA1 region was found, and the number of pyramidal cell reduced progressively by Nissl staining after ischemia/reperfusion. Chinese herbs 9602 reduced the threshold voltage of CA1 region in evoking population spike remarkably, enhanced the wave amplitude and prolonged the duration of PS enhancement; decreased the number of TUNEL positive cell, prevented the reduction of pyramidal cell in CA1 region. CONCLUSIONS:The excitability and reactivity were decreased and there was a gradual functional disturbance of synaptic transmission in CA1 pyramidal cell and most notable changes happened at 7 d ischemia/reperfusion, suggesting that was partly due to delayed neuronal death induced by ischemia/reperfusion. Apoptosis plays an important role in the functional deficiency of CA1 region of hippocampus induced by cerebral ischemia/reperfusion. The effects of 9602 on ameliorating the excitability and reactivity of CA1 pyramidal cells relate to inhibiting apoptosis, attanuating delayed neuron death induced by ischemia/reperfusion.     

Effects of astragaloside IV on autophagy in rats with cerebral ischemia/reperfusion injury

AIM: To investigate the effects of astragaloside IV (AS-IV) on autophagy in rats with cerebral ischemia/reperfusion (I/R) injury. METHODS: The focal cerebral ischemia/reperfusion of rat left middle cerebral artery occlusion (MCAO) was induced by suture method. Male SD rats (n=70) were randomly divided into sham operation group, I/R group, solvent control group, AS-IV group, AS-IV+autophagy inhibitor (3-methyladenine, 3-MA) group, 3-MA group and autophagy activator (rapamycin, Rapa) group. Except for sham operation group, the rats in other groups were subjected to ischemia for 2 h and reperfusion for 24 h. The rats with successful modeling were selected according to Zea Longa scoring criteria. The volume of cerebral infarction was measured by TTC staining. The morphological changes of nerve cells in the rats were observed with Nissl staining. The phenomenon of autophagy was observed under transmission electron microscope. The protein expression of beclin-1 and LC3-Ⅱ was determined by Western blot. RESULTS: No neurological deficit in sham operation group was observed, and the cerebral infarction was not found. Compared with sham operation group, obvious cerebral infarction was observed, the Nissl bodies were small in size and number and stained light, typical autophagosomes were observed, and the protein expression of beclin-1 and LC3-Ⅱ was increased in I/R group (P<0.05). Compared with I/R group, the volume of cerebral infarction was decreased obviously, neurological deficit restored significantly, and the number of autophagosomes and the protein expression of beclin-1 and LC3-Ⅱ were increased in AS-IV group and Rapa group (P<0.05). However, no significant difference between solvent control group and I/R group was observed (P>0.05). Compared with AS-IV group, the neurological deficit was serious, the volume of cerebral infarction and the number of autophagosomes were increased, while the expression of beclin-1 and LC3-Ⅱ was decreased in AS-IV+3-MA group and 3-MA group (P<0.05). CONCLUSION: Astragaloside IV may play an important role in atte-nuating cerebral ischemia/reperfusion injury by activating autophagy.     

Inhibitory effect of ischemic postconditioning on autophagy induced by focal cerebral ischemia reperfusion in rats

AIM: To investigate the effect of ischemic postconditioning (IPC) on autophagy induced by focal cerebral ischemia reperfusion (I/R) in rats. METHODS: Healthy male SD rats were assigned randomly into sham-operation (sham) group, I/R group and IPC group with 10 rats in each group. The rats in sham group were only exposed the right common, internal and external carotid artery surgically. The rats in I/R group were subjected to right middle cerebral artery occlusion (MCAO) by the modified Longa suture method for 2 h followed by 24 h of reperfusion. The rats in IPC group were subjected to MCAO for 2 h followed by reperfusion of the ipsilateral common carotid artery occlusion for 10 s for 5 episodes, and then reperfusion for 24 h. Autophagy was obeserved by transmission electron microscopy (TEM). The protein levels of mammalian target of rapamycin (mTOR), p-mTOR and microtubule associated protein light chain 3 (LC3)-II in brain tissue of the rats were determined by Western blot. Pathological changes of brain tissue were observed by HE staining. RESULTS: The protein levels of mTOR and p-mTOR in IPC group were significantly higher than those in I/R group (P<0.05). The expression of LC3-II in IPC group was significantly lower than that in I/R group (P<0.01). The cerebral infarction area and brain water content in IPC group were significantly lower than those in I/R group (P<0.01). HE staining showed that neurons degeneration and necrosis in IPC group were significantly alleviated compared with I/R group. TEM observation showed that IPC revealed fewer autophagosomes, with much less severe cell damage than that in I/R group. CONCLUSION: IPC reduces brain ischemia reperfusion damage by decreasing autophagy of brain cells, which might be related to the activation of mTOR.     

Effect of Ginkgo biloba extract on the expression of c-fos and HSP70 following focal cerebral ischemic reperfusion in rats

AIM: To investigate the influence of Ginkgo biloba extract (GBE) on the expression of c-fos, heat shock protein 70 (HSP70) during focal cerebral ischemic reperfusion in rats. METHODS: The middle cerebral artery occlusion (MCAO) model described by Zea longa was used. Healthy Wistar rats were randomized to 4 groups. Immunohistochemistry, in situ hybridization and terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling (TUNEL) were used to detect the expression of c-fos gene, HSP70 and cell apoptosis at different reperfusion time points: 1, 6, 12, 24 hours and 3, 7 days after recirculation. RESULTS: The positive reactions of both c-fos and HSP70 were significantly increased at different reperfusion time in GBE-pretreated ischemia/reperfusion (IR) group than those in ischemia/reperfusion group (P<0.01) and the number of TUNEL-positive cells was reduced in GBE-pretreated IR group. CONCLUSION: The GBE induced the expression of c-fos, HSP70 and contributes to neuroprotective activities after cerebral ischemia.     

Evaluation of rat MCAO model by laser Doppler flowmetry

AIM: To investigate the feasibility and reliability of using laser Doppler flowmetry (LDF) to evaluate the animal model of cerebral ischemia and reperfusion injury in vivo. METHODS: Ten Sprague-Dawley (SD) male rats, weighing 280-310 g, were subject to unilateral middle cerebral artery occlusion (MCAO) with the routine method of line-embolism, and the cortical blood flow was continuously monitored by LDF during ischemia and reperfusion in the rats. Meanwhile, the degree of injury induced by cerebral ischemia and reperfusion was evaluated after MCAO by the nervous scoring of rat criteria. Brain slices were obtained by the method of neck end breaking and brain autopsy at the time point of ischemia for 2 h and reperfusion for 24 h. The volumes of infarction in the brain slices were determined by TTC staining. RESULTS: (1) In the successful MCAO rats, the average local blood flow remarkably decreased from the baseline value of (224.99±75.00) PU to (67.23±6.90) PU in the ischemic period. The mean difference was 157.76 PU and decreasing amplitude of local blood flow was more than 70% by MCAO. In the reperfusion period, the average local blood flow was rapidly recovered to (216.01±7.30) PU after the embolus was pulled out, which was only slightly lower than that of the baseline level without statistical significance. However, the mean difference of 148.78 PU between the local blood flow of reperfusion and local blood flow of cerebral ischemia for 2 h was found (P<0.01). The average local nervous score was 10.35 at 24 h after cerebral ischemia and reperfusion,higher than that of the baseline (0 point). The infracted evidence with remarkable brain edema in the brain slices was clearly observed with TTC staining. (2) In the unsuccessful MCAO rats, the decrease in local blood flow was less than 50%. The local nervous score was 0 point at 24 h, which was equal to the baseline value. No local infraction and brain edema was observed in the brain slices. CONCLUSION: Besides using the local nervous functional scoring, continuously monitoring of blood flow by LDF in vivo is a reliable and useful method to confirm the successful establishment of rat MCAO model.     

Effect of limb ischemic postconditioning on brain focal ischemia and reperfusion injury in mice

AIM: To establish the mouse model in which the limbic ischemic postconditionning (LIPostC) enhances the tolerance against brain ischemia, and to investigate the effects of LIPostC on the ischemic extent and roles of heat shock protein 70 (HSP70) in ischemia and reperfusion injury. METHODS: The male Kunming mice were used in the study. The brain ischemia reperfusion (I/R) model was made by middle cerebral artery occlusion (MCAO). In the first test, the male mice were randomly divided into 9 groups (n=10): sham group, ischemia/reperfusion (I/R) groups (with ischemia for 0.5 h, 1 h,1.5 h and 2 h) and LIPostC+I/R groups (0.5 h+LIPostC,1 h+LIPostC,1.5 h+LIPostC,2 h+LIPostC). The reperfusion was performed after LIPostC for 24 h. After the neurologic deficit scores were evaluated, the brains were taken out to measure the infarct volume with TTC staining and to observe the pathological changes of cerebral cortex with HE staining. The neuronal apoptosis was determined by TUNEL. In the second test, the male mice were randomized into 4 groups (n=6): sham group, I/R group, LIPostC+I/R group and LIPostC+I/R+quercetin group (2 h ischemia). The neurological deficit scores were evaluated at 24 h after operation. The expression of HSP70 was determined by Western blotting.RESULTS: The duration of brain ischemia was related to the motor behavior and degree of brain injury. The longer the ischemic duration of the brain was performed, the more severe the pathological and behavioral changes were observed. The brain injury in 2 h MCAO mice was more severe than that in 1 h and 1.5 h MCAO mice (P<0.05). Compared to I/R group, each LIPostC group showed lower neurological score, less infarct volume and TUNEL positive neuron. The expression of HSP70 protein was increased and neurological functions were improved significantly in the mice with LIPostC. However, the neuroprotective role of LIPostC was attenuated by treating with quercetin, an inhibitor of HSP70.CONCLUSION: LIPostC promotes the expression of HSP 70, improves the neurological functions and attenuates the ischemia and reperfusion injury in MCAO mice. HSP70 produces a marked effect on the ischemic tolerance induced by LIPostC in MCAO mice.     

Preliminary study on pyroptosis involved in cerebral ischemia-reperfusion injury

AIM:To investigate the changes of pyroptosis in hippocampus and cortex at different time points after cerebral ischemia-reperfusion, and to explore its mechanism from NLRP3-mediated classical pyroptosis pathway, and to analyze the role of pyroptosis in different parts of cerebral injury. METHODS:SD rats were randomly divided into sham operation group (sham group) and model group (MCAO/R group). The rats in model group was further divided into cerebral ischemia-reperfusion 6 h group (MCAO/R 6 h group), 12 h group (MCAO/R 12h group)and 24 h group (MCAO/R 24 h group). The rat model was established on rats by middle cerebral artery occlusion and reperfusion (MCAO/R) induced by modified right-side thread method. Neurologic function score, 2, 3, 5-triphenyltetrazolium chloride (TTC) staining and morphological observation were used to evaluate the degree of nervous cell injury. TUNEL and caspase-1 immunofluorescence double staining were used to detect pyroptosis. The protein expression of NLRP3, cleaved caspase-1, pro-caspase-1 and interleukin-1β (IL-1β) was determined by Western blot. RESULTS:Neurological damage occurred at different times after cerebral ischemia-reperfusion. TTC staining showed that the volume of cerebral infarction gradually increased with the prolongation of reperfusion time (P<0.05). The hippocampal CA1 area and cortical area showed typical morphological features such as loose tissue structure, interstitial edema, disordered arrangement of nerve cells, deepening of nucleus staining, nuclear fragmentation and decreased cell number. Immunofluorescence double staining showed that there was a phenomenon of pyroptosis at different time after cerebral ischemia-reperfusion. The pyroptosis of hippocampal CA1 and cortical area was most obvious at 12 h and 24 h after reperfusion (P<0.05). Western blot analysis showed that the expression of NLRP3, cleaved caspase-1, pro-caspase-1 and IL-1β in NLRP3-mediated classic pyroptosis pathway was regulated in different degrees after cerebral ischemia-reperfusion. The protein expression of NLRP3 in hippocampus was significantly increased at 12 h and 24 h after reperfusion (P<0.05), and the protein expression of NLRP3 in cortex was significantly increased at 6 h after reperfusion (P<0.05). The protein expression of pro-caspase-1 in hippocampus was significantly increased at each time points of reperfusion (P<0.05), and the protein expression of pro-caspase-1 in the cortex was significantly increased at 24 h after reperfusion (P<0.05). The protein expression of cleaved caspase-1 in the hippocampus was significantly increased at 12 h after reperfusion (P<0.05), and increased in the cortex at 24 h after reperfusion (P<0.05). The protein expression of IL-1β in the hippocampus was significantly increased at 24 h after reperfusion (P<0.05), and increased in the cortex at 6 h after reperfusion (P<0.05). CONCLUSION:Pyroptosis is involved in neuronal injury after cerebral ischemia-reperfusion. The classic pyroptosis pathway plays an important regulatory role in hippocampus and cortex, especially in hippocampus, suggesting that hippocampus is the main part of secondary nerve impairment induced by pyroptosis and inflammation after cerebral ischemia-reperfusion.     

Neuronal damage and cell death following ischemia/reperfusion in diabetic rats

AIM:To study forms of cell death following cerebral ischemia/reperfusion in diabetic rats. METHODS:Based on the modles of diabetes and middle cerebral artery occlusion(MCAO), characteristics of cell death after ischemia/reperfusion were evaluated synthetically by the pathological, flow cytometry(FCM), TUNEL and the DNA agarose electrophoresis.RESULTS:The occurrence of cerebral injury after ischemia/reperfusion were accompanied by cell necrosis and cell apoptosis. And cell apoptosis was mainly located in ischeamic penumbra(IP) zone around the densely ischemic focus. Ischemic centre(IC)was characterized by cell necrosis. At the same time, the results showed that the process of ischemic cerebral injury worsen by diabetes mellitus was related to inducing cell apoptosis in IP and Mid zone.CONCLUSION:Neuronal damage following focal cerebral ischemia/reperfusion included cell necrosis and apoptosis, IC zone was mainly characterized by the former, however IP zone by the latter, and there had close internal relationship between them. Brain damage following cerebral ischemia/reperfusion was worsen instinctly under diabetic condition.     

Protective effect of sCR1-SCR15-18 on cerebral ischemia/reperfusion injury in rat via inhibition of complement

AIM: To explore the effect of complement on the cerebral ischemia/reperfusion injury in rat and the protection by sCR1-SCR15-18. METHODS: 75 male SD rats were randomly divided into three groups: sham operation group (SO, n=15), middle cerebral artery occlusion and reperfusion (MCAO) without treatment group (I/R, n=30); MCAO treated with sCR1-SCR15-18 group (sCR1-SCR15-18, n=30). After the MCAO for 2 h, then reperfusion for 24 h, the scores of neural behavioral functional deficits were determined. Infarction area was measured by TTC staining. Activity of MPO in cerebral cortex was detected. C3b deposition and pathological change were observed by immunohistochemial staining and HE staining, respectively. RESULTS: After reperfusion for 24 h, the neurological deficits score, infarction area and activity of MPO in sCR1-SCR15-18 group were decreased compared to I/R group. In sCR1-SCR15-18 group, C3b deposition in ischemic area was decreased and pathological injury was improved compared to I/R group. CONCLUSION: Complement plays a role in cerebral ischemia-reperfusion injury and sCR1-SCR15-18 exerts a protective effect by inhibiting the excessive activation of complement.     

Cell proliferation and nestin expression in cortex and SEZ of MCAO rats

AIM:To explore the effect of brain ischemia injury on cell proliferation and nestin expression in cortex and subependymal zone (SEZ).METHODS:Using a local brain ischemia model(MCAO), BrdU positive cells of cortex and subependymal zone (SEZ), also nestin positive cells, were observed by immunohistochemistry.RESULTS:BrdU and nestin positive cells in SEZ of MCAO rats were obviously increased. In cortex, only nestin positive cells were observed.CONCLUSION:Neural stem cells in SEZ and cortex were activated after brain ischemia, it may be related with neural recovery after brain ischemia injury.     

Study on changes of neurological function and neuron apoptosis after intravenous administration of bone marrow stromal stem cells for treating permanent focal cerebral ischemia in rats

AIM: To explore the survivorship and the mechanism of the intravenous administration of bone marrow stromal stem cells (BMSCs) for treating permanent focal cerebral ischemia in rats. METHODS: After purified, proliferated, and marked with BrdU, the BMSCs were injected intravenously into rats 1 d after focal cerebral ischemia.Modified neurological severity score (mNSS) was evaluated before and following 1, 7, 14 and 28 d after middle cerebral artery occlusion (MCAO). Rats were executed at 1, 7, 14 and 28 d after MCAO. Brain sections were stained with hematoxylin and eosin (HE) for determining the infarct volume. Slides were stained by the terminal deoxynucleotidyl transferase-mediated dUTP-biotin nick-end labeling (TUNEL) and immunostaining for cleaved caspase-3 method for apoptosis detection and mechanism exploration in situ.RESULTS: mNSS in BMSCs-transplanted group at 14th day and 28th day of MCAO was significantly lower than that in control group(P<0.05). TUNEL-positive cells in the hippocampus and thalamus area of BMSCs-transplanted rats were significantly fewer than those in control rats at 14th day and 28th day of MCAO(P<0.05). Double immunostaining showed that small grafted BMSCs and small endogenous neural cell apoptosis depended on the capase-3 in hippocampus.CONCLUSION: The intravenous administration of BMSCs promotes the recovery of neurological function of rats with focal cerebral ischemia. The therapeutic effect of BMSCs on rats with focal cerebral ischemia may be derived from the reduction of apoptosis and the mobility and migration of endogenous neural stem cells in the ischemic boundary zone.     

Upregulative effect of CGRP on expression of CREB and phospho-CREB protein during focal cerebral ischemia/reperfusion in rat parietal cortex

AIM: To investigate the effect of calcitonin gene related peptide (CGRP) on the expression of cyclic AMP response element binding protein (CREB) and phosphorylated-CREB in rat parietal cortex during focal cerebral ischemia/reperfusion (I/R).METHODS: Focal cerebral ischemia/reperfusion model was induced by occlusion of the right middle cerebral artery using the intraluminal suture method. The expressions of CREB and phospho-CREB in the parietal cortex in different groups (sham group, focal cerebral ischemia/reperfusion group and CGRP group) were detected with immunohistochemistry and Western blotting, and the positive products were analyzed by image analysis system.RESULTS: There was definite expression of CREB in right parietal cortex in sham group, while it was lesser in I/R group than that in sham group, but it became more in CGRP group than that in I/R group (P<0.05). Phospho-CREB was barely detected in right parietal cortex in sham group and it became more in I/R group than that in sham group. The expression of phospho-CREB increased in CGRP group than that in I/R group of the right parietal cortex (P<0.05).CONCLUSION: CGRP upregulates the expression of CREB and phospho-CREB in the ischemic neurons of the parietal cortex during focal cerebral ischemia/reperfusion and CREB probably involves in the mechanism of protective role of CGRP to ischemic neurons.