Effect of dexmedetomidine on astrocytes in rats with focal cerebral ischemia-reperfusion

AIM: To investigate the effects of dexmedetomidine on astrocytes in rats with focal cerebral ischemia-reperfusion. METHODS: Sixty female SD rats, weighing 230~250 g, were randomly divided into sham operation group, ischemia-reperfusion group, dexmedetomidine preconditioning group 1 and dexmedetomidine preconditioning group 2. The model of middle cerebral artery occlusion (MCAO) was established by thread embolism of middle cerebral artery. In sham operation group, the carotid arteries were exposed without performing MCAO. In ischemia-reperfusion group, NS was injected intraperitoneally 30 min before focal cerebral ischemia-reperfusion. The rats in dexmedetomidine preconditioning group 1 and dexmedetomidine preconditioning group 2 received intraperitoneal injection of dexmedetomidine at doses of 20 μg/kg and 40 μg/kg, respectively. The neurological scores were studied, and the pathological changes were observed under microscope with HE staining. The expression of glial fibrillary acidic protein (GFAP) and tumor necrosis factor α (TNF-α) in astrocytes was detected by the methods of immunohistochemistry and immunoblotting 24 h after cerebral ischemia-reperfusion. RESULTS: No neurological change was observed in sham operation group. The neurological deficiency scores in ischemia-reperfusion group were markedly higher than those in dexmedetomidine preconditioning group 1 and group 2 (P<0.05). Compared with sham operation group, the expression of GFAP and TNF-α in astrocytes and the level of GFAP increased significantly 24 h after focal cerebral ischemia-reperfusion. Pretreatment with dexmedetomidine significantly attenuated the expression of GFAP and reduced the infarct size and inflammation. CONCLUSION: Dexmedetomidine has a neuroprotective effect on focal cerebral ischemia-reperfusion injury by inhibiting the astrocytes.     

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.     

Effects of rolipram on learning and memory and the activity of PDE4 in hippocampus following the focal brain injury induced by ischemia- reperfusion in rats

AIM: To investigate the effects of rolipram on the ability of learning and memory and the activity of PDE4 in hippocampus following the focal brain injury induced by ischemia- reperfusion in rats. METHODS: The cerebral ischemia-reperfusion injury model was made by middle cerebral artery occlusion (MCAO) in rats. The rats were randomly divided into sham-operated group, model group, and rolipram group. Rolipram was administered once a day (1 mg/kg, ip) from 6 h after the onset of the operation for 2 weeks. Then the learning and memory abilities were tested after Morris water maze and step-though training. The activity of PDE4 in hippocampus was evaluated by HPLC. RESULTS: In the Morris water maze test, compared to sham-operated group, the platform-finding time and swimming distance in model group were significantly longer (P<0.05). Compared to model group, the platform-finding time and swimming distance in rolipram group were significantly shorter (P<0.05). In the step-through test, compared to sham-operated group, the lantent period in model group was significantly shorter (P<0.01) and the error times were statistically increased(P<0.05). Compared with model group, the lantent period in rolipram group were significantly longer (P<0.05), and the error times were markedly decreased. The assay of the HPLC demonstrated that the activities of PDE4 in hippocampus in model group were higher than those in the sham-operated group and rolipram group. CONCLUSION: Rolipram reduces the activity of PDE4 in hippocampus and enhances the ability of learning and memory after the injury induced by ischemia-reperfusion.     

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.     

Effects of ghrelin on brain edema and aquaporin 4 expression after cerebral ischemia/reperfusion in rats

AIM: To explore the effects of ghrelin on the brain edema, the permeability of blood-brain barrier (BBB) and the expression of aquaporin 4 (AQP4) after cerebral ischemia/reperfusion in rats. METHODS: Adult male Sprague-Dawley rats were randomly divided into sham operation group, middle cerebral artery occlusion (MCAO) group and ghrelin treatment group. The MCAO model was made with nylon thread for 2 h of occlusion following 22 h of reperfusion. Ghrelin at a dose of 10 nmol/kg was injected via femoral vein at the beginning of reperfusion. The cerebral infarct volume was measured by 2,3,5-triphenyltetrazolium chloride (TTC) staining. Brain functional deficits were evaluated by determining the neurological scores. The changes of brain swelling and water content were analyzed through volume calculation and dry/wet weight measurement. The permeability of BBB was detected by collecting extravascular Evans blue (EB) in the brain cortex. The changes of AQP4 expression were assessed by the methods of immunohistochemistry and Western blotting. RESULTS: Compared with MCAO group, the rats in ghrelin treatment group had smaller brain infarct volume, lower EB exudation content and neurological scores. The percentage of brain swelling, water content and AQP4 expression were lower in ghrelin treatment group than those in MCAO group. CONCLUSION: Ghrelin reduces the injury of cerebral ischemia/reperfusion, and lightens the brain edema and BBB damage in rats. Ghrelin also inhibits the expression of AQP4 in brain tissue.     

Effects of ischemic postconditioning on cerebral ischemia/reperfusion injury in rats

AIM: To study the effects of ischemic postconditioning on cerebral ischemia following middle cerebral artery occlusion in rats. METHODS: 21 rats were randomly divided into three groups: middle cerebral artery occlusion (MCAO), MCAO+transient unilateral common carotid artery occlusion (u-CCA-O), MCAO+transient bilateral common carotid artery occlusion (b-CCA-O)(n=7, respectively). u-CCA-O/b- CCA-O was generated by transient middle cerebral artery occlusion plus transient unilateral/bilateral common carotid artery (CCA) occlusion. After the suture was removed, ischemic postconditioning was performed by occluding CCA for 10s, reperfusion 10s, and then allowing for another 4 cycles of 10s of reperfusion and 10s of CCA occlusion. Rats were sacrificed 2 d later and infarct size was measured. Cerebral blood flow (CBF) was measured in different 15 time points: 0 min, 10 min, 1 h after MCA occlusion, 0 min after MCA reperfusion, 10s of CCA occlusion and 10s of CCA reperfusion in all five cycles, 30 min after MCA reperfusion. Functional neurological outcome was determined 1 h and 48 h after reperfusion. Infarct volume was measured 48 h after reperfusion. RESULTS: The infarct volumes in u-CCA-O group and b-CCA-O group diminished compared to the control group. The results of CBF demonstrated that b-CCA-O group diminished 9% compared with control and u-CCA-O group when 30 min after intervention. The rats in u-CCA-O and b-CCA-O group had better neurological performance at 1 h after reperfusion. CONCLUSION: Ischemic postconditioning reduces infarct size, improves functional neurological outcome, most plausibly by diminishing cerebral blood flow.     

Effect of ginsenoside Rg1 on activity and protein expression of NOS in rats with cerebral ischemic reperfusion injury

AIM: To observe the neuroprotective effects of ginsenoside Rg1 on focal cerebral ischemia reperfusion (I/R) injury in rats. METHODS: SD rats were applied to right middle cerebral artery occlusion (MCAO) for 2 h followed by 24 h of reperfusion. The rats were randomly divided into sham-operation group, I/R group and ginsenoside Rg1 pretreatment groups. The rats in ginsenoside Rg1 pretreatment groups were pretreated with ginsenoside Rg1 at doses of 10, 20 or 40 mg/kg once a day for 7 days and then subject to MCAO. The neurological deficit score was measured by Longa's method. The neurons were observed with Nissel staining. The nitric oxide (NO) content, the activity of nitric oxide synthase (NOS) and inducible NOS (iNOS) in the brain tissues were determined. The expression of neuronal NOS(nNOS) and iNOS was detected by Western blotting. RESULTS: Compared with sham-operation group, ginsenoside Rg1 significantly reduced the neurological deficit score and increased the neuron number in the hippocampus. The activity of NOS and iNOS, and NO content were decreased. Ginsenoside Rg1 also down-regulated the expression of nNOS and iNOS. CONCLUSION: Ginsenoside Rg1 has protective effect on the brain during cerebral I/R injury in rats. The mechanism may be related to reducing the content of NO and the activiy of NOS dose-dependently.     

Neuroprotective effect of L-serine on rats with permanent middle cerebral artery occlusion

AIM: To investigate the neuroprotective effect, therapeutic dosage and time window of L-serine against permanent cerebral injury in rats. METHODS: Permanent middle cerebral artery occlusion (pMCAO) was induced in the rats to determine the efficacy of L-serine (ip) by neurological evaluation, TTC staining and Nissl staining.L-serine was used at different doses (56 mg/kg, 168 mg/kg and 504 mg/kg) and for different time periods (1 h, 3 h, 6 h, 12 h and 24 h after pMCAO). Aminooxyacetic acid (AOAA), an inhibitor of serine racemase, was used to alter the efficacy of L-serine. Laser Doppler perfusion monitor was used to observe the regional cerebral blood flow (rCBF) in the ischemic cerebral cortex under the condition with or without L-serine treatment. RESULTS: Treatment with L-serine at doses of 168 mg/kg and 504 mg/kg at time point of 3 h after pMCAO greatly decreased the neurological deficit score and infarct volume,and attenuated the loss of hippocampal CA1 neuronal cells. In the observation of therapeutic time window, L-serine displayed a significant neuroprotective effect if used within 6 h after pMCAO, but did not exert any notable effect if used over 12 h after pMCAO. AOAA hardly changed the effect of L-serine. L-serine treatment notably raised rCBF in the area of ischemic cerebral cortex when it was injected 30 min after pMCAO. However, strychnine, an antagonist of strychnine-sensitive glycine receptor, did not alter this effect of L-serine. CONCLUSION: L-serine has neuroprotective effect on permanent ischemic brain injury in rats if administered early and sufficiently by augmentation of rCBF in the ischemic cerebral cortex.     

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.     

All-trans retinoic acid attenuates blood-brain barrier injury induced by cerebral ischemia-reperfusion in rats through JNK/P38 MAPK signaling pathway

AIM: To investigate the effect of all-trans retinoic acid (ATRA) on blood-brain barrier after cerebral ischemia-reperfusion (CIR) injury in rats and its possible role mechanism.METHODS: Male SD rats were randomly divided into sham group, model (CIR) group and CIR+ATRA (10, 30 and 90 mg/kg) groups. The rat model of CIR injury was established by MCAO thread occlusion method. After ischemia for 1.5 h and reperfusion for 24 h, the neurological functional behavioral score, cerebral infarction volume, brain water content and Evans blue content were determined. The activity of matrix metalloprotein-9 (MMP-9) was measured by gelatin zymography. The protein levels of claudin-5, occludin, ZO-1, JNK, p-JNK, P38, p-P38 and MMP-9 in the brain tissues were determined by Western blot.RESULTS: Compared with CIR model group, ATRA at 30 mg/kg significantly improved neurological function, and decreased cerebral infarction volume, brain water content, Evans blue content and the degradation of tight junction proteins in ischemic area (P<0.01). The activity and protein expression of MMP-9 in ischemic brain tissue were decreased (P<0.01). The phosphorylation of JNK and P38 was inhibited and the protein levels of p-JNK and p-P38 were decreased (P<0.01).CONCLUSION: ATRA reduces the damage of brain tissue and the destruction of blood-brain barrier induced by CIR in rats. The protective effect may be related to inhibiting the activation of JNK/P38 MAPK signaling pathway and MMP-9.     

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.     

Effect of apigenin on expression of VEGF in cerebral ischemia and reperfusion rats

AIM: To investigate the effect of apigenin on the expression of vascular endothelial growth factor (VEGF) in the rats under the condition of cerebral ischemia and reperfusion. METHODS: Ninety-one male SD rats were randomly divided into 13 groups: sham operation group (S), model groups (group M6 h, group M24 h, group M72 h, group M7 d), apigenin treatment groups (group A6 h, group A24 h, group A72 h, group A7 d) and dexamethasone treatment groups (group D6 h, group D24 h, group D72 h, group D7 d). The acute transient focal cerebral ischemia reperfusion model was established by modified method of inserting the nylon thread into middle cerebral artery, staying for 2 h and then withdrawing from the artery. In the experiment groups, the TTC staining of brain slices were performed and the neurological behavior scores were determined. The expression of VEGF by immunohistochemistry (ICH) was semi-quantitatively analyzed by measuring the integrated absorbance(IA). RESULTS: Abnormal neurological behaviors were observed in the animals of M groups, A groups and D groups, but the neurological behaviors of the rats in A7 d group were better than that in the other groups (P<0.05). Typical cortical infarct lesions in M groups, A groups and D groups were found by TTC staining, mainly in cerebral cortex and striatum. The immunnohistochemical results showed that the expression of VEGF was significantly higher in M, A and D groups than that in S group (P<0.05). Moreover,the expression of VEGF in A groups(A24 h and A72 h)was higher than that in M groups (M 24 h and M72 h,respectively)(P<0.01).The expression of VEGF in D72 h group was higher than that in M72 h group (P<0.05), and that in A7 d group was obviously higher than that in D7 d group (P<0.01).CONCLUSION: Apigenin promotes the expression of VEGF in the model of acute transient focal cerebral ischemia-reperfusion injury, improves the process of brain injury and recovers the brain functions in rats.     

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.     

Astragalus injection inhibits expression of Apaf-1 in rat hippocampus after cerebral ischemia and reperfusion

AIM: To investigate the effect of Astragalus injection on the expression of apoptotic protease-activating factor 1 (Apaf-1) in the hippocampus of global cerebral ische-mia-reperfusion rats. METHODS: Male SD rats were randomly divided into 4 groups with 30 each: sham operation group, cerebral ischemia-reperfusion group, cerebral ischemia-reperfusion+Astragalus injection group, and cerebral ischemia-reperfusion+vehicle group. The global cerebral ischemia-reperfusion model of the rats was established by 4-vessel occlusion. The rats in cerebral ischemia-reperfusion group, cerebral ischemia-reperfusion+Astragalus injection group and cerebral ischemia-reperfusion+vehicle group were further divided into 7 subsets, according to the reperfusion time of 0 h, 0.5 h, 2 h, 6 h, 24 h, 72 h and 120 h. After reperfusion, the brains were removed at the corresponding time points. The protein expression of Apaf-1 in hippocampal neurons was detected by immunohistochemistry and Western blotting. The mRNA expression of Apaf-1 was observed by RT-PCR. RESULTS: Compared with sham operation group, the expression of Apaf-1 at mRNA and protein levels at all time points except 0 h and 120 h increased obviously in cerebral ischemia-reperfusion group (P<0.05). Compared with cerebral ischemia-reperfusion group, the expression of Apaf-1 at mRNA and protein levels at all time points except 0 h and 120 h decreased obviously in cerebral ischemia-reperfusion+Astragalus injection group (P<0.05). However, those in cerebral ischemia-reperfusion+vehicle group had no obvious change (P>0.05). CONCLUSION: Astragalus injection inhibits the expression of Apaf-1 at mRNA and protein levels in hippocampus of global cerebral ischemia-reperfusion rats, thus inhibiting the apoptosis of hippocampal neurons.     

Effect of peurarin pretreatment on endothelial nitric oxide synthase in rat brain tissues at the early stage of cerebral ischemia in rats

AIM: To investigate the neuroprotective effect of puerarin on the expression of endothelial nitric oxide synthase (eNOS) in rat brain tissues at the early stage of cerebral ischemia.METHODS: Forty-five rats were randomized into 3 groups: 5 in sham-operated group (S group), 20 in cerebral ischemia group (M group) and 20 in puerarin pretreatment group (P group).The rats in M group and P group were further divided into 4 subgroups to apply cerebral ischemia for 0.5 h, 1 h, 2 h and 4 h,respectively.The rats were subject to middle cerebral artery occlusion (MCAO) except those in S group.Puerarin was administered with intraperitoneal injection (100 mg/kg, ip) in P group 10 min before MCAO.The equal volume of the vehicle was administered in M groups and S group at the same time.Neurological deficit scores were determined to evaluate the functional changes of the central nervous system.The pathological changes of the brain tissues were observed under microscope with neuron nissl body staining.The protein expression and distribution of eNOS in the brain tissues were evaluated by the methods of immunohistochemistry and Western blotting.RESULTS: Neurological deficit scores of the rats in all subgroups of P groups were significantly lower than those in the corresponding subgroups of M groups (P<0.05).The dissolution extent of neuron nissl body in P groups was lower than that in M groups.The protein expression of eNOS in the brain tissues in all subgroups of P groups was higher than that in the corresponding subgroups of M groups.CONCLUSION: Pretreatment with puerarin protects brain tissues from injury of cerebral ischemia at the early stage by up-regulating the protein expression of eNOS in the brain tissues.     

Mechanism of therapeutic effect of QingKaiLing-ingredient combination on focal cerebral ischemia-reperfusion injury

AIM:To elucidate the therapeutic effect and mechanism of QingKaiLing (QKL)-ingredient combination on cerebral ischemia. METHODS:Rat focal brain ischemia reperfusion injury was produced by occlusion in the middle cerebral artery. MRI and histological analysis were used to evaluate the brain injury induced by ischemia and the attenuations by the drugs including QKL-ingredient combination and the positive control nimodipine. In situ hybridization was used to measure the expression of BDNF mRNA in the brain. RESULTS:A significant neuroprotective effect was observed in the QKL-ingredient combination treatment group, which was superior to that in the nimodipine treatment group. The expression of BDNF mRNA in the brain was also significantly up-regulated by the QKL-ingredient combination treatment in a rat model of focal cerebral ischemia-reperfusion injury. CONCLUSION:The QKL ingredients show a neuro-protective effect, the mechanism may be related to the up-regulation of BDNF in the brain.     

Effects of progesterone on water,sodium, potassium and calcium contents in striatum of rats with focal cerebral ischemia/reperfusion

AIM: To explore the neuroprotective action of progesterone(PROG), which has been proved to be a "neuroactive steroid". METHODS: The model of focal cerebral ischemia was established in rats by reverserble inserting a nylon thread with a diameter of 0.2 mm into the anterior cerebral artery through the internal carotid artery. The effect of PROG was assessed by determining water,sodium, potassium, and calcium contents in striatum of rats subjected to 2 h ischemia followed by 22 h reperfusion. RESULTS: The water,sodium,and calcium contents of middle cerebral artery occlusion(MCAO) striatum were obviously higher,the potassium content was obviously lower than those of non-MCAO striatum in I/R and DMSO groups,but there was no significant difference between these two groups.Compared with the result in I/R and DMSO groups , water, sodium and calcium contents significantly decreased, but potassium(P＜0.01) obviously elevated in MCAO striatum in the PROG-pretreated group and PROG-pre or posttreated group.There was also significant reduction in water and sodium, but not significantly changed in calcium and potassium in PROG-posttreated group. The water,sodium,potassium,and calcium contents of MCAO striatum in each PROG-treated group were not remarkably different in comparision with those in dexamethasone treatment group(P＞0.05). CONCLUSION: Treatment with PROG can significantly reduce the striatal injury of rats with cerebral ischmia-reperfusion.