| Objective: Ischemic stroke is one of the highest mortality diseases in the world.After ischemic stroke,not only the nerve cells in the ischemic core area die,but also the neuronal structure and function around the infarct area are changed.Therefore,timely restoration of neuronal structure and function can promote the repair of nerve function injury after ischemic stroke.Early cell experiments showed that Schisandrin A(Sch A),as the main bioactive component of Schisandra Chinensis,could promote the proliferation and differentiation of neural stem cells in vitro.Animal experiments also confirmed that Schisandrin A could promote the proliferation and differentiation of neural stem cells in rat ependyma after cerebral ischemia-reperfusion injury,thus producing a neuroprotective effect on ischemia-reperfusion rats.After cerebral ischemia-reperfusion,neuronal apoptosis and autophagy will be activated.A certain degree of neuronal autophagy can reverse the occurrence of neuronal apoptosis and improve neuronal survival,thus the neuroprotective effect on ischemia-reperfusion.Therefore,the purpose of this study is to explore whether Sch A can produce a neuroprotective effect on cerebral ischemia-reperfusion rats by affecting neuronal autophagy in the cerebral ischemic penumbra area.Methods: SPF healthy male adult SD(Sprague Dawley)rats were randomly divided into five groups after 90 min reperfusion:sham operation group(Sham group),model group(MCAO group),Sch A low dose group(Sch A 40 μg/kg/d),Sch A medium dose group(Sch A 80 μg/kg/d)and high dose group(Sch A 160 μg/kg/d),The Sch A groups were Sch A 5 μL,in the left ventricle after reperfusion MCAO group was given 5 μL of the same concentration DMSO the left ventricle,Sham group only had left external carotid artery ligation,n=6.Nerve function injury score(modified neurological severity scores,)of rats in each group after 7 d administration m NSS)and TTC staining was used to evaluate the degree of nerve function injury in rats;Western Blot detects the changes of autophagy initiation protein Beclin1、 autophagosome marker protein in ischemic penumbra region LC3、 presenting protein P62、 membrane related protein,autophagy lysosomal hydrolase CTSB and protein expression level Ubiquitin ubiquitin substrate to evaluate the changes of autophagy level after medication;Detection of autophagy in the cerebral ischemic penumbra of rats by immunofluorescence double-standard method,Cell localization of autophagy in ischemic penumbra area.Results: TTC staining showed that the cerebral infarction area was formed after cerebral ischemia-reperfusion injury in rats.According to the m NSS score,the cerebral ischemia-reperfusion injury occurred in rats after cerebral ischemia-reperfusion.When Sch A lateral ventricle was administered,the cerebral infarction volume could be reduced(P<0.05),and reduced the m NSS score(P<0.05),and this neuroprotective effect showed a dose-dependent Sch A,and the neuroprotective effect of the Sch A 160 μg/kg/d group was the most obvious.Western Blot results showed that the expression levels of autophagy initiating protein Beclin1 and autophagosome formation marker LC3Ⅱ/I increased after cerebral ischemia-reperfusion in rats(P<0.05),but the expression level of cathepsin B decreased,while the expression of P62 and ubiquitin The level rises.Compared with the MCAO group after administration of Sch A to the lateral ventricle,the expression of Beclin1 and LC3Ⅱ/I increased,and Sch A significantly increased the expression of cathepsin B while reducing the expression of P62 and ubiquitin.The difference in the high-dose group was significant(P<0.05).LAMP1 only showed a trend of increasing expression after administration,but there was no significant difference(P>0.05).The results of immunofluorescence double-labeling showed that,compared with the Sham group,the expression of LC3 in the cerebral ischemic penumbra of the MCAO group increased,and it was mainly present in neurons.Compared with the MCAO group,the expression of LC3 in neurons in the ischemic penumbra area increased after Sch A administration(P<0.05),and the expression of LC3 in the Sch A 160 μg/kg/d group increased significantly.Conclusion: Sch A can reduce the nerve function injury and reduce the volume of cerebral infarction in cerebral ischemia-reperfusion rats,thus producing the neuroprotective effect.This neuroprotective effect is related to the regulation of neuronal autophagy and the reversal of autophagy-related protein expression in the cerebral ischemic penumbra of rats. |
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