| Cerebrovascular disease(CVD)is a common and frequently occurring disease that endangers human health and life.It is one of the three causes that lead to death,and is the first causes that lead to disability.At present,there are thrombolytic therapy in acute phase and drug treatment such as antiplatelet,anticoagulation,traditional Chinese medicine,and brain protective drugs after ischemia reperfusion,Neurosurgery,genetic therapy and neural tissue transplantation method also in the clinical treatment on ischemic cerebral vascular disease,but the effect is not satisfying.The new strategy of the treatment with stroke has attracted the attention of scientists in the world.In recent years,it was found that ischemic preconditioning(IP)is one of the effective methods that could to reduce the ischemia/reperfusion injury in animal heart,brain and kidney.A large number of experimental studies had proved that the IP induced brain tissue resisted to subsequent lethal ischemic/reperfusion injury.This is the phenomenon of cerebral ischemic tolerance(CIT).The exact mechanism of cerebral ischemic tolerance is unclear,it was regared that the protective effect were achieved by anti-apoptotic,inhibit inflammation,maintaining the energy metabolism and promoting to repair the damage.In this study,we observed the effects of ischemic preconditioning on cerebral ischemia reperfusion injury in rats,observe the changes of the expression of Fas,FasL,Caspase-8 and Caspase-3 protein in rats with cerebral ischemia reperfusion and the effect on neuronal apoptosis in order to explore the mechanism of Fas and FasL pathway in cerebral ischemictolerance induced by ischemic preconditioning.Male Spraque-Dawley rats were randomly divided into: ischemia reperfusion group(I/R,n=36),ischemia preconditioning+ischemia reperfusion group(IP+I/R,n=36)and Sham operation group(Sham-operated,n=36).Divide them into 6h,12 h,24h,48 h,72h groups according to five observation points.The right internal carotid artery of rats in ischemia preconditioning group was blocked transiently 10 minutes at one time.After 3 days,the focal cerebral ischemia reperfusion injury model was established by the middle cerebral artery occlusion.The ischemia group was established by the middle cerebral artery occlusion method.The sham operation group only isolated carotid artery.Rats were killed at each observation time.The neurobehavioral score use the method of Longa’s score;the infarct area of rats brain detected by TTC stianing;Immunohistochemical method was used for observing the expression of Fas,FasL,Caspase-8 and Caspase-3 protein in rats brain tissue.The apoptosis of nerve cells were detected by TUNEL method.The neural function defect score of rats was evaluated at each observation time points of 6h,12 h,24h,48 h and 72 h.The change of neurobehavior and neurological deficits was obvious that either the ischemia reperfusion group or ischemia preconditioning+ischemia reperfusion group rats compared with the sham operation group;the ischemia reperfusion rats’ nerve function score was higher than that of ischemia preconditioning treatment+ischemia reperfusion group,the difference was significant(P<0.05).After reperfusion 24 h,the percentage of infarct area of ischemia preconditioning+ischemia reperfusion group rats was significantly lower than that of ischemia reperfusion group,the difference was significant(P<0.05).Compared each group at the same time point: the expression of Fas,FasL,Caspase-8,and Caspase-3 protein and the number of apoptotic nerve cells of ischemia reperfusion group or preconditioning group was higher than that in the sham operation group.The expression of Fas,Fas L,Caspase-3 protein and the number of apoptotic nerve cells of ischemia reperfusion group was higher than that in the preconditioning group(P<0.05).Cerebral ischemia injury may promote the expression of Fas,Fas L Caspase-8 and Caspase-3 protein and the activation of Fas,FasL signaling pathway.Cerebral ischemia preconditioning could down regulated the expression of Fas,FasL,caspase-8 and caspase-3 protein and to inhibit neuronal apoptosis.Negative regulation of Fas and FasL pathway after ischemia preconditioning may be an important endogenous mechanism of resistance to damage. |
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