Effects Of Remifentanil Preconditioning On The Expression Of GFAP And MBP In Cerebral Ischemia-Reperfusion Injury In Rats

objective:To observe the effects of remifentanil preconditioning on the expression of glial fibrillary acidic protein(GFAP)and myelin basic protein(MBP)after cerebral ischemia-reperfusion injury in rats,and to explore some mechanisms of remifentanil preconditioning on cerebral protection in rats with cerebral ischemia-reperfusion injury.Methods:(1)Sixty SD rats were randomly divided into four groups: blank group(n=6),sham operation group(n=18),cerebral ischemia reperfusion(I/R)group(n=18),remifentanil preconditioning group(n=18).Except for the blank group,MCAO models were constructed in each group,and the embolus was removed 2 hours after successful modeling,all the remaining groups were further divided into 3subgroups,according to the three different execution time points 6 hours,12 hours and24 hours after operation,and each subgroups had 6 rats in it.(2)Scores of degree of defect in neurological function in rats were made according to the Longa 5 like-rt scale.(3)the pathological changes of cortical neurons in the ischemic side were observed by HE staining.(4)the apoptotic status of neurons in the ischemic side was detected by TUNEL method.(5)RT-PCR was used to detect the expression of GFAP and MBP in cerebral cortex of ischemic side.Results:(1)Neurological function deficit score: There was no defective neurologicalsymptoms in blank group and sham operation group at each time point(P>0.05);Compared with sham operation group,I/R group and remifentanil preconditioning group had different degrees of neurological deficit symptoms(P< 0.01);Compared with I/R group at the same time point,remifentanil preconditioning group had less neurological deficit symptoms(P< 0.05).(2)HE staining results: The structure of neurons in blank group and sham operated group was clear and complete,and no obvious abnormal changes were observed.In the I/R group,the number of nerve cells decreased.At 6h,the cell body swelled and arranged irregularly.At 12 h,the cells swelled obviously,stained loosely and arranged disorderly.At 24 h,the necrosis and apoptosis of neurons were obvious,the edema and were reduced,a large number of degenerated and necrotic nerve cells were observed,Inflammatory cells infiltrated and microvacuoles formed in the cytoplasm.The whole pathological changes of remifentanil preconditioning group were less than those of I/R group at each time point.(3)TUNEL method was used to detect apoptotic neurons: a small amount of apoptotic cells were observed in blank group and sham operated group;compared with sham operated group,the light density of positive reactants in I/R group increased significantly,and the number of apoptotic cells increased significantly at each time point(P<0.01);compared with I/R group at the same time point,the light density of positive reactants in remifentanil preconditioning group decreased,and the number of cells decreased significantly(P < 0.05).(4)The expression of GFAP and MBP showed that the GFAP,MBP mRNA in blank group and sham operated group did not change significantly at each time point(P> 0.05);.Compared with sham operated group,the expression of GFAP and MBP mRNA in the I/R group and remifentanil preconditioning group increased significantly at each time point(P< 0.01);compared with I/R group,the expression level of GFAP and MBP mRNA in remifentanil preconditioning group decreased significantly at each time point(P< 0.05).Conclusion:(1)Remifentanil preconditioning can alleviate the injury of neurons aftercerebral ischemia reperfusion in rats.(2)Remifentanil may participate in the brain protection process by regulating the expression of GFAP and MBP.