CIB1-siRNA对大鼠脑缺血-再灌注损伤后凋亡相关蛋白Caspase-3表达影响

Effect of CIB1-siRNA on the Expression of Caspase-3 in Brain Tissues of Rats with Brain Ischemia-reperfuslon Injury

目的探讨钙离子结合蛋白(calcium and integrin-binding protein,CIB1)双链RNA(CIB1.siRNA)对大鼠脑缺血-再灌注损伤的作用.方法 SD大鼠120只,体重290～310 g,随机分成三组:假手术组(S组,n=40)、局灶性脑缺血-再灌注组(A组,n=40)、局灶性脑缺血-再灌注+CIB1-siRNA组(B组,n=40).A组、B组行大脑中动脉阻断,阻断1 h再开放,制备大鼠局灶性脑缺血-再灌注模型,B组在缺血前即刻、16、24 h水压法尾静脉注射CIB1-siRNA 2.5 mg/kg(用PBS稀释至10 mL),S组给予等量PBS,S组只作切口,不作缺血再灌注.S组、B组、A组分别于再灌注1、5、11、23、47 h各处死8只大鼠,断头取脑,计算脑梗塞体积比,用RT-PCR法测定脑缺血半影区Caspase-3 mRNA表达水平.结果 B组、A组再灌注23 h时脑梗塞体积比达到高峰,再灌注47 h时B组、A组脑梗塞体积比均高于S组(P<0.01);与A组比较,B组脑梗塞体积比增加(P<0.01).A组和B组再灌注23 h时Caspase-3表达高峰,B组各时间段Caspase-3表达强于A组.结论 CIB1-siRNA预先给药可加重大鼠脑缺血-再灌注损伤.

Objective To investigate the protective effect of CIB1-siRNA pretreatment on the brain against ischemia-reperfusion in rats.Methods 120 male SD rats weighing 290～310 g were randomly divided into 3 groups：sham operation group（S group,n=40）;middle cerebral artery occlusion group（MCAO）（A group,n=40）and CIB1-siRNA ＋MCAO group（B group,n=40）.The middle cerebral arteries of rats in A group and B group were blocked,MCAO was maintained for lh and the nylon thread was withdrawn to allow reperfusion.In B group,CIB1-siRNA solution（2.5 mg/kg）was given i.v.immediately before MCAO,at 24 h and 16 h after MCAO.In S group,the internal carotid artery was exposed but no MCAO was performed,and PBS solution was given instead of CIB1-siRNA solution.The animals in all groups were killed at 1,5,11,23 and 47 h after reperfusion（n=8 at each time point）.Brains were immediately removed and sliced.The infarct size was estimated by using Kontron IBAS 2.5 image auto-analysis system.The Caspase-3 mRNA expression was measured by RT-PCR.Results The infarct size of rats in A group and B group reached the peak at 23 h after reperfusion,and was significantly bigger than that in S group at 47 h after reperfusion（P〈0.01）.The infarct size of rats in B group was significantly bigger than that in A group（P〈0.01）.The expression of Caspase-3 protein in A group and B group reached the peak at 23 h after reperfusion.The expression levels of Caspase-3 protein in B group was higher than that in A group.Conclusion CIB1-siRNA pretreatment can aggravate the brain I/R injury to some extent.