常压高浓度氧下调电压依赖性阴离子通道蛋白对脑缺血-再灌注损伤大鼠的保护作用

摘要

Objective To observe the effect of normobaric hyperoxia (NBO) on expression of voltage-dependent anion channel (VDAC),cytochrome C (CytC) and cleaved caspase-3 induced by cerebral ischemia-reperfusion injury in rats,and preliminarily explore the mechanism of NBO treatment on prevention of apoptosis.Methods Fifteen healthy adult male Sprague-Dawley (SD) rats (280-320 g) were divided randomly into three groups:Sham group (n =3),Normoxia group (n =6) and NBO group (n =6).A model operation of MCAO was performed using intraluminal suture method.The rats underwent MCAO for 1.5 h plus 24 h reperfusion.After model operation the rats of sham group and normoxia group breathed normal air,and instead NBO group rats breathed 100％ oxygen until reperfusion.Western blotting was used to test the expression of VDAC,CytC and cleaved caspase-3 protein in ischemic penumbra region.Results Western blotting results showed that compared with the sham group,the VDAC protein expression of ischemic penumbra was increased (P ＜ 0.05) in the normoxia group,and compared with the normoxia group,the expression of VDAC protein in ischemic penumbra region was statistically significantly reduced (P ＜ 0.05) in NBO group.Compared with the normoxia group,the expressions of CytC protein and cleaved caspase-3 protein in ischemic penumbra region were statistically significantly decreased (P ＜ 0.05) in NBO group.Conclusion NBO treatment may inhibit cerebral ischemia-induced apoptosis by downregulating the excessive expression of voltage-dependent anion channel protein in ischemic penumbra region,thus to play a protective role in the ischemia/reperfusion injured brain.%目的 观察常压高浓度氧治疗(normobaric hyperoxia,NBO)对脑缺血-再灌注大鼠电压依赖性阴离子通道蛋白(voltage-dependent anion channel,VDAC)以及凋亡蛋白细胞色素C(cytochrome C,CytC)和活化型半胱天冬酶-3(cleaved caspase-3)的影响,初步探讨其作用机制.方法 将15只健康成年雄性SD大鼠(280～320 g)采用数字表法分为3组:假手术组(Sham)、正常氧浓度组(Normoxia)和NBO组,采用线栓法制备大鼠大脑中动脉阻塞模型,模型大鼠缺血1.5h,再灌注24 h.Sham组和Normoxia组大鼠术后呼吸普通空气,NBO组大鼠术后至再灌注前呼吸100％常压氧气.采用Western blotting方法,检测脑缺血半影区VDAC、CytC和cleaved caspase-3蛋白的表达变化.结果 1)与Sham组相比,Normoxia组缺血侧半影区VDAC显著升高(P＜0.05);与Normoxia组相比,NBO组缺血侧半影区VDAC显著降低(P＜0.05);2)与Normoxia组相比,NBO组缺血侧半影区凋亡蛋白CytC和cleaved caspase-3显著减少(P＜0.05).结论 NBO治疗可能通过调节缺血侧半影区电压依赖性阴离子通道蛋白VDAC的表达来抑制脑缺血诱发的细胞凋亡,从而实现脑神经保护作用.