氧自由基-线粒体信号通路在Edaravone治疗创伤性脑创伤中的作用

目的 探讨创伤性脑损伤(traumatic brain injury,TBI)后在抗氧化剂Edaravone干预下大鼠大脑皮质凋亡相关蛋白表达改变情况并探讨氧自由基-线粒体信号通路在Edaravone治疗创伤性脑创伤中的作用.方法 成年雄性SD大鼠180只随机分为TBI组、Edaravone治疗组和对照组.每组设伤后1,3,6,24,48,72 h 6个时相点.Edaravone治疗组给予Edaravone(10 mg/kg),对照组、TBI组给予等量等渗盐水.HE染色观察大鼠TBI后皮层神经元的病理改变.免疫组化和TUNEL法以及硫代巴比妥酸缩合法观察不同时相点大鼠皮层Cyt-c、Bcl-2和Bax的表达情况,细胞凋亡和丙二醛(MDA)变化情况.结果 HE染色可见创伤后6 h大脑皮质出现散在变性坏死神经元,伤后24 h达高峰.Edaravone治疗组伤后6 h即可检测到自由基中间产物丙二醛(MDA)的升高,与对照组相比,48 h达高峰.与TBI组相比,MDA含量各时相点均降低,其中在24,48和72 h差异有统计学意义(P＜0.05).与对照组相比,TBI组Cytc阳性细胞免疫反应6 h增强,24 h达高峰,在3,6,24,48和72 h差异有统计学意义(P＜0.05).与TBI组相比,Edaravone治疗组Ctyc阳性细胞免疫反应在24,48和72 h降低.Bcl-2表达在伤后应激性增高,于3 h达高峰,以后逐渐下降.Bax在伤后表达逐渐增高,于48 h达高峰,Bax/Bcl-2于48 h达高峰.TBI后,TUNEL阳性细胞数逐渐增多,24 h以前以TUNEL Ⅰ型细胞为主,24 h后以Ⅱ型细胞为主,并于48 h达高峰.结论 大鼠TBI后皮质神经细胞死亡存在坏死和凋亡两种方式,以凋亡为主.氧自由基-线粒体是TBI后神经细胞凋亡的信号转导通路中的一条.Edaravone对TBI有治疗作用.

Role of oxygen free radical-mitochondria signal pathway in Edaravone treating traumatic brain injury

Objective To investigate the expression of apoptosis-related proteins in rat cerebral cortex following traumatic brain injuries(TBI)and discuss the role of oxygen free radical-mitochondria signal pathway in Edaravone treating TBI.Methods A total of 180 male adult Sprague-Dawley rats were randomly divided into TBI group,Edaravone treatment group and control group.Each group was divided into six subgroups at 1,3,6,24,48 and 72 hours after TBI.Edaravone treatment group was injected with Edaravone(10 mg/kg)and the other two groups injected with the same volume of 0.9%normal saline.The pathological change in the rat cortex following TBI was observed with HE staining.At different time points,the expressions of Cytc,Bcl-2 and Bax in rat cortex as well as cell apoptosis and MDA change were observed by means of immunohistechemistry,TUNEL and TAB.Results HE staining showed scattered degenerated and necrotic neurous in cerebral cortex six hours after neuron injury,which peaked at 24 hours.Compared with control group,intermediate product MDA of free radical was increased six hours after TBI and peaked at 48 hours in Edaravone treatment group,which was lower than TBI group especially at 24,48 and 72 hours(P＜0.05).Compared with control group,the immunity reaction of Cytc positive cells inereased at six hours and peaked at 24 hours in TBI group,with statistical difference at 3,6,24,48 and 72 hours(P＜0.05).Compared with TBI group,the immunity reaction of Cyte positive cells was decreased obviously at 24,48 and 72 hours in Edaravone treatment group.Hyperexcitability of Bcl-2 after TBI reached peak at 3 hours and decreased gradually.But the expression of Bax was increased gradually after TBI and peaked at 48 hours,when Bax/Bcl-2 reached peak too.Folowing TBI,TUNEL positive cells increased gradually and reached peak at 48 hours,with mainly type Ⅰ TUNEL cells before 24 hours and typeⅡTUNEL cells after 24 hours.Conclusions There exist necrosis and apoptosis of nerve cells in cortex after TBI,especially apoptosis.Oxygen free radical mitochondria is one of the signal transduction pathways of nerve cell apoptosis following TBI.Edaravone exerts certain therapeutic effect on TBI.