大鼠脑缺血再灌注损伤模型：C色素和Bax蛋白增加

［摘要］目的　制备局灶性脑缺血再灌注损伤大鼠模型，并观察大脑皮质细胞色素C(CytC)与Bax蛋白表达的变化。方法　雄性SD大鼠，采用线栓法闭塞大脑中动脉2h后进行再灌注3d，制备局灶性脑缺血再灌注损伤模型。采用神经缺失评分观察大鼠的行为学表现；TTC染色检查脑组织梗死情况；HE染色观察大鼠脑组织形态结构；Western blot技术检测大鼠大脑皮质CytC与Bax蛋白的表达。结果　假手术组大鼠无神经功能障碍表现；脑组织未见梗死灶；脑组织神经细胞形态规则；与正常组相比，大脑皮质CytC与Bax蛋白的相对表达量未见明显变化。与假手术组相比，局灶性脑缺血再灌注损伤模型大鼠出现神经功能障碍；左侧半球可见梗死灶；梗死侧脑组织形态学观察可见神经细胞大量坏死脱落、胞质呈空泡变性、疏松、胞核浓缩深染；大脑皮质CytC与Bax蛋白表达量明显增加。结论　大脑中动脉闭塞2h后进行再灌注3d可造成脑缺血再灌注损伤，可能与大脑皮质CytC与Bax蛋白的表达增加有关。

［关键词］脑缺血再灌注损伤；大鼠；细胞色素C；Bax

Increase of cytochrome C and Bax protein expression in cerebral cortex in a rat model of ischemia-reperfusion injury

［Abstract］Objective To observe the changes of cytochrome C and Bax protein expression in cortex of cerebral ischemia-reperfusion injury model rats.Methods Twenty-two male SD rats were randomly divided into three groups，normal group，sham group and model group.Focal cerebral ischemia-reperfusion injury model was induced for 2h by middle cerebral artery occlusion(MCAO)followed by 3d reperfusion.Behavioral performance were measured using neurologic deficit score，TTC staining was used to examine brain infarction，HE staining was to examine brain morphology，and Western blot was used to detect the expressions of cytochrome Cand Bax protein in the cerebral cortex.Results Rats in sham-operated group showed no neurological dysfunction，no brain infarction，no brain morphological changes and no significant difference in cortical cytochrome C and Bax protein compared with rats in normal group.Compared with rats in sham group，rats in model group showed neurological dy sfunction left hemisphere infarct，neuronal cell necrosis，cytoplasmic vacuolar degeneration and condensed stained nuclei in the left hemisphere.In addition，expressions of cytochrome C and Bax protein in cortex were significantly increased.Conclusion Middle cerebral artery occlusion(MCAO)for 2h followed by reperfusion for 3d can induce cerebral ischemia-reperfusion injury，which may be correlated with the increase of the expressions of cytochrome C and Bax protein.(www.xing528.com)

［Key words］cerebral ischemia-reperfusion injury；rat； cytochrome C；bax

脑血管疾病是危害人类生命和健康的主要疾病之一，缺血性脑血管病约占全部脑血管病患者的80%左右［1］，其中大多由大脑中动脉阻塞引起急性血流障碍，导致突发性局灶性脑功能障碍，导致感觉、运动功能丧失，甚至死亡。目前国际上通常采用溶栓疗法［2］以恢复脑组织血流供应，但再灌注本身有时也可加重组织的功能障碍和结构损伤，即引起脑缺血再灌注损伤。近年来对脑缺血再灌注损伤的病理生理过程进行了较多的研究，但其确切的发生机制仍不清楚。目前认为，细胞凋亡可能在脑缺血再灌注损伤的病理过程中起重要作用［3］。其中，CytC被认为是细胞凋亡信号传导过程的关键因素，也是第一个被发现的线粒体释放至胞质的促凋亡因子，而Bax通常被认为是促凋亡基因。然而脑缺血再灌注后大脑皮质CytC与Bax蛋白的表达究竟如何变化还不清楚，因此，本研究采用雄性SD大鼠，建立大脑中动脉栓塞(MCAO)缺血再灌注损伤模型，采用Western blot技术观察大脑皮质CytC与Bax蛋白表达的变化，为下一步研究药物或针灸神经保护机制奠定实验基础。