大鼠大脑皮质梗死后同侧丘脑组织蛋白酶B表达的动态变化

目的 探讨大鼠大脑皮质梗死后同侧丘脑腹后外侧核(ventroposterior nucleus of the thalamus, VPN) 组织蛋白酶B(cathepsin B, CathB)的表达变化.方法 成年雄性Sprague-Dawley大鼠随机分为假手术组和模型组,后者进一步分为术后1周组、2周组、3周组、4周组和8周组.电凝法闭塞大脑中动脉皮质支制作大脑皮质梗死模型.采用免疫组织化学染色和免疫荧光检测各时间点丘脑VPN CathB蛋白表达和细胞定位.结果 大脑皮质梗死后丘脑VPN CathB表达水平逐渐增高,4周时达高峰,8周时下降,但仍然高于对照组(P均<0.05);可见CathB从溶酶体释放到细胞质.此外,在大脑皮质梗死后3周时,活化星形胶质细胞CathB表达水平也显著增高.结论 大脑皮质梗死后1~8周期间,丘脑VPN CathB维持较高的表达水平,提示其可能在大脑皮质梗死后继发丘脑变性中起着一定的作用.

Dynamic changes of cathepsin B expression in the ipsilateral thalamus after cerebral cortical infarction in rats

ObjectiveTo investigate the expression change of cathepsin B (CathB) in the ventroposterior nucleus (VPN) of the ipsilateral thalamus after cortical infarction in rats.MethodsThe adult male Sprague-Dawley rats were randomly divided into either a sham operation group or a model group.The latter was further divided into postoperative 1-, 2-, 3-, 4-, and 8-week groups.A model of cerebral cortical infarction was induced by electrocoagulation the cortical branch of middle cerebral artery.Immunohistochemical staining and immunofluorescence were used to detect the protein expression and cellular localization of CathB in the VPN at each time point.ResultsThe expression level of VPN CathB in thalamus increased gradually after cerebral cortical infarction.It reached the peak at 4 weeks, and decreased at 8 weeks, however it was still higher than the control group (all P<0.05).The release of CathB from the lysosomes into the cytoplasm were found.In addition, the expression level of CathB in the activated astrocytes was significantly increased at 3 weeks after cerebral cortical infarction.ConclusionsDuring 1-8 week after cerebral cortex infarction, CathB in the VPN of the ipsilateral thalamus maintained higher expression level, suggesting that it might play a certain role in secondary degeneration in the thalamus after cerebral cortical infarction.