目的探讨Cav1/Notch1/Hes1通路在小鼠脑缺血后海马神经干细胞(neural stem cells,NSCs)增殖中的作用及补阳还五汤促神经再生的机制。方法采用大脑中动脉阻塞法(middle cerebral artery occlusion,MCAO)复制小鼠脑缺血模型,将野生型(wild type,WT)和小凹蛋白-1基因敲除小鼠(caveolin1 gene knockout,Cav1 KO)分别随机分为假手术组、模型组、补阳组,每组12只,腹腔注射Brd U标记增殖细胞,干预7 d后,采用免疫荧光Brd U/Nestin双标法检测小鼠缺血侧海马NSCs增殖情况,Western blot法检测Notch1、NICD、Hes1蛋白表达,Real time PCR法检测Notch1、Hes1m RNA表达。结果 MCAO法成功复制了小鼠脑缺血模型;WT模型组、补阳组和KO模型组、补阳组缺血侧海马Brd U/Nestin双标阳性细胞,Notch1、NICD、Hes1蛋白表达及Notch1、Hes1m RNA表达均增加,与相应假手术组比较,差异有统计学意义(P〈0.01,P〈0.05),同时,WT模型组要高于KO模型组(P〈0.05),WT补阳组要高于WT模型组和KO补阳组(P〈0.01,P〈0.05)。结论Cav1/Notch1/Hes1通路在小鼠脑缺血后海马NSCs增殖中发挥重要调控作用;通过上调Cav1/Notch1/Hes1通路活性是补阳还五汤促进缺血海马神经再生作用机理之一。
Objective To investigate the role of Cav1/Notch1/Hes1 pathway in the proliferation of hippocampal neural stem cells(NSCs) of mice after cerebral ischemia and to investigate the mechanism of Buyang Huanwu Decoction(BHD) in promoting neurogenesis.Methods Cerebral ischemia model in mice was established by the method of middle cerebral artery occlusion(MCAO).Wild type(WT)mice and caveolin1 gene knockout(Cav1 KO)mice were randomly divided into sham-operation group,model group,and BHD group,12 mice in each group.The mice were given intragastric administration with the corresponding medicine for 7 days,and at the same time,intraperitoneal injection of Brd U was used to label the proliferation cells.NSCs proliferation in mice ischemic hippocampus was detected using immunofluorescence after Brd U/Nestin double staining.Western blotting was used to detect the protein expression levels of Notch1,NICD and Hes1,and the m RNA expression levels of Notch1,NICD and Hes1 was tested by real-time PCR.Results Cerebral ischemia model in mice was successfully replicated with the method of MCAO.Compared with the WT and Cav1 KO sham-operation groups,the number of cells with Brd U/Nestin double staining positive in ischemic hippocampus of BHD groups and WT and Cav1 KO model groups was increased(P〈0.01 or P〈0.05),and the expression of Notch1,NICD,and Hes1 protein as well as Notch1,Hes1 m RNA expression was enhanced(P〈0.01 or P〈0.05).The expression levels of the indexes in WT model group were higher than KO model group(P〈0.05),and the levels in WT + BHD group were higher than WT model group and KO + BHD group(P〈0.01 or P〈0.05).Conclusion Cav1/Notch1/Hes1 pathway plays an important role in NSCs proliferation in hippocampus of mice after cerebral ischemia.Activating Cav1/Notch1/Hes1 pathway may be one of the mechanisms of BHD in promoting neurogenesis of ischemic hippocampus.