磷酸化Rb蛋白在正常成年大鼠与脑缺血大鼠神经元内的表达变化

目的观察正常成年大鼠与局灶性脑缺血大鼠神经元内磷酸化Rb蛋白(p-Rb)的表达及变化特点。方法应用免疫荧光组织化学染色方法观察成年大鼠不同脑区神经元内p-Rb表达特点,比较大鼠大脑中动脉闭塞(MCAO)后不同时间点(12h、1d、3d、7d)缺血半暗带内神经元p-Rb的变化特点。结果成年大鼠神经元内p-Rb主要在细胞核内表达;与对照组相比,MCAO再灌注后各时间点p-Rb免疫反应性均增强;再灌注1d,缺血半暗带内部分神经元p-Rb表达由细胞核转移到细胞浆。结论成熟神经元内p-Rb在细胞核内表达可能对于维持神经元的有丝分裂后状态有一定作用,当其发生核浆转移提示神经元细胞周期调控机制紊乱,可能再进入细胞周期。

Expression and subcellular localization of phospho-Rb in neurons of adult rats and rats subjected to focal cerebral ischemia

Objective To investigate the expression and changes of subcellular localization of phospho-Rb in neurons of adult rats and rats subjected to transient focal cerebral ischemia.Methods Immunofluorescence staining was used to detect the expression and subcellular localization of phospho-Rb in neurons of adult rats in different cerebral regions and in the penumbra zone at 12h,1d,3d and 7d after middle cerebral artery occlusion(MCAO)/reperfusion.Results Phospho-Rb was mainly located in the nuclei under normal conditions.Compared with sham-operated controls,increased phospho-Rb immunoreactivity was seen at each time point after MCAO/reperfusion.One day after reperfusion,it was showed that subcellular localization of phospho-Rb translocated from the nucleus to the cytoplasm in many neurons in the penumbra zone.Conclusion Located in the nuclei of mature neurons,phospho-Rb palys a potential role in maintaining neuronal postmitotic quiescence.Cytoplasmic translocation of phospho-Rb from nucleus occurs in impaired neurons,suggesting that these neurons attempt to reenter cell cycle mediated by dysregulation of the cell cycle machinery after focal cerebral ischemia.