细胞周期调控基因Chk1在脑缺血再灌注损伤中的作用

Study on gene expression of Chk1 after cerebral ischemia-reperfusion in rats

目的 研究缺血再灌注时大脑细胞Chk1基因表达及其调控机制。方法 从正常及不同缺血再灌注时点大鼠的大脑提取RNA ,采用半定量RT PCR法 ,图象经分析测出正常及各缺血再灌注时点大脑Chk1基因mRNA的相对水平。结果 在正常成年大鼠大脑皮质中 ,有一定量的Chk1基因的表达 ,约为GAPDH表达量的一半左右 ;脑缺血再灌注损伤对Chk1mRNA的表达有影响。在缺血 6 0min再灌注 6h ,Chk1mRNA表达明显下降 ,与对照组及其它组比较有显著差异。

Objective To investigate the gene expression of Chk1 gene in cerebrum after brain ischemia-reperfusion, trying to provide evidence to elucidate the molecular mechanism of brain injury.Methods Eighty-five male Wistar rats were divided into 3 groups.Group Ⅰ served as normal control.In group Ⅱ (non-ischemia group) animals underwent the whole experimental procedures except the occlusion of the bilateral vertebro-arteries and common carotid arteries.In group Ⅲ (ischemia-reperfusion group) animals were further divided into 3 subgroups according to the duration of ischemia: 10min, 30min and 60min.Each subgroup was again further divided based on the duration of reperfusion: 30min,2h and 6h.The cerebrum was immediately removed from rats after complete brain ischemia-reperfusion. The RNA was isolated and the reverse-transcription-polymerase chain reaction (RT-PCR) was carried out .The cDNA was analyzed by automatic system and the parameters were assessed to define the status of Chk1 mRNA expression in different ischemia and reperfusion groups.Results The quantity of Chk1 mRNA expression in the cerebral cortex of normal adult rat was about half of the glyceraldehyde-3-phosphate-dehydrogenase. When reperfused for 30min, 2h or 6h following 10min, 30 min cerebral ischemia and reperfused for 30min or 2h following 60 min cerebral ischemia, the expression of Chk1 mRNA was not significantly different from that in non-ischemia group.Only reperfused for 6h following 60 min cerebral ischemia, Chk1 mRNA expression decreased significantly.Conclusions The results indicate that Chk1 gene might be involved in molecular mechanism of cerebrum damage during complete global brain ischemia-reperfusion.