周期素依赖激酶抑制剂对大鼠大脑中动脉缺血后海马迟发性神经元死亡的影响

 目的探讨细胞周期素依赖激酶(CdK)抑制剂--olomoucine对大鼠局灶性脑缺血再灌流后海马迟发性神经元死亡的影响。方法 给予大脑中动脉阻塞再灌流大鼠腹腔注射olomoucine,观察再灌流后3,7 d皮层损伤侧海马半胱氨酰天冬氨酸特异性蛋白酶-3(caspase-3)和增殖细胞核抗原(PCNA)蛋白的表达水平;同时,应用免疫组织化学方法测定再灌流后3,7d皮层损伤侧海马CAl区神经元细胞核特异性抗原(NeuN)的表达。结果olomoucine能明显抑制大鼠局灶性脑缺血再灌流后海马PCNA蛋白的表达(P＜0.01),降低caspase-3水平(P＜0.01);同时显著减少了海马CAl区神经元的丢失(P＜0.01)。结论研究表明,olomoucine通过抑制细胞增殖活动、减少caspase-3生成,从而降低局灶性脑缺血再灌流后海马迟发性神经元死亡的发生。

Effects of cyclin-dependent kinase inhibitor on delayed neuronal death of hippocampus in rats after MCA occlusion

OBJECTIVE To explore the effects of olomoucine, a selective inhibitor of cyclin-dependent kinase (CdKs) , on delayed neuronal death of hippocampus in rats following focal cerebral ischemia . METHODS Ischemia/reperfusion injury was induced by temporary middle cerebral artery occlusion (MCAO). Olomoucine (4 mg·kg^-1) was administered immediately and 24 hours after MCAO. In the ipsilateral hippocampus of rats at 3 and 7 days of reperfusion, the expression levels of proliferating cell nuclear antigen (PCNA) and caspase-3 were analyzed by Western blot analysis. The localization of nuclear neural specific antigen (NeuN) in the ipsilateral hippocampal CA1 at 3 and 7 days of reperfusion was assessed by immunohistochemistry. RESULTS Western blot analysis of hippocampus extracts of olomoucine-treated animals showed a decrease in the expression of caspase-3 and PCNA at 3 and 7 days of reperfusion compared with control animals(P<0.01). The number of cells labelled with NeuN in hippocampus was significantly reduced at 7 days of reperfusion in control animals as compared with olomoucine treated animals(P<0.01). CONCLUSIONS These results suggested that olomoucine could reduce delayed neuronal death of hippocampus through modulating CDKs and downregulating the expression of caspase-3 and PCNA.