多聚(ADP-核糖)聚合酶不同时空的表达特征对缺血性脑损伤细胞修复的影响

Different spatio-temporal expression of poly(ADP-ribose) polymerase for repair ing the cells after ischemic brain injury

目的:研究局灶性脑缺血再灌注后多聚(ADP-核糖)聚合酶(PARP)表达的时空变化及其作用。方法:采用改良线栓法建立大鼠大脑中动脉缺血再灌注模型(MCAO-R,)运用免疫组织化学方法检测PARPM116000),PARP(r(Mr24000)和caspasse-3表达的时空变化,苏木精-伊红染色观察组织病理变化。结果:脑缺血2h再灌注12h,PARP(M116000)及caspase-3表达增r多,且随再灌时间的延长而表达逐渐增多(P<0.05),并向四周动态扩展。缺血3h组PARP(M116000)蛋白阳性表达也增强,但表达程度与r缺血2h组相比略有下降,在再灌注3d时表达最少。缺血6h组PARP(M116000)蛋白表达减少,且不随再灌注时间的延长而有明显变化。r而PARP(M24000)蛋白在缺血2h再灌注12h阳性表达增加,但不r随缺血时间及再灌注时间的延长而明显变化,呈平稳的低水平表达,与caspase-3的变化趋势也无相关性。结论:在脑缺血再灌注损伤中PARP活化的主要损伤作用是坏死而非凋亡。

AIM:To observe the spatio temporal changes and effects of the expression of p oly(ADP ribose) polymerase(PARP) after focal cerebral ischemia and reperfusion injury. METHODS:Reversible middle cerebral artery occlusion was performed with modifie d Koizumi's model.The spatio temporal changes in the expressions of PARP(Mr 116 000),PARP(Mr 24 000) and caspase 3 were investigated with immuno histochemist ry.The pathological changes were evaluated with hematoxylin and eosin staining. RESULTS:After two hour ischemia and 12 hour reperfusion, the expression of P ARP(Mr 116 000) and caspase 3 increased,which gradually increased with the prol ongation of reperfusion time(P< 0.05),and dynamically expanded around. The expre ssion of PARP(Mr 116 000) positive protein,which was at the lowest level three d ays after reperfusion, increased after three hour ischemia,but slightly decreas ed as compared with that after two hour ischemia.The expression of PARP(Mr 116 000) protein decreased 6 hours after ischemia, however,it had no obvious changes with the prolongation of reperfusion.Moreover,the positive expression of PARP(M r 24 000) protein increased after two hour ischemia and 12 hour reperfusion,an d did not change with the prolonged ischemia and reperfusion time, keeping a low level expression stably,and it had no correlation with caspase 3. CONCLUSION:PARP activation is involved in cell necrosis rather than apoptosis during ischemic reperfusion injury.