葛根素对大鼠肝缺血再灌注损伤脑组织c-fos和Bcl-2表达的影响

目的：观察肝缺血再灌注损伤时c-fos、Bcl-2与脑细胞凋亡的关系及葛根素对其影响的可能机制。方法：建立肝缺血再灌注损伤动物模型。选健康雄性SD大鼠56只,随机分为对照组、缺血30min组（I组）、缺血30min即刻再灌注组（I/R组）、缺血30min再灌注1h组（I/R1h）、缺血30min再灌注2h组（I/R2h）、30min再灌注4h组（I/R4h）及葛根素预处理组（PUE＋I/R4h组）,每组8只。观缺血察各组肝、脑HE染色;应用免疫组织化学方法测定各组大鼠脑组织c-fos、Bcl-2的表达;应用原位细胞凋亡法测定脑细胞凋亡。结果：I/R2h组、I/R4h组肝组织中散在分布大量炎症细胞,肝细胞明显肿胀,有的呈空泡状变性,肝脏结构紊乱;PUE＋I/R4h组上述改变明显改善。I/R2h、I/R4h组脑组织水肿明显,PUE＋I/R4h组明显改善。与对照组比较,其余各组脑组织c-fos表达均增高﹙P〈0.01）,I/R4h组水平最高,PUE＋I/R4h组较I/R1h组、I/R2h组、I/R4h组明显降低（P〈0.01）。与对照组比较,其余各组脑组织Bcl-2表达增高（P〈0.01）,I/R4h组与I/R2h组差异无统计学意义﹙P〉0.05）,PUE＋I/R4h组较对照组、组表达增多（P〈0.01）,较I/R1h组、I/R2h组、I/R4h组明显降低（P〈0.01）。I组、I/R组细胞I凋亡指数较对照组明显增加（P〈0.01）,随着再灌注时间的延长细胞凋亡指数逐渐增加。PUE＋I/R4h组较I/R2h组、I/R4h组明显降低（P〈0.01）。结论：肝缺血再灌注损伤可引起脑组织的损伤及脑细胞凋亡。随着再灌注时间的延长,脑组织中c-fos表达增高,脑细胞凋亡与c-fos的表达有关。Bcl-2在缺血期发挥了抑凋亡的作用,随着再灌注时间的延长,其作用减弱,脑细胞凋亡指数增加。葛根素可能通过抑制c-fos的表达、增加Bcl-2的表达发挥减轻肝缺血再灌注损伤所致脑细胞凋亡的作用。

Effect of puerarin on the expression of c-fos protein and Bcl-2 protein in brain tissue following liver schemia-reperfusion injury in rats

Objective：To observe the changes of c-fos protein and Bcl-2 protein in brain tis sue following liver ischemia-reperfusion injury and evaluate the contribution of two factors to brain cell apoptosis,to explore the effects of puerarin on the injury mechanisms.Methods：A model of liver ischemia-reperfusion injury was established by imitation.56 healthy rats were randomly divided into 7 groups as following（n=8）：the control group（the group of sham operation）,simply ischemia 30 min without reperfusion（I group）,reperfusion following ischemia 30 min（I/R group）,1 hour reperfusion following ischemia 30 min（I/R 1 h group）,2 hour reperfusion following ischemia 30 min（I/R 2 h group）,4 hour reperfusion following ishcemia 30 min（I/R 4 h group）,and puerarin pretreat ment group（PUE＋I/R 4 h）.Liver and brain tissue were observed by HE staining.The expressions of c-fos protein and Bcl-2 protein in brain tissue were examined individually by immunohistochemical technique in each group.The changes of brain cell apoptosis were measured by TUNEL labelling technique.Results：Liver ischemia/reperfusion induced the remarkable brain cell injury.The con tents of c-fos protein and Bcl-2 protein increased in I group and reached to the peak in I/R 4 h group（P0.01）.The index of apoptosis in brain cells showed increasing during different phase of liver is chemia-reperfusion injury（P0.01）.The injury of brain cell in PUE＋ I/R 4 h group was less than that of I/R 2 h group and I/R 4 h group（P0.01）.Conclusion：The injury of brain tissue and brain cell apoptosis might be induced following the process of liver ischemia/reperfusion injury.c-fos showed increasing and might be involved in the mechanism of liver cell apoptosis.Bcl-2 could play the role in anti-liver cell apoptosis during the period of liver ischemia-reperfusion.Puerarin pretreatment had an protect effect on brain injury by restraining expressions of c-fos protein and increasing contents of Bcl-2 protein at hepatic isehemia reperfusion.