热休克蛋白70入核转位参与缺血再灌注损伤的脱氧核糖核酸修复的实验研究

Heat shock protein 70 in nuclear translocation involved in DNA repair during ischemia-reperfusion injury

目的观察肝脏缺血再灌注损伤条件下HSP70改变细胞周期动力学影响的核机制。方法雄性SD大鼠随机分为5组:HSP70抑制组(H-/P+组)、热休克组(H+/P+组)、PARP-1蛋白抑制组(H+/P-组)、缺血再灌注组(PC组)、阴性对照组(NC组)。造模成功后取肝脏组织免疫组化染色检测PARP-1的表达;提取核蛋白,免疫共沉淀法检测HSP70与PARP-1的结合;免疫荧光组织化学双染法显示HSP70与CyclinD1的表达时间点。结果NC组与其他组比较PARP-1的表达低(P<0.01);免疫共沉淀提示HSP70进入细胞核中与PARP-1结合;免疫荧光组织化学双染显示HSP70回归胞质的时间点在IR1-2h与CyclinD1出现时间一致。结论可复性肝脏缺血再灌注损伤,HSP70进入细胞核与PARP-1结合,对于G2/M期进行负调控,抑制细胞进行DNA复制重组,阻滞其进入有丝分裂,修复受损DNA链;缺血再灌注对于G1/S期进行正调控,促进肝细胞再生和肝脏功能代偿。

Objective To explore the mechanism of HSP70 on cell cycle regulation in hepatic IR(ischemia - reperfusion) injury. Methods SD rats were randomly divided into HSP70 inhibitor group (H-/P+ ),heat shock group (H+ /P+ ),PARP-1 inhibitory group (H+ /P-),IR group (PC) and negative control group (NC),respectively.After the IR model was induced,the liver specimen underwent IHC staining to observe the changes of the PARP-1 expression;Co-immunoprecipitation was used to detect the binding of HSP70 with PARP-1. Results H+ /P-was significantly different from H+ /P+ ,H-/P+ ,PC,NC (P<0.01);Immunoprecipitation suggested that HSP70 entered into the nucleus to bind PARP-1,and immunofluorescence imaging analysis demonstrated both HSP70 and CyclinD1 expressed at the same timeline. Conclusion Under reversible hepatic ischemia-reperfusion injury,HSP70 enters the nucleus and binds to PARP-1,negatively regulates G2/M phase,blocks cells for DNA replication and recombination,blocks its entry into mitosis,repairs damaged DNA chain;Liver ischemia-reperfusion positively regulates the G1/S phase,promoting hepatocyte regeneration and liver function compensation.