HSP25对小鼠心肌缺血-再灌注所致肌动蛋白损伤的保护作用

PROTECTIVE EFFECTS OF HSP25 ON DAMAGE OF ACTIN DURING MYOCARDIAL ISCHEMIA-REPERFUSION IN MICE

目的 :观察肌动蛋白在小鼠心肌缺血 -再灌注损伤时的改变及小分子热休克蛋白HSP2 5和热休克预处理对其的保护作用。方法 :Langendorff离体小鼠心脏经缺血 30min再灌注 4 5min后 ,采用免疫双荧光标记 -激光共聚焦显微技术观察肌动蛋白和HSP2 5的改变 ;采用Westernblot检测HSP2 5对H2 O2 所致心肌组织肌动蛋白沉淀的影响 ;采用电镜、免疫双荧光标记 -激光共聚焦显微镜、MDA测定及Westernblot检测热休克预处理对小鼠心肌缺血再灌注损伤的保护作用。结果 :缺血 -再灌注导致心肌组织肌动蛋白排列紊乱、溶解及聚集 ;HSP2 5从胞浆向肌动蛋白骨架移位 ,并分布于受损肌动蛋白形成的聚集体中 ,两者形成“共分布” ;热休克预处理诱导心肌HSP2 5表达增加 ,并可明显减轻缺血 -再灌注所致的肌动蛋白损伤 ;蛋白质体外实验证实纯化的外源性HSP2 5可使H2 O2 所致肌动蛋白变性沉淀重新解聚复性为可溶性蛋白质。结论 :肌动蛋白是心肌缺血 -再灌注时受损的重要靶蛋白之一 ;HSP2 5对缺血 -再灌注所致肌动蛋白损伤的保护可能是心肌内源性保护的重要机制之一。

Objective:To observe the effect of HSP25 on myocardial actin damage induced ischemia-reperfusion(I/R) in isolated langendorff hearts of mice.Method:Double immunofluorescence labeling-confocal microscopy showed the changes of actin and HSP25 during myocardial I/R; Western blot showed the effect of HSP25 on myocardial actin precipitation induced by H 2O 2: Electronic microscopy, double immunofluorescence labeling-confocal microscopy, MDA levels and western blot showed the effect of heat shock pretreatment on myocardial I/R. Result: I/R caused disarrangment and aggregation of myocardial actin. I/R also caused translocation of HSP25 from cytoplasm to actin filament and colocalized with the aggregates of actin. Heat shock pretreatment induced expresstion of myocardial HSP25 and alleviated actin damage which caused by ischemia-reperfusion obviously. Purified exogenous HSP25 promoted re-solubilization of myocardial actin induced by H 2O 2.Conclusion:It is demonstrated that myocardial actin is one of important target proteins insulted by I/R and HSP25 is involved in the endogenous protective mechanisms of heart against myocardial I/R injury.