失血性休克不同时相sorcin转位及其与血管反应性变化的相关性分析

The Translocation of Sorcin and the Correlating Analysis with the Changes of Vascular Reactivity after Hemorrhagic Shock

目的:观察失血性休克后不同时相大鼠肠系膜动脉平滑肌sorcin蛋白表达及其对去甲肾上腺素(NE)的反应性,初步探讨sorcin是否参与失血性休克血管反应性的调节。方法:36只SD大鼠,12只用作非手术对照组,其余采用经股动脉放血法制成失血性休克(动脉压40 mmHg)模型。分别将成模大鼠再分为休克早期(30min)组及晚期(2h)组;各组开腹分离肠系膜动脉,采用离体器官张力测定技术检测肠系膜动脉对NE的反应性;采用Western Blotting(WB)检测肠系膜动脉平滑肌sorcin的表达及其分布;采用免疫共沉淀联合WB检测sorcin-肌浆网2型雷诺定受体(RyR2)表达,并分析休克大鼠sorcin水平与肠系膜动脉对NE反应的相关性。结果:失血性休克早期组大鼠肠系膜动脉对NE的收缩反应较对照组明显增强(P<0.05),而晚期组对NE较对照组明显降低(P<0.05)。早期组和晚期组大鼠肠系膜动脉血管平滑肌sorcin总蛋白表达无显著差异(P>0.05),但发生了明显转位现象,即早期组sorcin在胞浆及质膜内表达无明显差异(P>0.05),但晚期组sorcin在胞浆内的表达明显增强,而在质膜的表达显著降低(均P<0.05);免疫共沉淀发现,早期组大鼠肠系膜动脉平滑肌sorcin-RyR2复合子表达与对照组无显著性差异(P>0.05),而晚期组较对照组明显减少(P<0.05);相关性分析显示,晚期组sorcin由质膜向胞浆移位与其血管反应性呈显著负相关(P<0.01)。结论:失血性休克后2h,大鼠肠系膜动脉平滑肌sorcin从RyR2解离,导致sorcin从肌浆网向胞浆转位,至少部分参与肠系膜动脉对NE低反应性的形成。

Objective：To explore the expression and distribution of sorcin in superior mesenteric artery（SMA）during different stage after hemorrhagic shock and its role in the regulation of vascular reactivity after hemorrhagic shock.Method：30SD rats were divided into two groups,twelve as a nonsurgical control group and the rest of the rats were classified as hemorrhagic shock model group that suffered from femoral artery bleeding method（arterial pressure is 40mmHg）.The model group rats were divided into the early stage of shock group（30min）and the late stage of shock group（2h）.Isolated mesenteric arteries were isolated from each group.The reactivity of mesenteric artery to NE was detected by using in vitro organ tension test.The expression and distribution of sorcin protein in mesenteric artery smooth muscle was detected by using Western Blotting（WB）.The expression of sorcin-RyR2 was detected by using Co-immunoprecipitation combined with WB.Then analyze the correlation between the level of sorcin protein and the reactivity of mesenteric artery to NE in the shock rats.Results：During the early stage（30min）after hemorrhagic shock,the vascular reactivity to NE increased significantly,while the vascular reactivity to NE decreased during late stage（2h）,which suggested that there was bi-phasic vascular reactivity to NE in SMA during different stage after hemorrhagic shock.The total expression of sorcin had no significant changes but the distribution of sorcin in cytoplasm and plasmalemma fraction of VSMC changed significantly,characterized with the expression of sorcin in cytoplasm and in plasmalemma had no significant changes during the early stage（30min）after hemorrhagic shock,while the expression of sorcin in cytoplasm fraction was upregulated but its expression in plasmalemma fraction decreased significantly during the late stage（2h）after hemorrhagic shock.Immunoprecipitation analysis showed that formation of sorcin-RyR2 complex decreased during the late stage but not during the early stage after hemorrhagic shock.The correlation analysis showed that the increased expression of sorcin in cytoplasm closely associated with the blunted vascular hyporeactivity to NE during the late stage after hemorrhagic shock.Conclusion：At late stage after hemorrhagic shock,sorcin translocated from cytoplasm to plasmalemma in superior mesenteric artery in rat.The dissociation of sorcin from RyR2 at least partly associated with the development of vascular hyporeactivity to NE during the late stage after hemorrhagic shock.