右美托咪定对心肌细胞收缩相关蛋白表达的影响及机制研究

Effect of dexmedetomidine on expression of contraction related proteins in cardiomyocytes and its mechanism

目的研究右美托咪定对心肌细胞缺氧损伤后收缩蛋白表达的影响及其分子机制。方法采用低氧培养H9c2细胞建立心肌细胞缺氧损伤。实验分为空白对照组、低氧培养组、低氧+右美托咪定低剂量(0.01μmol/L)组、低氧+右美托咪定中剂量(1μmol/L)组、低氧+右美托咪定高剂量(100μmol/L)组。除空白对照组外,其余各组细胞培养在50 ml/L浓度氧环境下。采用MTT法测细胞存活率,流式细胞仪检测细胞凋亡水平,ELISA检测培养液中cTnI、LDH和CK-MB水平,Western blot法检测titin、β-MHC、PI3K、Akt、p-PI3K、p-Akt蛋白表达。结果与空白对照组相比,低氧培养组细胞存活率降低、凋亡增加,培养液中心肌酶谱蛋白水平增加(均P<0.01)。与低氧培养组比较,低氧+右美托咪定各剂量组细胞存活率增加,细胞凋亡降低,心肌酶谱蛋白水平降低(P<0.05或P<0.01);Western blot结果显示,与低氧培养组比较,低氧+右美托咪定各剂量组p-PI3K、p-Akt表达增加,titin、β-MHC表达降低(均P<0.05),并具有剂量依赖性。结论右美托咪定抑制缺氧损伤心肌细胞中收缩蛋白表达,其机制是否与激活PI3K/Akt信号通路有关有待进一步研究。

AIM To investigate the effect of dexmedetomidine on the expression of contraction protein in hypoxia-treated cardiomyocytes and its molecular mechanism.METHODS H9c2 cells were cultured with hypoxia to establish hypoxic injury.The cells were divided into blank control group,hypoxia culture group,hypoxia+dexmedetomidine low dose(0.01μmol/L)group,hypoxia+dexmedetomidine medium dose(1μmol/L)group,and hypoxia+dexmedetomidine high dose(100μmol/L)group.Except for those in the blank control group,the cells in other groups were cultured in 50 ml/L oxygen environment to establish a cell hypoxia injury model.MTT method was used to measure cell survival rate,flow cytometry was used to detect apoptosis level,ELISA was used to detect cTnI,LDH and CK-M levels in culture medium and Western blot was used to detect the expressions of titin,β-MHC,PI3K,Akt,p-PI3K and p-Akt protein.RESULTS Compared with those in the normal control group,the cell survival rate was decreased and apoptosis and the level of myocardial zymogram protein were increased in hypoxic culture group(P<0.01).Compared with those in the hypoxic culture group,the cell survival rate was increased(P<0.05,P<0.01)and apoptosis and the myocardial zymogram protein level in the hypoxic+dexmedetomidine groups were decreased(P<0.05,P<0.01).Western blot showed that compared with those in the hypoxic culture group,the expressions of p-PI3K and p-Akt were increased,while the expressions of titin andβ-MHC were decreased in a dose-dependent manner in dexmedetomidine-treated H9c2 cells under hypoxic condition(P<0.05).CONCLUSION Dexmedetomidine inhibits contractile protein expression in hypoxia-injured cardiomyocytes,and whether the mechanism is related to activation of PI3K/Akt signaling pathway needs further study.