mitoKATP和肌浆网钙ATP酶在预适应心肌保护中的相关性研究

目的探讨肌浆网钙ATP酶在心肌细胞缺血预适应及腺苷预适应中的作用以及其与mitoKATP开放的相关性。方法原代培养的新生SD大鼠心肌细胞,随机分为6组:正常培养组、缺氧/复氧损伤组、缺血预适应组、腺苷预适应组、5-HD(mitoKATP阻断剂)+缺血预适应组、5-HD(mitoKATP阻断剂)+腺苷预适应组。测定各组细胞上清中LDH的释放量,细胞存活指数及肌浆网钙ATP酶活性。结果缺血预适应组与缺氧复氧组比较,LDH的释放显著下降(P<0.01),存活指数明显上升(P<0.01),肌浆网钙ATP酶活性提高(P<0.01)。腺苷预适应组与缺氧复氧组比较,LDH的释放显著下降(P<0.01),存活指数显著上升(P<0.01),肌浆网钙ATP酶活性无明显提高(P>0.05)。5-HD+缺血预适应组较缺血预适应组LDH释放增多(P<0.05),细胞存活指数下降显著(P<0.01),肌浆网钙ATP酶活性下降(P<0.01)。而5-HD+腺苷预适应组较腺苷预适应组LDH释放无明显改变(P>0.05),细胞存活指数下降不显著(P>0.05),肌浆网钙ATP酶活性下降不明显(P>0.05)。结论肌浆网钙ATP酶与mitoKATP开放均参与了缺血预适应早期相的保护作用,且2者之间的作用具有相关性。但腺苷预适应的心肌保护作用与肌浆网钙ATP酶与mitoKATP开放无明显相关性。

Correlations between of mitoKATP and SR Ca2+-ATPase in cardiomyocyte protection of preconditioning

Objective To investigate the role of Ca2+-adenosine triphosphatase(ATPase) of sarcoplasmic reticulum(SR) in the protection of hypoxia preconditioning on myocardiocytes and its correlation to the opening of mitochondrial ATP-sensitive K+ channel(mitoKATP).Methods The primary cultured neonatal Rat cardiomyocytes were divided into six groups: ① normal control ② hypoxia/reoxygenation(H/R) group;③ hypoxia Preconditioning(HPC) group;④ adenosine preconditioning group;⑤ 5-HD(inhibitor of mitoKATP) plus hypoxia preconditioning group;⑥ 5-HD plus adenosine preconditioning group.The LDH release,cell viability and activity of Ca2+-ATPase of sarcoplasmic reticulum in each groups were measured.Results Compared with H/R group,The LDH release in HPC group decreased remarkably(P<0.01),myocytes viability in HPC group increased(P<0.01) and the activity of SR Ca2+-ATPase increased significantly(P<0.01).The LDH release in adenosine preconditioning group decreased remarkably(P<0.01),and myocytes viability in HPC group increased(P<0.01),however,the activity of SR Ca2+-ATPase did not increase significantly(P>0.05).In 5-HD plus HPC group,compared with HPC group,the LDH release increased(P<0.05).and myocytes viability and the activity of SR Ca2+-ATPase decreased(P<0.01).5-HD plus adenosine preconditioning group,compared with adenosine preconditioning group,the LDH release did not increase(P>0.05) and myocytes viability and the activity of SR Ca2+-ATPase did not decrease(P>0.05).Conclusion The Ca2+-ATPase of SR and mitoKATP may be involved in the protection mechanism of early hypoxia preconditioning,and there may be relativity in the two factors.However,there may be no relativity in adenosine preconditioning with Ca2+-ATPase of SR and mitoKATP.