缺氧预适应和前胡丙素预处理对心肌受磷蛋白磷酸化水平的影响

目的探讨缺氧预适应和前胡丙素预处理对大鼠心肌受磷蛋白磷酸化水平的影响。方法体外培养的乳鼠心肌细胞随机分为4组:对照组,缺氧复氧损伤组(HR组)、缺氧预适应组(HP组)和前胡丙素预处理组(PP组)。用蛋白激酶A抑制剂H-89进行干预,4组再分别分为H-89阴性组和H-89阳性组。检测各组间细胞上清乳酸脱氢酶(LDH);流式细胞术检测[Ca2+]i;放射自显影法检测受磷蛋白的磷酸化水平。结果与对照组比较,HR组的LDH和[Ca2+]i显著升高(P<0.05),HP组和PP组LDH和[Ca2+]i虽高于对照组,但差异无统计学意义(P>0.05);HP组和PP组受磷蛋白磷酸化水平与对照组比较增加15.6%和16.8%(P<0.05),而HR组较对照组降低29.3%(P<0.05)。H-89阳性组受磷蛋白的磷酸化水平较H-89阴性组显著下调(P<0.05)。结论缺氧预适应和前胡丙素预处理对缺氧复氧损伤后心肌细胞有保护作用,该作用与上调受磷蛋白磷酸化水平有关。

Effects of hypoxia preconditioning and praeruptorin C preconditioning on phospholamban phosphorylation in rat cardiomyocytes

Objetive To explore the effects of hypoxia preconditioning and praeruptorin C preconditioning on phospholamban(PLB)phosphorylation in rat cardiomyocytes.Methods The neonatal rat cardiomyocytes were randomly divided into 4 groups:control group,the hypoxia preconditioning(HP)group,the praeruptorin C preconditioning(PP)group and the hypoxia-reoxygenation(HR)group.Each group was untreated or treated with protein kinase A inhibitor H-89(H-89 negative/positive group).The value of LDH of cellular supernatant was determined by automatic biochemistry analyzer.The fluorescence intensity of intracellular Ca 2 was detected with Fluo-3/AM loading by the flow cytometer.PLB phosphorylation was measured by radioautographic technique.Results Compared with the control group,the value of LDH and the fluorescence intensity of intracellular Ca 2 were significantly higher in HR group(P<0.05),but there was no significant difference between the HP group and the control group(P>0.05).Compared with control group,the value of PLB phosphorylation in HP and PP groups increased by 15.6% and by 16.8%(P<0.05),while the value in HR group significantly decreased by 29.3%(P<0.05).The value of phosphorylation in groups unreated with H-89 was significantly higher than that in the groups treated with H-89(P<0.05).Conclusions Cardioprotection induced by hypoxia preconditioning and praeruptorin C preconditioning against hypoxia-reoxygenation injury may be related with upregulating PLB phosphorylation.