p38MAPK信号通路在钙调磷酸酶促心肌凋亡中的作用

Effects of p38 MAPK signal pathway on myocardium apoptosis mediated by calcineurin

目的:探讨钙调磷酸酶(CaN)在缺氧/复氧和肾上腺素能刺激诱导心肌凋亡中的作用及p38MAPK在CaN调节心肌凋亡中的作用。方法:采用体外培养新生Wistar大鼠心肌缺氧/复氧(H/R)模型,模拟在体缺血再灌注损伤,将心肌细胞随机分为3组:正常对照组(N组)、H/R+异丙基肾上腺素组(Ao组)、H/R+异丙基肾上腺素+环孢菌素A组(A1组)。采用流式细胞仪检测细胞凋亡,RT-PCR检测CaN mRNA的表达,Western免疫印迹法检测CaN及p38MAPK、p-p38 MAPK蛋白表达。结果:H/R和异丙基肾上腺素(Iso)共同作用心肌后,心肌细胞凋亡率明显增加,给予CaN抑制剂环孢菌素(CsA)后,细胞凋亡率显著少于干预前(P<0.05)。H/R和Iso共同作用下,心肌CaN mRNA及蛋白表达水平均明显上调,同时p38 MAPK的活化状态p-p38 MAPK蛋白表达也显著增加,CsA干预后,CaN表达并无明显变化,但p-p38 MAPK蛋白表达显著减少(P<0.05)。结论:CaN促进缺氧/复氧和肾上腺素能刺激诱导心肌细胞凋亡,可通过活化p38 MAPK而发挥促凋亡的作用。

AIM： To explore the effect of calcineurin （CaN） on the myocardium apoptosis induced by hypoxia/reoxygenation （H/R） and adrenergic stimulation and the influence of p38 MAPK on myocardium apoptosis mediated by CaN. METHODS ： Primary cultures of cardiac myocytes were prepared from ventricles of 3 - day olds Wistar rats, which were disposed with isoproterenol （Iso, 10 μmol/L） and H/R （24 h/4 h）. The cultured myocardium cells were divided into three groups randomly： normal group （N）, H/R ＋Iso group and H/R ＋Iso ＋ cyclosporin A （CsA, 500 μg/L, CaN inhibitor） group. The rate of the cardiac myocyte apoptosis was evaluated by flow cytometry. The level of CaN mRNA was measured by reverse transcription - polymerase chain reaction （ RT - PCR） and the levels of CaN, p38MAPK and p - p38 protein were determined by Western blotting. RESULTS： After H/R and Iso stimulating, the rate of cardiac myocytes apoptosis was increased obviously. The rate of apoptosis was decreased after CsA added. Pretreatment of cardiac myocytes with H/R and Iso stimulated CaN mRNA and protein expression. The expression of p - p38MAPK protein was also increased. However, interference of CsA inhibited p - p38MAPK protein expression and no significant change was observed in CaN mRNA and protein expression. CONCLUSION： CaN has the promoting effect on the cardiac myocyte apoptosis induced by H/R and Iso. Activated p38 MAPK might be involved in the course of pro - apoptotic effect of CaN.