钙调磷酸酶在β肾上腺素能刺激诱导心肌凋亡中的作用

Effect of calcineurin on myocardial apoptosis through beta-adrenergic stimulation

目的:探讨钙调磷酸酶(calcineurin,CaN)在β肾上腺素能刺激诱导的心肌凋亡中的作用及其机制。方法:将原代培养的乳鼠心肌细胞随机分为6组:正常对照组(N组),Iso组(A组),β1受体拮抗剂-比索洛尔组(B组),β2受体拮抗剂-ICI11851组(C组),α1受体拮抗剂-哌唑嗪组(D组),β、α1受体拮抗剂-卡维地洛组(E组)。B、C、D、E组在A组基础上分别给予上述药物,终浓度分别为10μmol/L、0.1μmol/L、0.1μmol/L、50μmol/L。流式细胞仪和DNALadder测定各组心肌细胞凋亡的情况,RT-PCR检测CaNmRNA的表达水平。结果:A、B、C、D、E与N组相比,细胞凋亡率升高(P<0.05),并有CaNmRNA表达;B、E组与A组比较,细胞凋亡率分别降低30.12%,44.55%(P<0.01),并且CaNmRNA相应表达下降,差异有显著性(P<0.05),而对D组来说,凋亡率及CaNmRNA却有所增加(P<0.05),C组与A组相比变化无显著性。结论:β肾上腺素能刺激诱导心肌凋亡作用主要通过β1受体介导,伴随CaN表达升高,β1受体阻断剂使其表达降低,说明CaN参与了β1受体介导的心肌凋亡,有促凋亡的作用,为临床应用β-受体阻断药提供了新的理论依据。

Objective To investigate the effect and mechanism of calcineurin (CaN) on the apoptosis of cardiac myocytes through beta adrenergic stimulation. Methods Primary cultured neonatal rat myocardial cell were randomly divided into six groups: normal control group(N), isoproterenol group(A), bisoprolol group(B), ICI11851 group(C), prazosin group(D) and carvedilol group(E). B,C, D and E groups were added to the corresponding drug on the basis of A group (10 μmol/L bisoprolol, 0.1 μmol/L ICI11851, 0.1 μmol/L prazosin, 50 μmol/L carvedilol), respectively. The apoptotic rate of myocardium was determined by flow cytometry and DNA Ladder. The expression level of CaN mRNA was evalued by RT PCR. Results Compared with normal group, apoptotic rate and CaN mRNA increased significantly (P< 0.05). Compared with A group, apoptotic rate in B and E group lowered by 30.12%and 44.55%(P< 0.01) respectively; the level of CaN mRNA reduced significantly (P< 0.05). However in D group apoptotic rate and CaN mRNA increased significantly(P< 0.05),there was no difference between C and A group(P >0.05). Conclusion β adrenergic stimulation can lead to the myocardial apoptosis. The effect is mediated by β1 adrenergic receptor. The level of CaN mRNA is on the rise in the myocardial apoptosis. β adrenergic receptor antagonist lowers the level of CaN mRNA. It suggest that CaN has pro apoptotic effect on the cardiac myocytes and that the new academic proof was provided for the clinical use of β adrenergic receptor antagonist.