细胞内钙调控剂对心肌细胞生长的作用

Effect of intracellular calcium regulation on the growth of cultured cardiomyocytes

目的 探讨干预细胞内钙 ([Ca2 + ]i)对心肌细胞生长和钙调神经磷酸酶 (calcineurin ,CaN)信号通路的作用。方法 原代乳鼠心肌细胞培养 ,应用免疫印迹 (westernblot)检测心肌细胞CaN蛋白表达。心肌细胞蛋白质、核酸合成速率分别用氚 亮氨酸 (3 H Leu)、氚 胸腺嘧啶 (3 H TdR)掺入量测定 ;环孢素A(CsA)抑制CaN信号通路 ,血管紧张素Ⅱ (AngⅡ )、雷尼丁 (RY)和三磷酸肌醇 (IP3 )干预心肌细胞 [Ca2 + ]i。结果 AngⅡ、RY和IP3 明显增加心肌细胞CaN蛋白表达并提高3 H Leu、3 H TdR的掺入量。提高的3 H Leu、3 H TdR掺入量在一定范围内呈量效和时间依赖关系 ,各刺激组与对照组相比差异有显著性 (P <0 .0 5或 <0 .0 1)。RY 10 -6mol/L刺激心肌细胞蛋白核酸合成速率最高 ;环孢素A可抑制AngⅡ引起的3 H Leu、3 H TdR掺入量增加。结论 干预细胞 [Ca2 + ]i对心肌细胞蛋白及核酸合成有明显影响 ;心肌细胞CaN蛋白表达及生长似与细胞 [Ca2 + ]i变化有明显关系而与其来源无关 ,阻断CaN能有效地抑制心肌细胞生长 。

Objective To investigate the effects of intracellular calcium ([Ca 2+ ]i) regulation on the growth of cultured cardiomyocytes and calcineurin (CaN) dependent signaling pathway. Methods CaN expression was measured by western blot in primary cultured cardiomyocytes from Wistar rat. The incorporation of 3H Leucine ( 3H Leu) and 3H Thymidine ( 3H TdR) determined the synthesis rates of protein and DNA respectively. Cyclosporine A (CsA) was used to inhibit the CaN dependent signaling pathway. Angiotension Ⅱ (AngⅡ), ryanodine (RY), inositol(1,4,5) trisphosphate (IP 3) were applied to modulate the [Ca 2+ ]i. Results AngⅡ, Ry and IP 3 increased CaN expression and 3H Leu, 3H TdR incorporation in cultured cardiomyocytes copmpared with control ( P <0.05 or <0.01). The promoted 3H Leu and 3H TdR incorporation was in concentration and time dependent manner. The highest velocity of 3H Leu and 3H TdR incorporation could be obtained by RY(10 -6 mol/L). CsA considerably inhibited the AngⅡ induced 3H Leu, 3H TdR incorporation in cultured cardiomyocytes. Conclusion The growth of cardiomyocytes is associated with the changes of cellular [Ca 2+ ]i, but not with its resource. Inhibition of CaN reduced the growth of cardiomyocytes effectively, indicating that CaN signaling pathway plays an important role in the growth of cardimyocytes.