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目的研究肿瘤坏死因子α(TNF-α)对心肌细胞内钙离子浓度([Ca2+]i)的影响以及Ca2+信号在TNF-α诱导心肌细胞肥大中的作用。方法 TNF-α刺激原代培养的心肌细胞,细胞内钙离子螯合剂BAPTA或L型Ca2+通道阻断剂维拉帕米阻断钙信号通路,通过Lowry法测蛋白含量;[3H]亮氨酸掺入法测蛋白合成;计算机图像分析系统测细胞体积;Till阳离子测定系统观察胞内[Ca2+]i瞬变。结果①TNF-α(10、20、50、100μg/L)呈浓度依赖性诱导心肌细胞蛋白含量、蛋白合成和体积的增加;胞内Ca2+螯合剂BAPTA明显抑制TNF-α诱导的心肌细胞肥大,但L型Ca2+通道阻断剂维拉帕米对其无明显影响。BAPTA对正常心肌细胞生长无显著影响。②TNF-α(10、20、50、100μg/L)呈浓度依赖性引起[Ca2+]i瞬变增高。BAPTA明显抑制TNF-α诱导的心肌[Ca2+]i瞬变升高,维拉帕米对其无明显影响。结论 TNF-α在10～100μg/L浓度范围内呈浓度依赖性升高心肌[Ca2+]i以及诱导心肌肥大。[Ca2+]i升高在TNF-α诱导心肌肥大中具有重要作用,但与L型Ca2+通道开放无关。
Objective To investigate the effect of tumor necrosis factor α (TNF-α) on intracellular calcium concentration ([Ca2 +] i) and the role of Ca2 + in TNF-α-induced cardiomyocyte hypertrophy. Methods TNF-α stimulated primary cultured cardiomyocytes, verapamil, an intracellular Ca2 + chelator BAPTA or L-type Ca2 + channel blocker, and detected protein content by Lowry method; [3H] leucine Incorporation assay to measure protein synthesis; computerized image analysis system to measure cell volume; Till cation assay system to observe intracellular [Ca2 +] i transients. Results ①TNF-α (10, 20, 50, 100μg / L) induced a significant increase of protein content, protein synthesis and volume in cardiomyocytes in a concentration-dependent manner. BAPTA, an intracellular Ca2 + chelator, significantly inhibited cardiomyocyte hypertrophy induced by TNF- L-type Ca2 + channel blocker verapamil had no significant effect. BAPTA had no significant effect on normal cardiomyocyte growth. ② TNF-α (10,20,50,100μg / L) induced a [Ca2 +] i transient increase in a concentration-dependent manner. BAPTA significantly inhibited TNF-α induced myocardial [Ca2 +] i transient increase, verapamil had no significant effect. Conclusions TNF-α can increase myocardial [Ca2 +] i and induce cardiac hypertrophy in a concentration-dependent manner in the range of 10 ~ 100μg / L. Elevated [Ca2 +] i plays an important role in TNF-α-induced cardiac hypertrophy but not with L-type Ca2 + channels.