TNF-α对培养乳鼠心肌细胞的作用

Effect of TNF-α on cultured neonate cardiomyocytes

目的:探讨不同浓度肿瘤坏死因子-α(TNF-α)对培养的乳鼠心肌细胞活力、蛋白合成、分泌AngⅡ及AT1受体表达的影响。方法:体外培养的SD乳鼠心肌细胞随机分为对照组和不同浓度TNF-α(20、40、60、80、100μg/L)干预组,用BCA法测定心肌细胞蛋白合成总量,MTT比色法和LDH检测反映心肌细胞的活力,ELISA法检测心肌细胞培养液中AngⅡ的含量,免疫细胞化学染色法检测心肌细胞膜AT1受体表达的变化。结果:TNF-α浓度依赖性地增强乳鼠心肌细胞活力、增加蛋白合成,20、40、60、80μg/L TNF-α组细胞活力较对照组分别增加1.21(P<0.05)、1.42、1.51和1.73倍(均P<0.01),蛋白合成分别增加27.8%(P<0.05)、38.9%、46%和66.7%(均P<0.01),而LDH含量差异无显著性。100μg/L TNF-α组与对照组比较,心肌细胞活力降低18.5%(P<0.01)、蛋白合成降低18.3%(P<0.01)及心肌LDH生成增加1.48倍(P<0.01)。TNF-α浓度依赖性地增加乳鼠心肌细胞AngⅡ分泌,与对照组比较分别增加0.5、1.1、1.6、3和3.6倍(均P<0.01)。TNF-α还具有诱导AT1受体的表达的作用。结论:TNF-α可促进心肌细胞内源性AngⅡ产生,引起心肌细胞活力、蛋白合成改变,AT1受体表达上调,可能介导了心肌肥大、心肌受损等心肌改建的病理生理过程。

To explore the effects of TNF-α of different concentrations on cardiomyocyte vitality, protein synthesis, AngII secretion and AT1 receptor expression. METHODS： Cardiomyocytes were primarily cultured in Sprague Dawley neonate rats. Protein and cell vitality of myocytes were determined, respectively, by BCA method and MTr and LDH assay. Content of Ang II in cell culture fluid was detected by enzyme-linked immunosorbent assay and expression alteration of AT1 receptor in myocytes was examined by immunocytochemical assay. RESULTS： TNF-α promoted AngII secretion in cardiomyoeytes in a con- centration-dependent manner. Low concentrations of TNF-α increased cell viability and promoted protein synthesis and AT1 receptor expression in myocytes. High concentrations of TNF-α induced myocyte injury. CONCLUSION： TNF-α promotes the secretion of Ang II in myocytes and is involved in cardiac remodeling.