【摘要】 目的探讨心脏营养素-1(CT-1)对培养乳鼠心肌细胞存活的促进作用以及丝裂原激活蛋白激酶(MAPK)信号传导途径在CT-1促进心肌细胞存活中的作用。方法差速贴壁纯化培养新生大鼠心肌细胞,MTT比色法测定各孔细胞存活率。结果无血清DMEM培养心肌细胞24 h后,加入4个剂量组CT-1(10-10~10-7mol/L),呈明显剂量依赖性增加MTT计数;培养基中加入CT-1(10-8mol/L),1、2、3和4 d MTT计数呈明显的时间依赖性增加;预先用MAPK抑制剂PD098059(5×10-5mol/L),再加入CT-1,心肌细胞存活率明显低于单纯CT-1组,而单纯用PD098059则无明显影响;预先用PKC激动剂PMA(10-5mol/L),再加入CT-1,MTT计数明显增加;先用PD098059,再加入PMA和CT-1,MTT计数明显降低,而先用PKC抑制剂Calphostin C(Cal)再加CT-1,MTT计数也明显降低。结论CT-1增加心肌细胞存活率的效应是由MAPK信号分子介导实现的;该效应的胞内信号传导通路可能是先激活PKC信号分子,然后再激活MAPK信号分子。更多还原

【Abstract】 Objective Cardiac muscle cells play a critical role in maintaining normal function of the heart.Cardiotrophin-1(CT-1),a potent cardiac survival factor,is capable of inhibiting apoptosis or promoting survival in cardiomyocytes.To elucidate the mechanism of CT-1 promoting cardiac myocyte survival in cultured neonatal rat cardiomyocytes.To explore the potential signaling pathway that might be responsible for this effect.Methods We examined the cardiac myocyte survival effect of CT-1 in cultured neonatal rat cardiomyocytes.The cardiomyocytes were stained [3-(4,5-dimethyl-thiaziazol-2-yl)-2-5-diphenyltetrazolium bromide,MTT] and the counted.Results The survival rate of cardiac myocytes was increased by CT-1 in a dose-dependent manner(10-10～10-7 mol/L) and in a time-dependent manner(1～4 d,10-8 mol/L) in cultured neonatal rat cardiomyocytes.Pretreatment of PD098059(5×10-5mol/L),a MAPK blocker,decreased significantly survival rate of cardiac myocytes by promoted CT-1.The phorbol 12-myristate 13-acetate(PMA)(10-5mol/L),a PKC activator,increased significantly this effect of CT-1,but inhibited significantly by MAPK blocker PD098059.Conclusion CT-1 is a potent factor of promoting cardiac myocyte survival,and increase significantly survival rate of cardiac myocytes in a dose-dependentand a time-dependent manner in cultured neonatal rat cardiomyocytes.The MAPK signaling pathway mediates CT-1 induced cardiac myocyte survival.PKC signaling molecule may be a upstream signaling transduction pathway which cascades of MAPK in CT-1 induced cardiac myocyte survival.更多还原