Objective To study the effects of nifedipine on H2O2 - induced cardiac fibrosis and its mechanism. Methods Primary cultured rat cardiac fibroblasts (CFs) were stimulated with H2O2 (100 μM). The effects of nifedipine on H2O2 - induced connective tissue growth factor (CTGF) , fibronectin (FN) expression , as well as the phosphorylation of MAPK (mitogen activated protein kinases ) were identified by Western blot analysis. The selective fluorescent probe fluo - 4/AM was used to measure intracellular calcium concentration ( [ Ca2+];) changes. Results Nifedipine signifi -cantly depressed The H2O2 - induced up - regulation of CTGF and FN , as well as the phosphorylation of extracellular sig -nal -regulate kinases 1/2 (ERK1/2) and c - Jun NH(2) -terminal kinase (JNK) , were significantly depressed by nifedipine ; no effect on H2O2 - induced [ Ca2+]; increase in CFs was observed. The H2O2 - induced up - regulation of CTGF and FN was also depressed by ERK inhibitor PD98059. Conclusion Nifedipine inhibits H2O2 -induced cardiac fibrosis through interference with the ERK1/2 signaling pathway , but not via the classic calcium channel blocking.%目的 研究硝苯地平(nifedipine)对过氧化氢(H2O2)引起的心肌纤维化的影响及机制.方法 原代培养大鼠心脏成纤维细胞(CFs),用100 μmol/L H2O2刺激,蛋白免疫印迹法(Western blot)检测硝苯地平(10 μmol/L)以及对照药维拉帕米(verapamil,10 μmol/L)对H2O2诱导的结缔组织生长因子(CTGF)、纤维粘连蛋白(FN)的蛋白表达以及信号蛋白MAPK磷酸化的影响;利用fluo-4/AM钙荧光探针法测定硝苯地平对H2O2刺激引起CFs内钙离子浓度([Ca2+]i)变化的影响.结果 (1)硝苯地平能够显著抑制H2O2诱导的CTGF、FN蛋白表达上调以及细胞外信号调控蛋白激酶1/2 (ERK1/2)、c-Jun N端激酶(JNK)磷酸化,而对p38MAPK磷酸化没有影响,维拉帕米对以上蛋白表达均无抑制作用;(2) 硝苯地平对H2O2刺激引起的CFs中的[Ca2+]i增加没有影响;(3) ERK信号通路抑制剂PD98059(10 μmol/L)可抑制H2O2诱导的CTGF、FN的蛋白表达上调.结论 硝苯地平可抑制H2O2刺激引起的CTGF、FN蛋白表达上调,而对[Ca2+]i变化没有影响,其抗纤维化的作用不依赖于经典的钙离子阻断作用,可能与抑制ERK1/2磷酸化有关.
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