ERK1/2信号通路介导PDGF-CC诱导的鼠心肌纤维化及其机制

目的 研究ERK1/2通路在血小板源性生长因子(PDGF)-CC诱导的鼠心肌纤维化中的作用及其可能的机制.方法 取SD大鼠乳鼠心脏组织,差速贴壁法分离并纯化心肌成纤维细胞.按不同药物处理随机分成对照组(CON组)、PDGF-CC(P组)、PDGF-CC+ERK1/2抑制剂U0126(PU组).MTT法检测心肌成纤维细胞的增殖,qRT-PCR法检测mRNA含量,Western blot法分析蛋白表达量.结果 MTT法显示P组细胞数较CON组显著增加(P＜0.01),而PU组细胞数较P组明显减少(P＜0.01).qRT-PCR法显示P组中PDGF-α受体(PDGFR-α)、ERK1、ERK2、Ⅰ型和Ⅲ型胶原蛋白(Col Ⅰ、ColⅢ)的mRNA表达水平均明显高于CON组(P ＜0.001),PDGFR-β的mRNA表达量在P组与CON组间差异无统计学意义.与P组相比,PU组中PDG-FR-α、ERK1、ERK2、Col Ⅰ和ColⅢmRNA表达均明显下降(P＜0.01).Western blot法显示P组中磷酸化PDGFR-α(p-PDGFR-α)、ERK1/2、p-ERK1/2、Col Ⅰ和ColⅢ的表达量均明显高于CON组(P ＜0.001),PU组中p-PDGFR-α、ERK1/2、p-ERK1/2、Col Ⅰ和ColⅢ蛋白表达量均显著低于P组(P＜0.001).结论 PDGF-CC可能通过结合PDGFR-α激活ERK 1/2信号通路,诱导鼠心肌成纤维细胞过量增殖伴胶原蛋白的合成,参与心肌纤维化的发生.

ERK1/2 signaling pathway mediates PDGF-CC-induced rat cardiac fibrosis and its mechanism

Objective To investigate the role and mechanism of ERK1/2 pathway in PDGF-CC-induced cardiac fibrosis in rats.Methods The cardiac fibroblasts were isolated and purified from cardiac tissues of SD neonatal rats by differential time attachment,then divided into 3 groups randomly:control group (CON),PDGF-CC group (P) and group of PDGF-CC + ERK1/2 inhibitor U0126(PU).MTT assay was used to detect the proliferation of cardiac fibroblasts.The mRNA expression levels were detected by real-time fluorescent quantitative PCR (qRT-PCR).The protein expressions were detected by Western blot.Results MTT showed that the number of cells in P group was significantly higher than that in CON group(P ＜ O.01),while the number of cells in PU group was significantly lower than that in P group(P ＜ 0.01).qRT-PCR showed that the mRNA expressions of PDGFR-α (PDGF receptorα),ERK1,ERK2,collagen type Ⅰ and type Ⅲ (Col Ⅰ,Col Ⅲ) were significantly higher than CON group (P ＜ 0.001),PDGFR-β mRNA expression showed no significant difference between P and CON group,and that PDGFR-α,ERK1,ERK2,Col Ⅰ and Col]]Ⅲ in PU group was markedly reduced as compared to P group(P ＜0.01).Western blot showed that the protein expressions of phosphorylated PDGFR-α(p-PDGFR-α),ERK1/2,p-ERK1/2,Col Ⅰ and Col Ⅲ were significantly higher than that in CON group(P ＜0.001),and those expressions were significantly decreased in the PU group compared with P group(P ＜ 0.001).Conclusion PDGF-CC may activate the ERK1/2 signaling pathway by binding to PDGFR-α,leads to excessive proliferation of rat cardiac fibroblasts with collagen synthesis and participate in the development of myocardial fibrosis.