AcSDKP经由PDGF介导的细胞外信号调节激酶1/2的调节通路在大鼠矽肺纤维化形成中的作用

Antagonistic effect of AcSDKP on pulmonary fibrosis of silicosis through regulating PDGF-ERK1/2 pathway in rats

探讨抗纤维化短肽N-乙酰基-丝氨酰-天门冬酰-赖氨酰-脯氨酸(AcSDKP)经由血小板源性生长因子(PDGF)介导的细胞外信号调节激酶1/2(ERK1/2)的调节通路在矽肺纤维化形成中的作用。采用一次性支气管内灌注二氧化硅(SiO2)粉尘制作矽肺大鼠模型,将其分为对照组(4周组和8周组)、矽肺模型组(4周和8周组)、AcSDKP治疗组(抗纤维化治疗组和预防治疗组)。采用贴块法进行肺成纤维细胞的原代和传代培养。HE染色观察肺组织形态学变化,Western blot法检测肺组织、肺成纤维组织Ⅰ型、Ⅲ型胶原蛋白和ERK1/2及磷酸化-ERK1/2蛋白的表达以及肺组织PDGF及其受体蛋白的表达。与对照比较,矽肺大鼠肺内PDGF及其受体蛋白、Ⅰ型和Ⅲ型胶原蛋白以及磷酸化-ERK1/2蛋白表达均增强,而AcSDKP治疗组则见上述蛋白表达减弱;在培养的肺成纤维细胞,PDGF能够刺激其Ⅰ型、Ⅲ型胶原蛋白表达增加,同时上调磷酸化-ERK1/2蛋白的表达,而AcSDKP则显示出与PD98059(细胞外信号调节激酶通路特异性抑制剂)相同的作用,即能够抑制PDGF刺激成纤维细胞Ⅰ型、Ⅲ型胶原蛋白表达和上调磷酸化-ERK1/2蛋白表达。提示AcSDKP可能通过阻断PDGF介导的ERK1/2信号转导通路抑制矽肺纤维化的形成与发展。

Objective To investigate the effect of an anti-fibrotic tetrapeptide AcSDKP on pulmonary fibrosis of silicosis by regulating ERK1/2 activity through PDGF.Methods Rats administrated with silica dust intratracheally,were divided into 4 week and 8 week control groups,4 week and 8 week silicosis groups and AcSDKP pretreated and treated groups.Culturing pulmonary fibroblasts of the rats from all the experimental groups,observing pulmonary morphological change under microscope by hematoxylin-eosin staining,detecting the expressions of type Ⅰ and type Ⅲ collagen proteins,of phospho-ERK 1/2 and ERK 1/2 proteins,of PDGF and its receptor proteins in lung or cultured fibroblasts by Western blot.Results Compared with control group the protein expressions of PDGF and its receptor,type Ⅰ and type Ⅲ collagen and phospho-ERK1/2 were all increased in silicosis groups,and the expression of the proteins mentioned above showed reduced in AcSDKP treated groups.Meanwhile in cultured rat pulmonary fibroblasts,PDGF showed some stimulating effect on the protein-expressions of type Ⅰ and type Ⅲ collagen and up-regulated the expression of phospho-ERK1/2,while AcSDKP showed the same effect as PD98059,the specific inhibitor of extracellular signal-regulated pathway,that inhibited the expressions of type Ⅰ and type Ⅲ collagen through the stimulation of PDGF and up-regulated the expression of phospho-ERK1/2.Conclusion The results suggested that AcSDKP could inhibit the formation and development of pulmonary fibrosis in silicosis through blocking ERK1/2 pathway mediated by PDGF.