• Yuan Yuan, Fang Yang, Hong Xu, Wan-ying Yu, Yue Sun, Hai-jing Deng, Wen-dong Ma, Zhong-qiu Wei, and Rui-min Wang.
• Hebei United University, Tangshan, Hebei Province 063000, China.
• Zhonghua Lao Dong Wei Sheng Zhi Ye Bing Za Zhi. 2013 Sep 1; 31 (9): 654-60.

ObjectiveTo investigate whether N-acetyl-seryl-aspartyl-lysyl-proline (Ac-SDKP) can inhibit the differentiation of pulmonary fibroblasts into myofibroblasts by regulating Rho-associated coiled-coil forming protein kinase (ROCK) pathway mediated by transforming growth factor-β1 (TGF-β1).MethodsPrimary culture of pulmonary fibroblasts was performed by trypsinization method. Four generations of pulmonary fibroblasts were divided into control group, TGF-β-induced differentiation group, Y-27632 treatment group, and Ac-SDKP treatment group. The intracellular distributions of ROCK, serum response factor (SRF), and α-smooth muscle actin (α-SMA) were observed by confocal laser scanning microscopy. The protein expression of ROCK, SFR, α-SMA, and type I and type III collagen in pulmonary fibroblasts was measured by Western blot. The mRNA expression of ROCK, SFR, and α-SMA was measured by real-time quantitative PCR.ResultsCompared with the control group, the pulmonary fibroblasts stimulated by TGF-β1 had a lot of α-SMA antibody-labeled myofilaments in parallel or cross arrangement, as observed by confocal laser scanning microscopy, and the mRNA and protein expression of ROCK, SRF, and α-SMA and protein expression of type I and type III collagen increased significantly after 6, 12, and 24 h of stimulation (P < 0.05). Compared with the TGF-β1-induced differentiation group, the Y-27632 treatment group and Ac-SDKP treatment group had significantly decreased mRNA and protein expression of ROCK, SRF, and α-SMA and protein expression of type I and type III collagen at the same time point (P < 0.05).ConclusionAc-SDKP can inhibit the differentiation of pulmonary fibroblasts into myofibroblasts and the synthesis of collagen in rats by regulating the ROCK pathway mediated by TGF-β1. That may be one of the mechanisms by which Ac-SDKP acts against (silicotic) pulmonary fibrosis.

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