Total polysaccharide of Yupingfeng protects against bleomycin‐induced pulmonary fibrosis via inhibiting transforming growth factor‐β1‐mediated type I collagen abnormal deposition in rats

Objective This study was to explore the antifibrotic effect and the possible mechanism of total polysaccharides of Yupingfeng (YPF-P) on bleomycin (BLM)-induced pulmonary fibrosis in rats. Methods Pulmonary fibrosis was induced in Sprague-Dawley rats by BLM (5 mg/kg), killed 14 and 28 days after BLM administration by abdominal aorta exsanguination and removed the lungs. Lung coefficient was counted at the same time. Besides, H&E and Masson's trichrome staining for histopathological changes of lung tissues were observed. Additionally, western blotting and immunohistochemical staining techniques were used to detect expression of transforming growth factor-β1 (TGF-β1), type I collagen (Col-I) and α-smooth muscle actin (α-SMA). Finally, the levels of Col-I and hydroxyproline (HYP) in lung tissues were also utilized. Key findings YPF-P alleviated the increase of lung coefficient induced by BLM instillation in pulmonary fibrosis rat, pathologic changes and collagen distribution were obviously ameliorated, while the increase of α-SMA-positive cells and TGF-β1 expression was prevented after YPF-P treatment. Moreover, the contents of HYP and Col-I were decreased in YPF-P group. Conclusions YPF-P had antifibrotic effect in experiment, which may reduce the synthesis and promote the deposition of Col-I via suppressing the increase of TGF-β1-mediated activation of myofibroblasts.