Inhibitory effect of lycium barbarum polysaccharide on bleomycin-induced pulmonary fibrosis in mice and its mechanisms / 医学研究生学报

ABSTRACT

Objective Pulmonary fibrosis ( PF) is a group of pulmonary interstitial pathological changes caused by various factors, and its pathogenesis is not yet fully elucidated .This article discussed the effect of lycium barbarum polysaccharide ( LBP) on ble-omycin-induced PF in mice and its action mechanisms . Methods The C57/BL6 mice were randomly divided into 6 groupssham-opera-tion, PF model, dexamethasone ( DM), high-dose LBP, medium-dose LBP, and low-dose LBP.The mice in the sham-operation group were injected into the trachea with isotonic saline and those in the oth-er groups with 5 bleomycin at mg/kg for establishing the PF model . Two days after modeling , the mice in the DM and high-, medium-,and low-dose LBP groups were treated with DM at 5 mg/kg and LBP at 0.8, 0.4, and 0.2 g/kg, while those in the sham-operation and PF model groups with the same volume of isotonic saline , respectively , qd, for 4 consecutive weeks .Then, the pathological chan-ges of the lung tissue were observed and the hydroxyproline ( HYP) content in the lung tissue was detected for all the animals .RT-PCR was used to determine the relative expressions of the PF-related COL1A1 and α-SMA genes. Results Compared with the PF mod-els, the the high-, medium-, and low-dose LBP groups showed significant increased body weight after 4 weeks of medication ([14.29 ±0.38] vs [16.12 ±0.37], [15.58 ±0.25] and [15.07 ±0.21] g, P<0.01), the high-and medium-dose groups ex-hibited remarkably decreased lung indexes ([0.887 ±0.13] vs [0.847 ±0.22] and [0.859 ±0.18]%, P<0.05), and the high-dose group presented markedly reduced alveolitis score (3.40 ±0.23 vs 3.09 ±0.22, P<0.05), PF score (3.57 ±0.27 vs 3.07 ± 0.31, P<0.01) and HYP content ([0.831 ±0.05] vs [0.786 ±0.07] μg/mg wet weight, P<0.05).In comparison with the mod-el group, the DM, high-dose LBP and medium-dose LBP groups showed significantly decreased gene expressions of COL 1A1 (1.53 ± 0.13 vs 1.26 ±0.10 and 0.98 ±0.17, P<0.05) and α-SMA (5.67 ±0.47 vs 4.19 ±0.28 and 2.29 ±0.31, P<0.05). Conclusion LBP can suppress the progression of bleomycin-induced pulmonary fibrosis by inhibiting the gene expressions of COL 1A1 andα-SMA and decreasing the HYP content in the lung tissue .