ABSTRACT
Aim To investigate the effect of magnesi-um isoglycyrrhizinate (MgIG)on radiation -induced pulmonary fibrosis in mice and the mechanism.Meth-ods Fifty female C57BL/6 mice were randomly divid-ed into control group,irradiation (RT)group,MgIG group,RT +MgIG group and RT +dexamethasone (DXM)group,with 1 0 mice in each group.Except for control group and MgIG group,the remaining mice were given a single 1 5Gy 60 Co γray on whole lung. The mice in each group were administered 2 h before irradiation and each day after irradiation:MgIG group and RT +MgIG group were administered with MgIG (1 00 mg·kg -1 )by intraperitoneal injection;control group and RT group were administered with normal sa-line (20 mL·kg -1 )by intraperitoneal injection;RT+DXMgroup was administered with DXM(0.5 mg· kg -1 )by intraperitoneal injection.After 1 2 weeks,the mice were sacrificed and lung tissues were taken out. The degree of alveolitis and pulmonary fibrosis were observed by HE staining and Masson staining.The ex-pressions of type Ⅰ collagen,type Ⅲ collagen and TGF-β1 protein were detected by immunohistochem-isty.Results The alveolitis,pulmonary fibrosis and expressions of type Ⅰ collagen,type Ⅲ collagen, TGF-β1 ,p-Smad2,p-Smad3 increased significantly in RT group compared with control group (P <0.05 ), and were significantly lower in RT +MgIG group and RT +DXMgroup than those in RT group(P <0.05). Conclusion MgIG can improve radiation-induced pulmonary fibrosis in mouse lung tissue,and its mech-anism may be related to the influence of MgIG on TGF-βsignaling pathway.