The effects of methanolic extract of Glycyrrhiza glabra on the prevention and treatment of bleomycin-induced pulmonary fibrosis in rat: experimental study.

Idiopathic pulmonary fibrosis (IPF) is a chronic lung disease characterized by dyspnea and progressive loss of lung function. In this study, the preventive and therapeutic effects of methanolic extract of Glycyrrhiza glabra on pulmonary fibrosis were investigated. Pulmonary fibrosis was induced by administration of bleomycin (BLM) into the left lung of rats. Methyl-prednisolone (M-pred, 4 mg/kg) and methanolic extract of G. glabra (500 mg/kg) were injected intraperitoneally from the 1st to 14th days in the preventive group and from the 14th to 28th days in the therapeutic group once every day. Pulmonary inflammatory and fibrotic indices were evaluated by hematoxylin and eosin (H&E) and Masson's trichrome, respectively. The level of hydroxyproline as an index of pulmonary fibrosis and malondialdehyde (MDA) as an oxidative stress biomarker and catalase were measured by the related ELISA Kits. Pulmonary inflammatory and fibrotic indices in the G. glabra and M-pred groups significantly reduced compared with BLM group. G. glabra decreased the level of hydroxyproline in pulmonary tissue similar to M-pred. MDA reduced in G. glabra and M-pred groups compared with BLM group. The activity of catalase increased in the G. glabra preventive group. According to the results, G. glabra prevented and treated pulmonary fibrosis and inflammation in rats. Therefore, G. glabra may be suggested for the prevention and treatment of pulmonary fibrosis and inflammation.