IL17A and pulmonary fibrosis: Glycyrrhizin blocked pulmonary fibrosis by downregulating the expression of monocyte chemokine-1 and inhibiting the secretion of growth factors such as TGFβ1, thereby suppressing collagen fibril synthesis and fibroblast proliferation (He et al., 2006; He et al., 2008; 2009), and by inhibiting the IL-17/TGFβ1/Smad pathway in pulmonary fibrosis (Ye et al., 2007).