Ferulic acid ameliorates the progression of pulmonary fibrosis via inhibition of TGF-β/smad signalling

Natural products are one of the best sources for the discovery of novel drugs and compounds for multiple diseases. Pulmonary fibrosis (PF) is a chronic, progressive, irreversible, and fatal fibrotic disorder of lungs with unknown etiology and finite therapeutic choices. The use of naturally occurring phytomedicines has emerged to counteract many fibrotic disorders involving oxidative stress and inflammation. In the present study, we evaluated the protective effects of ferulic acid (FA), in an animal model of silica-induced PF. Pulmonary function of mice was evaluated by performing radiological analysis, bronchoalveolar lavage fluid (BALF), inflammatory cytokines, histology and protein expression studies. Our findings revealed that mice challenged with silica displayed characteristic features of pulmonary injury and fibrosis. However, treatment with FA significantly restored the accumulation of inflammatory cells in BALF. FA led to a partial reversal of silica-induced fibrotic changes in the pulmonary tissue. Subsequently, FA halts the progression of PF in a dose-dependent manner by ameliorating the expression of fibrotic proteins including collagen-I, TGF-β, p-smad2/3 and prevented epithelial-mesenchymal transition (EMT). Collectively, the present study suggests that the inhibition of oxidative stress, inflammatory and TGF-β/smad signalling might be involved in the observed anti-fibrotic benefits of FA against silica-induced PF in mice.