Submicron emulsion of cinnamaldehyde ameliorates bleomycin-induced idiopathic pulmonary fibrosis via inhibition of inflammation, oxidative stress and epithelial-mesenchymal transition

Abstract

AimsIdiopathic pulmonary fibrosis (IPF) is the most frequent and severe form of idiopathic interstitial pneumonias. The pathogenesis is associated with inflammation and oxidative stress and epithelial-mesenchymal transition (EMT). Cinnamaldehyde exhibits antiinflammatory and antioxidant properties, but its effect on IPF is unknown. The present study is to investigate the anti-fibrotic effect and action mechanism of cinnamaldehyde on IPF. Materials and methodsIPF was induced by intratracheal bleomycin in mice. Submicron emulsion of cinnamaldehyde was given by intraperitoneal injection once everyday for 7 or 21 continuous days after bleomycin administration. Lung histological and injury indexes were analyzed. The protein expressions of inflammation and oxidative stress as well as EMT markers alpha-smooth muscle actin (α-SMA) and E-cadherin in mice and cultured A549 cells were measured. ResultsCinnamaldehyde attenuated the bleomycin-induced histological injury, reduced hydroxyproline level and improved pulmonary function by the inhibiting inflammatory cytokines and reactive oxygen species production as well as enhancing total superoxide dismutase activity in bleomycin-induced mice. Cinnamaldehyde also inhibited EMT in both bleomycin-induced mice and TGF-β1-stimulated A549 cells. ConclusionsCinnamaldehyde ameliorated bleomycin-induced IPF via inhibition of inflammation and oxidative stress and EMT.