PEDF inhibits LPS-induced acute lung injury in rats and promotes lung epithelial cell survival by upregulating PPAR-γ

Background The progression of acute lung injury (ALI) involves numerous pathological factors and complex mechanisms, and cause the destruction of epithelial and endothelial barriers. Pigment epithelium-derived factor (PEDF) is an angiogenesis inhibitor and a potential anti-inflammatory factor. The purpose of this study was to investigate the effect of PEDF on lipopolysaccharide (LPS)-induced ALI in rats. Methods In vivo, pathological and injury related factors examination were performed on rat lung to investigate the effect of PEDF on ALI. In vitro, the effect of PEDF on inflammatory injury and apoptosis of lung epithelial type II RLE-6TN cell was evaluated, and the expression of inflammatory factors and related pathway proteins and PPAR-gamma (in the presence or absence of PPAR-gamma inhibitors) were analyzed. Results In vivo results showed that PEDF inhibited the inflammatory factor expression (TNF-alpha, IL-6 and IL-1 beta) and progression of ALI and reduced lung cell apoptosis in rats. In vitro results showed that PEDF could effectively inhibit LPS-stimulated inflammatory damage and apoptosis of RLE-6TN cells. PEDF inhibited the RLE-6TN cell injury by enhancing the expression of PPAR-gamma. Conclusions PEDF is an anti-inflammatory factor, which can inhibit apoptosis of lung epithelial cells by upregulating the expression of PPAR-. and reducing LPS-induced ALI in rats.