Nitro-oleic acid inhibits the high glucose-induced epithelial-mesenchymal transition in peritoneal mesothelial cells and attenuates peritoneal fibrosis

As an electrophilic nitroalkene fatty acid, nitro-oleic acid (OA-NO2) exerts multiple biological effects that contribute to anti-inflammation, anti-oxidative stress, and antiapoptosis. However, little is known about the role of OA-NO2 in peritoneal fibrosis. Thus, in the present study, we examined the effects of OA-NO2 on the high glucose (HG)-induced epithelial-mesenchymal transition (EMT) in human peritoneal mesothelial cells (HPMCs) and evaluated the morphological and immunohistochemical changes in a rat model of peritoneal dialysis-related peritoneal fibrosis. In in vitro experiments, we found that HG reduced the expression level of E-cadherin and increased Snail, N-cadherin, and a-smooth muscle actin expression levels in HPMCs. The above-mentioned changes were attenuated by pretreatment with OA-NO2. Additionally, OA-NO2 also inhibited HG-induced activation of the transforming growth factor-beta(1)/Smad signaling pathway and NF-kappa B signaling pathway. Meanwhile, OA-NO2 inhibited HG-induced phosphorylation of Erk and JNK. The results from the in vivo experiments showed that OA-NO2 notably relieved peritoneal fibrosis by decreasing the thickness of the peritoneum; it also inhibited expression of transforming growth factor-beta(1), alpha-smooth muscle actin, N-cadherin, and vimentin and enhanced expression of E-cadherin in the peritoneum. Collectively, these results suggest that OA-NO2 inhibits the HG-induced epithelial-mesenchymal transition in HPMCs and attenuates peritoneal dialysis-related peritoneal fibrosis.