Protective effects and mechanisms of omega‐3 polyunsaturated fatty acid on intestinal injury and macrophage polarization in peritoneal dialysis rats

AIM: This study was conducted to investigate the chronic injury of peritoneal glucose injection on the peritoneum and intestine and the protective effects of omega‐3 polyunsaturated fatty acid (ω‐3PUFA) during peritoneal dialysis (PD). METHODS: Peritoneal dialysis animal models were established by intraperitoneal injection of 4.25% glucose for 28 days. Protein expression in ileum and peritoneum was measured by immunofloresence and immunohistochemistry. Protein expression in macrophages was measured by Western blot. Fibrosis was analyzed by Masson staining. RESULTS: Peritoneal dialysis significantly increased the structural injury and decreased junction‐related protein ZO‐1 and occludin expression in ileum, the expression of proteins relating to the activation of M2 (Erg2, IRF4), but not M1 (CD38, IRF5) macrophages. PD significantly increased the expression of TGF‐β1, VEGF and ALK5 protein in peritoneal tissues. PD significantly increased fibrosis (Masson staining) and the expression of fibroblast marker α‐SMA in peritoneal tissues. Injection of macrophage clean reagent and ω‐3PUFA significantly inhibited M2 activation, and decreased Masson staining, α‐SMA, TGF‐β1, VEGF and ALK5 protein expression in peritoneal tissues in PD treated rats. ω‐3PUFA injection significantly decreased PD‐induced injury in ileum and normalized the expression of ZO‐1 and occludin in the ileum of PD rats. CONCLUSION: Omega‐3 fatty acids can provide a protective role on PD‐induced peritoneal fibrosis and injury of the intestine.