Abstract: 【Abstract】Object To explore the effect and mechanisms of miRNA-302c on the expression of connective tissue growth factor (CTGF) and epithelial-to-mesenchymal transition (EMT) in peritoneal mesothelial cells from peritoneal dialysis (PD) patients. Methods Human peritoneal mesothelial cells were isolated by collection of overnight peritoneal lavage from PD patients and centrifugation of the lavage. The expression of miR-302c, CTGF and EMT related factors were assayed. Human peritoneal mesothelial cells were transfected with miR-302c and cultured containing 5ng/ml transforming growth factor-β1 (TGF-β1) for 48h, and the expression of CTGF and EMT related factors were then measured by western blot. Results There was a marked reduction of miR-302c level in human peritoneal mesothelial cells from prolonged PD patients (F=443.165, P＜0.001). miR-302c level was negatively correlated with Vimentin (r=-0.887) and CTGF (r=-0.840), and was positively correlated with Zonula occludens-1 (Zo-1) (r=0.873). Over-expression of miR-302c inhibited the down-regulation of E-cadherin (F=13.910，P=0.043) and upregulation of anti-α smooth muscle actin (α-SMA) (F=11.833, P=0.026), collagen I (F=10.673, P=0.031)
and CTGF (F=8.34, P=0.044) induced by TGF-β1 in cultured human peritoneal mesothelial cells. Conclusion MiR-302c is a vital factor protecting peritoneal mesothelial cells from undergoing EMT and fibrosis in PD patients, probably through inhibition of CTGF expression.

Key words: peritoneal dialysis, microRNA-302c, epithelial–to-mesenchymal transition, fibrosis, connective tissue growth factor