Objective To study the effect of tranilast on cyclosporine A (CsA)-induced epithelial-to-mesenchymal transition in human renal tubular epithelial cells, and investigate the mechanism of its antifibrotic effect. Methods Cultured HK-2 cells were divided into four groups: (1)In the control group, cells were treated without any medicine; (2) The cell were treated with CsA (4. 2μmol/L) for 72 h; (3) The cells were treated with a combination of CsA (4. 2 μmol/L) and tranilast (100μmol/L); (4) The cells were treated with tranilast (100 μmol/L) alone for 72 h.Morphological changes of the cells were assessed by phase-contrast microscopy. The immunofluorescence and Western blotting were adopted to detect the expression of E-cadherin, α-SMA and OPN mRNA and proteins respectively. Results Tranilast could markedly ameliorate the morphological changes of HK-2 cells stimulated by CsA. The irmmunofluorescence staining revealed the expression of E-cadherin was markedly decreased in HK-2 cells stimulated with CsA for 72 as compared with the control group, while the expression of α-SMA and OPN was significantly higher in CsA group than the control group. The expression of E-cadherin in the CsA + Tranilast group was higher than the CsA group, while the expression of α-SMA and OPN in the CsA + Tranilast group was lower than the CsA group. Western blotting showed that protein expression level of E-cadherin in CsA group was dramatically lower than that in the control group (P＜0. 05), while that of α-SMA and OPN in CsA group was significantly higher than in the control group (P＜0.05). The protein expression level of E-cadherin in HK-2 cells in the CsA + Tranilast group was markedly higher than in the CsA group (P＜0.05), and that of α-SMA and OPN in CsA + Tranilast group was significantly lower than in the CsA group (P＜0. 05). Conclusion Tranilast can block the CsA-induced epithelialto-mesenchymal transition in HK-2 cells probably by suppressing the expression of OPN.

Objective To investigate the expression of OPN, α-SMA, E-cadherin and their correlation in the chronic allograft nephropathy (CAN) rat model, and to explore the possible role of OPN in CAN.Methods Orthotopic renal-transplantation using Fisher rats as donors and Lewis rats as recipients was done to establish CAN group, and Lewis to Lewis rats as control group. Rats in each group were sacrificed 12 weeks after the surgery. Blood and urine were collected for further test. Allograft samples were collected and sectioned for HE, Sirus-red staining, immunohistochemistry and Western blot.Results There were CAN morphological changes of the allograft in CAN group. As compared with control group, immunohistochemistry and Western blot revealed that the expression of OPN and α-SMA in CAN group was significantly increased, and that of E-Cadherin reduced. Its trend was correlated with the inflammatory response and the EMT of tubule epithelial cells.Conclusions OPN expression in rat CAN model is significantly up-regulated. OPN may play a role in CAN. OPN might affect the CAN by promoting EMT of tubule epithelial cells.