[Effect of aldosterone and its antagonist spironolactone on epithelial-mesenchymal transition of normal rat kidney epithelial cells in high glucose].

Objective To determine the effect of aldosterone and its antagonist,spironolactone on epithelial-mesenchymal transition(EMT)of normal rat kidney epithelial cells(NRK-52E)in a high glucose milieu,and to explore the mechanism of renoprotection in diabetic nephropathy(DN)in rats involving aldosterone and spironolacton.Methods NRK-52E cells were simultaneously cultured in the serum-free Dulbecco's modification of Eagle's medium Dulbecco(DMEM)for 12 hours.Then the low glucose(LG)group was cultured in LG(1000 mg/L)DMEM:The high glucose(HG)group was cultured in high glucose(4 500 mg/L)DMEM.The aldosterone(Aldo)groups were cultured in high glucose DMEM with the addition of 10,50 and 100 nmol/L aldosterone respectively.The SP group was cultured in high glucose(4 500 mg/L)DMEM plus 10-7mol/L spironolactone.Immunohistochemistry,RT-PCR and Western blot were used to detect E-cadherin and α smooth muscle actin(α-SMA)mRNA expression.Results RT-PCR showed that compared with the LG Group,E-cadherin mRNA expression in the HG group was significantly lower,and α-SMA mRNA expression was significantly increased(P0.05).E-cadherin mRNA expression in the 50 nmol/L Aldo group and 100 nmol/L Aldo group was significantly lower than that in the HG group,while the expression of α-SMA mRNA was significantly increased in the HG group(P0.05),with a dose-dependent relationship with aldosterone(r=-0.70,P0.05;r=0.67,P0.05).E-cadherin mRNA in the SP group was significantly higher,while α-SMA mRNA expression was lower than that in the HG group(P0.01).Immunohistochemistry and Western blot showed that compared with the LG group,E-cadherin protein expression was significantly reduced,and α-SMA expression was significantly increased in the HG group(P0.01).In the 10 nmol/L Aldo,50 nmol/L Aldo,and the 100 nmol/L Aldo groups,E-cadherin protein expression was significantly lower,and α-SMA protein expression was significantly higher than that in the HG group(P0.05),with a dose-dependent relationship with aldosterone(r=-0.83,P0.05;r=0.81,P0.05).In the SP group,E-cadherin protein expression was higher,and α-SMA protein level was lower than that in the HG group(P0.05).Conclusion Aldosterone can promote EMT of tubular epithelial cells in a high sugar milieu,leading to renal interstitial fibrosis in Diabetic nephropathy.Spironolactone can inhibit high glucose-induced renal tubular epithelial cells EMT,which may be an important mechanism for the inhibition of renal interstitial fibrosis.