Effect Of 1,25（OH）₂D₃ On TGF-β1 Induced Transdifferentiation In Renal Tubular Epithelial Cells On The Expression Of SIRT1

Objective:To investigate the effect of 1,25（OH）₂D₃ on the transdifferentiation and the expression of SIRT1 of HK-2 cells induced by TGF-β1,and to explore the effect of1,25（OH）₂D₃ on the transdifferentiation of HK-2 cells and its possible mechanism.The above results provide more theoretical basis for 1,25（OH）₂D₃ to exert anti-renal interstitial fibrosis.Methods:To explore the optimal stimulation concentration of TGF-β1:Different concentrations of TGF-β1（1ng/ml,5ng/ml,10ng/ml）were used to stimulate HK-2 cells for 48 hours and a normal control group was established.The expression ofα-SMA mRNA in each group was detected by Real-time PCR.And the optimal stimulation concentration was selected according to the results.The experiment was officially divided into the following groups:normal control group,TGF-β1（5ng/ml）stimulation group,TGF-β1+1,25（OH）₂D₃(10^-10mol/L)treatment group,TGF-β1+1,25（OH）₂D₃(10^-9mol/L)treatment group+TGF-β1+1,25（OH）₂D₃(10^-8mol/L)treatment group,cell protein was collected after 48h,and each group expression of SIRT1,α-SMA,and E-Cadherin proteins was detected by Western blot.Results:（1）According to the different expression levels ofα-SMA mRNA under different stimulation conditions,the optimal stimulation concentration were 5ng/ml.After HK-2cells were treated with 5ng/ml TGF-β1 for 48 hours,the expression of SIRT1 protein decreased,the expression ofα-SMA protein increased,and the expression of E-cadherin protein decreased.Compared with the normal control group,the difference was statistically significant（P<0.005）.The morphology of the cells was observed under an inverted phase contrast microscope:HK-2 cells in the normal control group showed the shape of paving stones,and tight junctions between cells.The HK-2 cells in the TGF-β1-stimulated group showed Long fusiform,and the connection is loose.（2）Atfer different concentration gradients of 1,25（OH）₂D₃ and TGF-β1 for 48h of co-action,increased expression of SIRT1 protein,decreased expression ofα-SMA protein,and increased expression of E-cadherin protein were statistically significant（P<0.005）compared with the TGF-β1 stimulation group.（3）The expression of SIRT1 protein and E-cadherin protein of 10^–9mol/L,10^-8 mol/L dose of 1,25（OH）₂D₃ was relatively higher,compared with 10^-10 mol/L dose of 1,25（OH）₂D₃.And the difference was statistically significant（P<0.005）.The protein expression level ofα-SMA was not statistically different between the different concentrations of 1,25（OH）₂D₃ treatment group.Conclusion:1.TGF-β1 can inhibit the expression of SIRT1 in renal tubular epithelial cells;2.1,25（OH）₂D₃ can attenuate renal tubular epithelial cell transdifferentiation induced by TGF-β1,and its mechanism may be related to the regulation of SIRT1expression.