Effects of parathyroid hormone on apoptosis in cultured renal tubular epithelial cells

LI Xiaodong; LI Ying; DING Xinguo

Abstract：Objective To investigate the effects of parathyroid hormone(PTH)on apoptosis in cultured renal tubular epithelial cells(HK-2)and its mechanism.Methods Cultured HK-2 was treated with PTH of different concentrations.The morphologic changes of HK-2 nuclei were observed by Hoechst 33258 staining,while the apoptosis of HK-2 was detected by flow cytometry via Annexin V/PI staining.Western blot was used to measure the Bax and Bcl-2 protein expressions:RT-PCR was used to measure the Bax and Bcl-2 gene expressions.Results Hoechst33258 staining showed that condensed or broken nuclei were observed in HK-2 after treatment with PTH for 48 h.PTH induced HK-2 apoptosis in a dose dependent manner.Flow cytometry demonstrated PTH significantly increased the rate of apoptotic HK-2 in a dose dependent manner,compared with control group(P＜0.05).Western blot and RT-PCR methods showed the Bax protein and gene expressions were up-regulated,but the Bcl-2 expressions were down-regulated in dose and time dependent manners,and the rate of Bax/Bel-2 was increased apparently when HK-2 were treated with PTH.Conclusion PTH may promotes apoptosis of renal tubular epithelial cells by regulating Bax and Bcl-2 expressions,resulting in renal interstitial fibrosis.