Cyclosporine Induces Endothelin-1 mRNA Synthesis and Nitric Oxide Production in Human Proximal Tubular Epithelial Cell Cultures

Background. Cyclosporine (CsA) is implicated in the development of chronic allograft nephropathy, which is related to reduced long-term allograft survival. The activation of tubular epithelial cells is involved in the renal scarring process via stimulation of factors such as endothelin-1 (ET-1) and nitric oxide (NO). The effect of CsA on the activation of tubular epithelial cells towards increased production of ET-1 and NO was investigated in this study. Methods. Human tubular epithelial cells (HK-2) were cultured in the presence of CsA at different concentrations (125, 250, 500, and 1,000 ng/mL). ET-1 m-RNA and NO production were measured using RT-PCR and Griess method, respectively. The cytotoxic effect of CsA was examined by the MTT method and cell count. Results. A statistically significant and dose-dependent cytotoxic effect of cyclosporine on HK-2 cells was observed. A dose-dependent up-regulation of ET-1 mRNA production and NO accumulation was observed under the influence of CsA. Conclusion. Increased synthesis of endothelin-1 mRNA and nitric oxide as well as a significant cytotoxic effect on tubular epithelial cells under the influence of CsA might be related to the development of CsA nephrotoxicity.