Comparison of expression of TGF-β1, its receptors TGFβ1R-I and TGFβ1R-II in rat kidneys during chronic nephropathy induced by cyclosporine and tacrolimus

Objective. Chronic rejection is a major cause of graft dysfunction after kidney transplantation. Long-term treatment with cyclosporine (CsA) or tacrolimus (FK506) results in chronic nephrotoxicity. Transforming growth factor-betal (TGF beta 1) and its receptors type I (TR-I) and type II (TR-II) have been known to contribute to this side effect. The expression of TGF-beta 1, TR-I, and TR-II in rat kidneys has not been compared during chronic nephropathy induced by CsA or FK506. Methods. Rat models of chronic CsA- or FK506-induced nephropathy were established using Sandimun Neoral or Prograf administration. The kidneys were dissected and TGF-beta 1, TR-I, and TR-II proteins and TR-I and TR-II mRNAs measured by immunohistochemistry and in situ hybridization, respectively, to compare the results of the two groups. Results. The functional and morphologic studies showed that in the rats the nephrotoxic effects of FK506 were not as significant as those of CsA. The results of immunohistochemistry and in situ hybridization showed that the expression of renal TGF beta 1, TR I, TR-II proteins and TR and TR II mRNA in the FK506 group were lower than those in the CsA groups. Conclusion. These results showed that both FK506 and CSA display nephrotoxicity, but that the nephrotoxicity of FK506 was less than that of CsA in chronic nephropathy.