Aim: To analyse the impact of the most commonly used immunosuppressive drugs on the occurrence of apoptosis in the native kidneys of Wistar rats.
Method: The study involved 36 rats. the animals being grouped according to the immunosuppressive regimen used (tacrolimus, mycophenolate mofetil, cyclosporine A, rapamycin and prednisone). The rats in all study groups were treated with a 3-drug protocol for 6 months. The medication dose was adjusted based on available literature data. No drugs were administered to the control group. The rats were then killed. Autopsies of all animals were performed and the kidneys were isolated for histopathology (HE + PAS). To assess cell apoptosis the TUNEL reaction was performed. Blood trough levels of immunosuppressive drugs as well as the parameters of peripheral blood were determined.
Results: 1. In rats treated with cyclosporine A distal nephron tubules were characterised by more pronounced apoptosis. 2. In tacrolimus-treated rats a lower intensity of apoptosis was found in the distal tubules. 3. In rapamycin-treated rats the apoptosis was inhibited both in the distal and proximal nephron tubules. 4. In MMF treated rats intense apoptosis was observed in the proximal nephron tubules. 5. There were no significant changes in renal histopathology (HE + PAS).
Conclusions: The apoptosis in nephron tubules caused by immunosuppressive therapy is not accompanied by any histopathological changes (eg fibrosis, inflammation, tubular atrophy, vacuolation of the tubular cells) in light microscopy.