The Effect of Chronic Immunosuppressive Regimen Treatment on Apoptosis in the Heart of Rats

Chronic immunosuppressive therapy is currently the only effective method to prevent acute rejection of a transplanted organ. Unfortunately, the expected effect of treatment brings a number of grave side effects, one of the most serious being cardiovascular complications. In our study, we wanted to investigate how treatment with commonly used immunosuppressive drugs affects the occurrence of programmed cardiac cell death. For this purpose, five groups of rats were treated with different triple immunosuppressive regimens. Cardiac tissue fragments were subjected to the TUNEL assay to visualize apoptotic cells. The expression of Bcl-2 protein, Bax protein, caspase 3 and caspase 9 was also assessed. This study indicates that all immunosuppressive protocols used chronically at therapeutic doses result in an increased percentage of cells undergoing apoptosis in rat heart tissue. The greatest changes were recorded in the TMG (rats treated with tacrolimus, mycophenolate mofetil and glucocorticosteroids) and CMG (rats treated with cyclosporin A, mycophenolate mofetil and glucocorticosteroids) groups. The TRG (rats treated with rapamycin, tacrolimus and glucocorticosteroids) group showed the lowest percentage of apoptotic cells. The internal apoptosis pathway was confirmed only in the TMG group; in the remaining groups, the results indicate programmed cell death via the receptor pathway.