BACKGROUNDPachymic acid (PA), a natural triterpenoid, is known to significantly reduce cell proliferation and induce apoptosis in vitro through initiation of mitochondria dysfunction. However, its effect on immune cells and anti-rejection following organ transplantation remains unknown.

METHODSIn this study, we investigated PA as a treatment to control acute rejection occurred in rats which had accepted cardiac transplantation. We measured apoptosis of peripheral blood lymphocyte (PBLs), and CD4(+) lymphocyte, as well as the number of CD4(+) and CD8(+) lymphocytes and the effect of PA on acute rejection in rats 7 days after cardiac transplantation.

RESULTSPA treatment might decrease allograft rejection, protect PBLs from apoptosis, and reduce the percentage of CD8(+) lymphocyte. PA neither regulated the number nor the apoptosis rate of CD4(+) lymphocyte.

CONCLUSIONSOur findings indicated that PA has an anti-apoptotic effect acting on PBLs through a novel mechanism involving stabilization of the PBLs mitochondrial transmembrane potential, an anti-rejection effect in rats after cardiac transplantation and an inhibiting effect to CD8(+) lymphocyte.