Olmesartan attenuates tacrolimus-induced biochemical and ultrastructural changes in rat kidney tissue.

Tacrolimus, a calcineurin inhibitor, is clinically used as an immunosuppressive agent in organ transplantation, but its use is limited due to its marked nephrotoxicity. The present study investigated the effect of olmesartan (angiotensin receptor blocker) on tacrolimus-induced nephrotoxicity in rats. A total of 24 rats were divided into four groups, which included control, tacrolimus, tacrolimus + olmesartan, and olmesartan groups. Tacrolimus-induced nephrotoxicity was assessed biochemically and histopathologically. Tacrolimus significantly increased BUN and creatinine level. Treatment with olmesartan reversed tacrolimus-induced changes in the biochemical markers (BUN and creatinine) of nephrotoxicity. Tacrolimus significantly decreased GSH level and catalase activity while increasing MDA level. Olmesartan also attenuated the effects of tacrolimus on MDA, GSH, and catalase. In tacrolimus group histological examination showed marked changes in renal tubule, mitochondria, and podocyte processes. Histopathological and ultrastructural studies showed that treatment with olmesartan prevented tacrolimus-induced renal damage. These results suggest that olmesartan has protective effects on tacrolimus-induced nephrotoxicity, implying that RAS might be playing role in tacrolimus-induced nephrotoxicity.