Abstract
Accumulating data confirms that Methotrexate (MTX), a well-known immunosuppressive and anticancer drug, causes nephrotoxicity. Infliximab (INF), the inhibitor of tumor necrosis factor-alpha (TNF-α), was proven to have anti-inflammatory properties. Thus, it may have potential in preventing MTX-induced nephrotoxicity. Therefore, this study aimed to inspect the prospective nephroprotective effect of INF on MTX-induced rat nephrotoxicity through investigating the possible molecular mechanisms, including its interference with different death routes, oxidative stress as well as mitochondrial biogenesis. Rats received an INF intraperitoneal single dose of 7 mg/kg 72 h prior to a single 20 mg/kg MTX injection. MTX nephrotoxicity was demonstrated by significantly increased serum levels of the renal indicators urea and creatinine as well as renal inflammatory markers TNF-α and Interleukin-6 (IL-6) and the renal oxidative stress marker malondialdehyde (MDA), while renal antioxidant enzyme superoxide dismutase (SOD) was significantly decreased compared to control. INF injection prior to MTX markedly reversed these MTX-induced effects. Besides, MTX impaired mitochondrial biogenesis, while INF attenuated this impairment, as indicated by increased expression of peroxisome proliferator-activated receptor-γ coactivator-1α (PGC-1α). Finally, MTX triggered apoptotic and autophagic cascades in renal tissues as evidenced by reduced anti-apoptotic Bcl-2 protein expression as well as elevated expression of the pro-apoptotic protein Bax and both key regulators of autophagy; beclin-1 and LC-3, whereas INF pretreatment counteracted these apoptotic and autophagic effects of MTX. Summarily, these results suggest that INF provides protection against MTX-induced nephrotoxicity which could be elucidated by its antioxidant, anti-inflammatory, anti-apoptotic and anti-autophagic effects as well as upregulating mitochondrial biogenesis.