Introduction: Methotrexate, an antagonist of folic acid used in the treatment of many cancers and inflammatory diseases, is associated with side effects that limit its usage. Infliximab has been reported to have a protective effect against nephrotoxicity induced by some drugs and ischemic reperfusion. We aimed to investigate whether infliximab has a protective effect against methotrexate-induced nephrotoxicity.
Materials and methods: We administered methotrexate at a dose of 20 mg/kg as a single intraperitoneal injection in 10 rats (methotrexate group). Another group of 10 rats received a single dose of infliximab, 7 mg/kg, intraperitoneally (infliximab group). The methotrexate and infliximab group received a similar single injection of infliximab 72 hours prior to methotrexate injection. After 72 hours a single dose of methotrexate, 20 mg/kg, was administered intraperitoneally. Five days after methotrexate injection, blood samples were collected and the kidney tissues were removed for biochemical and histological examination.
Results: The methotrexate group had significantly higher tissue levels of tumor necrosis factor-α (P = .008), interleukin-1β (P = .04), nitric oxide (P < .001), and adenosine deaminase (P < .001) than the methotrexate and infliximab group after the 5-day study. The methotrexate group also had significantly higher total histological scores (P < .001) and carbonic anhydrase-II activity (P < .001) when compared to the methotrexate and infliximab group.
Conclusions: Infliximab has a strong protective effect against methotrexate-induced nephrotoxicity by suppressing cytokines release. It may decrease methotrexate-induced nephrotoxicity by regulating carbonic anhydrase-II enzyme activities and slowing down purine metabolism.