Renoprotective effects of montelukast, a cysteinyl leukotriene receptor antagonist, against methotrexate-induced kidney damage in rats.

Methotrexate (MTX) is a cytotoxic chemotherapeutic agent used for treatment of several cancers. Nephrotoxicity, an adverse side effect of high-dose MTX, is attributed to abnormal production of reactive oxygen species (ROS), inflammatory mediators, and neutrophil infiltration. Montelukast (MON) is a cysteinyl leukotriene receptor antagonist. Recently, it has gained a considerable interest as a ROS scavenger and inflammatory modulator. In this study, we investigated the effect of MON against MTX-induced nephrotoxicity. Rats were divided into four groups: control group, MON group (10 mg/kg, orally), MTX group (20 mg/kg, i.p., single injection), and MON + MTX group (MON was administered 5 days before and 5 days after MTX administration). At the end of the experiment, serum was collected for analysis of blood urea nitrogen (BUN) and creatinine. Glutathione (GSH), lipid peroxides (malondialdehyde), tumor necrosis factor alpha (TNF-α) levels, superoxide dismutase, myeloperoxidase activities, and nuclear factor kappa beta (NF-κB) protein expression were determined in renal tissues. In addition, kidney tissues were examined histopathologically and immunohistochemically for NF-κB. MTX administration produced acute renal damage as indicated from severe elevation in BUN and serum creatinine. The role of oxidative stress and inflammatory mechanisms in MTX-induced nephrotoxicity was evidenced from the unbalance in tissue oxidative parameters, increased TNF-α levels, and NF-κB expression in renal tissues. On the other hand, MON significantly reduced the toxic effects of MTX as indicted from normalization of kidney-specific parameters, oxidative stress, and inflammatory mediators. This data was further supported by histopathological studies. Thus, co-administration of MON may be promising in alleviating the systemic side effects of MTX.