Effects of quercetin on methotrexate-induced nephrotoxicity in rats

OBJECTIVE: This experimental study was conducted to elucidate the possible protective/therapeutic effects of quercetin against methotrexate (Mtx)-induced kidney toxicity with biochemical and histopathological studies. METHODS: Twenty-four adult male rats were randomly divided into four groups, as follows: control group (saline intraperitoneally (i.p.), 9 days), Mtx group (20 mg/kg i.p., single dose), Mtx + quercetin group (50 mg/kg quercetin was orally administered 2 days before and 6 days after Mtx administration) and only quercetin group (50 mg/kg oral, 9 days). Structural changes were evaluated by hematoxylin-eosin and periodic acid-Schiff stainings. Apoptotic changes were investigated by terminal deoxynucleotidyl transferase dUTP nick end labeling assay and caspase-3 antibody. Superoxide dismutase (SOD) and malondialdehyde (MDA) levels were measured in tissue and plasma samples. RESULTS: Mtx compared with the control group, there was significant increase in nephrotoxic tissue damage findings, in addition to apoptotic index (APOI) and caspase-3 expression ( p < 0.05). Mtx + quercetin group revealed significantly lower histopathological damage and APOI and caspase-3 expression decreased when compared to Mtx group. MDA levels were increased in Mtx group compared to others, and by the use of quercetin, this increase was significantly reduced. SOD levels were higher in Mtx group than others. This increase was evaluated as a relative increase arising from oxidative damage caused by Mtx. CONCLUSION: As a result, Mtx administration may involve oxidative stress by causing structural and functional damage in kidney tissue in rats. Quercetin reduced the Mtx-induced oxidative stress through its antioxidant properties and so quercetin may be promising to alleviate Mtx-induced renal toxicity.