LAUSR

Background: The protective effect of mistletoe extract (Helixor®, HLX) against methotrexate (MTX)-induced acute oxidative stress and nephrotoxicity in rats was evaluated by histological and biochemical methods as well as the comet assay. Material and Methods: 32 female Wistar albino rats were divided into 4 groups: control group, HLX group (5 mg/kg body weight (bw), days 1-10, intraperitoneally (i.p.)), MTX group (10 mg/kg bw, days 7, 8, and 9, i.p.), and MTX + HLX group (10 mg/kg bw, days 7, 8, and 9, i.p. + 5 mg/kg bw, days 1-10, i.p.). At the end of the experiment, the glutathione peroxidase (GSH-Px), superoxide dismutase (SOD), nitric oxide (NO), and myeloperoxidase (MPO) levels were measured, and a histopathological analysis and comet assay were carried out. Results: MTX induced renal oxidative stress and nephrotoxicity in the rats. Pretreatment with HLX significantly improved the renal GSH-Px and SOD activities in the MTX + HLX group compared to the MTX group. The decrease in the NO and MPO levels in the rat groups pretreated with HLX was not significant. The histochemical evaluation revealed that HLX provided significant improvement in the MTX-induced renal degenerative changes, including tubule distension, interstitial inflammation, perirenal inflammation, glomerular congestion, glomerular degeneration, and parenchymal hemorrhage, in the MTX + HLX group compared to the MTX-administered group. According to the comet assay, pretreatment with HLX lowered the MTX-induced DNA damage in endogenous lymphocytes, although not significantly. Conclusion: This study demonstrated that HLX administration markedly reduced the MTX-induced acute oxidative stress and nephrotoxicity in rats through its antioxidant and anti-inflammatory properties.