The Effect of Whey Proteins on the Brain and Small Intestine Nitric Oxide Levels: Protein Profiles in Methotrexate-Induced Oxidative StressSümeyye Yılmaz, Elif Tufan, Güzin Göksun Sivas, Begüm Gürel Gökmen, Ercan Dursun, Dilek Özbeyli, Göksel Şener, Tuğba Tunalı Akbay
Objectives: The aim of this study was to determine the effects of whey proteins on methotrexate (MTX)-induced brain and small intestine damage. Materials and Methods: 30 Sprague Dawley rats (200-300 g) were divided into four groups: Control, control + whey, MTX, and MTX+whey. MTX was administered at 20 mg/kg (single dose) intraperitoneally to the MTX group rats, and 2 mg/kg of whey protein were administered by oral gavage for 10 days to the whey groups. Lipid peroxidation, glutathione, and nitric oxide (NO) levels, as well as glutathione-S-transferase and superoxide dismutase activities were measured in the brain and small intestine. SDS-polyacrylamide gel electrophoresis of the brain and intestine tissues were also carried out. Results: While MTX treatment caused oxidative damage in the brain and small intestine, whey protein administration ameliorated MTXinduced oxidative stress. MTX administration did not change the brain’s NO level, while an increase in intestinal NO level was detected. Conclusion: MTX induced oxidative stress in the brain and small intestine changed the protein metabolism in these tissues regardless of reduced food intake. Consecutive 10-day administration of whey proteins has shown its therapeutic effect on MTX-induced brain and small intestine oxidative damage.