This study investigated the effect of protein malnutrition on metabolism and toxicity of cisplatin (CP), 5-fluorouracil (FU) and mitomycin C (MMC) in rat stomach. Weanling male Wistar rats received a normal (24%) or low (2.5%) protein diet for 28 days and were allocated into: normally-fed control, protein-malnourished control (PM), 3 normally-fed drug-treated groups and 3 protein-malnourished drug-treated groups (PM-CP, PM-FU and PM-MMC). Cisplatin and MMC were injected intraperitoneally (8 mg/kg on day 26 and 1 mg/kg/day for 7 days, respectively). 5-Fluorouracil was given orally (50 mg/kg/day for 5 days). Compared with normally-fed counterparts, PM-CP rats exhibited higher glutathione S-transferase, aminopeptidase N and cysteine S-conjugate beta-lyase (CCBL) and lower gamma-glutamyltransferase activities, PM-FU rats exhibited decreased dihydropyrimidine dehydrogenase and cytochrome P450 1A1/2 activities and PM-MMC rats showed higher quinone reductase and depleted xanthine oxidase activities. Protein-malnourished drug-treated groups exhibited exacerbated gastrotoxicity, relative to normally-fed counterparts, manifested by lower mucus levels, higher permeability and histopathological deterioration, along with increased oxidative stress in PM-CP rats and exaggerated prostaglandin E2 production in PM-MMC rats. Conclusively, protein malnutrition alters CP, FU and MMC metabolism in rat stomach by enhancing CCBL pathway for CP activation, delaying FU elimination and activating two-electron reduction of MMC, potentiating their gastrotoxicity.
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