ABSORPTION AND GASTROINTESTINAL OXIDATIVE INJURY IN KM MALE RATS FED OXIDIZED
CASEIN
S. Y Ann Nutr Metab 2013;63(suppl 1): 361
Protein oxidation is one of the important causes of many degenerative diseases. Protein oxidation in food process is of frequent occurence. However, the health impacts of oxidized products of food proteins in vivo have been unexplored. The aim of this study was to determine whether oxidized casein products can enter blood circulation, and to evaluate oxidative effects on the digestive organs of rats.
Methods: Westar male rats were administered orally with origin casein (control£¬C) and casein oxidized by H2O2 (0.4mmol/g prot) combined with Cu (H2O2-Cu) and HClO (0.4mmol/g prot).The chyme of intestine, blood of portal and peripheral vascular were taken for determination after 0.5, 1.0,
1.5, 2 hr.
Results: Advanced oxidation protein products (AOPPs), dityrosine (Dtyr) and carbonyls were significantly (p<0.05) increased in rats administered with oxidized casein, while thiol content decreased. Reactive oxygen species (ROS) levels in blood were also higher than in controls 0.5~2 h after perfusion, levels of AOPPs, Dtyr, carbonyl, and thiol in blood exhibited strong correlations with those in casein samples. Furthermore,
analysis of chyme£¬plasma of portal and peripheral vascular via HPLC-MS demonstrated the absorption of oxidized-casein products including Dtyr and peptide carbonyls. ROS, malonyladehyde and protein carbonyls in blood, liver, duodenum and jejunum were significantly (p<0.05) elevated. Total antioxidants and activities of superoxide dismutase, catalase and glutathione peroxidase were decreased.
Conclusions: Oxidized casein products could be absorbed and possibility causing oxidative damage to digestive organs in rats.