ROLE OF REACTIVE OXYGEN SPECIES IN SALMONELLA TYPHIMURIUM-INDUCED ENTEROCYTE DAMAGE

Background: Reactive oxygen species (ROS) are potent mediators of infl ammatory cell-mediated tissue destruction and may be of pathophysiolog ic importance in Salmonella typhimurium-induced tissue damage. Methods : In this study the ligated rat ileal loops were injected with Salmone lla live culture or toxin. The ROS generation was detected by measurin g the mucosal myeloperoxidase (MPO) activity; the enterocyte xanthine oxidase (XO) activity, and the chemiluminescence response of gut macro phages. The enterocyte damage was estimated by measuring the extent of lipid peroxidation and cell viability. Results: Treatment with Salmon ella Live culture or toxin resulted in an increase in the mucosal MPO activity, the enterocyte XO activity, and the chemiluminescence respon se of macrophages. Treated loop enterocytes had an increased extent of Lipid peroxidation and decreased cell viability. Cell viability was a lso decreased when the enterocytes were ct-cultured with macrophages i solated from the treated loops. Lipid peroxidation decreased, and cell viability increased in the presence of superoxide dismutase (SOD) or catalase. Conclusions: The S. typhimurium-mediated intestinal infectio n is accompanied by an increased generation of ROS, which may induce t he lipid peroxidation of the enterocyte membrane, thereby leading to a loss of cell viability.