BACKGROUND: The aim of this study was to evaluate the plasma concentrations of malondialdehyde (MDA) and nitric oxide (NO) and the plasma activities of oxidant and antioxidant enzymes in patients with IBS.

MATERIAL AND METHODS: A total of 36 patients with IBS were included in the study. Thirty-five healthy subjects were selected to form the control group. Superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GSH-Px), xanthine oxidase (XO), adenosine deaminase (AD) activities, and malondialdehyde (MDA) and nitric oxide (NO) concentrations were studied in the serum samples of all patients and controls.

RESULTS: Plasma XO and AD activities, and MDA and NO concentrations were significantly higher in IBS patients than in controls. The SOD, CAT, and GSH-Px activities in the serum of patients with IBS were significantly lower than that of controls.

CONCLUSIONS: These results suggest that lipid peroxidation and alterations in the oxidant-antioxidant enzymatic system may play a role in the pathogenesis of IBS. Increased lipid peroxidation in IBS may be related to an increase in NO level and XO activity and a decrease in antioxidant enzymes activities. In addition, increased AD activity may have a role in immunological changes of IBS patients.

Keywords: Catalase - blood, Adenosine Deaminase - blood, Glutathione Peroxidase - blood, Irritable Bowel Syndrome - physiopathology, Lipid Peroxidation - physiology, Malondialdehyde - blood, Nitric Oxide - blood, Oxidoreductases - blood, Superoxide Dismutase - blood, Xanthine Oxidase - blood