INTERACTION OF REACTIVE OXYGEN SPECIES AND MUCOSAL DEFENCE ENZVMES IN THE PATHOGENESIS OF MUCOSAL DAMAGE IN GASTRODUODENAL DISEASES

Abstract

Lipid Peroxidation products are present under physiological conditions in gastroduodenal mucosa, in micromolars concentration. This is in keeping with previous studies, which showed the presence of such products in blood, urine [Acworth et a1, 1997] and oesophageal tissue [Levy et a1, 1998] under physiological conditions. This also proves the theory that it the delicate balance between oxidative stress and cellular defence mechanism that should be disturbed before damage can occur. LPO products were found to be significantly increased in

gastroduodenal infla mmation

and ulceration. In spite of the wide

scatter of results, which show individual variation within each group of patients in responding to oxidative stress, there was a statistically significant increase in LPO product concentration in gastric and duodenal ulcers when compared to the normal healthy mucosa. Moreover, in paired samples taken from the same patients , we were able to show the increase of LPO product in ulcer edge compared to adjacent inflamed mucosa. This work provides a direct evidence that lipid peroxidation is one of the important mechanisms by which oxidative stress can cause damage to gut mucosa, and can be a practical application of the work of Yajima et al (1995) who showed that oxidative stress cause lipid peroxidation in rat cultured cells that is followed by cytolysis. Results of Enzyme expression

It has been shown now that LPO product are themselves toxic to the cells in many ways [Moore & Roberts, 1998]. Therefore, it is clear that the classic endogenous antioxidants (GSH and the enzymes SOD,