Peroxidase activity in the intestinal tract of Wistar-Furth, BBc and BBdp rats

BACKGROUND: The development of immune-mediated diabetes in BB rats may involve an inflammatory lesion of the intestinal tract. METHODS: In order to further explore this issue, the activity of peroxidase was measured, in the absence and presence of either bromide or dapsone, at day 10, 30, 45, 70, 95 and 120 in three segments (top, mid and bottom) of the intestinal tract from Wistar-Furth rats and both diabetes-resistant and diabetes-prone BB rats fed after weaning either diabetes-promoting diets or a protective diet, which decreases the incidence of diabetes in the BB rats. RESULTS: In the present study, from day 30 onwards, an age-related increase in peroxidase activity was found in the intestine of diabetes-prone BB rats (BBdp rats) fed diabetogenic diets, when compared with either Wistar-Furth or diabetes-resistant BB rats (BBc rats). This increase was most pronounced in the distal segments of the intestinal tract. Even when fed a protective diet, higher peroxidase activity was found in BBdp than BBc rats. Yet, in BBc rats, and to a lesser extent in BBdp rats, the diabetogenic diets lowered peroxidase activity below the value found in rats of the same strain fed the protective diet. There was a tight correlation between the activity of peroxidase and its susceptibility to be increased by bromide. CONCLUSION: It is proposed that diabetogenic diets may decrease peroxidase activity in intestinal cells, this effect becoming masked in BBdp rats by an age-related increase in the contribution of inflammatory cells. The latter phenomenon affects preferentially the distal segments of the intestinal tract.