Leukocyte infiltration and anti-myeloperoxidase immunoreactivity in granulocytes of the mucosa and submucosa of the large intestine of horses submitted to dietetic starch overload

Abstract

This study was carried out to evaluate leukocyte infiltration and anti-myeloperoxidase immunoreactivity in granulocytes of the mucosa and submucosa of the large intestine of horses submitted to dietetic starch overload. Eight adult horses were allocated randomly in three treatments: Treatment I (Control) (n = 2), animals euthanized without starch overload; and Treatments II (n = 3) and III (n = 3), animals undergoing starch overload, with gastric infusion of 17.6 g starch per kg of body weight, euthanized after 24 and 36 hours, respectively. Only afflux of neutrophils in the intestinal mucosa and submucosa blood vessels (leukocyte stasis) was observed. Eosinophils were the predominant cells in the mucosa and submucosa in all horses, independent of dietetic overload, with infiltration grade from mild to moderate. Lymphocyte infiltration was also observed in all horses, but with lower intensity when compared to eosinophils. Congestion, edema and dilatation of lymphatic vessels were the main circulatory alterations observed, with more intensity in the submucosa. Higher immunoreactivity to the anti-myeloperoxidase antibodies was observed in the mucosa and submucosa of horses 36 hours after overload. Horses submitted to dietetic starch overload showed intestinal inflammatory response with prevalence of eosinophils, leukocyte stasis and circulatory alterations, varying from discreet to moderate.