POSTNATAL DEVELOPMENT OF LYMPHOID FOLLICLES IN THE PEYER'S PATCHES OF MALE ALBINO RAT HISTOLOGICAL AND HISTOCHEMICAL STUDIES

Abstract

The present research was done to study some histological and histochemical features of the Peyer's patches of male albino rat at different postnatal ages. Sixty-six animals were used at one, three, seven, fifteen and twenty-one days, one, two and three months, one and two years of ages. Each age include six animals. The ileum of each age was obtained immediately after anathesia and divided into proximal, middle and distal parts. Each part was examined by using some histological and histochemical procedures. It was found that the aggregated lymphoid follicles of Peyer's patches in the adult rats occupying the submucosa of the ileum and extends into the lamina propria. Four areas were observed: the eccentrically placed germinal center, the peripheral dark zone of small lymphocytes, interfollicular and dome areas, each of these areas has its own cell types and pattern of reticular fibers. Histochemically, the dome epithelium give positive reaction for alkaline phosphates enzyme that are intemtpted by irregular negative gaps which are corresponding to theM­ cell surfaces. Positive reactions were found within the follicle corresponding to dendritic cells and in the subepithelial area corresponding to the reticular cells. The Peyer's patches of newly born rat appear as diffuse lymphatic infiltration within the submucosa and extend to the lamina propria and projecting in some areas into the lumen fonning the dome. lntraepithelial lymphocytes, which are mostly infranuclear with no goblet cells, were observed in the dome epithelium. The primary follicles has been developed by the fifteen days of age which were corresponding to the appearance ofM-cells that demonstrated by histochemical method for alkaline phosphatase enzyme.