Goblet cells and intestinal Alkaline phosphatase expression (IAP) during the development of the rat small intestine

This study aimed to evaluate the temporal and spacial distribution of the mucins produced by goblet cells and intestinal alkaline phosphatase (IAP) expression during the development of the small intestine of the rat. Intestines were removed from rats on the 15th, 17th and 18th days of intratuterine life (i.u.) and on the 3rd, 10th, 17th and 25th days after birth (a.b.). Intestines were processed for routine histological procedures and sections were submitted to histochemistry using PAS to stain neutral glycoproteins and Alcian blue for acidic glycoproteins, as well as immunohistochemistry to detect IAP. In rats, glycoprotein production was seen to begin in the intestinal epithelium cell at around the 17th day of i.u. life; however, this production was not accompanied by morphological indications of the presence of goblet cells. By the 18th i.u. day, the villus epithelium was undergoing differentiation and the first goblet cells could be identified from this time. At around the 10th day a.b., both compartments of the small intestine were detected; i.e. the villi and the crypts. At this timepoint, goblet cells were present in the villi, and also in the upper regions of the crypts. On the 3rd, 10th 17th and 25th days a.b., the presence of the goblet cells increased and presented regional differences in the sections evaluated. IAP was not detected during i.u. life, but was weakly detected in the cells of the villi from the 3rd day a.b., along the entire extension of the villi. On the 10th day, IAP was detected at the tip of the villi, while on the 25th day, it was detected along the extension of the villi, but with a weaker intensity. In conclusion, a temporal and spacial distribution of goblet cells and IAP activity occurs during the development of the small intestine, suggesting a possible regulatory control in accordance with the suckling and weaning phases of food intake in the rat's life.