Meeting Abstract
16.2 Sunday, Jan. 4 Plasticity of the intestinal enterocytes of the Burmese Python. CECILE , Helmstetter; ROBERT , Pope; STEPHEN, Secor; JEAN-HERVE, Lignot*; University Louis Pasteur; University Louis Pasteur; University of Alabama; University Louis Pasteur J-H.Lignot@c-strasbourg.fr
Morphological changes observed in the intestinal lining of fed and fasting Burmese pythons were studied using immunohistochemistry, Western blotting, scanning and transmission electron microscopy techniques. During the first half of the postprandial period, absorbing enterocytes of fed snakes are enlarged, filled with lipids and possess elongated microvilli. Furthermore, the expression of the sodium pump is readily activated after feeding but mostly along the lateral membranes. Animals examined during the second part of the postprandial period as well as fasting snakes, possess numerous endosomes and related organelles such as numerous apical multivesicular bodies, early and late lysosomes as well as large lamellar lysosomes filled with concentric rings of lipid membranes. During this period, while some lysosomes are phagocytised by intraepithelial macrophages, others are moved to the chorion and submucosa where degradation inside macrophages takes place. Enterocytes also hypotrophy and drastically reduce the length of their apical microvilli. Furthermore, a new cell type within the mucosal epithelium is described that has an apical crypt that is empty in fasting animals. This cell type is only present in the proximal part of the intestine, is connected to the basal membrane, is devoid of large lipid droplets, possesses a large nucleus, and is less stained than its neighbouring absorbing enterocytes. In fed animals, the crypt is usually filled with a multi-layered spheroid particle made of calcium and phosphorus indicating therefore that this cell type is involved in calcium and phosphorus trafficking coming from the meal. Gut plasticity is therefore of crucial importance in Burmese pythons and relies mostly on rapid and massive morpho-functional changes of the enterocytes.
