Meeting Abstract

P2.81  Sunday, Jan. 5 15:30  Compensatory Changes in the Small Intestine Morphology in Response to Lactation and Dietary Protein SHORT, K.E.*; DERRICKSON, E.M.; Loyola University Maryland, Baltimore; Loyola University Maryland, Baltimore keshort@loyola.edu

Digestive systems exhibit morphological flexibility in response to different dietary demands and constraints. Previous research in our lab indicated that mice may have morphological adaptations that allow them to accommodate a lower level of protein in their diet. Our hypothesis is that mice modify their gut to increase assimilation efficiency in response to low dietary protein. Our prediction is that villus height, crypt depth, and cell size will increase on low protein diets. Mice (Mus musculus, ICR strain) were randomly placed on isocaloric diets containing either 11.5% protein (low) or 23.0% protein (control). Mice were divided into reproductive and non-reproductive groups, and were maintained on their diets for six weeks. Mice were dissected and intestinal segments from the proximal, mid, and distal areas were excised, fixed, embedded, sectioned, and stained. Measurements of villus height, apex width, base width, crypt depth, intestinal perimeter and enterocyte size were taken. All measurements differed by intestinal location. Lactating mice exhibited greater perimeters, villus height, crypt depth and apex width. Diet had no effect on villus measurements at the tissue level which was partially attributable to small sample size and variation in tissue shrinkage by location and diet. Decreased dietary protein, however, was associated with increased enterocyte width at the proximal location, especially in lactating mice, and increased enterocyte width at the distal location, especially in lactating mice. The results for enterocytes give support to our hypothesis that mice modify their intestine in response to dietary deficiency of protein.