Abstract

This study was designed to investigate the long-term effects of a high-protein diet on the functional and histological structure of the intestinal epithelium. Sixteen adult male Wistar rats (180 ± 2.27 g) were divided into two groups: 1) the control group, (n = 30) were fed a normal diet of 14% protein; 2) the P50-group (n = 30) were fed a 50% protein diet. The effects of a high-protein diet were studied over a period of 2 months. Functional and morphological differences between the high-protein and control groups were compared. Internal organs (liver, stomach, lungs, heart, kidneys, spleen, intestine, skin, surrenal glands, white and brown adipose tissues) were removed from each sacrificed animal. The organs were weighed, and histological studies were performed on jejunal fragments. The weight of the P50 group rats increased 79%, while the weight of the control-group increased 98% (p< 0.01 ≤ 0.05). The weight of the white adipose tissue, the skeleton and the skin were significantly greater in control-group rats (p< 0.01). An important modification of the epithelial structure in the intestine was observed in rats of the P50 group. The average length of their villi was significantly reduced and there was a significant increase in their IEL (p< 0.01).  Our results indicate that ingestion of a protein-rich diet over a long period leads to modification of the histological structure of the intestinal epithelium, as indicated by; pronounced atrophy of mucosa; marked inflammatory infiltration of lymphocytes in the chorion; and many intra-epithelial lymphocytes.

Key words: Food intake, high-protein diet, intestine, intra-epithelial lymphocytes, milk proteins.