Effects of chronic protein-calorie malnutrition on small intestinal repair after an acute bacterial enteritis: a study in infant rabbits.

The aim of this study was to determine if recovery of intestinal function in infant rabbits subjected to protein-calorie malnutrition was delayed as a result of inflammatory injury induced by an experimental bacterial enteritis. Rabbits were malnourished by expanding litter size at 7 days of age and infecting undernourished animals and dietary controls with Yersinia enterocolitica at either 17 or 21 days of age. Intestinal morphology and function were evaluated in infected and noninfected animals from both dietary groups at 27 days of age. Undernutrition alone significantly reduced animal weight, small intestinal weight, segmental jejunal and ileal mucosal weight, villus height, crypt depth, disaccharidase activities, mucosal protein and DNA contents, but increased ileal short-circuited glucose-stimulated Na+ absorption compared to controls. The jejunum of undernourished rabbits at 6 days postinfection exhibited an intestinal injury, as evidenced by a mild inflammatory infiltrate and further reductions in villus height, mucosal weight, lactase activity, protein and DNA content, not seen in infected dietary controls. Jejunal recovery was complete by 10 days postinfection. In the ileum of infected animals of both dietary groups at 6 days post-infection, a severe inflammatory response, decreased villus height, elongated crypts, and depressed stimulation of Na+ absorption by glucose was observed. By 10 days after infection, while recovery was nearly complete in dietary controls, intestinal damage persisted in the undernourished rabbits, as evidenced by absent glucose-stimulated Na+ absorption, continued severe inflammation and microabscess formation. We conclude that intestinal injury is more severe and chronic in the undernourished, compared to dietary control infant rabbits subjected to an acute bacterial enteritis.