LUMINAL FACTORS STIMULATE INTESTINAL REPAIR DURING THE REFEEDING OF MALNOURISHED INFANT RABBITS

We examined the role of luminal versus systemic factors in promoting i ntestinal recovery during the refeeding of previously malnourished inf ant rabbits. Malnutrition was induced by litter expansion at 7 days of age. A 20-cm Thiry-Vella (T-V) loop was created in the intestine of e ach malnourished and dietary control animal at 21 days of age. Beginni ng on day 28, controls and one half of the malnourished group (malnour ished-refed) were fed chow ad libitum, whereas the remainder of the ma lnourished group received half the amount of chow given to the malnour ished - refed group. On day 35, proximal and distal segments from the intact intestine that remained in continuity as well as segments from the excluded T-V loops were examined. Malnutrition severely reduced mu cosal mass and disaccharidase activities in the intact distal intestin e. A brief period of refeeding led to a rapid recovery of these parame ters. In contrast, the excluded T-V loop segments of the control, maln ourished, and malnourished-refed groups all displayed decreased mucosa l mass and impaired function to a degree similar to that observed in t he intact distal segment from the malnourished group. These results in dicate that luminal factors are essential for (i) the maintenance of n ormal intestinal structure and function in infant rabbits and (ii) the promotion of mucosal repair following nutritional rehabilitation of m alnourished animals.