TOTAL PARENTERAL-NUTRITION DECREASES LUMINAL MUCOUS GEL AND INCREASESPERMEABILITY OF SMALL-INTESTINE

The distribution of fluorescein isothiocyanate dextran 70,000 (FITC-de xtran) and mucous gel across the lumen of small intestine was observed as an investigation into the role of mucous gel on permeability in to tal parenteral nutrition (TPN). Thirty-two rats were randomly divided into two groups fed with either TPN or oral rat food. On day 4 or 7, F ITC-dextran (750 mg/kg body weight) was given through the gastroduoden al tube. After 1 hour, blood samples were taken by aortic puncture to analyze plasma FITC-dextran by fluorescence spectrometry. Samples of s mall intestine with luminal contents were frozen and sectioned in a cr yostat for fluorescence microscopy; the same sections were placed in a 0.2% celloidin solution for 3 minutes to preserve mucous gel and stai ned by periodic acid-Schiff reaction for light microscopy. The plasma level of FITC-dextran after 1 hour of this marker injection showed a s ignificant increase (p < .01) in the TPN group compared with the mt fo od group on days 4 and 7. Morphologic findings on days 4 and 7 were si milar in both the jejunum and ileum: The mucous gel filled the spaces between villi and FITC-dextran centered in the lumen in the rat food g roup, whereas the mucous gel decreased and FITC-dextran filled the spa ces between villi in the TPN group. FITC-dextran and mucous gel showed complementary distributions in both groups. These data suggest that T PN decreases luminal mucous gel and increases permeability of small in testine in rats.