Quantitative study of changes in intestinal morphology and mucus gel on total parenteral nutrition in rats

Quantification of changes in gastrointestinal morphology and mucus gel has been difficult to study. In the present study, we investigated changes in r at intestine under total parenteral nutrition (TPN) using fluoresceinated l ectin staining and image analysis. Wistar rats (n = 34) were divided into t wo groups: one group received TPN for 2 weeks, and a control group received standard rat chow and water ad libitum for the same period. A l-cm segment of distal ileum was removed and cut into cross sections. Sections were sta ined with hematoxylin and eosin, and to stain the mucus, periodic acid-Schi ff (PAS), alcian blue (AB), and fluoresceinated lectin, that is, FITC-label ed Ulex europaeus agglutinin I (FITC-UEA-I), were used. Light microscope im ages were stored in a personal computer and analyzed using image analysis. We measured perimeter length, mucosal thickness, villus area, villus surfac e area index, mucus stain-positive area, mucosal area ratio, and mucosal su rface area ratio. Perimeter length, mucosal thickness, villus area, and vil lus surface area index in the TPN group were significantly less than those in the control group (P < 0.001 for each parameter). In all mucus stainings , the stain-positive area in the TPN group was significantly less than that in the control group. However, there were no significant differences in mu cosal area or mucosal surface area ratios between the two groups. The FITC- UEA-I-positive area was significantly greater than the PAS- or and AB-posit ive area. There were significant positive correlations between the FITC-UEA -I-positive area and both the PAS positive and AB-positive areas. TPN for 2 weeks promoted intestinal atrophy and decreased absolute quantity of mucus gel. We successfully introduced the FITC-UEA-I staining method to evaluate changes in mucus gel. (C) 2000 Academic Press.