Induction of precocious intestinal maturation in T-cell deficient athymic neonatal rats

Figure 1 Epithelial maturation in the distal small intestine expressed as adult-type epithelium replacing the foetal-type vacuolated epithelium. A: Photomicrograph (× 200, scale bar 100 μm) of H&E stained distal small intestine representative of a rat after PHA gavage (right) as compared to a control rat (left), with white bar connectors showing the portion of adult-type epithelium along the villus. B: Degree of intestinal epithelial maturation (%) in nude 14 day old rat pups treated by gavage with a kidney bean lectin - PHA (n = 4) or water (Control n = 3) and reared by their own mothers (Nude/Nude) and nude rat pups gavaged with PHA (n = 5) once or once a day for 3 d (PHAx3 n = 7), a protease once (Prot n = 4) or once a day for 3 days (Protx3 n = 7) or water (Control n = 5) and fostered by conventional SD dams (Nude/SD). Data presented as mean ± SD and differences were considered significant when P < 0.05. Significant differences between groups within nurturing groups (Nude/Nude or Nude/SD) indicated with ^aP < 0.05, ^bP < 0.01, ^cP < 0.001, ^dP < 0.0001 or non-significant (ns).

Figure 2 Intestinal in vivo permeability. Plasma concentrations 3 h after gavage of the marker molecules: A: Bovine IgG (BIgG); B: Bovine serum albumin (BSA) in nude 17-day-old suckling rats after luminal provocation; C: Transfer of passive immunity via milk as plasma concentrations of immunoglobulin G (RIgG) in nude suckling 17-day-old rats after luminal provocation and compared to 17-day-old suckling conventional pups. Nude 14-day-old rat pups treated by gavage with PHA (n = 11) or water (Control, n = 8) and reared by their own mothers (Nude/Nude), and nude rat pups gavaged with PHA (n = 5) once or once a day for 3 d (PHAx3, n = 7), a protease once (Prot, n = 4) or once a day for 3 d (Protx3, n = 7) or water (Control, n = 5) and fostered by conventional SD dams (Nude/SD). Data presented as mean ± SD and differences were considered significant when P < 0.05. Significant differences between groups within nurturing groups (Nude/Nude or Nude/SD) and between control groups from different nursing sets indicated with ^aP < 0.05, ^bP < 0.01, ^cP < 0.001, ^dP < 0.0001 or non-significant (ns).

Figure 3 CD3⁺ cells in the intestinal mucosa of nude rats. Immunostaining of the proximal and distal small intestine in nude 17-day-old suckling rats after luminal provocation with PHA at 14 d of age or water-gavage (controls), nurtured by their mothers (Nude/Nude) or by conventional foster SD dams (Nude/SD) as compared to 17-day-old suckling conventional SD pups (SD/SD). Representative photomicrographs (× 200, scale bar 100 μm) of immunostained CD3⁺-cells in the small intestine. Positive cells indicated by arrows. PHA: phytohaemagglutinin.