Alteration of intestinal barrier function during activity-based anorexia in mice.

BACKGROUND & AIMS: Anorexia nervosa is a severe eating disorder often leading to malnutrition and cachexia, but its pathophysiology is still poorly defined. Chronic food restriction during anorexia nervosa may induce gut barrier dysfunction, which may contribute to disease development and its complications. Here we have characterized intestinal barrier function in mice with activity-based anorexia (ABA), an animal model of anorexia nervosa.
METHODS: Male C57Bl/6 ABA or limited food access (LFA) mice were placed respectively in cages with or without activity wheel. After 5 days of acclimatization, both ABA and LFA mice had progressively limited access to food from 6 h/d at day 6 to 3 h/d at day 9 and until the end of experiment at day 17. A group of pair-fed mice (PF) was also compared to ABA.
RESULTS: On day 17, food intake was lower in ABA than LFA mice (2.0 ± 0.18 g vs. 3.0 ± 0.14 g, p < 0.001) and weight loss was more pronounced in ABA and PF compared to LFA mice (23.6 ± 1.6% and 24.7 ± 0.7% vs. 16.5 ± 1.2%; p < 0.05). Colonic histology showed decreased thickness of the muscularis layer in ABA compared to LFA mice (p < 0.05). Colonic permeability was increased in both ABA and PF compared to LFA mice (p < 0.05) but jejunal paracellular permeability was not affected. Expression of claudin-1 in the colon was lower in the ABA than the LFA group (p < 0.05), whereas occludin expression remained unaffected.
CONCLUSION: Increased colonic permeability and histological alterations found in ABA mice suggest that intestinal barrier dysfunction may also occur in anorexia nervosa. The role of these alterations in the pathophysiology of anorexia nervosa should be further evaluated.