Age-associated derangement of intestinal permeability could permit increased systemic absorption of lumen antigens and contribute to concomitant inflammatory status, closely associated with many age-related diseases. GLP-2 can improve the function of the intestinal barrier in patients with gastroenterological diseases and critical illnesses. However, the mechanism, by which GLP-2 influences intestinal barrier function during ageing, still remains unclear. In this study, twelve 26-month-old male Sprague-Dawley rats were randomized to old group and old+GLP-2 group. 3-month-old male SD rats were used as control group. Compared with young rats, the old rats had a significantly thinner intestinal mucosa and shorter, rare villi. The ileum villi of old rats were significantly thicker after GLP-2 treatment. By using fluorescein isothiocyanate (FITC)-labeled dextran, the intestinal permeability in GLP-2 treated old rats were decreased. The plasma GLP-2 levels were negatively correlated with the FITC levels (r=-0.610, P<0.01). The tight junction of intestinal epithelial cells, as detected by transmission electron microscopy, was clearer in the old+GLP-2 group than that in old rats. Moreover, GLP-2 treated rats showed the increased mRNA and protein expression of Zonula Occludens-1 (ZO-1) and Occludin. These results indicated GLP-2 improve the small intestinal epithelial barrier function in aged rats by alleviating an increasing permeability and morphological changes through up-regulation of the tight junction protein ZO-1 and Occludin.
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