Effects of alanyl-glutamine on gut barrier function.

Traditional parenteral nutrition (PN) and chemotherapy may lead to changes of mucosal morphology and gut barrier function. This study investigated the effect of alanyl-glutamine (Ala-Gln) on intestinal morphology and gut barrier function in PN-fed rats challenged with 5-fluorouracil (5-FU). Male Wistar rats were centrally catheterized and then randomized to receive PN devoid of glutamine (control group; n = 10) or 3% Ala-Gln-supplemented PN (study group; n = 10) for 7 d. Intestinal permeability to lactulose and mannitol was measured before and 72 h post 5-FU administration on day 4. Serum glutamine concentration and jejunal mucosal structure were maintained in the study group compared with the control group (P < 0.05). The bacterial translocation rates of mesenteric lymph nodes in the study group were significantly lower than the control (30% versus 90%; P < 0.05). No significant differences was found between the control and study groups with respect to ratio of lactulose and mannitol excreted in urine (L/M) (0.026 +/- 0.005575 versus 0.022 +/- 0.03079; P > 0.05) on day 3. On day 7, L/M was unaltered in the study group, whereas it increased in the control (0.042 +/- 0.004634 versus 0.029 +/- 0.002020; P < 0.05). We concluded that glutamine dipeptide maintained intestinal mucosal morphology and barrier function in PN-fed rats challenged with 5-FU.