The prophylactic and therapeutic effects of glutamine- and arginine-enriched diets on radiation-induced enteritis in rats

Background. Recent studies indicated that glutamine and arginine support the mucosal barrier in several ways. This experimental study hypothesized that administration of glutamine- and arginine-enriched diets before abdominal radiation therapy would provide a radioprotective effect on intestinal mucosa, and this would augment the therapeutic effectiveness provided by postirradiation administration. Materials and methods. A rat model of radiation enteritis was designed with a single dose of 1100 cGy to the abdomen. Thirty-five rats were randomized into five groups of seven, A 7-day glutamine-enriched diet for Group I and a 7-day arginine-enriched diet for Group II were administered both pre- and postradiation. For Groups III and IV, the same glutamine and arginine diets were given, respectively, postradiation only. Group V was fed a glutamine- and arginine-free diet and was the control group. The rats underwent laparotomy for culture of mesenteric lymph nodes and removal of segments of ileum, jejenum, and colon for microscopic examination. Results. Bacterial translocation was significantly higher in Group V (P < 0.05), while intestinal villus count and villus height were significantly higher in all of the groups fed glutamine and arginine when compared with the control group (P < 0.0001 and P < 0.05, respectively). Conclusion. Both arginine- and glutamine-enriched diets have protective effects on gut mucosa in the postirradiation state; however, pre- and postirradiation administration together does not provide superior protection versus postradiation administration alone. (C) 2000 Academic Press.