Effects of parenteral glutamine supplementation on modulating the immune response in rats undergoing a total gastrectomy.

The present study investigated the effect of parenteral glutamine (Gln) supplementation on cellular adhesion molecule expression and release of chemokines responsible for inflammatory cell recruitment in rats undergoing a total gastrectomy. Normal rats with internal jugular catheters were assigned to one control group and two experimental groups and received total parenteral nutrition (TPN). A total gastrectomy was performed in the experimental groups, whereas the control group received a sham operation (Sham). The TPN solutions were isonitrogenous and identical in nutrient composition except that the Sham group and one of the experimental group received conventional (Conv) TPN solution, whereas the other experimental group received 25% of the amino acid nitrogen as Gln. Half of the rats in each group were killed 1 or 3 d after surgery or the Sham to examine their immune response. The results showed that the surgery produced higher polymorphonuclear leucocyte CD11b/CD18 expressions, and Gln supplementation lowered CD11b/CD18 expressions compared with the Conv group post-operatively. The levels of monocyte chemotactic protein-1 and macrophage inflammatory protein-2 in peritoneal lavage fluid were higher in the Gln group than those in the Conv group 1 d post-operatively; these chemotactic proteins had returned to the levels comparable with those in the Sham group on post-operative day 3. These results suggest that Gln supplementation attenuated polymorphonuclear leucocyte integrin expression. In addition, Gln-enriched parenteral nutrition induced an earlier more intensive and rapid immune response to injury than the Conv parenteral nutrition after a total gastrectomy.

Effects of omega-3 fatty acids on inflammatory mediators and splenocyte cytokine mRNA expressions in rats with polymicrobial sepsis.

OBJECTIVES: Many studies have shown that omega-3 fatty acids (FAs) have immunomodulatory effects. However, the influence of omega-3 FAs on septic conditions is not certain. This study examined the effect of fish oil (FO)-enriched diets before and/or omega-3 FA-containing total parenteral nutrition (TPN) after sepsis on the distribution of T-lymphocyte subpopulations and splenocyte cytokine mRNA expressions in rats with polymicrobial sepsis. METHODS: Rats were assigned to a control group and four experimental groups. The control group and groups 1 and 2 were fed a semipurified diet, and groups 3 and 4 had 20% soybean oil replaced by FO. After feeding the diets for 10 d, sepsis was induced by cecal ligation and puncture (CLP) in the experimental groups, whereas sham operation was performed on the control group. TPN was maintained for 3 d after CLP or sham operation. The control group and groups 1 and 3 were infused with conventional TPN, whereas the TPN solution of groups 2 and 4 was supplemented with FO. All rats were sacrificed 3 d after the operation to examine their immune responses. RESULTS: Messenger RNA expressions of interleukin-2 and tumor necrosis factor-alpha in splenocytes were higher in groups 3 and 4 than in the control group and group 1. Interleukin-10 mRNA expression in group 3 was higher than in the control group and group 2. Blood CD4 percentage and CD4/CD8 ratio in group 1 were significantly lower, whereas no differences were observed in FO-supplemented groups compared with the control group. CONCLUSION: FO administration before and/or after CLP maintained blood T-lymphocyte subpopulations and modulated T-helper type 1 and 2 cytokine mRNA expressions in rats with polymicrobial sepsis.

Effects of oral arginine and glutamine on radiation-induced injury in the rat.

BACKGROUND: Exposure of the abdominal region to ionizing radiation is associated with serious untoward symptoms of intestinal dysfunction and some reports indicate that nutrient supplements may reduce these adverse effects. This study was designed to investigate the possible beneficial effects of oral arginine or glutamine supplementation on the radiation-induced tissue injury. MATERIALS AND METHODS: Rats were given one of three feeding regimens: standard diet and water (control group), diet and water containing 2% arginine (arginine group), diet and water containing 2% glutamine (glutamine group) for 3 days prior to radiation. All rats were then subjected to a single does of 1100 cGy to the abdomen. Several serum biochemical parameters and the histologic alterations in different segments of gastrointestinal tract and liver were measured 4 days after irradiation. RESULTS: All the arginine-fed rats developed diarrhea on Day 4 postirradiation, compared to 71% incidence in control rats and 86% in glutamine-fed rats. Serum levels of aspartate aminotransferase (AST) and lactate dehydrogenase (LDH) in the arginine group were markedly higher than those in other groups. On histological examination, radiation caused more serious damage to various segments of intestine in the arginine-fed rats compared to rats on other feeding regimens. CONCLUSION: These observations seriously question the beneficial effects of arginine and glutamine supplementations on radiation-induced tissue injury.