Glutamine-supplemented parenteral nutrition improves gut mucosa integrity and function in endotoxemic rats

The effects of glutamine-supplemented parenteral nutrition on protein metabolism, small intestinal mucosal metabolism, morphology, and barrier function were studied in endotoxin-treated rats. Forty-six male Wistar rats were randomized to two groups of 23 animals each and received total parenteral nutrition solutions supplemented with either glutamine (GLN group) or glycine (GLY group) at 2% wt/vol. Endotoxemia was induced by continuous intravenous infusion of endotoxin at a dose of 2 mg/kg per day throughout the 4-day study period. The GLN group had a less-negative cumulative nitrogen balance (-14.0 +/- 132.8 mg of nitrogen in the GLN group and -86.8 +/- 161.7 mg of nitrogen in the GLY group, p < .05) and less cumulative excretion of urinary 3-methylhistidine (2910 +/- 593 nmol) than the GLY group (4447 +/- 933 nmol, p < .01). Jejunal mucosal glutaminase activity and the arterio-portal venous blood glutamine concentration differences were significantly higher in the GLN group compared with the GLY group (15.6 +/- 2.3 vs 11.1 +/- 1.9 mumol/g per minute, p < .05, and 181 +/- 52 vs 147 +/- 36 nmol/mL, p < .05, respectively). The morphology of the jejunal mucosa in the GLN group was significant for having greater mucosal weight (23.4 +/- 3.1 vs 17.6 +/- 2.5 mg/cm), villus height (445 +/- 75 vs 357 +/- 57 microns), crypt depth (197 +/- 34 vs 161 +/- 28 microns), and wall thickness (751 +/- 77 vs 648 +/- 102 microns) than the GLY group (p < .05).(ABSTRACT TRUNCATED AT 250 WORDS)