Immunomodulatory effects of ornithine alpha-ketoglutarate in rats with burn injuries

To investigate the influence of enterally administered ornithine alpha-ketoglutarate (OKG) on muscular amino acid content, eicosanoid release, and polymorphonuclear leukocyte responsiveness after induction of burn injury in rats.

Experimental trial.

Four groups of rats were considered: (1) healthy rats that received a standard diet supplemented with 5 g/kg per day of OKG; (2) rats with burn injuries that received the same nutrition as group 1; (3) healthy rats that received standard diet supplemented with glycine in an isonitrogenous amount relative to OKG; and (4) rats with burn injuries that received the same nutrition as group 3. The thymus and 1 skeletal muscle were weighed. The oxidative metabolism of pleural polymorphonuclear leukocytes was measured by means of superoxide generation (O2-) and the chemiluminescent response to opsonized zymosan. Prostaglandin E2 and 6-keto-prostaglandin F1 alpha were measured in the supernatants of pleural and peritoneal cells.

The weights of the thymus and the muscle from healthy rats were similar. Those of rats from group 4 were significantly lower (P < .05), whereas those of rats from group 2 were not. Metabolism of OKG led to enhanced amounts of arginine and glutamine in skeletal muscle. The metabolic bursts of polymorphonuclear leukocytes from healthy rats were similar. Those of glycine-treated rats with burn injuries were significantly depressed (P < .05), whereas those of the OKG-treated group were not. Pleural and peritoneal cells from the rats with burn injuries that received OKG generated significantly more prostaglandins (P < .01) than did cells from the other groups of rats.

Ornithine alpha-ketoglutarate administered to rats with burn injuries displays immunomodulatory properties that can enhance host-defense mechanisms in animals that are affected by a severe injury.