Enternal arginine supplementation stimulates DNA synthesis in skin donor wound

Background & aims: Arginine infusion has been demonstrated to increase wound protein deposition; however, the effects of its enteral supplementation on wound cell proliferation have not been studied. Methods: Skin donor wound was created on the back of rabbits. The rabbits were randomly assigned to receive a control enteral diet, or the control enteral diet with supplemental arginine. On day 5 l-[ring-¹³C₆]phenylalanine and d-[U-¹³C₆]glucose were infused to measure the fractional synthetic rates of DNA (reflecting cell proliferation) and protein in the wound. Results: In the arginine group (n = 6) plasma arginine concentration was increased to 2.8 fold that in the control group (n = 8), which was a less increase than that of 6.4 fold for ornithine. Wound DNA fractional synthetic rate was 5.37 ± 0.21%/day in the arginine group, greater (p < 0.05) than that of 4.27 ± 0.35%/day in the control group. Protein fractional synthetic rates in the wound were comparable between the two groups. Conclusions: Enternal arginine supplementation increased wound DNA synthesis, which is anticipated to promote cell proliferation for wound healing. The failure of enteral arginine to stimulate protein synthesis is explained by limited increase in plasma arginine. Decreased availability of essential amino acids, especially branched chain amino acids, may also contribute to the failure to stimulate protein synthesis.