The early influence of albumin administration on protein metabolism and wound healing in burned rats

Hypoalbuminemia is often claimed to impair wound healing, and therefore albumin has traditionally been administered to derive beneficial effects on general physiologic conditions including the nutritional state. However, the influence of albumin administration on systemic protein metabolism and wound healing is still unclear. Therefore, the objective of this study was to investigate the influence of albumin administration on protein metabolism and wound healing in burned rats. After receiving basic total parenteral nutrition (TPN) for 4 days, Sprague-Dawley rats underwent a 6-cm skin incision in the back and a burn involving 20 percent of the whole body surface. The rats were divided into three groups. Group I continued to receive basic TPN. Group II was given basic TPN, but 20 percent of the total nitrogen was replaced by albumin. Group III was administered basic TPN plus albumin equivalent to 20 percent of the total nitrogen of basic TPN. Group IV had the skin incision but no burn, receiving only basic TPN. All the groups were euthanized 4 days after the burn or skin incision. The wound healing potential in terms of tensile strength was enhanced by replacement and addition of albumin (groups II and III, respectively) after a 20 percent burn. Hydroxyproline levels in the wound tended to increase in group II, and significantly increased in group III. Whereas albumin replacement (group II) did not remarkably change the protein metabolism, albumin addition (group III) significantly increased both protein synthesis (S) and breakdown (B) with the S/B ratio and nitrogen balance remaining the same as with albumin-free nutrition (group I). The urinary 3-methyl-histidine/creatinine ratio significantly increased after burn in group III. We conclude that intravenous albumin administration enhanced incisional wound healing in burned rats. Increased protein synthesis with concurrent myolysis and protein breakdown by albumin addition (group III) was observed during wound healing.