ACUTE PROTEIN-CALORIE MALNUTRITION IMPAIRS WOUND-HEALING - A POSSIBLEROLE OF DECREASED WOUND NITRIC-OXIDE SYNTHESIS

BACKGROUND: Nitric oxide is synthesized in wounds. Systemic inhibition of wound nitric oxide synthesis decreases wound collagen accumulation and wound mechanical strength. The role of nitric oxide during impair ed healing is not known. In a model of impaired wound healing is not k nown. In a model of impaired wound healing induced by acute protein-ca lorie malnutrition, we correlated wound healing parameters with wound nitric oxide synthesis. STUDY DESIGN: One group of Sprague-Dawley rats was rendered acutely malnourished by restricting its food intake to 5 0 percent of the food intake of an ad libitum-fed group. Wound collage n accumulation and types I and III collagen gene expression were measu red 10 days postwounding in subcutaneously implanted polyvinyl alcohol sponges. Nitric oxide synthesis was determined in wound fluid an din supernatants of wound cell cultures. RESULTS: Animals with acute prote in-calorie malnutrition lost 10.4+/-0.8 percent, while controls gained 17.5+/-1.2 percent of their original body weight. Protein-calorie mal nutrition reduced sponge hydroxyproline contents (995+/-84 compared wi th 1,580+/-109 mu g/100 mg sponge, p<.001), indicating diminished woun d collagen accumulation. Gene expression of type III, but not type I, collagen was decreased in wounds of protein-calorie malnutrition anima ls. Nitrite/nitrate and citrulline concentrations in wound fluid (p<0. 1) and in wound cell supernatants (p<.001) were also lower in protein- calorie malnutrition animals, indicating a net decrease in nitric oxid e production CONCLUSIONS: Impaired wound collagen accumulation caused by protein-calorie malnutrition may be a reflection of reduced nitric oxide synthesis within the wound.