Is impaired wound healing caused by infection or nutritional depletion?

Since infection and malnutrition both impair wound repair, we examined the interactions of an intra-abdominal abscess and its nutritional alterations on wound healing. Mice subjected to a left paraspinal incision then underwent either cecal ligation and puncture (CLP) or sham operation (sham). Abscesses and an early decrease in food intake developed in all CLP mice, but the animals resumed normal food consumption by day 7. The CLP animals had an initial 20% weight loss; however, by day 11 they had a gradual return toward control weight. Fresh and formalin-fixed wound disruption strengths determined on days 7 through 35 revealed a significant weakness in CLP animals. To examine the role of nutritional intake, an additional set of experiments were performed with the following groups: CLP, sham, no operation (control), or sham operation with pair-feeding an amount equal to that consumed by the CLP group to reproduce only the nutritional deficit (sham/dep). At 7 and 11 days, fresh wound-disruption strengths of both CLP and sham/dep animals were significantly weaker than those of control or sham animals. A defect in formalin-fixed healing also existed for sham/dep mice at day 11. These findings suggest that short-term reduction in nutrient intake as a result of infection may be a major determinant of impaired wound healing.