The route of nutrition support affects the early phase of wound healing

Nutrition support via the enteral route has been shown to be superior to parenteral administration in maintaining immune function, decreasing septic complications, and increasing survival after severe trauma and surgical injury. Whether the route of nutrition support affects wound healing, another important determinant of outcome following injury, is not known.

Forty-nine Sprague-Dawley rats, 290 to 360 g body wt, underwent identical surgical manipulation consisting of central venous catheterization, fashioning of gastrostomy and dorsal skin incision, and placement of polyvinyl alcohol sponges into subcutaneous pockets. Identical infusates of 25% dextrose, 4.25% amino acids, and vitamins were given, half the animals receiving the infusion via the gastrostomy and the other half via the venous catheter. Animals were killed on day 5, 7, or 10. Wound breaking strength, sponge hydroxyproline content (an index of wound collagen deposition), and types I and III collagen gene expression were measured.

There were no nutritional differences between the two groups in terms of energy intake, body weight gain, and plasma levels of albumin, total protein, or urea nitrogen. On day 5 wound breaking strength was significantly higher in the enterally supported group (89.3 +/- 90.7 vs 64.9 +/- 40.2 g for the parenteral group, p < .05). This was paralleled by enhanced wound collagen accumulation (182 +/- 19 vs 132 +/- 13 microg, p < .05). Gene expression of type I, but not type III, collagen also was increased in the enterally fed group. There were no differences noted between the two groups in wound healing parameters 7 and 10 days after injury.

The data demonstrate that the route of nutrition administration can influence wound healing. The beneficial effect of the enteral feeding route is limited to the early phases of healing.