Neutrophil-dependent decrease in early wound margin strength

We evaluated the effect of neutropenia or administration of a serine proteinase inhibitor on the early suture-holding capacity of intestinal anastomoses in rats. One group of rats was treated with antineutrophil serum, and another group received the soybean trypsin inhibitor. Controls received inactivated serum or saline. Anastomotic suture-holding capacity (breaking strength), myeloperoxidase activity, and collagen were measured 0 and 72 hours after surgery. Suture-holding capacity decreased by 70% in controls and 35% in soybean trypsin inhibitor-treated rats, but remained on level with immediate postoperative strength in neutropenic rats, where low myeloperoxidase levels reflected effective wound margin neutropenia. Collagen content and solubility were similar in all groups. These findings indicate that reduction in early wound margin strength is neutrophil dependent, and that neutrophil serine proteinases are important mediators in that process.