The effects of topical nitric oxide on healing of partial thickness porcine burns

•Nitric oxide is an important mediator involved in wound healing.•We evaluated the effects of topical nitric oxide gel on healing of partial thickness porcine burns.•Nitric oxide accelerated reepithelialization and angiogenesis but did not reduce scar depth. Nitric oxide is a wound mediator that promotes wound healing. We hypothesized that topical application of nitric oxide would speed reepithelialization, enhance angiogenesis, and reduce scar thickness in a partial thickness porcine burn model. While under general anesthesia, 20 partial thickness burns were created on the backs of four female Yorkshire swine using a 2.5cm×2.5cm×7.5cm, 150-g aluminum bar, preheated to 80°C and applied for 20s. The necrotic epidermis was removed and the burns were randomized to low, medium, and high concentrations of a novel nitric-oxide (NO) releasing drug or its ointment vehicle applied 3 times weekly for 28 days. Full thickness punch biopsies were performed at 8, 11, 14 and 28 days after injury to determine percentage wound reepithelialization and scar thickness using H&E staining and blood vessel density using CD31 staining. At day 11, the percentages (SD) wound reepithelialization were: control, 26.3 (34.6); low NO, 23.9 (36.9); medium NO, 43.3 (42.9); and high NO, 59.9 (43.6); ANOVA, P=0.02. The number of CD31 stained blood vessels at days 8 and 11 were greater in wounds treated with high dose NO vs. controls (48.1 vs. 22.9 [P