Generation of peroxynitrite in localised, moderate temperature burns

Simultaneous generation of nitric oxide (NO√) and superoxide (O2−) can lead to the formation of peroxynitrite (ONOO−), a potent oxidant that has been implicated in the pathogenesis of a number of disease states. This study was designed to investigate the possible generation of ONOO− in local cutaneous tissues following thermal injury. Male Wistar rats were anaesthetised in a nonrecovery procedure and subjected to a small (1 cm diameter), abdominal burn of moderate temperature (50°C, 5–15 min). At either the 60 or 180 min time point postburn the animals were killed, and skin sites were removed and homogenised. An ELISA was used to quantify protein bound 3-nitrotyrosine (3NT), a biomarker for ONOO− in the rat skin. In separate experiments the accumulation of [125I]-albumin in thermally injured skin was used to calculate plasma extravasation. Thermal injury (50°C, 10 min) to rat abdominal skin caused a significant increase in both 3NT (p<0.05) and oedema formation (p<0.001) when compared to unheated control sites at the 180 min time point postburn. This data is the first to show protein nitration in thermally injured, oedematous skin and strongly suggests that ONOO− is generated in thermally damaged cutaneous tissue.