Expression of oxygen-regulated protein 150 (ORP150) in skin wound healing and its application for wound age determination

Immunohistochemical study combined with morphometry was carried out to examine the expression of oxygen-regulated protein 150 (ORP150) using 58 human skin wounds of different ages (group I, 0–12 h; II, 1–5 days; III, 7–14 days; and IV, 17–21 days). In human wound specimens aged 4–12 h, neutrophils recruited at the wound showed no positive signals for ORP150. With the increase in wound age of ≥7 days, granulation tissue and angiogenesis were observed, with the migration of macrophages and fibroblasts with ORP150-positive reactions. In semi-quantitative analysis, the average of ORP150-positive ratios in group III was highest. In group III, all samples had an ORP150-positive ratio of >40%, and 17 samples showed >50%. In group IV, three out of ten samples showed a positive ratio of 40–45% and the remaining seven cases less than 40%. Collectively, with regard to the practical applicability with forensic safety, these observations suggest that an ORP150-positive ratio of >50% strongly indicates a wound age of 7–14 days.