Immunohistochemical analysis on aquaporin-1 and aquaporin-3 in skin wounds from the aspects of wound age determination.

Immunohistochemical investigation of aquaporin (AQP)1 and AQP3 was performed in human skin wounds obtained from forensic autopsy cases. A total of 55 human skin wounds of different postinfliction intervals were collected as follows: group I, 0-3 days (n = 16); II, 4-7 days (n = 11); III, 9-14 days (n = 16); and IV, 17-21 days (n = 12). In uninjured skin samples, AQP1 and AQP3 could be slightly detected in dermal vessels and keratinocytes, respectively. The percentage of AQP1 vessels and the number of AQP3 keratinocytes were apparently elevated in accordance with wound ages. The number of AQP3 keratinocytes was distinctly evident in groups II and III. Morphometrically, both AQP1 vessel area and AQP3 cell number were markedly increased in group II, compared with other three groups. With regard to forensic safety, AQP1 vessel area of over 5% would imply wound ages of 4-12 days. Moreover, the positive area of > 15% would suggest wound age of 7-10 days. Especially, most samples of skin wounds aged 5-10 days except for only one sample (a 10-day-old wound) showed AQP3 cell number of > 300, and the remaining other samples had that of < 300. Thus, the AQP3 cell number of > 300 would indicate wound ages of 5-10 days. Collectively, immunohistochemical analyses of AQP1 and AQP3 in human skin wounds would support the objective accuracy of wound age determination.