Localization and quantification of histamine in injured skin as parameters for the timing of wounds

Localization and estimation of the histamine (HA) content in skin wound edges in 86 Sprague-Dawley rats and three cases of human injuries were carried out by a microfluorimetric method specific for this amine which forms a complex with o-phthalaldehyde (OPT). Distribution and density of the mast cells in the same areas were observed at the same time by toluidine blue stain. In all skin specimens with antemortem wounds, both the epidermis and upper dermis exhibit extracellular yellowish fluorescence of the HA-OPT complex. The fluorescent zone spreads in the wound edges with the lapse of time in vital injuries. The HA content increases gradually up to 30 min and then the yellow histamine fluorescence in areas 0-200 microns from the wound edge decreases. None of these features can be observed in normal skin and postmortem-injured skin. Mast cell degranulation can be demonstrated in all antemortem-injured skin. No statistical relationship exists between the number of mast cells and the HA-OPT fluorescence in either ante- or postmortem-injured groups. This study indicates that skin HA microfluorimetry by the OPT method is of practical value for distinguishing ante- from the postmortem wounds and for timing antemortem wounds.