Abstract: Objective To investigate the expressi on of caspase-3during skin wound healing and explore the applicability of caspase-3to determination of wound age.Methods The expression of caspase-3were performed on33mice skin incised wounds at different posttraumatic intervals and3mice as c ontrol by immunohistochemical technique.Results Expression of caspase-3was detec table in polymorphonuclear cells(PMNs)in the wound specimens aged6h.In the wound specimens aged from12h to24h after injury,caspase-3was identified in a large nu mber of infiltrating PMNs and part of mononuclear cells(MNCs).Afterwards,the MNC s and fibroblastic cells(FBCs)accounted in the most part of the caspase-3positiv e cells.Morphometrically,the ratio of the number of the caspase-3stained PMNs,MN Cs and FBCs to total number of the cells in the wounds was evaluated and calcula ted.The ratio of the caspase-3positive cells was low in the wound specimens aged from0h to3h(4.53 ± 6.53)%,and maximized in the wound speci-mens aged3day(62.66 ± 4.84)%.Thereafter,the ratio decreased and minimized in the specimens aged14d ay(21.56 ± 4.54)%.Conclusion The results suggest that caspase-3may play an important ro le in inducing neutrophil,macrophage and fibroblast apoptosis during skin wound healing.Furthermore,caspase-3may be used as a marker for the wound age determination.

Key words: skin wound, apoptosis, wound age determination, caspase-3, immunohis tochemistry