Relationship between the expression of MMP-2 and MMP-9 in rat skin and the injury time

Objective:To explore the expression of MMP-2 and MMP-9 in rat skin after injury and its relationship with the wound time,in order to supply an experimental evidence for the prediction of injury time.Methods:After a model of incision of rat's skin was set,immuno-histochemistry technique and auto-image analysis were used to study the expression of MMP-2 and MMP-9 at different post-traumatic time intervals in both antemortem and post-mortem groups.Results:The expression of MMP-2 and MMP-9 in ante mortem group was higher than that in the normal control group(P0.05).However,in post-mortem injury group,there were no significant changes in anti-MMP-2 and MMP-9 immuno-reactivities in the area of injury and around the area of injury,compared with the normal control group(P0.05).Further,the expression of MMP-2 could be detected as increasing at 0.5 h,and reached maximum on 3 d,maintained the high level to the 5th day,then decreased gradually ,returned to norma1 lastly on 12～14 d.Compared with MMP-2,the expression of MMP-9 could be detected increasing at l h,and reached maximum on 3 d,maintained the high level to the 5th day,then decreased gradually,returned to norma1 lastly on 12～14 d .From 0.5 h to 3 d of wound interva1,the expression of MMP isoforms were identified in a large number of infiltrating neutrophilic granulocytes ,afterwards the fibroblastic cells(FBCs) and the vascular endothelial cells accounted for the most part of the MMP-2and MMP-9 positive cells.Conclusion:The expression of MMP-2 and MMP-9 in rat's skin is time dependent after skin injury,which could be used as a bio-marker to determine the time of injury.