Time‐dependent Expression of MMP‐2 and TIMP‐2 after Rats Skeletal Muscle Contusion and Their Application to Determine Wound Age

The ability to determine vitality and estimate the survival period after a wound is critical in routine forensic practice. The mRNA levels of MMP-2 and TIMP-2 were examined using quantitative real-time RT-PCR to determine the age of a wound. Furthermore, the colocalization of them with Macrophage Marker, respectively, was detected by double immunofluorescence, and a standardized rat model of skeletal muscle contusion was established. In the antemortem contused groups, a large number of macrophages showed positive staining for MMP-2 and TIMP-2, and the expression of MMP-2 and TIMP-2 mRNA increased sharply at 3 days postinjury, with relative quantities of 5.75 and 2.98. No samples in the other groups showed relative quantities of >5.75 and 2.98; therefore, relative quantities exceeding 5.75 and 2.98 were strongly indicated 3 days after contusion. In addition, there was a significant decrease in the relative quantity in the postmortem contused groups, indicating that they were useful for diagnosing vitality.