Method: Two 8mm diameter excisional wounds were made on the dorsal skin of 7-week-old BALB/c female mice (n=10). A 10mm x 10mm template square was placed around the excisional wound and each corner marked with an indelible marker. Wounds were photographed daily for 10 days at a fixed distance from the wound. For each time point, image analysis was performed using AxioVision 4.5 to measure the area of the square for wound contraction and the area of the wound for wound closure. The percent wound contraction and closure were each calculated using the formula (1-area on day x/area on day 0)x100.
Result: Murine 8mm wounds demonstrated a predictable pattern of increasing wound closure, reaching an average of 89.7 + 3.1% closure at day 10. Wound contraction also increased over time, reaching a maximal level of 34.2 + 5.9% at day 9; the amount of contraction then dropped slightly at day 10.
Conclusion: As measured in this study, the maximal contraction in 8mm diameter murine wounds was about 34%, a level that is much less than previously reported rates of up to 90%. The results suggest that although contraction plays an important role in murine wound closure, a large percentage of wound healing in mice involves cellular proliferation and migration to fill the wound bed.