An Improved Humanized Mouse Model for Excisional Wound Healing Using Double Transgenic Mice

Abstract

<b>Objective:</b> Splinting full-thickness cutaneous wounds in mice has allowed for a humanized model of wound healing. Delineating the epithelial edge and assessing time to closure of these healing wounds via macroscopic visualization have remained a challenge. <b>Approach:</b> Double transgenic mice were created by crossbreeding K14-Cre and ROSA^mT/mG reporter mice. Full-thickness excisional wounds were created in K14-Cre/ROSA^mT/mG mice (<i>n</i> = 5) and imaged using both normal and fluorescent light on the day of surgery, and every other postoperative day (POD) until wound healing was complete. Ten blinded observers analyzed a series of images from a single representative healing wound, taken using normal or fluorescent light, to decide the POD when healing was complete. K14-Cre/ROSA^mT/mG mice (<i>n</i> = 4) were subsequently sacrificed at the four potential days of rated wound closure to accurately determine the histological point of wound closure using microscopic fluorescence imaging. <b>Results:</b> Average time to wound closure was rated significantly longer in the wound series images taken using normal light, compared with fluorescent light (mean POD 13.6 vs. 11.6, *<i>p</i> = 0.008). Fluorescence imaging of histological samples indicated that reepithelialization was complete at 12 days postwounding. <b>Innovation:</b> We describe a novel technique, using double transgenic mice K14-Cre/ROSA^mT/mG and fluorescence imaging, to more accurately determine the healing time of wounds in mice upon macroscopic evaluation. <b>Conclusion:</b> The accuracy by which wound healing can be macroscopically determined <i>in vivo</i> in mouse models of wound healing is significantly enhanced using K14-Cre/ROSA^mT/mG double transgenic mice and fluorescence imaging.