RESEARCH ARTICLE A Comparative Analysis of Gene Expression Profiles during Skin Regeneration inMus and

The African spiny mouse (Acomys spp.) can heal full thickness excisional skin wounds in a scar-free manner with regeneration of all dermal components including hair and associated structures. Comparing Acomys scar-free healing fromMus scarring identifies gene expres-sion differences that discriminate these processes. We have performed an extensive com-parison of gene expression profiles in response to 8mm full-thickness excisional wounds at days 3, 5, 7 and 14 post-wounding between Acomys andMus to characterize differences in wound healing, and identify mechanisms involved in scar-free healing. We also identify sim-ilarities with scar-free healing observed in fetal wounds. While wounding inMus elicits a strong inflammatory response, wounding in Acomys produces a moderated immune response and little to no increase in expression for most cytokines and chemokines assayed. We also identified differences in the ECM profiles of the Acomys wounds, which appear to have a collagen profile more similar to fetal wounds, with larger increases in expression of collagen types III and V. In contrast,Mus wounds have very high levels of col-lagen XII. This data suggests that an overall lack of induction of cytokines and chemokines, coupled with an ECM profile more similar to fetal wounds, may underlie scar-free wound healing in Acomys skin. These data identify candidate genes for further testing in order to elucidate the causal mechanisms of scar-free healing