title: Scarless skin repair in immunodeficient mice.
abstract: Scarring, the end result of the wound healing process in adult mammals, is a problem of significant clinical importance. We observed that athymic nude-nu mice, similar to mammalian fetuses, are able to restore the structure and integrity of injured skin through a process resembling regeneration, where scar formation is absent. Among the postinjured skin tissues collected from athymic nude-nu, wild-type controls (C57BL/6J), severe-combined immunodeficient, Rag (lack of B and T cells), athymic (thymectomized neonates and adult C57BL/6J), and mice treated with an immunosuppressant (cyclosporin A), only athymic nude-nu mice showed: a lack of scar by histological examination (hematoxylin & eosin and Masson's trichrome staining), low levels of collagen (as determined by hydroxyproline content), high levels of hyaluronic acid, a statistically significant increase in elastic modulus for injured samples over unwounded (biomechanical testing) and low levels of the pro-scarring cytokines platelet-derived growth factor-B and transforming growth factor beta1. Additionally, immunohistochemical and Western blot analyses of postinjured tissues as well as flow cytometry analysis of blood samples showed the presence of CD8-positive cells in all studied animals except nude-nu mice. We conclude that scarless skin healing in athymic nude-nu mice provides a new model to study the influence of the immune system on tissue regeneration.
authors.affiliation: Regenerative Biology, Pennington Biomedical Research Center, Baton Rouge, Louisiana State University 70808, USA. kozakB@pbrc.edu
authors.forename: Barbara
authors.initials: B
authors.lastname: Gawronska-Kozak
authors.forename: Marek
authors.initials: M
authors.lastname: Bogacki
authors.forename: Jong-Seop
authors.initials: JS
authors.lastname: Rim
authors.forename: W Todd
authors.initials: WT
authors.lastname: Monroe
authors.forename: Jessica A
authors.initials: JA
authors.lastname: Manuel
mesh_terms: D000818:Animals; D002921:Cicatrix / Q000276:immunology*; D003094:Collagen / Q000378:metabolism; D004548:Elasticity; D005434:Flow Cytometry; D006820:Hyaluronic Acid / Q000378:metabolism; D006909:Hydroxyproline / Q000378:metabolism; D007150:Immunohistochemistry; D051379:Mice; D008810:Mice, Inbred C57BL; D008819:Mice, Nude; D012867:Skin / Q000276:immunology* / Q000378:metabolism / Q000473:pathology; D012879:Skin Physiological Phenomena; D013718:Tensile Strength; D014945:Wound Healing / Q000276:immunology*
chemical_list: D006820:Hyaluronic Acid; D003094:Collagen; D006909:Hydroxyproline