title: Improved cutaneous wound healing after intraperitoneal injection of alpha-melanocyte-stimulating hormone.
abstract: Skin wound healing is a complex process involving many types of cells and molecules and often results in scar tissue formation in adult mammals. However, scarless healing occurs in foetal skin and minimal scars may occur after cutaneous healing in the adult with reduced inflammation. Alpha-melanocyte-stimulating hormone (α-MSH) is widely distributed within the central nervous system and in other body regions, such as the skin, and has strong anti-inflammatory activity. The aim in the present experiments was to learn whether intraperitoneal (i.p) injection of α-MSH just before skin wounds antagonize inflammation and improves skin wound healing in adult mice. C57BL/6 young adult mice received an i.p. injection of 1 mg/kg of α-MSH and, 30 min later, two circular through-and-through holes (6.5 mm diameter) were made in their dorsal skin under anaesthesia. Control mice were wounded after vehicle injection. The wound healing process was analysed macroscopically and microscopically at 3, 7, 40 and 60 days. Skin samples were fixed in formalin, embedded in paraffin, sectioned at 5 μm, stained with H&E or toluidine blue for cell analysis or Gomori's trichrome for extracellular matrix (ECM) analysis. Other samples were fixed in DMSO+methanol, embedded in paraplast and incubated with anti-CD45, antismooth muscle actin, anticollagen-I and anticollagen-III for immunofluorescence analysis. Alpha-MSH significantly reduced the number of leucocytes, mast cells and fibroblasts at 3 and 7 days after injury. On days 40 and 60, α-MSH reduced scar area and improved the organization of the collagen fibres indicating that it may direct the healing into a more-regenerative/less-scarring pathway.
authors.affiliation: Departamento de Morfologia, Universidade Federal de Minas Gerais, Belo Horizonte, Brasil.
authors.forename: Kênia Soares
authors.initials: KS
authors.lastname: de Souza
authors.forename: Thiago Anselmo
authors.initials: TA
authors.lastname: Cantaruti
authors.forename: Geraldo Magela
authors.initials: GM
authors.lastname: Azevedo
authors.forename: Daniel Antero de Almeida
authors.initials: DA
authors.lastname: Galdino
authors.forename: Claudiney Melquíades
authors.initials: CM
authors.lastname: Rodrigues
authors.forename: Raquel Alves
authors.initials: RA
authors.lastname: Costa
authors.forename: Nelson Monteiro
authors.initials: NM
authors.lastname: Vaz
authors.forename: Cláudia Rocha
authors.initials: CR
authors.lastname: Carvalho
mesh_terms: D000818:Animals; D002921:Cicatrix / Q000517:prevention & control; D003094:Collagen / Q000187:drug effects / Q000378:metabolism / Q000648:ultrastructure; D005347:Fibroblasts / Q000187:drug effects; D006728:Hormones / Q000494:pharmacology*; D007249:Inflammation / Q000517:prevention & control; D007274:Injections, Intraperitoneal; D007958:Leukocyte Count; D008297:Male; D008407:Mast Cells / Q000187:drug effects; D051379:Mice; D008810:Mice, Inbred C57BL; D012867:Skin / Q000166:cytology* / Q000187:drug effects; D012879:Skin Physiological Phenomena / Q000187:drug effects; D014945:Wound Healing / Q000187:drug effects*; D000521:alpha-MSH / Q000494:pharmacology*
chemical_list: D006728:Hormones; D000521:alpha-MSH; D003094:Collagen
keywords: alpha-melanocyte-stimulating hormone and scarless healing; inflammation; scars; wound healing