title: Temporal expression of the transforming growth factor-Beta pathway in the rabbit ear model of wound healing and scarring.
abstract: BACKGROUND
  Despite numerous studies that have investigated the cellular and molecular mechanisms underlying scar formation, this process still remains poorly understood. The importance of transforming growth factor-beta (TGF-beta) in these processes has been well recognized, and this study sought to define the temporal expression of the key members in this pathway in a well-established, clinically relevant, rabbit ear model of hypertrophic scarring.
  
  
  METHODS
  Seven-millimeter (hypertrophic) and 5-mm (nonhypertrophic) punch wounds were made on the ears of 12 rabbits. Wounds were harvested at days 0, 7, 15, 28, and 40.
  
  
  RESULTS
  There were no appreciable histologic differences between the 5- and 7-mm wounds at days 7 and 15. At day 28, however, the 7-mm scars were considerably more hypertrophic compared with the 5-mm control scars (p<0.001). The mRNA levels of TGF-beta1 and collagen Ialpha2 were notably higher in the hypertrophic 7-mm scars at day 28 than in the nonhypertrophic 5-mm scars (p<0.03). Although not pronounced, levels of TGF-beta2 were higher in the hypertrophic scars. There were no other statistically significant differences between the 7- and 5-mm scars.
  
  
  CONCLUSIONS
  Elevated levels of TGF-beta1, and possibly TGF-beta2, are associated with hypertrophic scar formation.
authors.affiliation: Wound Healing Research Laboratory, Division of Plastic and Reconstructive Surgery, Feinberg School of Medicine, Northwestern University, Chicago, IL 60611, USA.
authors.forename: Zol B
authors.initials: ZB
authors.lastname: Kryger
authors.forename: Mark
authors.initials: M
authors.lastname: Sisco
authors.forename: Nakshatra K
authors.initials: NK
authors.lastname: Roy
authors.forename: Leonard
authors.initials: L
authors.lastname: Lu
authors.forename: David
authors.initials: D
authors.lastname: Rosenberg
authors.forename: Thomas A
authors.initials: TA
authors.lastname: Mustoe
mesh_terms: D000818:Animals; D017439:Cicatrix, Hypertrophic / Q000209:etiology / Q000378:metabolism*; D004195:Disease Models, Animal; D004423:Ear; D005260:Female; D012333:RNA, Messenger / Q000378:metabolism; D011817:Rabbits; D018125:Receptors, Transforming Growth Factor beta / Q000235:genetics / Q000378:metabolism*; D051785:Smad Proteins / Q000235:genetics / Q000378:metabolism*; D013997:Time Factors; D016212:Transforming Growth Factor beta / Q000235:genetics / Q000378:metabolism*; D014945:Wound Healing / Q000502:physiology*; D014950:Wounds, Penetrating / Q000150:complications / Q000378:metabolism*
chemical_list: D012333:RNA, Messenger; D018125:Receptors, Transforming Growth Factor beta; D051785:Smad Proteins; D016212:Transforming Growth Factor beta