Temporal Expression of the Transforming Growth Factor-Beta Pathway in the Rabbit Ear Model of Wound Healing and Scarring
Received 15 November 2006; received in revised form 23 February 2007; accepted 5 March 2007.
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-β (TGF-β) 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.
Study Design
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-β1 and collagen Iα2 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-β2 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-β1, and possibly TGF-β2, are associated with hypertrophic scar formation.
Wound Healing Research Laboratory, Division of Plastic and Reconstructive Surgery, Feinberg School of Medicine, Northwestern University, Chicago, IL.
Correspondence address: Prof Thomas A Mustoe, Department of Surgery, Division of Plastic and Reconstructive Surgery, Northwestern University, 645 N St Clair, Suite 19-250, Chicago, IL 60611.
ABSTRACT