Exogenous transforming growth factor β2 modulates collagen I and collagen III synthesis in proliferative scar xenografts in nude rats

Background Keloid and hypertrophic scars are fibrous dermal tumors characterized by overabundant collagen deposition. Previous studies demonstrated that exogenous transforming growth factor beta (TGF-beta) might increase collagen production in incisional wound models and in vitro. Using an in vivo model of human scar xenografts maintained in congenitally athymic, asplenic "nude" rats, we examined endogenous TGF-beta(2) collagen I, and collagen III levels in keloids and burn hypertrophic scars treated with TGF-beta(2) and TGF-beta(2) antibody. Methods. Fresh keloid and burn hypertrophic scar specimens excised from human subjects were explanted to pedicled flaps based on the superficial inferior epigastric vessels in athymic "nude" rats. These flaps were allowed to mature for 3 weeks, after which the scar explants were directly perfused with 200 ng of TGF-beta(2) or 250 Eng of TGF-beta(2) antibody daily for 5 consecutive days, then again on Days 10, 15, and 20. Biopsies were taken 30 and 120 days following the initiation of treatment. Immunohistochemical staining was then performed for TGF-beta(2), collagen I, and collagen III. The intensity of staining was quantified. Results. Our results demonstrated that treatment of human proliferative scars with exogenous TGF-beta(2) results in a significant increase in endogenous TGF-beta(2) collagen I, and collagen III production. By contrast, exogenous addition of anti-TGF-beta(2) antibody significantly decreased endogenous TGF-beta(2) collagen I, and collagen III production. Conclusion. This study supports a causative role for TGF-beta(2) in the formation of proliferative scars and suggests that TGF-beta(2) antibody may be a new potential antiscarring agent. (C) 1999 Academic Press.