Transforming Growth Factor β3 (TGFβ3) Accelerates Wound Healing Without Alteration of Scar Prominence

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Abstract
Background: Transforming growth factor (TGF) β3 is a new isoform of the TGFβ superfamily and is presumed to play an important role in wound repair and scarring. Objective: To examine the effects of TGFβ3 on wound healing and on reducing scarring. Design and Interventions: Dermal ulcers were created on the ears of 75 anesthetized young female rabbits. Either TGFβ3 or vehicle was applied topically to the wounds. Wounds were bisected and analyzed histologically at postwounding day 7. A second group of wounds was treated with topical TGFβ3 and TGFβ2 or vehicle at days 0 and 3 and harvested at days 21 through 42 as an excessive scarring model. The third group of wounds was treated with TGFβ1, TGFβ2, and TGFβ3 and vehicle. The granulation tissue was harvested at day 7, and cellular RNA was extracted for performing competitive reverse-transcription polymerase chain reaction. Main Outcome Measurement: The amount of new epithelium and granulation tissue was measured in TGFβ3- and vehicle-treated wounds. The hypertrophic index was calculated for scarring wounds treated with TGFβ2 and TGFβ3 or vehicle. Levels of TGFβ1 messenger RNA were measured in those wounds that were treated with TGFβ1, TGFβ2, and TGFβ3 and in their controls. Results: The use of TGFβ3 (0.3-0.75) μg per wound) increased granulation tissue formation by more than 100% (P<.005). Epithelialization showed a biphase, either increasing 30% (P<.04) or decreasing 25% (P<.001) dependent on dose. No significant difference in the hypertrophic index was noted in TGFβ3-treated wounds compared with controls. Levels of TGFβ1 messenger RNA increased (7.1- to 14.9-fold) in those wounds treated with TGFβ2 compared with controls at day 7. Conclusions: Exogenous TGFβ3 displays substantial vulnerary properties in wound healing and may be useful in treating nonhealing wounds. However, the observation that TGFβ3 can reduce scarring was not confirmed in this study, and the messenger RNA level in response to TGFβ3 suggests that it behaves similarly to TGFβ1. Arch Surg. 1997;132:753-760