Neutralisation of TGF-β1 and TGF-β2 or exogenous addition of TGF-β3 to cutaneous rat wounds reduces scarring

Exogenous addition of neutralising antibody to transforming growth factor-β1,2 to cutaneous wounds in adult rodents reduces scarring. Three isoforms of transforming growth factor-β (1, 2 and 3) have been identified in mammals. We investigated the isoform/isoforms of TGF-β responsible for cutaneous scarring by: (i) reducing specific endogenous TGF-β isoforms by exogenous injection of isoform specific neutralising antibodies; and (ii) increasing the level of specific TGF-β isoforms by exogenous infiltration into the wound margins. Exogenous addition of neutralising antibody to TGF-β1 plus neutralising antibody to TGF-β2 reduced the monocyte and macrophage profile, neovascularisation, fibronectin, collagen III and collagen I deposition in the early stages of wound healing compared to control wounds. Treatment with neutralising antibodies to TGF-βs 1 and 2 markedly improved the architecture of the neodermis to resemble that of normal dermis and reduced scarring while the control wounds healed with scar formation. Exogenous addition of neutralising antibody to TGF-β1 alone also reduced the monocyte and macrophage profile, fibronectin, collagen III and collagen I deposition compared to control wounds. However, treatment with neutralising antibody to TGF-β1 alone only marginally reduced scarring. By contrast, wounds treated with neutralising antibody to TGF-β2 alone did not differ from control wounds. Interestingly, exogenous addition of the TGF-β3 peptide also reduced the monocyte and macrophage profile, fibronectin, collagen I and collagen III deposition in the early stages of wound healing and markedly improved the architecture of the neodermis and reduced scarring. By contrast, wounds treated with either TGF-β1 or with TGF-β2 had more extracellular matrix deposition in the early stages of wound healing but did not differ from control wounds in the final quality of scarring. This study clearly demonstrates isoform specific differences in the role of TGF-βs in wound healing and cutaneous scarring. TGF-β1 and TGF-β2 are implicated in cutaneous scarring. This study also suggests a novel therapeutic use of exogenous recombinant, TGF-β3 as an anti-scarring agent.