Expression of TGF-β and its receptors in murine fetal and adult dermal wounds

The transforming growth factor-β (TGF-β) are of major importance in wound healing and have been implicated in the scar-less wound repair observed in fetuses. Few studies have characterised the role of TGF-β in fetal wound repair and to date no studies have characterised the expression of its receptors within non-scarring fetal wounds. We have localised the TGF-β isoforms β1, β2 and β3 and its two receptors, TGF-βRI and TGF-βRII in both adult and fetal dermal murine wounds. We observed low level immunofluorescence of TGF-β1 and TGF-β2 in fetal wounds and although TGF-β3 staining was observed in the epidermis of fetal skin, there was no upregulation in response to injury. By contrast, all three isoforms were strongly expressed in adult wounds. Similar to its ligands, TGF-β receptor expression was increased post-wounding in the adult wounds. However, in contrast, no mRNA or protein for either of the TGF-β receptors was observed in response to wounding in the fetal dermis although there was both mRNA and protein expression of both the receptors localised within the fetal alimentary tract, one of the few fetal organs which does scar post-injury. The differences that we observed in the expression of TGF-β and its receptors in adult and fetal wounds could be important in the absence of scar formation that is observed in the fetus.