OBJECTIVETo explore the regulatory mechanisms of transforming growth factor-beta1 (TGF-beta1) and two transcriptional factors Smad 2, 3 on hypertrophic scar formation and fetal scarless healing.

METHODSThirty-two cases were detected to compare the gene expression of TGF-beta1, Smad 2 and Smad 3 with RT-PCR. Among those cases, there were 8 cases of hypertrophic scars, 8 cases of control skins, 8 cases of fetal skins and 8 cases of adult skins.

RESULTSTGF-beta1, Smad 2 and Smad 3 gene expression could all be detected in hypertrophic scars, fetal and adult skins. Among 8 groups examinated in this experiment (each group comprised a hypertrophic scar and its corresponding normal skin), there were 5, 8 and 5 groups in which TGF-beta1, Smad 2 and Smad 3 gene expression were higher in hypertrophic scars than in normal skins respectively. The fetal skins showed significantly lower level of TGF-beta1 and Smad 3 gene expression compared with adult skins (t = 2.204, P < 0.05 and t = 4.269, P < 0.01 respectively), while mRNA contents of Smad 2 were obviously higher in fetal skins than in adult skins (t = 6.685, P < 0.01).

CONCLUSIONTGF-beta1 and its downstream signal molecules Smad 2, Smad 3 might be involved in hypertrophic scar formation. Higher gene expression of TGF-beta1, Smad 2 and Smad 3 in hypertrophic scars might lead to stimulating extracellular matrix deposition, inducing fibroblast proliferation and accelerating fibrogenesis. Lower mRNA contents of TGF-beta1 and Smad 3 in fetal skins compared with adult skins might be associated with fetal scarless healing.