OBJECTIVETo study the signal roles of protein tyrosine kinase (PTK) on proliferation and collagen synthesis of fibroblasts derived from hypertrophic scar(HS-FB) and normal skin (NS-FB) by interferon-gamma (IFN-gamma) or transforming growth factor beta1 (TGF-beta1).

METHODSHS-FB and NS-FB were cultured and passaged in Dulbecco's modified Eagle's medium(DMEM). The PTK activity in unstimulated or IFN-gamma or TGF-beta1-stimulated HS-FB and NS-FB (10,30,60 and 120 min) were assayed by phosphorus (32P) incorporation. Cell proliferation was determined with MTT stain. The type III procollagen was measured by radioimmunoassay.

RESULTSTGF-beta1 did not change PTK activity but it increased predominately proliferation and collagen synthesis of HS-FB and NS-FB in time-dependent fashion. Genistein, an inhibitor of PTK, inhibited HS-FB and NS-FB to proliferate and synthesize collagen but it could not change the roles on proliferation and collagen synthesis by TGF-beta1. IFN-gamma activated transiently PTK (P < 0.05) and increased proliferation and collagen synthesis of both fibroblast (P < 0.05, at 30 min, 60 min). As the recovery of PTK activity, the proliferation and collagen synthesis were inhibited by IFN-gamma at 120 min. Furthermore, Genistein abrogated the transient increased roles and partly reversed the longterm inhibitory functions by IFN-gamma (P < 0.05) . There were no difference on PTK activity, proliferation and collagen synthesis between HS-FB and NS-FB.

CONCLUSIONSPTK did not mediate the signal of TGF-beta1 but transduced the signal of transient increased roles of IFN-gamma. Inhibited or activated PTK might mediate the signal of decreasing or increasing proliferation and collagen synthesis of fibroblast.