RESUMEN
Objective To explore the effects of fibroblast transdifferentiation for myofibroblast (MFB) in the pathogenesis of systemic sclerosis (SSc) and to explore the antifibrotic mechanism of interferon γ (IFN-γ) in SSc.Methods The fibroblasts derived from the skin lesions of SSc patients and healthy adult controls were cultured in vitro and the MFB proportion in fibroblasts was examined by qualitative and quantitative α-smooth muscle actin (α-SMA) detection.By adding IFN-γ to the culture system with several doses,the influence on fibroblast proliferation and transdifferentiation for MFB in SSc was observed with MTT and enzyme linked immunosorbent assay (ELISA) respectively.Differences in the means of two independent samples were tested by Student' t-test.The means among multiple independent samples were com-pared by ANOVA.Results The means of positive α-SMA in SSc fibroblasts were higher than those in the controls (P＜0.01).With extended culture time,α-SMA levels of the two groups all increased gradually (P＜ 0.01 all),but there were higher α-SMA levels in SSc fibroblasts (24 h:130±19,48 h:183±21,72 h:249± 22) than those in controls (24 h:98±21,48 h:143±16,72 h:174±19) (P＜0.05 all).Although fibroblast proliferation and α-SMA levels were not influenced after adding of IFN-γ 10 U/ml (P＞0.05 all),but IFN-γ at concentration of 100 U/ml and 1000 U/ml could obviously repress fibroblast proliferation and α-SMA levels (P＜0.05 all),and 1000 U/ml had the strongest inhibiting effect at 24,48,72 h.Conclusion The fibroblasts in the skin of SSc patients have a strong potency to transdifferentiate to MFB.Early appropviate dose of IFN-γ could repress fibroblast proliferation and transdifferentiation in SSc.