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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.
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Objective To explore the mechanism of vitamin E on delaying skin aging by observ-ing the expression of hyaluronic acid synthetase-2 (HAS-2) in human dermal fibroblasts in vitro. Methods Human skin fibroblasts were cultured in vitro, and these fibroblast cells were then divided into 3 groups: different concentration of vitamin E (0, 0.1 × 10-10, 1 ×109mol/L) was added in the medium in the different group. 24 hours later, the fibroblasts were collected, RNAs extracted, and then amplified by RT-PCR. The PCR product was determined by agarose gel electrophoresis, to analyze the level of HAS-2 mRNA expression. Results RT-PCR showed the lever of HAS-2 mRNA was higher in the low-dose group than the control group, with significant difference (P<0.05) ; the lever of HAS-2 mRNA was higher in the high-dose group than control group, with significant difference (P<0.05). There was no significant difference in the lever of HAS-2 mRNA between the low-dose group and the high-dose group. Conclusions Vitamin E can enhance the expression of hyaluronic acid synthetase-2 mRNA, may increase the synthesis of HAS in skin fibroblasts and increase water content in the skin, so that it might reverse or delay the skin aging.