AIM:To investigate the effects of transforming growth factor-β₁(TGF-β₁)on gene expression of main components of Smads family including Smad3, Smad4 and Smad7 in orbital fibroblasts(OF)of fibrosis extraocular muscle with thyroid -associated ophthalmopathy(TAO).

METHODS: OF were treated with 5μg/L TGF-β₁ at different time points(0min, 15min, 30min,1h, 2h and 4h), and real-time quantitative RT-PCR was performed to observe the effects of TGF-β₁ on the expression of Smad3, Smad4 and Smad7 mRNA.

RESULTS: The expression of Smad3 mRNA was 10.71 times to that of control group at 15min and 25.07 times at 1h(P<0.01); Smad4 mRNA was 1.54 times to that of control group at 15min and 15.99 times at 1h(P<0.01); Smad7 mRNA was 3.21 times to that of control group at 30min and 14.66 times at 4h(P<0.01).

CONCLUSION: TGF-β₁ up-regulate the expression of Smad3, Smad4, Smad7 mRNA in OF in a time dependent fashion, TGF-β₁/Smad pathway may play an important role in the pathogenesis of extraocular muscle fibrosis with TAO.