Abstract
Purpose: :
Connective tissue growth factor (CTGF) is one of the downstream mediators of TGF-βthat acts to maintain tissue fibrosis. In this study, to determine the function of CTGF in corneal fibroblasts in vitro, we investigated the effects of CTGF on the expression of α-smooth muscle actin (α-SMA) and fibronectin production, as well as its possible influence on the collagen gel contraction by corneal fibroblasts.
Methods: :
Corneal fibroblasts from human donors were treated with TGF-β, CTGF, or a combination of both for 48 hours. First, the fibroblasts treated with TGF-βwere evaluated by western blot analysis to examine the effect of TGF-β on CTGF induction. Secondly, the effects of TGF-β, CTGF, and their combination on fibronectin production and on the expression of α-SMA in the corneal fibroblasts were assessed by western blot analysis. Thirdly, the corneal fibroblasts were embedded in a collagen gel and cultured with various concentrations of TGF-β, CTGF, or their combination. The diameters of the gels at specified time points were measured to estimate the collagen gel contraction by the corneal fibroblasts.
Results: :
The addition of TGF-β to the corneal fibroblasts elicited CTGF induction in a dose-dependent manner. Regarding fibronectin production, the corneal fibroblasts with the combination of TGF-β and CTGF showed more effective results than those with TGF-β or CTGF alone. On the other hand, no difference in α-SMA expression was seen between the fibroblasts with CTGF alone and those with the combination. In the collagen gel with TGF-β, the diameter of the gel decreased with the concentration of TGF-β in a dose-dependent manner, while no difference in the gel diameter was seen that with the combination.
Conclusions: :
In a dose-dependant manner, CTGF in combination with TGF-β effectively facilitates TGF-β-induced fibronectin production in corneal fibroblasts. This study suggested that CTGF could have modified the action of TGF-β on corneal fibroblasts and played an important role in corneal wound healing.
Keywords: cornea: stroma and keratocytes • wound healing • extracellular matrix