TRANSFORMING GROWTH-FACTOR-BETA STIMULATES COLLAGEN AND FIBRONECTIN SYNTHESIS BY HUMAN CORNEAL STROMAL FIBROBLASTS IN-VITRO

The effects of transforming growth factor-beta (TGFbeta) and epidermal growth factor (EGF) on the synthesis of collagen and fibronectin, and on the proliferation of human corneal stromal fibroblasts in vitro, w ere evaluated. Human corneal stromal fibroblasts in culture were incub ated for 48 hours with TGFbeta or EGF in the absence of serum. Collage n and fibronectin in the culture media were measured by a collagenase- digestion assay and a competitive ELISA, respectively. The effects of the growth factors on proliferation were assessed by H-3-thymidine inc orporation. Collagen synthesis was dose-dependently stimulated by TGFb eta; at a concentration of 1 ng/ml of TGFbeta, a 120% increase in coll agen synthesis was seen over that of controls (p<0.01). EGF, at a conc entration of 10 ng/ml, induced a 40% increase in collagen synthesis ov er that of controls (p<0.01). The maximum stimulation by TGFbeta was g reater than that by EGF (p<0.05). Fibronectin synthesis was stimulated by TGFbeta and EGF in a dose-dependent manner; 230% (p<0.001) and 210 % (p<0.01) increases in fibronectin synthesis were caused by 10 ng/ml TGFbeta and EGF, respectively. TGFbeta and EGF dose-dependently stimul ated H-3-thymidine incorporation. The maximum increases in H-3-thymidi ne incorporation reached 180% (p<0.001) and 190% (p<0.001) over that i n controls, at 10 ng/ml concentrations of TGFbeta and EGF, respectivel y. In conclusion, both TGFbeta and EGF are potent stimulants of collag en and fibronectin synthesis and proliferation. Therefore, these two g rowth factors may be effective alternatives or additional choices for the treatment of corneal ulcer.