INFLUENCE OF RETINOIC ACID AND TGF-BETA ON DERMAL FIBROBLAST PROLIFERATION AND COLLAGEN PRODUCTION IN MONOLAYER-CULTURES AND DERMAL EQUIVALENTS

The effects of transforming growth factor-beta1 (TGF-beta1) and all-tr ans retinoic acid (RA) on human dermal fibroblast proliferation and co llagen production were investigated in 'attached' and 'detached' derma l equivalent (DEs) systems compared with fibroblasts grown in monolaye rs. The combined effects of TGF-beta1 with epidermal growth factor (EG F) on fibroblast proliferation and collagen production were also studi ed. Fibroblast proliferation was stimulated 0.7-fold by TGF-beta1 in a ttached DEs and 0.3-fold in detached DEs compared with untreated contr ol DEs. RA stimulated fibroblast proliferation 1.1-fold in attached DE s and 0.6-fold in detached DEs. Neither TGF-beta1 nor RA had a signifi cant effect on fibroblast proliferation in monolayer cultures. In the presence of EGF, the action of TGF-beta1 on fibroblast proliferation w as slightly suppressed in attached DEs. At S ng/ml TGF-beta1, collagen production was stimulated 6. 1 -fold in attached DEs, by 3.S-fold in monolayer at 4 ng/ml and 2.9-fold in detached DEs at 1 ng/ml. RA at 5 X 10(-10) M to S X 10(-6) M Stimulated collagen production in all thre e systems. The stimulation of collagen production by 5 ng/ml TGF-beta1 was suppressed by EGF in both attached DEs and monolayer culture. Fib roblasts in attached DEs had elongated, bipolar morphology with a tend ency to line up in the same direction. Fibroblasts in detached DEs wer e randomly distributed and exhibited stellate morphology. These data i ndicate that the extracellular matrix strongly influences the actions of growth factors and of RA on dermal fibroblasts. When stimulated wit h TGF-beta1 collagen production in attached DEs was higher than that b y fibroblasts in monolayer culture and detached DEs. The attached and detached DEs offer a model which resembles the in vivo situation more closely than monolayer culture with respect to collagen production and fibroblast proliferation and morphology.