Cultures of fibroblasts in fibrin lattices: models for the study of metabolic activities of the cells in physiological conditions.

Two techniques for fibroblast culture in three-dimensional fibrin matrices (fibrin lattices) were used to study the behavior and metabolism of cells in this physiological support. When the fibrin lattices were prepared in silicone-coated glass petri dishes, fibroblasts induced retraction of lattices to an extent dependent on both cell density and serum concentration, the cells stopped dividing, and their protein and collagen syntheses proceeded at a lower rate, like that in collagen lattices. When fibrin lattices were prepared in plastic petri dishes, the matrix attached to the walls, there was no retraction, and the protein synthesis was very active even as regards collagen. The optimal concentration of ascorbic acid in nonretracting fibrin lattices was lower (10 micrograms/ml) than in monolayers (50 micrograms/ml). The comparison of collagen and fibrin lattices showed that the collagenic nature of the lattice was not compulsory for supporting the phenomenon of retraction and that fibroblasts, when exposed to a stress in a fibrin matrix prevented from retracting, secreted far more collagen.