In vitro assay of collagen gel contraction by cardiac fibroblasts in serum-free conditions.

The aim of the present study was to investigate whether collagen gel contraction can be induced by cardiac fibroblasts in serum-free conditions. Cardiac fibroblasts (from normal male adult rats) from passage 2 were cultured to confluency and added to a hydrated collagen gel in Dulbecco's Modified Eagle's Medium with or without fetal bovine serum for 1, 2, 3 or 7 days. Control gels containing adult rat cardiac fibroblasts showed a significant amount of contraction after 2 days of incubation in a serum-free medium, causing a contraction to 47% of the area at the start of the incubation. Increasing the percent of fetal bovine serum induced further stimulation of the collagen gel contraction by cardiac fibroblasts. Optimal conditions for collagen gel contraction by adult fibroblasts were obtained with 100,000 cells incubated for 1 (up to 3) days. The presence of insulin-transferrin-selenium in the medium caused a more pronounced stimulation of the collagen gel contraction by cardiac fibroblasts, while sodium azide inhibited this contraction.