Message and protein expression and cellular morphology in released versus constrained gels cultured in M199 supplemented with 5% FBS for 6-48 h. Panel A shows gene expression of col1a1, col3a1, TGF-β, and α-SMA in released (left panels) or constrained (right panels) fibroblast-seeded gels. Panel B shows merged images of constrained (left panel) and released (right panel) collagen gels stained for DAPI (blue), actin (red), and α-SMA (green). Panel C shows quantification of the immunofluorescence images shown in Panel B, using a circularity parameter.