Primary embryonic chick fibroblasts were seeded into a fibrin gel for the formation of 3D cell cultures containing aligned ECM. A. The expression of Arhgap6, Arhgap18, Arhgap28, Col1a1, and Fn were quantified by qPCR (n = 3). B. 3D tissue constructs were treated with 5 µM LPA or 10 µM Y27632 for 2 hours in serum-free conditions and changes to the actin cytoskeleton were observed by phalloidin staining. Bars = 50 µm. Arrows indicate the alignment of the tissue. C. The recoil baseline, which is the calculated length of the construct at the end of the exponential fit (see Materials and Methods for details). D. The half-time, which is the time required to achieve half of the recoil baseline. E. The expression of Arhgap6, Arhgap18 and Arhgap28 were quantified by qPCR during tissue recoil (n = 3). Fold changes in gene expression were normalized to Gapdh (2−ΔΔCt values). Bars show SEM. *** and * indicate significant differences found, p<0.001 and p<0.05, respectively, one way ANOVA.