Dependence of fibroblast expression of various ECM proteins on time in culture. Results are shown for (A) COL1A1 mRNA, (B) COL3A1 mRNA, (C) FN1 mRNA, (D) COL1A1 and FN1 protein.

<p>Control fibroblasts were cultured for 1, 2, 4, 7, and 12 days. For the last time point, cells were passaged (P1) after 7 days of culture and then grown to confluence (∼5 days). Representative Western blot images for COL1A1 and FN1 are shown in the upper panels of (D), with mean±SEM data beneath. Protein levels were measured from culture supernatant for the 24 hours preceding cell collection. *<i>P</i><0.05, **<i>P</i><0.01, ***<i>P</i><0.001 by ANOVA with Bonferroni post-hoc tests, number of dogs indicated in figure.