Figure 4. Immunoblot Analysis of Collagen Produced by Cardiac Fibroblasts in Fibrin Gels.

A). Procollagen processing and total amounts of soluble collagen recovered from primary fibroblast cultures were performed using immunoblot analysis with anti-murine collagen I antibodies. Three protein bands representing procollagen alpha 1(I), pC collagen alpha 1(I), and fully processed collagen alpha 1(I) were detected on blots. A representative blot is shown in (A). In addition to collagen I, levels of SPARC and p85 (housekeeping control) are shown from each type of primary culture. B). Quantification of collagen I immunoblots (n=4 for each age and genotype) showed significantly less total collagen I (i.e. procollagen, pC collagen, and processed collagen) was detected in fibrin gels populated with old fibroblasts versus neonate or adult cultures. *p<0.05 versus respective genotype-specific neonate and adult values by Student T-test. C). Quantification of collagen I immunoblots (n=4 for each age and genotype) demonstrated that of the collagen I produced by WT old fibroblasts, a significantly decreased proportion of this total collagen was present as procollagen. * p<0.05 versus either neonate or adult WT fibroblasts.