Figure 4.

By 45 weeks, the fibrous caps of PDGF −/− chimeras are indistinguishable from those of PDGF-B +/+ chimeras. A: Mean lesion volume in PDGF-B +/+ and −/− chimeras was determined by evaluation of the entire length of the brachiocephalic trunk at 75-μm intervals using a random start site within the first 75 μm of the vessel. The mean ± SEM is shown for each PDGF-B +/+ and −/− chimera and representative of an additional 12 PDGF-B +/+ and 13 PDGF-B −/− chimeras analyzed for all criteria shown in this figure. B: The frequency and extent (thin and intermediate plus thick) of fibrous cap formation were evaluated along the entire brachiocephalic trunk of all mice in a second group (+/+, n = 10; −/−, n = 10) as described in A. The extracellular matrix content of the fibrous cap is highlighted for PDGF-B +/+ (C) and PDGF-B −/− (D) chimeras with GAF staining. Magnification, ×20.