Figure 3
Correlation of VEGF and PECAM-1 immunostaining with FGF-2–containing Matrigel implants. A, Matrigel implants containing Matrigel alone (MG), Matrigel with heparin (MG+hep), and MG with heparin and FGF-2 (MG+hep+FGF-2) were evaluated for the expression of vascular endothelial growth factor (VEGF) and platelet-endothelial cell adhesion molecule 1 (PECAM-1) at 7 days postimplantation. Note the prominent detection of VEGF (anti-VEGF) in the FGF-2–containing implant stromal interface (arrows). Very little VEGF was detected in the heparin control and none in the Matrigel control. The detection of PECAM-1 (anti-PECAM-1) was also selectively restricted to the highly angiogenic FGF-2–induced stromal interface with both lumenal vascular capillary structures and individual cells invading into the Matrigel matrix (arrows). B, Higher power view of anti-PECAM-1 staining (blue signal) in Matrigel with heparin (MG + hep) and Matrigel with heparin and FGF-2 (MG+hep+FGF-2) (original magnification, × 900). Dermal, interface, and Matrigel regions indicated as D, I, and MG, respectively. Arrowheads show PECAM-1 positive capillaries in dermal regions and arrows show PECAM-1 positive vessels in the interface regions. C, Quantification of VEGF and PECAM-1 immunostaining in the FGF-2 and control Matrigel implants at Day 7 postimplantation. The number of positive cells per high-power field were averaged as described in “Materials and Methods.” Statistical significance of the FGF-2 implants compared with the Matrigel + heparin control was performed by Student's t test for n = 4. * p < 0.05; ** p < 0.001.
