Localization of MMPs in endothelial cells present in the capillarylike tubular structures in a fibrin-collagen matrix.

hMVECs were cultured on top of a 3-dimensional fibrin matrix containing 10% collagen in M199 with 10% human serum and 10% NBCS and were stimulated with 50 ng/mL VEGF₁₆₅ and 10 ng/mL TNF-α. After 4 days of culture, nonphase micrographs were taken (A), the matrices were fixed and embedded as described, and 4-μm cross-sections perpendicular to the matrix surface were cut and stained for MMP-2 (B) and MT1-MMP (MMP-14) (C). Immunohistochemistry was performed as described. Arrows indicate areas of positive staining. Scale bar = 300 μm (A) or 50 μm (B-C).