FIGURE 3.

Erk5 is critical for PEDF anti-angiogenic action in vivo. A, cryogenic sections of the Matrigel plugs containing control HMVECs (WT), or HMVECs expressing dominant negative or constitutively active MEK5 (DN and CA, respectively). Angiogenesis was induced with 200 ng/ml VEGF and blocked with 100 μm 34-mer, where indicated. The sections were stained for the endothelial cell marker, CD31 (PECAM1). B, morphometric analysis of the digital images of the sections shown in A with MetaMorph software package. Microvascular density was quantified as relative CD31-positive area. **, p < 0.01; **, p < 0.001.