The combination of PDGFBB and FGF2 induces robust angiogenesis with well-organized vascular structure.

<p>A schematic diagram of the cornea micropocket assay (a-d). A hydrogel with releasable pro-angiogenic factor is implanted into the cornea micropocket (a) and induced vessels grow toward implanted hydrogel from the limbal region (b). For analysis, the cornea is dissected from the rest of the eye (c) and flat mounted as four quadrants (d). Flk1-myr::mCherry+ vessels induced by VEGF (e) or PDGFBB/FGF2 (f) were examined at 10 days post-implantation. Vessel density induced by PDGFBB/FGF2 was significantly higher than VEGF (i, n = 3, ***<i>P</i><0.001), as well as the total vessel length (j, n = 3, **<i>P</i><0.01). Vessel structure was compared between VEGF- (g) and PDGFBB/FGF2- (h) induced vessels in regions that have similar vessel coverage on the surface of hydrogel. VEGF–induced vessels appeared as disorganized with extensive sprouting while PDGFBB/FGF2-induced vessels appeared more established and lumenized. Lacunarity parameter measurements indicated that PDGFBB/FGF2-induced vessels have larger spaces between vessels compared to VEGF-induce vessels (k, n = 3, *<i>P</i><0.05). Values are presented as mean ± SEM.