RGC-derived Sema3A partakes in vaso-obliteration, hinders vascular regeneration, and contributes to preretinal neovascularization in OIR. (A) Representative photomicrographs of Griffonia simplicifolia lectin-stained flat-mount retinas at P12 reveal that mice receiving an intravitreal injection of Lv.shSema3A show a 32% reduction in the area of vaso-obliteration compared with contralateral eyes receiving Lv.shGFP injections and noninjected eyes (basal) revealing the vasotoxic properties of Sema3A in the first phase of OIR (n = 13-15; additional quantification is presented in supplemental Figure 4A). The inhibition of RGC-derived Sema3A significantly enhanced the rate of vascular regeneration secondary to OIR as determined at P12 (n = 13-15), P14 (n = 12-13), and P17 (n = 15-18). Values are presented as the rate change in vaso-obliterated areas relative to Lv.shGFP-treated controls ± SEM. P = .02 by ANOVA factoring for time and group. (B) At peak neovascularization (P17) lectin-stained flat-mount retinas reveal that inhibition of Sema3A (n = 9-12) significantly reduced areas of pathologic neovascularization from 9.3% to 4.5%, as determined using the SWIFT-NV quantification protocol (supplemental Figure 4B). Values are presented as areas of neovascularization relative to total retinal area ± SEM. ***P = .0002 compared with control. Scale bars in panels A and B represent 500 μm.