Oxygen Induced Retinopathy (OIR) in A10ΔEC mice. (A) Quantitative analysis of cell nuclei found vitreal to the internal limiting membrane after OIR in A10ΔEC and control mice (A10ΔEC: 68.9 ± 4.2, n = 12; controls: 33.3 ± 2.6, n = 8). (B,C) Histologic analysis revealed an abnormal sheet-like vascular structure (marked by an arrow) in an A10ΔEC retina (B) and a typical neovascular tuft (pointed by an arrow) in a control retina (C). (D-E) Micrographs of a segment of an Isolectin B4-stained retina from an A10ΔEC mouse showed a sheet-like vascular structure (outlined by a dotted line in panel D), whereas typical neovascular tufts were visible in a retina from a control mouse (marked by arrows in panel E). (F) Quantification of the size of the central avascular area in A10ΔEC eyes compared with controls after a 5-day period at room air (p17; A10ΔEC: 11.3 ± 1.5%, n = 9; controls: 25.7% ± 1.1% n = 8), and corresponding representative micrographs of A10ΔEC (G) or control (H) retinas. (I) Quantification of the avascular area in A10ΔEC (J) and control (K) retinas after 5 days at 75% oxygen (p12; A10ΔEC: 43.2 ± 2.0%, n = 6; controls: 43.8% ± 0.6%, n = 5). The central avascular area is bounded by a yellow line in panels G,H,J and K. ***P < .001 in a 2-tailed Student t test. Scale bars in panels B-C: 50 μm; D-E: 400 μm; G-H,J-K: 750 μm.