Figure 1. Inducible Vegfa deletion in adult RPE cells promotes rapid choriocapillaris degeneration and vision loss.

(A) Electron micrographs of control (upper panel, Vegfa^f/f without Cre) and mutant (lower panels, Vegfa^f/f with VMD2-Cre) murine retinas 3 days after Vegfa deletion in adult RPE. Right panels are enlargements of the boxed regions of the left panels. Note that Vegfa mutants lack choriocapillaris normally observed in controls (asterisks). (B) ERG of Vegfa mutant eyes shows loss of photopic and flicker signals. b-wave amplitudes from flash, or first peaks from flicker, ERG in photopic light-adapted conditions captured in Vegfa mutants are significantly attenuated compared with the same retina prior to Vegfa gene deletion (n = 4 for each time point). This dramatic attenuation is consistent with vision loss. (C) Immunohistochemical analyses for cone-opsin in Vegfa mutants and controls 7 days after induction. The absence of cone outer segments is apparent in the Vegfa mutants. ^#P < 0.01; 2-tailed Student’s t tests. Error bars indicate mean ± SD. Scale bars: 10 μm (A ); 20 μm (C). ONL, outer nuclear layer; OS, outer segments; CC,choriocapillaris.