Figure 5

Effects of prolonged time exposure on retinal degeneration. (A) Equatorial retinal section obtained 7 days after 5 min exposure to 6,000 lux. (A) Cone arrestin (green) and ethidium staining (red) show that a large fraction of the retinal surface has undergone major photoreceptor loss. The ONL is reduced to 3–4 rows across approximately 80% of the retinal extension; cones are appear intact only close to the retinal margins, where the ONL has a normal thickness (arrows). ONH: optic nerve head. (B) High magnification of the arrowhead-indicated zone in (A). Rhodopsin staining (green) shows extreme reduction of rod outer segments. In this central area, cones (stained with arrestin, red) are rare and show aberrant morphologies. Hoechst DNA staining (blue) shows large apoptotic bodies in the outer retina (asterisk). This preparation conveniently recapitulates in space the degeneration progression typical of Tvrm4 mutants. (C) ERG traces obtained 7 days after exposure to inducing lights of different brightness and duration. The larger decrement of the retinal response is observed when exposure length increases from 3 to 5 minutes. Scotopic brightest flash: 83.7 cd*s/m².