FIGURE 6.
Light exposure accelerates retinal degeneration. Light exposure (10,000 lux for 60 min) accelerated retinal degeneration in Rdh8-/-Abca4-/- mice as seen by DAPI nuclear staining. Prior to examination, mice were maintained in the dark for 7 days after light exposure. Top, inferior retina of a light-exposed 4-week-old Rdh8-/-Abca4-/- mouse shows widely distributed pathology, including severe photoreceptor loss with rosette formation. Bottom, mild changes occurred in light-exposed retinas from 3-month-old Rdh8-/- and Abca4-/- mice as compared with normal retina from light-exposed 3-month-old WT mice. Retinylamine (Ret-NH2) treatment (1-mg gavage 6 h prior to the light exposure) prevented the severe degeneration observed in retinas of 4-week-old light-exposed Rdh8-/-Abca4-/- mice. OS, outer segment; IS, inner segment; ONL, outer nuclear layer; OPL, outer plexiform layer; INL, inner nuclear layer; IPL, inner plexiform layer; GCL, ganglion cell layer. Bars, 20 μm.