Photoreceptor survival and morphology in mice raised in ST and EE.

<p>(A to D) Vertical retinal sections from 45 (A, B) and 60-day-old (C, D) rd10 mice raised in standard conditions (ST) or in environmental enrichment (EE). Rhodopsin staining (red) and nuclear counterstaining (green). Extensive rod degeneration and pronounced outer segment loss in ST (A). EE (B) is associated with a greater number of nuclear rows and preservation of rod outer segments (arrows). Compared here are two samples (A and B) of central retina, where photoreceptor degeneration is faster. (C and D) Cone-opsin staining (red) and nuclear counterstaining (green). Note preservation of cone outer segments (arrows) in EE (D) compared to ST (C). C and D are taken from peripheral retina, where photoreceptor degeneration is slower. Here and in the following pictures: ONL, INL and IPL: outer nuclear, inner nuclear and inner plexiform layer, respectively.