Degenerative changes and neovascularization in the retina of bigenic mice following cyclic intensive light exposure. Hematoxylin and eosin (H & E) staining was performed on retinal cross sections as described in Methods. (A) A part of a retinal cross section through the optic nerve head of a 12-month old non-Tg control mouse (non-Tg) showing normal architecture and morphology. (B) A part of a retinal cross section from an age-matched APPswe/PS1 bigenic control mouse (control) (demonstrates similar morphology to the non-Tg control). (C) A part of a retinal cross section from a bigenic mouse following 3-month CILE (light-3 m) shows remarkable thinning outer nuclear layer/photoreceptor outer segment. (D) A part of a retinal cross section from a bigenic mouse following 6-month CILE (light-6 m) exhibits thinning neuroepithelial layers and newly-developed vessels. (E-G) Cross sections from the bigenic mice after 6-month CILE showing hypo-pigmentation (E, arrowheads), proliferating RPE (F, arrow), hyperpigmentation and a newly-developed vessel originated from choroicapillaris disrupt the RPE layer with red blood cells inside (G, arrow) in the RPE layer. (H-J) Show different types of newly-developed vessels that disrupt retinal architecture. Boxed area in (H) is shown in (I) at a higher magnification, in which the arrow indicates a red blood cells in the newly-developed vessel. (K) Quantification of the retinal thickness for each group of animals. (L) Quantification of neovessels in the outer retina on the cross section for each group of animals. Bars depict mean ± SEM. *: P < 0.001 (N = 6-8). CC: choroicapillaris; RPE, retinal pigment epithelium; OS, outer segment; ONL, outer nuclear layer; OPL, outer plexiform layer; INL, inner nuclear layer; IPL, inner plexiform layer; RGC, retinal ganglion cell layer. Scale bars = 50 μm for (A-D), 20 μm for E, F, G, J, 50 μm for H, 15 μm for I.
Dong et al. BMC Neuroscience 2012 13:34 doi:10.1186/1471-2202-13-34