Fig. 4.
Lipofuscin accumulation and structural changes in RPE of AhR−/− mice. For lipofuscin analysis, eyes from 11-mo-old C57BL/6J wild-type and AhR−/− mice were assessed by laser confocal microscopy. (A) Representative confocal fluorescence micrographs of the RPE layers showing lipofuscin granules in wild-type and AhR−/− knockout mice. (B) Spectral profile analyzed from λ scans displays the autofluorescence spectra profile from RPE of AhR−/− and wild-type animals. (C) Quantification of autofluorescence in the RPE layer in AhR−/− and wild-type mice. Data are means ± SEM, n = 3 sections per mouse, n = 4–5 mice per genotype, P < 0.05. (D) Flat mounts of the posterior eye from an 11-mo-old AhR−/− and wild-type mouse (n = 4 mice per genotype) stained with phalloidin (red), to outline the individual RPE cells. Disrupted RPE cell boarders are indicated by white arrows. Hoechst (blue) stains the nuclei in RPE/choroid/sclera (RPE facing up). Light microscopic images show photoreceptor outer segments/RPE/Bruch’s membrane/choroid interface in (E) 11-mo-old AhR−/− mice, with diffuse sub-RPE deposits (outlined by dotted line), focal sub-RPE deposit (white arrowheads), and vacuolization (black arrow) and (F) 16-mo-old AhR−/− mice, with considerable RPE pigmentary changes, extensive vacuolization, RPE atrophy, and depigmentation. (Scale bar: 20 μm.) n = 6–10 images per mouse, n = 11–12 mice per genotype were examined with light microscopy.