Fig. 2.

Inhibiting vitamin A dimerization prevents lipofuscin granule accumulation in the RPE. Representative transmission electron micrographs of a RPE cell taken from 9-mo-old Abca4^−/− mutant mice administered either vitamin A (control, A) or C20-D₃-vitamin A mice (treated, B). Lipofuscin granules were reconstructed from 20 serial sections taken at 100-nm intervals and overlaid in red on a representative section of the RPE shown in light gray. (C) Average lipofuscin volume per cytoplasmic volume, with 95% confidence intervals from animals described in A and B. −/−, Abca4^−/− mutant mice; WT, wild-type, Abca4^+/+, controls. Unless noted with a bar, asterisks represent significant deviations (P < 0.05, as determined by one-way analysis of variance) from wild-type animals given vitamin A (WT Control). (Scale bar, approximately 1 μm.)