Rod degeneration characterized with lower expression of rhodopsin and downstream phototransduction proteins as well as morphological alterations in APP23 mice at 12 and 18 months
(A) Expression of rhodopsin in retinas from APP23 and WT mice was evaluated using Western blot analysis using anti-rhodopsin(1D4) antibody. Rhodopsin monomer levels were analyzed using densitometry and normalized by the GAPDH level.
(B) Rhodopsin levels were significantly lower in APP23 mice than in WT mice (Up: 12 month old, Down: 18 month old).
(C) Expression of rho in the retinas was validated by RT-PCR. Rho levels were significantly lower in APP23 mice than in WT mice at 12 months.
(D) Expression of rod-specific phototransduction proteins GNAT1 and recoverin in retinas from APP23 and WT mice was evaluated using Western blot. Expression levels were analyzed using densitometry and normalized by the GAPDH level.
(E) GNAT1 and recoverin levels were significantly lower in APP23 mice than in WT mice at 12 months.
(F) GNAT1 and recoverin levels of APP23 and control WT mice at 18 months.
(G) Representative images of rhodopsin labeling on retinal cross sections of APP23 and control WT mice at 12 months.
(H) Left: Quantitative analysis of fluorescence intensities of rhodopsin showed a 50% decrease in APP23 mice compared with control WT mice at 12 months. Right: Thicknesses of rod outer segment (OS), inner segment (IS), and outer nuclear layer (ONL) of APP23 mice were not different from those of control WT mice at 12 months.
(I) Representative images of rhodopsin labeling on retinal cross sections of APP23 and control WT mice at 18 months.
(J) Left: Quantitative analysis of fluorescence intensities of rhodopsin showed a lower intensity in APP23 mice than in control WT mice at 18 months. Right: Thicknesses of rod OS, IS, and ONL of APP23 mice were not different from those of control WT mice at 18 months. Data are represented as mean ± SEM. ns: not significant, ∗: p < 0.05, ∗∗: p < 0.01, ∗∗∗: p < 0.001, Student's t test. Scale bar = 20 μm