Figure 2. BAC hOPTN^E50K retinas exhibit normal retina layers and RGC axon projections.

(A) Normal gross histological layers in retinas from 18-month old BAC hOPTN^E50K (E50K) and wildtype (WT) mice. PKCα staining (green) labeled bipolar cells while calretinin (red) identifies amacrine cells, RGC, and the three dendritic strata between sublaminae of the IPL. No significant decreases in photoreceptors nuclei were observed in the ONL. Scale bar, 50 m. (B) Quantitation of retinal layers show they were grossly similar for both genotypes, except GCL and ONL layers in peripheral BAC hOPTN^E50K retinas, which were slightly increased. Data presented as mean ± S.E.M. (C) Fluorescently-labeled cholera toxin (ct) was used as an anterograde tracer. Ct-A595 (red) was injected into the right eye while ct-A647 (cyan) was injected into the left eye to visualize ipsilateral and contralateral RGC axonal projections in the brains of old (>18 months) BAC hOPTN^E50K and wildtype mice (n = 3 animals per genotype). Coronal brain sections showed normal RGC terminals from both eyes are found in the binocular area labeled by both red and cyan fluorescence. (D) Sagital brain sections showing Ct-A595 in the superior colliculus (SC) with blue DAPI nuclear stain. Occasional segmental loss of fluorescence is observed in BAC hOPTN^E50K mice. Scale bar, 1 mm, 500 μm (high magnification).