*2.6. Histology*/*Immunohistochemistry*

The methodologies used in this study have been described in detail previously [23]. Briefly, for conventional histology, eyes (n ≥ 4 per condition) were fixed by immersion in freshly prepared 4% paraformaldehyde in 0.125 M Na-phosphate buffer, pH 7.4, at 4 ◦C overnight, embedded in paraffin, and tissue sections (toluidine blue-stained) were viewed with an Olympus BH2 photomicroscope equipped with a Nikon digital camera. Digitized images were collected and further analyzed with ImagePro

Plus ® software, Version 4.1 (Media Cybernetics; Rockville, MD, USA). For immunohistochemistry, frozen sections of retinal tissue (embedded in Tissue-Plus ™ Optimal Cutting Temperature (O.C.T.) compound; Thermo Fisher Scientific, Waltham, MA, USA), obtained with a cryostat and collected on glass microscope slides were incubated with suitable primary antibodies, with detection by application of species-specific, fluor-conjugated secondary antibodies, counterstaining nuclei with DAPI, followed by laser confocal immunofluorescence microscopy (Leica TCS SPE scanning confocal microscope; Leica Microsystems Inc., Bu ffalo Grove, IL, USA), as previously reported [24].
