CHANGES IN THE ORGANIZATION AND EXPRESSION OF CYTOSKELETAL PROTEINS DURING RETINAL DEGENERATION INDUCED BY RETINAL-DETACHMENT

Purpose. The goal of this study was to determine the changes in the or ganization of the retinal cytoskeleton after experimental retinal deta chment. Methods. Cat retinas were detached from the retinal pigment ep ithelium and then processed for Western blot analysis and fluorescence microscopy. Proteins examined included glial fibrillary acidic protei n (GFAP), vimentin, tubulin, and actin. Sections were viewed using a l aser scanning confocal microscope. Results. GFAP and vimentin: At 1 da y after detachment, there was an aggregation of intermediate filaments in the endfoot of Muller cells. At 3 days, intermediate filament cont aining Muller cell processes could be detected within the subretinal s pace, and, at 28 days, these processes formed large glial scars in the subretinal space. Beta-tubulin: At 3 days after detachment, an increa se in immunolabeling could be detected within the Muller cell endfoot and in Muller cell processes within the subretinal space. Actin: At 3 days after detachment, rhodamine-phalloidin staining decreased in the inner segments, the photoreceptor synaptic terminals, and the outer li miting membrane. Conclusions. The decrease in labeling of the photorec eptor inner segment and synaptic terminal cytoskeleton may be a key in dicator of early changes in photoreceptors after detachment. The incre ase in cytoskeletal proteins GFAP, vimentin, and tubulin within the re tinal Muller cells after detachment may help to stabilize this cell ty pe as it hypertrophies during glial scar formation. Inhibition of this response may aid in the treatment of diseases in which Muller cell hy pertrophy plays a role.