The ability of rapid retinal reattachment to stop or reverse the cellular and molecular events initiated by detachment.

PURPOSE To determine the effects of reattachment on the molecular and cellular events initiated by a retinal detachment lasting 1 hour or 1 day. METHODS Experimental retinal detachments were created in the right eyes of nine cats. Reattachments were performed 1 hour (n = 3) or 1 day (n = 3) after the detachment, and the animals were killed 3 days after detachment. Three-day detached (n = 3) and normal (n = 3) retinas were used for comparisons. Agarose-embedded sections were double labeled with a panel of antibodies. Some sections were also probed with the TUNEL technique to detect apoptotic cells. Wax-embedded sections were labeled with the MIB-1 antibody to the Ki67 protein to detect proliferating cells. RESULTS The 1-hour and 1-day detachments followed by reattachment showed a very similar and consistent reduction in photoreceptor deconstruction and the Müller cell gliotic response when compared with 3-day retinal detachments without reattachment. Light microscopy and immunolabeling with opsin antibodies showed a significant reduction in both rod and cone outer segment (OS) degeneration, even though OS length was shorter than normal. The reattachments also showed a reduction in opsin redistribution, retraction of rod terminals, TUNEL-labeled photoreceptors, loss of cytochrome oxidase staining in photoreceptors, neurite outgrowth from second-order neurons, the number of proliferating cells, and the increase in intermediate filaments and loss of soluble proteins from Müller cells. The apparent re-ensheathing of the OS by the apical processes of the retinal pigment epithelium had begun but was not completely normal. CONCLUSIONS These data indicate that, even though the length of the OS is less than normal, retinal reattachment within 1 day of detachment can either greatly retard or reverse many of the molecular and cellular changes initiated by detachment.