Minocycline Inhibition of Photoreceptor Degeneration

Abstract

To determine whether systemic minocycline can protect photoreceptors in experimental retinal detachment (RD). Retinal detachment was induced in mice by subretinal injection of sodium hyaluronate, 1.4%. In 1 experiment, mice received daily injections of minocycline (group 1) or saline (group 2). In a second experiment, mice were treated with minocycline or saline beginning 24 hours prior, immediately after, or 24 hours after experimental RD. In both experiments, photoreceptor cell survival and apoptosis were assessed by immunohistochemistry with primary antibodies against photoreceptor cell markers, rod rhodopsin, and cone opsin, and by terminal deoxynucleotidyl transferase-mediated dUTP-biotin end labeling. Photoreceptor cell apoptosis was detected at day 1 after experimental RD, with apoptotic cells peaking in number at day 3 and dropping by day 7. Treatment with minocycline significantly reduced the number of apoptotic photoreceptor cells associated with RD when given 24 hours before or even 24 hours after RD. Our data suggest that minocycline may be useful in the treatment of photoreceptor degeneration associated with RD, even when given up to 24 hours after RD. Use of minocycline in patients with macula-off RD may prevent photoreceptor apoptosis and glial cell proliferation, improving final visual outcomes.