Acute systemic 11-cis-retinal intervention improves abnormal outer retinal ion channel closure in diabetic mice.

To test the hypothesis that in dark-adapted diabetic mice subnormal manganese uptake in the outer retina can be ameliorated with exogenous 11-cis-retinal intervention.Three groups were studied: age-matched controls and mice that had been diabetic for 3 months with and without acute, systemic 11-cis-retinal treatment administered 30 min before the manganese injection. Mice in each group were examined with manganese-enhanced magnetic resonance imaging (MEMRI) to assess central intraretinal manganese uptake and extraocular muscle manganese uptake. Bodyweights and glycated hemoglobin were determined.Both diabetic groups had lower bodyweights and higher glycated hemoglobin levels relative to controls; no differences in these parameters between diabetic groups were noted. No substantial differences in muscle uptake were noted between any of the groups. Diabetes produced a subnormal intraretinal uptake of manganese; acute exogenous 11-cis-retinal significantly corrected only outer retinal uptake, although not to control levels.The present results provide for the first time evidence that raises the possibility of a critical role of 11-cis-retinal, a key participant of the visual cycle, in diabetes-evoked outer retinal dysfunction.