Long-term treatment with 9-cis-β-carotene rich alga Dunaliella Bardawil inhibits photoreceptor degeneration in a mouse model of retinoid cycle defect

Abstract

Purpose : To examine the therapeutic effect of oral treatment with 9-cis β-carotene rich alga Dunaliella Bardawil on retinal function and structure in Rpe65rd12 mice, a model of genetic defect in retinoid cycle.

Methods : Thirteen RPE65rd12 mice at age of 28 days were fed with Teklad Global 18% Protein Rodent Diet (normal diet), vitamin A deficiency diet (VAD) or VAD diet supplemented with extracts of 9-cis β-carotene rich Dunaliella Bardawil algae (DUNA) for 14 months. Retinal function was recorded once a month in both eyes simultaneously by electroretinograph (ERG). Histological analysis and immunofluorescence staining with anti- M opsin antibody were used to determine retinal structure.

Results : At 14 months, mice fed with DUNA presented significantly higher maximal a-wave coampared with mice fed with VAD or normal diet (30μV [SE=5] vs. 5 μV [SE=3] p=0.006 and vs. 3 μV [SE=2] p=0.007, respectivley) and significantly higher maximal b-wave compared with mice fed normal diet (82μV [SE=8] vs. 30 μV [SE=10] p=0.002). These results are assosicated with histological analysis revealing increased number of M-opsins in retina of mice treated with DUNA.

Conclusions : Long term oral treatment with Dunaliella powder rich in 9-cis-β-carotene preserves retinal function and rescues M-cones from degeneration in Rpe65rd12 mice. Our findings suggest that 9-cis β-carotene may possibly be an effective treatment for retinal dystrophies involving the retinoid cycle.

This is an abstract that was submitted for the 2016 ARVO Annual Meeting, held in Seattle, Wash., May 1-5, 2016.