Retinal Toxicity of Lutein and Zeaxanthin associated to Brilliant Blue in Rabbit Model

Abstract

Purpose: : To evaluate the safety profile of solutions containing lutein and zeaxanthin (L/Z) in isolated formulations or associated to brilliant blue (BB

Methods: : The dye solutions were developed using pharmaceutical technology. Twenty-six dutch-belted rabbits were used in the toxicity study. Four different dye solutions containing lutein and zeaxanthin (L/Z 0,5%, L/Z 0,3%+BB 0,025%, L/Z 0,5%+BB 0,0125%, Lut 0,25% + BB 0,05% ) isolated or associated to brilliant blue in a formulation named Retidyne™ were injected at the vitreous cavity of the right eye from each rabbit while the left eye was injected with BSS in order to be used as controls. Scotopic and photopic electroretinograms (ERGs) curves were measured in all eyes at different follow-up periods. The animals were sacrificed at 1 and 7 days and eyes analyzed by light and electron scanning microscopy. Histological evaluation of retinal cells was performed to define morphological abnormalities and number of cells.

Results: : No statistical differences at A and B wave amplitudes as well as latency were observed at the ERGs profile among the different solutions injected at the vitreous cavity and the control eyes at baseline as well as at all follow-up periods (p>0.05). The light and electron microscopy showed no histological abnormalities at all follow-up. Particularly, histological examination disclosed no case of diffuse cellular edema and vacuolization within the ganglion cells, bipolar cells, and photoreceptors. All subgroups showed slight retinal abnormalities similar to BSS injection.

Conclusions: : A lutein and zeaxanthin natural de solution associated to brilliant blue showed a safe profile in this rabbit model. Additional studies are necessary in order to use these natural dyes in human subjects for vitreoretinal surgery.

Keywords: vitreoretinal surgery • injection • macula/fovea