Protective effect of crocin against blue light- and white light-mediated photoreceptor cell death in bovine and primate retinal primary cell culture.

Purpose: The present study was performed to investigate the effect of crocin on blue light- and white light-induced rod and cone death in primary retinal cell cultures.

Methods: Primary retinal cell cultures were prepared from primate and bovine retinas. Fifteen-day-old cultures were exposed to blue actinic light or to white fluorescent light for 24 hours. Cultures were treated by the addition of different concentrations of crocin for 24 hours before light exposure or for 8 hours after light exposure. Cultures kept in the dark were used as controls. Green nucleic acid stain assay was used to evaluate cell death. Rods and cones were immunolabeled with specific antibodies and counted. TUNEL labeling was used to detect fragmented DNA in fixed cells after light exposure.

Results: Primary retinal cell cultures contained a mixture of retinal cells enriched in photoreceptors, bipolar cells, and Müller cells. Twenty-four-hour exposure to blue and white light induced death in 70% to 80% of the photoreceptors in bovine and primate retinal cell cultures. Crocin protected the photoreceptors against blue light- or white light-mediated damage in a concentration-dependent manner with an EC50 of approximately 30 microM. TUNEL assays confirmed that crocin protected photoreceptors from light damage.

Conclusions: These results show that blue and white light selectively induce rod and cone cell death in an in vitro model. Crocin protects retinal photoreceptors against light-induced cell death.