Light Induced and Circadian Effects on Retinal Photoreceptor Cell Crystallins

• Authors: Daniel Organisciak, Wright State University; Ruth Darrow, Wright State University; Linda Barsalou, Wright State University; Christine Rapp, Wright State University; Benjamin McDonald, University of Alberta; Paul Wong, Emory University
• Journal Title: Photochemistry and Photobiology
• Volume: Volume 87, Number 1
• Publisher: Wiley: 12 months | 2011-01-01, Pages 151-159
• Type of Work: Article | Post-print: After Peer Review
• Publisher DOI: http://doi.org/10.1111/j.1751-1097.2010.00844.x
• Subjects: Health Sciences, Opthamology; Chemistry, Biochemistry
• Keywords: Science & Technology; Life Sciences & Biomedicine; Biochemistry & Molecular Biology; Biophysics; ALPHA-B-CRYSTALLIN; MESSENGER-RNA; A-CRYSTALLIN; GENE-EXPRESSION; PROTEIN; MOUSE; DEGENERATION; AGE; TRANSLOCATION; PATHOLOGY

Abstract

Crystallins in the retina may serve a chaperone-like protective function. In this study we measured mRNA levels for alpha-, beta- and gamma-crystallins in rat retinas following treatment with potentially damaging levels of light. We also determined crystallin protein patterns in photoreceptor cell rod outer segments (ROSs) isolated from rats exposed to intense light. Weanling albino rats were maintained in a dim cyclic light environment or in darkness for 40 days. At P60 animals were treated with intense visible light, for as long as 8 h, beginning at various times of the day or night. Retinas were excised immediately after light treatment and used for quantitative RT-PCR, or to prepare ROSs for western analysis. Some eyes were frozen in OCT for crystallin immunohistochemistry. Intense light exposure led to increases in mRNA expression for all retinal crystallins and to changes in ROS crystallin immunoreactivity. These light-induced changes were found to depend on the time of day that exposure started, duration of light treatment and previous light rearing history. We suggest that crystallin synthesis in retina exhibits a dependence on both light stress and circadian rhythm and that within photoreceptor cells crystallins appear to migrate in a light-independent, circadian fashion.