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Abstract #20627 Published in IGR 10-1
The influence of visible light exposure on cultured RGC-5 cells
Wood JPM; Lascaratos G; Bron AJ; Osborne NNMolecular Vision 2008; 14: 334-344
PURPOSE: To determine the effects of visible light on normal or metabolically compromised cultured rat RGC-5 cells. METHODS: Cultured RGC-5 cells were exposed to different durations as well as intensities of optical radiation, filtered to exclude wavelengths below 400 mn. Some cells were also subjected to metabolic compromise by depriving them of serum (serum deprivation; SD): Treated cells were assayed for cell viability using the 3,(4,5-dimethylthiazol-2-y1)-2,5-diphenyltetrazolium bromide (MTT) reduction assay, for DNA breakdown by terminal deoxynucleotidyl transferase (TdT)-mediated d-UTP-linked nick end labeling (TUNEL), apoptotic protein activation by immunoblotting, and the production of reactive oxygen species (ROS) with dihydroethidium. A. subset of cells was treated with 100 pM rotenone as an alternative means to induce metabolic stress; this was to determine that the influence of light on compromised cells was not specific to serum-deprivation alone. RESULTS: Exposure to the light for 48 h activated both caspase-3 Bcl-associated X-protain (Bax) in cultured RGC-5 cells. Furthermore, light (1000 or 4000 lux), SD, and rotenone caused minor but significant decreases in cellular MTT reduction. SD and light also led to cellular DNA breakdown, although only ligth caused ROS production. Light (48 h) significantly exacerbated the effect of SD on MTT reduction and DNA cleavage. Furthermore, the antioxidant, trolox, significantly blunted the detrimental influence of light on cell viability, increase in TUNEL-positive cells and the generation of ROS. CONCLUSIONS: Exposure to light was slightly, but significantly, harmful to healthy RGC-5 cells alone, but was much more toxic to those cells that were energetically compromised. Continuous light exposure can therefore detrimentally affect metabolically stressed RGC-5 cells. This may have implications for some ocular retinopathies such as glaucoma.
Dr. N.N. Osborne, Nuffield Laboratory of Ophthalmology, University of Oxford, Walton Street, Oxford OX2 6AW, United Kingdom. Neville.osborne@eye.ox.ac.uk
Classification:
2.13 Retina and retinal nerve fibre layer (Part of: 2 Anatomical structures in glaucoma)
3.6 Cellular biology (Part of: 3 Laboratory methods)