Abstract
Purpose: :
We wished to develop a light box that alleviates some of the problems associated with the classic light chambers used for light induced retinal degeneration in mice. This study demonstrates the use of a low cost LED light box for conducting light damage on single animals.
Methods: :
Fancier 500-A LED lamps were chosen because they can be modified slightly to fit on clear polycarbonate model 750 cages from Lab Supply Inc (standard mouse housing cages) and because they have can be adjusted in intensity by turning on/off banks of lights and adjusting the intensity of the LEDs over a wide range with a dial. We used white and black acrylic paint to paint the outside of the cages to obtain a highly reflective interior of the cage. The light level in boxes with bedding can be adjusted from 500-65000 lux. Retinal light damage was assessed in cyclically reared Balb-C mice from Charles River and The Jackson Laboratory, and C57BL/6 mice from Charles River. The C57BL/6 mice were treated with 1% atropine eye drops 30 min prior to light damage to dilate their pupils. Comparisons between a "classic" light chamber designed by Dan Organisciak (IOVS 26:1580-8, 1985) and our LED light boxes were done with the Balb-C mice. Measurements of visual outcome were done using ERG analysis 1 week and 3 weeks following light damage. Histology was performed on eyes after ERGs to measure morphological changes in the retina including ONL nuclei counts. We were also able to induce significant light damage in C57BL/6J mice treated with atropine to dilate their pupils using 40000 lux for 6 hours.
Results: :
The cost per LED light box ranges from $215-265 depending on the sale price of the LED lamps, as compared to approximately $4250 to have a custom "classic" light box built (cost for manufacture in 2006). We compared the amount of light damage using equivalent light intensity (8400 lux for 4 hours) using the classic model and the LED model and found that the LED model caused 80% as much damage as measured by ERG amplitudes 1 week following light damage. Using single Balb-C mice per box and 10000 lux for 4 hours in the LED light box, we found complete abrogation of the ERG response.
Conclusions: :
The LED boxes offer significant advantages (lower cost, much higher light output, standard caging, reduced variability) over prior light damage systems.
Keywords: apoptosis/cell death • retinal degenerations: cell biology