Light-induced photoreceptor degeneration in the retina of the zebrafish.

Exposure of the zebrafish retina to intense light is a noninvasive method to elicit the selective degeneration of photoreceptors. In zebrafish, photoreceptor degeneration is followed by robust photoreceptor regeneration from stem cells that are intrinsic to the teleost retina. Two recent light-lesioning methods have been developed, each with specific advantages. The first involves a prolonged period of dark adaptation followed by exposure to high-intensity halogen lighting at ∼3,000-20,000 lux for 3-4 days. This causes widespread degeneration of rod and cone cells in the dorsal and central regions of the retina. The second method uses ultrahigh-intensity lighting at intensities greater than 120,000 lux, with an exposure time of 30 min. This causes degeneration of rod and cone cells within a relatively narrow naso-temporal band in the central retina. The advantages of the first (lower light intensity) technique are the widespread destruction of photoreceptors and the lower cost of equipment. The advantages of the second (higher light intensity) technique are the elimination of the prolonged dark adaptation and short duration of the exposure, thereby allowing experiments to be conducted more rapidly.