The effects of light on transdifferentiation and survival of chicken neural retina cells

The effects of light on the development of chicken embryo neural retina cultures were studied with a view to investigating similarities between the enhancement of transdifferentiation by light and light-induced degeneration of the retina in vivo. Normal levels of laboratory illumination were found to stimulate early mitotic events in the cultures, promoting formation of pigment cells. Short exposure of the cells to bright white light caused widespread cell death and a decrease in the area of the cell sheet. Minimal Essential Medium which had been irradiated with bright white light inhibited expansion of the cell sheet, but had no mitogenic effect. Illumination of the cells with red light had no effect on survival or mitosis; yellow light promoted mitosis, but did not affect cell survival. Blue and green light both reduced the areas occupied by undistinguished cells. Light-induced retinal degeneration has a comparable action spectrum. It is suggested that a study of the physiological basis of light-induced destruction and transdifferentiation of neural retina in culture could play an important role in the development of therapeutic measures for the control of retinal degeneration in man.