[Effects of combined influence of ionizing radiation and light on the retina]

The continuous irradiation of rats with a light (3500 1x) for 48 hours led to destruction of 7.5 +/- 0.43% of neurosensoric cells (the control value was 0.2 +/- (0.02%). Longer photodamage caused progressing decrease in a population of the cells, narrowing followed by disappearance of corresponding layers of retina by the 30th day of the experiment. Preliminary exposure to X-rays with a dose of 5 Gy modified light damages of retina. The combination of two factors caused death of more than 30% of neurosensoric cells and redused the number of rows of nucleis of the external nuclear layer twice for the first 48 hours of illumination. After a longer influence of light a preliminary ionizing irradiation increased the number of destructively changed neurosensoric cells, reaching minimun of 41.7% by 30th day of the experiment. At the same time after a long combined irradiation less changes in row number quantity, numerical density of nucleus of the external nuclear layer and a population of neurosesoric cells in general was observed than after only one light exposure. Changes of choriocapillaries (thrombosis, obliteration, narrowing of a gap) which were more expressed at a combination of factors, led to infringement of blood circulation and played the important role in mechanisms of retina degeneration. Radial glia and neurons of internal layers of retina showed relative resistance to the investigated influences.