Effects of light on the development of melanoposin containing retinal ganglion cells in rats.

The present study was planned to evaluate the effect of light on the development of light-sensitive retinal ganglion cells.The Sprague-Dawley (SD) rats were segregated into 3 groups (n=18) which included routine feeding 10-day group 1, routine feeding 14-day group 2 and light-deprivation feeding 14-day group 3. The group 1 animals were routinely fed for 10 days in normal light conditions and were sacrificed for analyses on day 10. Similarly, group 2 animals were routinely fed for 14 days in normal light conditions and were sacrificed for analyses on day 14. The group 3 animals were kept were routinely fed for 7 days which was followed by their feeding in a light-deprived conditions and were sacrificed on day 14.The expression of the opsin gene determined by real-time PCR in retinal tissues showed a significant decline in the light-deprived group 3 when compared to other two groups. Furthermore, the melanopsin protein also showed a significant decline in its protein expression in light-deprived group 3 as observed by immune-blot analyses. The immuno-fluorescence analyses also showed the similar trend confirming the effect of light on the development of retinal ganglion cells.Light is essential for the proper development process of retinal ganglion cells as light directly affects regulatory opsin gene expression.