The Impact of Cumulative Exposure to Blue Light during the Developmental Period of Melanopsin ipRGCs

Abstract

Previous study revealed that exposure to blue light during postnatal period decrease the function of NIF in mice. However, duration effect of blue light exposure during the developmental period of melanopsin ipRGCs is still unknown. Twenty four Swiss-Webster pregnant mice exposure to 470 nm blue light spectrum of the LED lights and sunlight. As a control group pregnant mice was keep in no light condition. The length of exposure was varies based on the stage of development: (1) from gestation day 9 (E9) up to 18 days of gestation (E18), (2) newborn to 6 days old, (3) from gestation day 9 until aged 6 days old. At 6 days old, selected mice pups were performed for negative phototaxis using cylindrical bore assay. The sunlight mice groups showed that the fastest response occur on longer exposure. However, on blue light mice groups, the longer the exposure actually decreases the activity more compare to only postnatal exposure. These conditions maybe due to interference on synaptogenesis during developmental period of melanopsin ipRGCs. Thus it can be concluded that exposure to blue light since in utero until neonatal is harmful especially to NIF response behavior.