# ipRGCs Sensitive Blue Light Exposure Promotes the Robustness of Circadian and Neural Stem Cells in Sleep Deprived Conditions

## TL;DR

Exposure to blue light helps stabilize circadian rhythms and improve cognitive and emotional behaviors in sleep-deprived mice.

## Contribution

The study introduces a novel strategy using ipRGCs-sensitive blue light to alleviate circadian rhythm-related cognitive and emotional issues.

## Key findings

- 480 nm blue light exposure stabilizes disrupted clock genes and increases nocturnal activity in sleep-deprived mice.
- Blue light reduces anxiety-like behaviors and enhances cognitive abilities in sleep-deprived mice.
- Exposure to blue light reduces fluctuations in NSCs stemness gene expression caused by sleep deprivation.

## Abstract

Circadian rhythm abnormalities due to sleep deprivation (SD) may promote the development of emotional and cognitive disorders. Though light therapies have been employed to treat circadian disorders, the exact treatments and their underlying biology are still unclear. Our study aimed to investigate the effects of intrinsically photosensitive retinal ganglion cells (ipRGCs) sensitive 480 nm blue light on circadian rhythms affecting emotional and cognitive behaviors and the expression of neural stem cells (NSCs) stemness genes. In this study, we demonstrate that for mice with acute SD for 24 h, exposure to ipRGCs sensitive 480 nm blue light at ~ 1300 lux for 30 min at 8:00 a.m. and 8:00 p.m. improves the stability of disrupted clock genes, increases nocturnal activity, reduces anxiety-like behaviors, and enhances cognitive abilities. Furthermore, 480 nm blue light exposure reduces fluctuations in NSCs stemness gene expression induced by SD, potentially through its effect on enhancing the amplitude of suprachiasmatic nucleus (SCN) circadian oscillations. These findings may provide novel strategy for alleviating rotating circadian rhythm-related anxiety and learning and cognitive obstruction.