Exploring the Effects of Blue Light on Circadian Rhythm in SD Rat

Purpose: The hypothalamic suprachiasmatic nucleus (SCN) is the master clock of the circadian rhythms, coordinating the entire circadian system of the body, including the secretion of melatonin. Methods: In this study, we aimed to clarify the transcriptome profile influenced by blue light in Sprague Dawley (SD) rats. Rats in the experimental group were exposed to blue light with wavelengths of 450nm and 465nm for 3 and 6 hours respectively during nighttime. After a 6-week intervention of blue light exposure, the retinal tissue was used for histological analysis, the blood were investigated using ELISA, and hypothalamus samples were collected for the full-length RNA-seq. Differentially expressed genes were validated by reverse transcription-quantitative RT-qPCR and Western blot. The relationships between the expression levels of clock genes and the concentrations of melatonin and AA-NAT were evaluated via correlation analysis. Results: Our findings demonstrated the retinal cytoarchitecture of SD rats exposed to blue light was damaged, melatonin and AA-NAT in the blood of SD rats exposed to blue light was disordered. Differentially expressed genes were identified, and KEGG analysis revealed that TGF-beta signaling pathway may be related to exposure to blue light. Despite the limitations imposed by the sample size and difference parameters, RT-qPCR analysis was employed to validate the accuracy and reliability of the results, and it was found that they were indeed both accurate and reliable. Conclusion: The findings of this study provide a novel insight into the potential mechanisms underlying the impact of blue light exposure and may offer a novel approach to the treatment of photopathogenesis by modulating circadian rhythms.