Effects and neural mechanisms of light-at-night exposure on anxiety and depression behaviors in mice
10.7644/j.issn.1674-9960.2025.06.008
- VernacularTitle:夜间蓝光暴露诱发小鼠焦虑、抑郁行为及其神经机制研究
- Author:
Ke BAO
1
;
Hongxiang KANG
;
Shaojun HOU
;
Yuyuan HU
;
Chen XING
;
Lun SONG
;
Xin HUANG
Author Information
1. 安徽医科大学病理生理学教研室,合肥 230032;军事科学院军事医学研究院,北京 100850
- Keywords:
light-at-night exposure;
anxiety;
depression;
hypothalamic-pituitary-adrenal axis;
synaptic structure;
brain-derived neurotrophic factor
- From:
Military Medical Sciences
2025;49(6):450-457
- CountryChina
- Language:Chinese
-
Abstract:
Objective To investigate the effects of light-at-night exposure on anxiety and depression behaviors in mice and to explore the underlying neural mechanisms.Methods Six-week-old male C57BL/6J mice were randomly assigned to a control(Ctrl)group and a light-at-night exposure(LAN)group.Mice in the LAN group were exposed to 460 nm blue light for 1 h daily during the zeitgeber time(ZT)13-14 while the Ctrl group mice were maintained under a 12-h light/12-h dark cycle.Behavioral tests were conducted at different time points following LAN exposure to evaluate anxiety and depression behaviors in the mice.Immunofluorescence staining was used to observe the effect of LAN on c-fos expressions in the medial prefrontal cortex(mPFC),basal ateral amygdala(BLA),paraventricular nucleus(PVN)and paraventricular thalamus(PVT).ELISA was performed to measure changes in serum corticosterone,adrenocorticotropic hormone(ACTH)and corticotropin-releasing hormone(CRH)levels.Golgi staining was applied to measurethe dendritic spine density and morphology from mPFC and CA1.Western blotting analysis was conducted to detect expression levels of brain-derived neurotrophic factors(BDNFs),phosphorylated tropomyosin receptor kinase B(p-TrkB)/TrkB,postsynaptic density protein 95(PSD95)and synaptophysin(SYP)in the mPFC.Results Mice exhibited anxiety-like behaviors after 14 days of LAN exposure,with depression-like behaviors emerging after 28 days.LAN exposure of 28 days led to a significant increase in the number of c-fos-positive neurons in the mPFC,BLA,PVN and PVT(P＜0.05),resulted in elevated serum corticosterone levels(P＜0.01)and reduced protein expression levels of BDNF and SYP(P＜0.05).Furthermore,there was a marked decrease in synapse numbers and synaptic density in the mPFC(P＜0.01).Conclusion Prolonged exposure to blue light at night enhances neuronal activity in the mPFC and BLA and suppresses the BDNF/TrkB signaling pathway by activating the hypothalamic-pituitary-adrenal axis(HPA),thus leading to synaptic structural and functional damage and inducing anxiety and depression behaviors in mice.
