Department of Neuroscience, Rockefeller Neuroscience Institute, Morgantown, West Virginia, USA.
Department of Medicine, Division of Oncology/Hematology at West Virginia University, Morgantown, West Virginia, USA.
Chronobiol Int. 2022 Dec;39(12):1674-1683. doi: 10.1080/07420528.2022.2135442. Epub 2022 Oct 21.
Circadian rhythms are endogenous biological cycles that regulate physiology and behavior for optimal adaptive function and survival; they are synchronized to precisely 24 hours by daily light exposure. Disruption of the daily light-dark (LD) cycle by exposure to artificial light at night (ALAN) dysregulates core clock genes and biological function. Exposure to ALAN has been associated with increased health risks in humans, and elderly individuals are at elevated risk for poor outcome from disease and often experience elevated exposure to ALAN due to increased care requirements. The role of disrupted circadian rhythms in healthy, aged animals remains unspecified; thus, we hypothesized that disrupted circadian rhythms via chronic exposure to dim ALAN (dLAN) impair immune response and survival in aged mice. Twenty-month-old C57BL/6 male and female mice were exposed to 24 weeks of LD conditions or dLAN (5 lux); then, cell-mediated immune response was assessed using a delayed-type hypersensitivity test. Aged female mice exposed to dLAN displayed dysregulated hypersensitivity and inflammation as a measure of cell-mediated immune response and decreased lifespan compared to females housed in dark nights. Nighttime lighting did not affect cell-mediated immune response or lifespan in males but dysregulated body mass and increased adrenal mass after immune challenge after chronic exposure to dLAN. Together, these data indicate that chronic exposure to dLAN affects lifespan in aged females and suggest that females are more susceptible to the detrimental consequences of disrupted circadian rhythms.
昼夜节律是调节生理和行为以实现最佳适应功能和生存的内源性生物周期；它们通过每天的光照暴露被精确地同步到 24 小时。夜间人工光照（ALAN）对日常光暗（LD）周期的破坏会扰乱核心时钟基因和生物功能。接触 ALAN 与人类健康风险增加有关，而老年人由于护理需求增加，往往面临更高的疾病不良预后风险，并且经常接触到更高水平的 ALAN。昼夜节律紊乱在健康老年动物中的作用仍未明确；因此，我们假设通过慢性接触弱 ALAN（dLAN）破坏昼夜节律会损害老年小鼠的免疫反应和存活能力。将 20 个月大的 C57BL/6 雄性和雌性小鼠暴露于 24 周的 LD 条件或 dLAN（5 勒克斯）；然后，使用迟发型超敏反应试验评估细胞介导的免疫反应。与在黑暗夜晚中饲养的雌性相比，暴露于 dLAN 的老年雌性小鼠表现出免疫反应失调和炎症，作为细胞介导免疫反应的衡量标准，并且寿命缩短。夜间照明不会影响雄性的细胞介导免疫反应或寿命，但会在慢性暴露于 dLAN 后对免疫挑战后的体重和肾上腺质量产生负面影响。总的来说，这些数据表明，慢性接触 dLAN 会影响老年雌性的寿命，并表明雌性更容易受到昼夜节律紊乱的不利后果的影响。
