The impact of daytime light exposure on diurnal and circadian rhythms in the diurnal rodent Rhabdomys pumillio

白天光照对日间啮齿动物横纹鼠昼夜节律的影响

• 批准号: BB/P009182/1
• 负责人: Robert Lucas
• 金额: $ 64.25万
• 依托单位: University of Manchester
• 依托单位国家: 英国
• 项目类别: Research Grant
• 财政年份: 2017
• 资助国家: 英国
• 起止时间: 2017 至 无数据
• 项目状态: 已结题
• 来源: https://gtr.ukri.org/projects?ref=BB%2FP009182%2F1
• 关键词: impact; daytime; light; exposure; diurnal

Throughout our evolutionary history, the rotation of the earth upon its axis imposed a highly predictable and large amplitude twenty four hour rhythm in the amount of light to which we were exposed. The advent of artificial lighting has fundamentally disrupted this relationship in two ways. Firstly, it allows us to experience unnaturally high levels of light at night. Secondly, it allows us to spend most of our waking time indoors, exposed to unnaturally low light levels during the day. Significant attention has been paid to the deleterious effects of light at night, with evidence from both animal and human studies that this disrupts the endogenous timing mechanisms (circadian clocks) that define 24hr rhythms in our physiology and behaviour and inhibits sleep, with knock-on consequences for general health and daytime performance. By contrast, the impact of reduced light intensity during the day has been much less studied. This is a shame because, while it is practically inconceivable that we could reverse the progress of the last >100 years and persuade people to avoid unnatural sources of light at night, increasing levels of daytime light could be readily achieved by changes to architectural lighting design or even just by encouraging people to spend more time outdoors. There is evidence from humans that increasing light during the day improves alertness and cognitive performance, and that in the long term it can change the phase, increase the amplitude, and reduce the photosensitivity of circadian rhythms. However, the literature is sparse and lacks a systematic study of the impact of daytime light levels on temporal physiology. Here we set out to address this deficit and ask what impact, if any, changing daytime light exposure has on 24hr rhythms in behaviour and physiology. We then continue to ask whether increases in daytime light intensity can ameliorate some of the disruptive effects of light at night. We will address these questions by studying laboratory rodents. There is a rich history of translating findings from laboratory animals to humans in the field of circadian biology. Working in laboratory animals has the huge advantage of allowing researchers to carefully control environmental conditions over many days/weeks in a way that is difficult to achieve in human studies in the laboratory, let alone under field conditions. Fortunately, general principles established in the laboratory have proven to have good utility for understanding rhythmic physiology of humans in the real world. A substantial challenge in applying this well-worn approach to the questions posed in this proposal is that commonly employed laboratory rodents (mice, rats, hamsters) are nocturnal and would not normally experience bright daytime light. Indeed, in the lab they employ behavioural strategies to reduce their daytime light exposure - build nests, seek shade, shield their eyes during sleep. If we are to understand the impact of changing daytime light levels on circadian organisation and the disruptive effects of light at night we therefore need a species that, like humans, actively seeks daytime light exposure. We have established a colony of such animals in Manchester in preparation for this proposal. Rhabdomys pumillio is a species of mouse from Africa, slightly larger than ordinary lab mice. Importantly though, in both their natural environment and in the lab they are substantially day active. Accordingly, they also have a visual system that, like our own, is optimised for seeing in bright light. In this proposal we will carefully change the intensity of daytime light and monitor the impact on daily rhythms in behaviour and physiology in Rhabdomys. We will then ask whether increasing daytime light exposure ameliorates the disruptive effects of nighttime light exposure, with especial emphasis on the sort of nocturnal lighting patterns experienced by people.

在我们的整个进化史上，地球在其轴上的旋转施加了高度可预测的，大幅度二十四小时节奏，以我们暴露的光量。人造照明的出现从根本上破坏了这种关系。首先，它使我们能够在夜间体验不自然的光线。其次，它使我们能够在室内度过大部分的清醒时间，白天暴露于不自然的光线水平。人们对光线在夜间的有害影响引起了极大的关注，这是动物和人类研究的证据，这些证据破坏了内源性的时序机制（昼夜节律时钟），这些机制定义了我们的生理学和行为中24小时的节奏，并抑制睡眠，并抑制了对一般健康和白天表现的敲门后果。相比之下，研究中光强度降低的影响的研究少得多。这是一种耻辱，因为虽然实际上是不可想象的，但我们可以扭转过去100年的进步，并说服人们避免在夜间进行不自然的光源，但通过改变建筑照明设计的变化，甚至通过鼓励人们花费更多的时间来淘汰更多时间，可以很容易地实现白天光的水平。人类有证据表明，白天的光线增加可以提高机敏性和认知性能，从长远来看，它可以改变阶段，增加振幅并减少昼夜节律的光敏性。但是，文献稀疏，缺乏对白天光水平对时间生理的影响的系统研究。在这里，我们着手解决这一赤字，并询问改变白天的光暴露对行为和生理学的24小时节奏的影响。然后，我们继续询问白天的光强度增加是否可以改善晚上光的某些破坏性影响。我们将通过研究实验室啮齿动物来解决这些问题。在昼夜节律生物学领域，有丰富的历史将发现从实验动物转化为人类。在实验室动物中工作的巨大优势是，在实验室的人类研究中很难实现，研究人员可以在许多天/几周内仔细控制环境条件，更不用说在野外条件下。幸运的是，在实验室中建立的一般原则已被证明具有良好的效用，可以理解现实世界中人类的节奏生理学。将这种破旧的方法应用于本提案中提出的问题的一个重大挑战是，常见的实验室啮齿动物（小鼠，老鼠，仓鼠）是夜行性的，通常不会体验到白天光明的光线。确实，在实验室中，他们采用行为策略来减少白天的光线曝光 - 建立巢穴，寻找阴影，遮住睡眠期间的眼睛。如果我们要了解改变白天光水平对昼夜节律组织的影响以及晚上光的破坏性影响，因此，我们需要一个像人类一样，积极寻求白天的光曝光的物种。我们已经在曼彻斯特建立了这样的动物殖民地，为这一提议做准备。 rhabdomys pumillio是来自非洲的小鼠物种，比普通的实验室小鼠大。但是，重要的是，在他们的自然环境和实验室中，它们都活跃起来。因此，它们还具有像我们自己一样优化可在明亮的光线上进行优化的视觉系统。在此提案中，我们将仔细改变白天光的强度，并监控横纹肌行为和生理学对每日节奏的影响。然后，我们将询问日间光线曝光的增加是否可以改善夜间光暴露的破坏性影响，并特别强调人们所经历的那种夜间照明模式。

项目成果

Recommendations for daytime, evening, and nighttime indoor light exposure to best support physiology, sleep, and wakefulness in healthy adults.

• DOI: 10.1371/journal.pbio.3001571
• 发表时间: 2022-03
• 期刊: PLoS biology
• 影响因子: 9.8
• 作者: Brown TM;Brainard GC;Cajochen C;Czeisler CA;Hanifin JP;Lockley SW;Lucas RJ;Münch M;O'Hagan JB;Peirson SN;Price LLA;Roenneberg T;Schlangen LJM;Skene DJ;Spitschan M;Vetter C;Zee PC;Wright KP Jr
• 通讯作者: Wright KP Jr

The impact of temporal modulations in irradiance under light adapted conditions on the mouse suprachiasmatic nuclei (SCN).

• DOI: 10.1038/s41598-017-11184-2
• 发表时间: 2017-09-05
• 期刊: Scientific reports
• 影响因子: 4.6
• 作者: Dobb R;Martial F;Elijah D;Storchi R;Brown TM;Lucas RJ
• 通讯作者: Lucas RJ

Melanopsin Contributions to the Representation of Images in the Early Visual System.

• DOI: 10.1016/j.cub.2017.04.046
• 发表时间: 2017-06-05
• 期刊: Current biology : CB
• 作者: Allen AE;Storchi R;Martial FP;Bedford RA;Lucas RJ
• 通讯作者: Lucas RJ

Daily electrical activity in the master circadian clock of a diurnal mammal

• DOI: 10.1101/2020.12.23.424225
• 发表时间: 2020-12
• 期刊: eLife
• 影响因子: 7.7
• 作者: Beatriz Baño-Otálora;Matthew Moye;T. Brown;R. Lucas;C. Diekman;M. D. Belle

Slow vision: Measuring melanopsin-mediated light effects in animal models.

视力慢：在动物模型中测量黑视蛋白介导的光效应。

• DOI: 10.1016/bs.pbr.2022.04.009
• 发表时间: 2022
• 期刊: Progress in brain research
• 作者: Allen AE