Modern 24-h society lifestyle is associated with experiencing frequent shifts in the lighting conditions which can negatively impact human health. Here, we use the degus, a species exhibiting diurnal and nocturnal chronotypes, to: (a) assess the impact of chronic shifts of the light:dark (LD) cycle in the animal's physiology and behaviour and (b) test the therapeutic potential of melatonin in enhancing rhythmicity under these conditions. Degus were subjected to a "5d + 2d" LD-shifting schedule for 19 weeks. This protocol aims to mimic lighting conditions experienced by humans during shift work: LD cycle was weekly delayed by 8h during 5 "working" days (Morning, Afternoon and Night schedule); during weekends (2 days), animals were kept under Morning schedule. After 9 weeks, melatonin was provided daily for 6h in the drinking water. The "5d + 2d" shifting LD schedule led to a disruption in wheel-running activity (WRA) and body temperature (Tb) rhythms which manifested up to three separate periods in the circadian range. This chronodisruption was more evident in nocturnal than in diurnal degus, particularly during the Afternoon schedule when a phase misalignment between WRA and Tb rhythms appeared. Melatonin treatment and, to a lesser extent, water restriction enhanced the 24-h component, suggesting a potential role in ameliorating the disruptive effects of shift work.

中文翻译：

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褪黑素减轻了章鱼中明暗周期的长期变化引起的昼夜节律系统破坏。

现代的24小时社会生活方式与照明条件的频繁变化有关，这可能会对人体健康产生负面影响。在这里，我们使用表现出昼夜型和夜间型的德格斯（Degus）来：（a）评估光：暗（LD）周期的慢性变化对动物的生理和行为的影响，以及（b）测试该动物的治疗潜力在这些条件下褪黑激素可增强节律。对Degus进行“ 5d + 2d” LD移位计划，持续19周。该协议旨在模拟人类在轮班工作中遇到的光照条件：LD周期在5个“工作”天（早上，下午和夜间时间表）每周延迟8h。在周末（2天）中，将动物饲养在早晨时间表内。9周后，每天在饮用水中提供褪黑激素6小时。“ 5d + 2d”移动LD时间表导致轮转活动（WRA）和体温（Tb）节律中断，在昼夜节律范围内最多出现三个单独的周期。在夜间，这种昼夜节律比昼夜阴部更为明显，特别是在下午的时间表中，当WRA和Tb节律之间出现相位失调时。褪黑素处理以及在较小程度上限水增强了24小时成分，表明在改善轮班工作的破坏性作用中具有潜在作用。在夜间，这种昼夜节律比昼夜阴部更为明显，特别是在下午的时间表中，当WRA和Tb节律之间出现相位失调时。褪黑素治疗以及在较小程度上限水增强了24小时成分，表明在改善轮班工作的破坏性作用中具有潜在作用。在夜间，这种昼夜节律比昼夜阴部更为明显，特别是在下午的时间表中，当WRA和Tb节律之间出现相位失调时。褪黑素治疗以及在较小程度上限水增强了24小时成分，表明在改善轮班工作的破坏性作用中具有潜在作用。