Time-restricted feeding does not improve daily rhythms in locomotion and drinking disrupted by artificial light at night

• Published in: Physiology & behavior 2025-03, Vol.290, p.114780, Article 114780
• Main Authors: Rumanova, Valentina Sophia, Foppen, Ewout, Okuliarova, Monika, Zeman, Michal, Kalsbeek, Andries
• Format: Article
• Language: English
• Subjects: Behavior; Daily rhythms; Light at night; Time-restricted feeding; Water intake
• ISSN: 0031-9384; 1873-507X; 1873-507X
• DOI: 10.1016/j.physbeh.2024.114780

•Time-restricted feeding does not restore daily activity rhythm in ALAN-exposed rats.•Anticipatory thirst remains suppressed in ALAN rats fed only during the dark period.•Results stress the importance of dark nights for intact behavioral rhythms. Exposure to artificial light at night (ALAN) disrupts natural darkness and desynchronizes daily rhythms in physiological processes and behavior. Previously, in rats, we have shown that dim ALAN disturbed the central circadian control and the temporal organization of behavior, and hormonal and metabolic pathways. The measurements of undisturbed daily behavioral (locomotor activity, feeding and drinking) patterns revealed reduced amplitudes and a transitory activity peak in the middle of the light (i.e. resting) period. Recent studies indicated that time-restricted feeding during the active period (TRFd) can strengthen daily rhythms and improve metabolic health. Therefore, the aim of our study was to prevent the dim ALAN-induced attenuation of daily behavioral rhythms by applying TRFd. Male Wistar rats were kept in a 12/12 light/dark cycle in metabolic cages for one week with free access to food and water. After acclimation, rats were divided into two groups: 1) ad libitum food or 2) time-restricted food during the dark period. After one week, both groups were exposed to dim ALAN for two weeks. Despite the enhanced amplitude of the daily feeding rhythm in TRFd animals, ALAN still suppressed the rhythm of locomotor activity, induced the extra peak during the resting period and reduced the bimodal pattern during the night. Furthermore, TRFd did not prevent the drop in anticipatory thirst caused by ALAN at the end of the active period. In conclusion, TRFd was not able to fully prevent the weakning of daily behavioral rhythms by dim ALAN.