Guerrero-Vargas Natalí N, Espitia-Bautista Estefania, Escalona Rene, Lugo-Martínez Haydée, Gutiérrez-Pérez Mariana, Navarro-Espíndola Raful, Setién María Fernanda, Boy-Waxman Sebastián, Retana-Flores Elizabeth Angélica, Ortega Berenice, Buijs Ruud M, Escobar Carolina
Departamento de Anatomía, Facultad de Medicina, Universidad Nacional Autónoma de México, Mexico City, Mexico.
Centro de Ciencias de la Complejidad, Universidad Nacional Autónoma de México, Mexico City, Mexico.
Front Nutr. 2022 Sep 20;9:999156. doi: 10.3389/fnut.2022.999156. eCollection 2022.
Light at night is an emergent problem for modern society. Rodents exposed to light at night develop a loss of circadian rhythms, which leads to increased adiposity, altered immune response, and increased growth of tumors. In female rats, constant light (LL) eliminates the estrous cycle leading to a state of persistent estrus. The suprachiasmatic nucleus (SCN) drives circadian rhythms, and it interacts with the neuroendocrine network necessary for reproductive function. Timed restricted feeding (RF) exerts a powerful entraining influence on the circadian system, and it can influence the SCN activity and can restore rhythmicity or accelerate re-entrainment in experimental conditions of shift work or jet lag. The present study explored RF in female rats exposed to LL, with the hypothesis that this cyclic condition can rescue or prevent the loss of daily rhythms and benefit the expression of the estrous cycle. Two different feeding schedules were explored: 1. A 12-h food/12-h fasting schedule applied to arrhythmic rats after 3 weeks in LL, visualized as a rescue strategy (LL + RFR, 3 weeks), or applied simultaneously with the first day of LL as a preventive strategy (LL + RFP, 6 weeks). 2. A 12-h window of food intake with food given in four distributed pulses (every 3 h), applied after 3 weeks in LL, as a rescue strategy (LL + PR, 3 weeks) or applied simultaneously with the first day of LL as a preventive strategy (LL + PP, 6 weeks). Here, we present evidence that scheduled feeding can drive daily rhythms of activity and temperature in rats exposed to LL. However, the protocol of distributed feeding pulses was more efficient to restore the day-night activity and core temperature as well as the c-Fos day-night change in the SCN. Likewise, the distributed feeding partially restored the estrous cycle and the ovary morphology under LL condition. Data here provided indicate that the 12-h feeding/12-h fasting window determines the rest-activity cycle and can benefit directly the circadian and reproductive function. Moreover, this effect is stronger when food is distributed along the 12 h of subjective night.
夜间光照是现代社会出现的一个问题。夜间暴露于光照下的啮齿动物会出现昼夜节律丧失，进而导致肥胖增加、免疫反应改变以及肿瘤生长加快。在雌性大鼠中，持续光照（LL）会消除发情周期，导致持续发情状态。视交叉上核（SCN）驱动昼夜节律，并且它与生殖功能所需的神经内分泌网络相互作用。限时进食（RF）对昼夜节律系统具有强大的同步影响，它可以影响SCN的活动，并能在轮班工作或时差的实验条件下恢复节律性或加速重新同步。本研究探讨了在暴露于LL的雌性大鼠中进行RF，假设这种周期性条件可以挽救或预防日常节律的丧失，并有利于发情周期的表达。研究了两种不同的喂食方案：1. 在LL环境中3周后，对节律紊乱的大鼠采用12小时进食/12小时禁食方案，可视作一种挽救策略（LL + RFR，3周），或者在LL的第一天同时应用作为预防策略（LL + RFP，6周）。2. 在LL环境中3周后，采用12小时进食窗口，食物分四次投喂（每3小时一次），作为挽救策略（LL + PR，3周），或者在LL的第一天同时应用作为预防策略（LL + PP，6周）。在此，我们提供的证据表明，定时喂食可以驱动暴露于LL的大鼠的日常活动和体温节律。然而，分散投喂脉冲的方案在恢复昼夜活动和核心体温以及SCN中c-Fos的昼夜变化方面更有效。同样，分散喂食在LL条件下部分恢复了发情周期和卵巢形态。此处提供的数据表明，12小时进食/12小时禁食窗口决定了休息-活动周期，并且可以直接有益于昼夜节律和生殖功能。此外，当食物在主观夜间的12小时内分散投喂时，这种效果更强。
