Dauchy Robert T, Wren-Dail Melissa A, Hoffman Aaron E, Hanifin John P, Warfield Benjamin, Brainard George C, Hill Steven M, Belancio Victoria P, Dauchy Erin M, Blask David E
Departments of Structural and Cellular Biology, Tulane University School of Medicine, Tulane, Louisiana, Pennsylvania, USA.
Departments of Epidemiology, Tulane University School of Medicine, Tulane, Louisiana, Pennsylvania, USA.
Comp Med. 2016;66(5):373-383.
Regular cycles of exposure to light and dark control pineal melatonin production and temporally coordinate circadian rhythms of metabolism and physiology in mammals. Previously we demonstrated that the peak circadian amplitude of nocturnal blood melatonin levels of rats were more than 6-fold higher after exposure to cool white fluorescent (CWF) light through blue-tinted (compared with clear) rodent cages. Here, we evaluated the effects of light-phase exposure of rats to white light-emitting diodes (LED), which emit light rich in the blue-appearing portion of the visible spectrum (465-485 nm), compared with standard broadspectrum CWF light, on melatonin levels during the subsequent dark phase and on plasma measures of metabolism and physiology. Compared with those in male rats under a 12:12-h light:dark cycle in CWF light, peak plasma melatonin levels at the middark phase (time, 2400) in rats under daytime LED light were over 7-fold higher, whereas midlight phase levels (1200) were low in both groups. Food and water intakes, body growth rate, and total fatty acid content of major metabolic tissues were markedly lower, whereas protein content was higher, in the LED group compared with CWF group. Circadian rhythms of arterial plasma levels of total fatty acids, glucose, lactic acid, pO, pCO, insulin, leptin, and corticosterone were generally lower in LED-exposed rats. Therefore, daytime exposure of rats to LED light with high blue emissions has a marked positive effect on the circadian regulation of neuroendocrine, metabolic, and physiologic parameters associated with the promotion of animal health and wellbeing and thus may influence scientific outcomes.
明暗的周期性循环控制着松果体褪黑素的分泌，并在时间上协调哺乳动物新陈代谢和生理的昼夜节律。此前我们证明，通过蓝色（与透明相比）啮齿动物笼暴露于冷白色荧光（CWF）光下后，大鼠夜间血液褪黑素水平的昼夜峰值幅度高出6倍多。在此，我们评估了将大鼠在光照阶段暴露于白光发光二极管（LED）（其发出富含可见光谱蓝色部分的光（465 - 485 nm））与标准广谱CWF光相比，对随后黑暗阶段的褪黑素水平以及代谢和生理的血浆指标的影响。与处于CWF光下12:12小时光照:黑暗循环的雄性大鼠相比，白天暴露于LED光下的大鼠在黑暗中期（时间，2400）的血浆褪黑素峰值水平高出7倍多，而两组在光照中期（1200）的水平都较低。与CWF组相比，LED组的食物和水摄入量、身体生长速率以及主要代谢组织的总脂肪酸含量明显较低，而蛋白质含量较高。暴露于LED光下的大鼠动脉血浆中总脂肪酸、葡萄糖、乳酸、pO、pCO、胰岛素、瘦素和皮质酮的昼夜节律通常较低。因此，白天将大鼠暴露于高蓝光发射的LED光下，对与促进动物健康和福祉相关的神经内分泌、代谢和生理参数的昼夜调节具有显著的积极影响，从而可能影响科学研究结果。
