Laboratory of Neurochemical Studies, Department of Physiology and Behavior, Biosciences Center, Federal University of Rio Grande do Norte, Natal, Brazil.
International Institute Edmond and Lily Safra, Santos Dumont Institute, Macaíba, Brazil.
PLoS One. 2023 Oct 4;18(10):e0292342. doi: 10.1371/journal.pone.0292342. eCollection 2023.
The aging effects on circadian rhythms have diverse implications including changes in the pattern of rhythmic expressions, such as a wide fragmentation of the rhythm of rest-activity and decrease in amplitude of activity regulated by the suprachiasmatic nucleus (SCN). The study of blue light on biological aspects has received great current interest due, among some aspects, to its positive effects on psychiatric disorders in humans. This study aims to evaluate the effect of blue light therapy on the SCN functional aspects, through the evaluation of the rest-activity rhythm, in aging rats. For this, 33 sixteen-months-old male Wistar rats underwent continuous records of locomotor activity and were exposed to periods of 6 hours of blue light during the first half of the light phase (Zeitgeber times 0-6) for 14 days. After this, the rats were maintained at 12h:12h light:dark cycle to check the long-term effect of blue light for 14 days. Blue light repeated exposure showed positive effects on the rhythmic variables of locomotor activity in aged rats, particularly the increase in amplitude, elevation of rhythmic robustness, phase advance in acrophase, and greater consolidation of the resting phase. This effect depends on the presence of daily blue light exposure. In conclusion, our results indicate that blue light is a reliable therapy to reduce circadian dysfunctions in aged rats, but other studies assessing how blue light modulates the neural components to modulate this response are still needed.
衰老对昼夜节律的影响有多种表现，包括节律表达模式的变化，例如休息-活动节律的广泛碎片化和由视交叉上核（SCN）调节的活动幅度减小。由于蓝光在人类精神疾病方面的积极影响等方面，对其生物方面的研究目前引起了极大的兴趣。本研究旨在通过评估昼夜节律的休息-活动节律，来评估蓝光疗法对 SCN 功能方面的影响，实验中使用了 33 只 16 个月大的雄性 Wistar 大鼠，它们连续记录了运动活动，并在光期的前半段（ Zeitgeber times 0-6）接受了 6 小时的蓝光照射，持续 14 天。之后，这些大鼠被维持在 12h：12h 光：暗周期下，以检查蓝光的长期影响，持续 14 天。重复暴露于蓝光对老年大鼠的运动活动节律变量有积极影响，特别是振幅增加、节律稳健性提高、峰相位提前和休息期更巩固。这种效应取决于每日蓝光暴露的存在。总之，我们的结果表明，蓝光是一种可靠的治疗方法，可以减少老年大鼠的昼夜节律紊乱，但仍需要其他研究评估蓝光如何调节神经成分来调节这种反应。
