El-Hennamy Rehab E, Elmasry Heba A
Zoology and Entomology Department, Faculty of Science, Helwan University, Cairo, Egypt.
Sleep Biol Rhythms. 2023 Nov 5;22(2):181-190. doi: 10.1007/s41105-023-00495-9. eCollection 2024 Apr.
The aging process is characterized by circadian rhythm disruption, in physiology and behavior, which could result from weak entrainment. Light is the most potent cue that entrains the central circadian clock, which in turn synchronizes peripheral clocks in animal tissues. Period 2 ) is one of the clock genes that respond to light. Moreover, oxidative stress could entrain the clock. Therefore, the present work aimed to investigate the role of light when applied late at night on the , B cell lymphoma 2 () gene expression, and oxidative status in aged rats. Aged rats were divided into a control group and a group exposed to a 30-min light pulse applied daily during the subjective night at 5 am (ZT 22) for 4 weeks. and gene expression were quantified in liver tissue. To evaluate oxidative status, Glutathione (GSH), nitric oxide (NO), and malondialdehyde (MDA) were estimated. The light pulse reduced the expression levels of and mRNA. Although it diminished the levels of malondialdehyde (MDA), nitric oxide (NO) levels were elevated and the glutathione (GSH) levels were declined. In conclusion, the light pulse late at night abolished mRNA circadian rhythm and reduced its expression in the liver of the aged rat. Similarly, it diminished the anti-apoptotic gene expression, . Moreover, it might attenuate oxidative stress through the reduction in MDA levels.
衰老过程的特征是生理和行为上的昼夜节律紊乱，这可能是由于同步作用减弱所致。光是调节中枢生物钟的最有效信号，而中枢生物钟又会使动物组织中的外周生物钟同步。周期蛋白2（Per2）是对光有反应的生物钟基因之一。此外，氧化应激也可以调节生物钟。因此，本研究旨在探讨深夜光照对老年大鼠B细胞淋巴瘤2（Bcl-2）基因表达及氧化状态的影响。将老年大鼠分为对照组和实验组，实验组大鼠在每天凌晨5点（ Zeitgeber时间22，ZT22）的主观夜间接受30分钟的光脉冲照射，持续4周。检测肝脏组织中Per2和Bcl-2基因的表达。为评估氧化状态，检测了谷胱甘肽（GSH）、一氧化氮（NO）和丙二醛（MDA）的水平。光脉冲降低了Per2和Bcl-2 mRNA的表达水平。虽然它降低了丙二醛（MDA）的水平，但一氧化氮（NO）水平升高，谷胱甘肽（GSH）水平下降。总之，深夜的光脉冲消除了老年大鼠肝脏中Per2 mRNA的昼夜节律并降低了其表达。同样，它也降低了抗凋亡基因Bcl-2的表达。此外，它可能通过降低MDA水平来减轻氧化应激。
