Pham Kevin, Lazenby Madeline, Yamada KayLene, Lattin Christine R, Wada Haruka
Department of Biological Sciences, Auburn University, Auburn, AL 36849, USA.
Department of Biological Sciences, Auburn University, Auburn, AL 36849, USA.
Gen Comp Endocrinol. 2025 Jan;361:114644. doi: 10.1016/j.ygcen.2024.114644. Epub 2024 Nov 26.
The ability for traits to recover after exposure to stress varies depending on the magnitude, duration, or type of stressor. One such stressor is circadian rhythm disruption stemming from exposure to light at night. Circadian rhythm disruption may lead to long-term physiological consequences; however, the capacity in which individuals recover and display stress resilience is not known. Here, we exposed zebra finches (Taeniopygia castanotis) to constant light (24L:0D) or a regular light/dark cycle (14L:10D) for 23 days, followed by a recovery period for 12 days. We measured body mass, corticosterone, and glucose levels at multiple timepoints, and relative protein expression of glucocorticoid receptors at euthanasia. Body mass significantly increased over time in light-exposed birds compared to controls, but a 12-day recovery period reversed this increase. Baseline levels of circulating glucose decreased in light-exposed birds compared to controls, but returned to pretreatment levels after the 12-day recovery period. In contrast, the glucose stress response did not show a similar recovery trend, suggesting longer recovery is needed or that this is a persistent effect in light-exposed birds. Surprisingly, we did not detect any differences in baseline corticosterone or reactivity of the hypothalamic-pituitiary-adrenal (HPA) axis between groups throughout the experiment. Moreover, we did not detect differences between relative protein expression of glucocorticoid receptors or a relationship with HPA axis reactivity. Yet, we found a positive relationship between glucocorticoid receptors and the glucose stress response, but only in the light group. Our results indicate that physiological and morphological traits differ in their ability to recover in response to constant light and warrants further investigation on the mechanisms driving stress resilience under a disrupted circadian rhythm.
性状在受到应激后恢复的能力因应激源的强度、持续时间或类型而异。一种这样的应激源是夜间暴露于光导致的昼夜节律紊乱。昼夜节律紊乱可能会导致长期的生理后果；然而，个体恢复并表现出应激恢复力的能力尚不清楚。在这里，我们将斑胸草雀（Taeniopygia castanotis）暴露于持续光照（24小时光照：0小时黑暗）或常规光照/黑暗周期（14小时光照：10小时黑暗）下23天，随后进行12天的恢复期。我们在多个时间点测量了体重、皮质酮和葡萄糖水平，并在安乐死时测量了糖皮质激素受体的相对蛋白表达。与对照组相比，光照组鸟类的体重随时间显著增加，但12天的恢复期逆转了这种增加。与对照组相比，光照组鸟类循环葡萄糖的基线水平降低，但在12天的恢复期后恢复到预处理水平。相比之下，葡萄糖应激反应没有显示出类似的恢复趋势，这表明需要更长的恢复期，或者这是光照组鸟类的一种持续效应。令人惊讶的是，在整个实验过程中，我们没有检测到两组之间基线皮质酮或下丘脑-垂体-肾上腺（HPA）轴反应性的任何差异。此外，我们没有检测到糖皮质激素受体相对蛋白表达之间的差异或与HPA轴反应性的关系。然而，我们发现糖皮质激素受体与葡萄糖应激反应之间存在正相关，但仅在光照组中。我们的结果表明，生理和形态性状在对持续光照的反应中恢复能力不同，需要进一步研究在昼夜节律紊乱情况下驱动应激恢复力的机制。
