Department of Animal, Veterinary and Food Sciences, University of Idaho, 875 Perimeter Dr., MS 2330, Moscow, ID 83844-2330, USA.
Gen Comp Endocrinol. 2021 Dec 1;314:113916. doi: 10.1016/j.ygcen.2021.113916. Epub 2021 Sep 20.
Maternal exposure to stressors during lactation has previously been demonstrated to impact various aspects of milk synthesis and to have long-term physiological effects on offspring. Much of the current literature investigating the effects of stress during lactation has used acute stressors, and the studies investigating the effects of chronic stressors largely focus on neurological changes. Further, temporal variation in glucocorticoids across lactation in response to stressors has rarely been assessed. The present work uses a novel male intruder paradigm to model the effects of chronic stress on maternal fecal corticosterone metabolites (FCMs) in Sprague-Dawley rats across lactation. FCM levels were elevated in chronically-stressed mothers relative to the control group. Further, FCMs in the stress group were time-dependent either due to repeated exposure to the stressor or lactation stage. Together, this work demonstrates the efficacy of this established paradigm in increasing circulating glucocorticoids in lactating rats. These results highlight the need for repeated temporal sampling, as glucocorticoid levels in response to a chronic stressor may change across lactation.
哺乳期母体暴露于应激源先前已被证明会影响乳汁合成的各个方面，并对后代产生长期的生理影响。目前许多研究哺乳期应激影响的文献都使用了急性应激源，而研究慢性应激源影响的文献主要集中在神经变化上。此外，很少有研究评估应激源对哺乳期糖皮质激素的时间变化。本工作使用一种新的雄性入侵者范式，在整个哺乳期内，在 Sprague-Dawley 大鼠中模拟慢性应激对母体粪便皮质酮代谢物（FCM）的影响。与对照组相比，慢性应激组母鼠的 FCM 水平升高。此外，由于反复暴露于应激源或哺乳期阶段，应激组的 FCM 呈时间依赖性。总之，这项工作证明了这种已建立的范式在增加哺乳期大鼠循环糖皮质激素方面的有效性。这些结果强调了重复时间采样的必要性，因为对慢性应激源的糖皮质激素水平可能会随哺乳期而变化。
