Loss of Environmental Enrichment Elicits Behavioral and Physiological Dysregulation in Female Rats
Loss of Environmental Enrichment Elicits Behavioral and Physiological Dysregulation in Female Rats
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DOI：
10.3389/fnbeh.2018.00287
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发表时间：
2019-01-21
影响因子：
3
通讯作者：
Herman, James P.
中科院分区：
文献类型：
--
作者：
Morano, Rachel;Hoskins, Olivia;Herman, James P.
慢性压力会导致与多种精神疾病状态相关的行为和生理变化。在啮齿类动物中，绝大多数慢性压力模型涉及施加外部压力源，而在人类中，压力通常由内部线索驱动，通常与失落感相关。我们之前将几组大鼠暴露在环境浓缩物（EE）中一段较长的时间（1个月），然后去除浓缩物（ER），以诱导雄性大鼠丧失体验。 ER在强迫游泳试验（FST）中增强了不动性，导致下丘脑垂体肾上腺（HPA）轴功能减退，并导致相对于连续富集（EE）、单舍（Scon）和配对（Pcon）组的食欲亢进，其中大多数可通过抗抑郁治疗逆转（Smith等人，2017）。在这里，我们应用相同的方法来研究雌性大鼠的富集损失。与雄性相似，与单养和配对饲养对照相比，雌性的富集去除导致在 FST 中不动的时间增加，并且白天食物摄入量增加。与雄性不同，ER 雌性表现出对蔗糖的偏好降低，并且表现出发情周期依赖性 HPA 轴对急性束缚应激的过度活跃。被动应对（不动）的增加、蔗糖偏好测试中的快感缺失样行为以及 HPA 轴失调表明，富集去除在女性中产生了与男性不同的损失表型，这在本质上可能更为明显。
Chronic stress drives behavioral and physiological changes associated with numerous psychiatric disease states. In rodents, the vast majority of chronic stress models involve imposition of external stressors, whereas in humans stress is often driven by internal cues, commonly associated with a sense of loss. We previously exposed groups of rats to environmental enrichment (EE) for a protracted period (1 month), followed by removal of enrichment (ER), to induce an experience of loss in male rats. ER enhanced immobility in the forced swim test (FST), led to hypothalamic pituitary adrenal (HPA) axis hypoactivity, and caused hyperphagia relative to continuously enriched (EE), single-housed (Scon) and pair-housed (Pcon) groups, most of which were reversible by antidepressant treatment (Smith et al., 2017). Here, we have applied the same approach to study enrichment loss in female rats. Similar to the males, enrichment removal in females led to an increase in the time spent immobile in the FST and increased daytime food intake compared to the single and pair-housed controls. Unlike males, ER females showed decreased sucrose preference, and showed estrus cycle-dependent HPA axis hyperactivity to an acute restraint stress. The increase in passive coping (immobility), anhedonia-like behavior in the sucrose preference test and HPA axis dysregulation suggest that enrichment removal produces a loss phenotype in females that differs from that seen in males, which may be more pronounced in nature.