Porras Abishag, Jackson Jeffy, Nguyen Christine H, Rincón-Cortés Millie
Department of Neuroscience, School of Behavioral and Brain Sciences, University of Texas at Dallas, Richardson, TX 75080, USA.
Department of Neuroscience, School of Behavioral and Brain Sciences, University of Texas at Dallas, Richardson, TX 75080, USA.
Psychoneuroendocrinology. 2025 Jul;177:107452. doi: 10.1016/j.psyneuen.2025.107452. Epub 2025 Mar 30.
Maternal behavior is disturbed by exposure to environmental adversity, including resource scarcity, which can impair maternal care and increase adverse caregiving behaviors like abuse and maltreatment. In rats, exposure to resource scarcity disrupts mother-infant interactions and results in adverse pup-directed maternal behaviors. These changes in maternal behavior are thought to be due to hyperactivity within the hypothalamic-pituitary-adrenal (HPA)-axis, which mediates the stress response. In accordance, upregulation of HPA-axis function is sufficient to drive changes in maternal behavior in rodents. Based on these data, we hypothesized that scarcity-adversity induced changes in maternal behavior would be associated with HPA-axis hyperactivity, as indexed by elevated basal levels of the stress hormone corticosterone (CORT) in rat dams. To test this, we employed a scarcity-adversity paradigm based on creating an impoverished cage environment during postpartum days (PD) 2-9 and examined effects on naturalistic maternal behaviors and basal fecal boli CORT levels (PD 3, PD 5, PD 7) or basal and stress-induced serum CORT levels (PD 9). Surprisingly, rat dams exposed to scarcity-adversity exhibited increases in adverse pup-directed behaviors (e.g., stepping, dragging, shoving) but no elevations in basal or stress-induced CORT levels at any of the time-points assessed. These findings suggest that scarcity-adversity can increase adverse caregiving in a CORT-independent manner. Thus, increases in basal CORT levels are not necessary to induce aberrant maternal behavior in the scarcity-adversity paradigm.
暴露于包括资源稀缺在内的环境逆境会扰乱母性行为，这可能会损害母性关怀，并增加虐待等不良养育行为。在大鼠中，暴露于资源稀缺会破坏母婴互动，并导致母鼠对幼崽产生不良行为。母性行为的这些变化被认为是由于下丘脑-垂体-肾上腺（HPA）轴的活动亢进，该轴介导应激反应。相应地，HPA轴功能的上调足以驱动啮齿动物母性行为的变化。基于这些数据，我们假设稀缺逆境诱导的母性行为变化将与HPA轴活动亢进有关，以大鼠母鼠应激激素皮质酮（CORT）的基础水平升高为指标。为了验证这一点，我们采用了一种稀缺逆境范式，即在产后第2至9天创造一个贫困的笼养环境，并检查其对自然母性行为以及基础粪便CORT水平（产后第3天、第5天、第7天）或基础及应激诱导血清CORT水平（产后第9天）的影响。令人惊讶的是，暴露于稀缺逆境的大鼠母鼠对幼崽的不良行为（如踩踏、拖拽、推搡）有所增加，但在评估的任何时间点，其基础或应激诱导的CORT水平均未升高。这些发现表明，稀缺逆境可以以一种不依赖CORT的方式增加不良养育行为。因此，在稀缺逆境范式中，基础CORT水平的升高并非诱导异常母性行为所必需。
