Zoladz Phillip R, Del Valle Colin R, Smith Ian F, Goodman Cassandra S, Dodson Jordan L, Elmouhawesse Kara M, Kasler Charis D, Rorabaugh Boyd R
Psychology Program, The School of Health and Behavioral Sciences, Ohio Northern University, Ada, Ohio, OH, United States.
Department of Pharmaceutical Sciences, Marshall University School of Pharmacy, Huntington, WV, United States.
Front Behav Neurosci. 2021 Jun 18;15:675206. doi: 10.3389/fnbeh.2021.675206. eCollection 2021.
People with post-traumatic stress disorder (PTSD) exhibit heightened anxiety and enhanced negative feedback of the hypothalamus-pituitary-adrenal (HPA) axis. We previously reported that male rats exposed to a predator-based psychosocial stress model of PTSD exhibited comparable changes in anxiety-like behavior and HPA axis activity, including lower baseline levels of corticosterone and a greater suppression of corticosterone after dexamethasone administration. Here, we assessed whether we would observe similar effects in female rats exposed to this model. Adult female Sprague-Dawley rats were exposed to a cat on two occasions (separated by 10 days), in combination with chronic social instability. Three weeks after the second cat exposure, we assessed anxiety-like behavior on an elevated plus maze (EPM) and collected blood samples from rats in the absence or presence of dexamethasone to quantify serum corticosterone levels. Although stressed females did not display heightened anxiety on the EPM, they exhibited significantly lower overall corticosterone levels and a greater suppression of corticosterone after dexamethasone administration. The observation of significantly lower overall corticosterone levels in stressed females was replicated in a separate, independent experiment. These findings suggest that the predator-based psychosocial stress model of PTSD may be useful for studying mechanisms that underlie changes in HPA axis function in females exposed to trauma.
创伤后应激障碍（PTSD）患者表现出焦虑加剧以及下丘脑-垂体-肾上腺（HPA）轴负反馈增强。我们之前报道，暴露于基于捕食者的PTSD心理社会应激模型的雄性大鼠在焦虑样行为和HPA轴活动方面表现出类似变化，包括皮质酮基线水平较低以及地塞米松给药后皮质酮抑制作用增强。在此，我们评估了暴露于该模型的雌性大鼠是否会出现类似效应。成年雌性斯普拉格-道利大鼠分两次（间隔10天）暴露于猫，并伴有慢性社会不稳定因素。第二次猫暴露三周后，我们在高架十字迷宫（EPM）上评估焦虑样行为，并在大鼠有无地塞米松的情况下采集血样以量化血清皮质酮水平。尽管应激雌性大鼠在EPM上未表现出焦虑加剧，但它们的总体皮质酮水平显著较低，且地塞米松给药后皮质酮抑制作用增强。在一项单独的独立实验中重复观察到应激雌性大鼠总体皮质酮水平显著较低。这些发现表明，基于捕食者的PTSD心理社会应激模型可能有助于研究创伤暴露雌性大鼠HPA轴功能变化的潜在机制。
