Department of Psychology, University of New England, Biddeford, ME, USA.
Center for Excellence in the Neurosciences, University of New England, Biddeford, ME, USA.
Stress. 2021 Sep;24(5):504-513. doi: 10.1080/10253890.2020.1825674. Epub 2020 Oct 12.
Early life adversity, including that which occurs in a medical setting, has been increasingly shown to have lasting consequences on both physical and mental health. In order to understand the lasting effects of early-life adversity, such as that might occur in the neonatal intensive care unit (NICU), several rodent models have been developed including maternal separation, neonatal handling, and repeated needle prick pain. However, in the clinical scenario, these stressors are often combined. Thus, the current study seeks to observe the lasting impacts of both neonatal pain and maternal separation in a rodent model. Rats were separated from their dam for 6 h per day during the first 7 days of life, during which they were subjected to repeated needle prick pain or handling. A separate group was left undisturbed. All rats were subsequently tested for threat processing using a 3-day Pavlovian fear conditioning model and for somatosensation using measures of mechanical and thermal thresholds. Results indicated that rats subjected to maternal separation and pain had enhanced fear conditioning in adolescence as well as displaying a modest age-independent tactile hypersensitivity compared to undisturbed controls. These data show that experiencing combined neonatal pain and maternal separation may create a latent vulnerability to subsequent stressors.
早期生活逆境，包括在医疗环境中发生的逆境，已越来越多地被证明对身心健康都有持久的影响。为了了解早期生活逆境（如新生儿重症监护病房中可能发生的逆境）的持久影响，已经开发了几种啮齿动物模型，包括母婴分离、新生儿处理和反复针刺疼痛。然而，在临床情况下，这些应激源通常是组合在一起的。因此，本研究旨在观察啮齿动物模型中新生儿疼痛和母婴分离的持久影响。在生命的前 7 天，每天将幼鼠与其母鼠分离 6 小时，在此期间，它们会经历反复的针刺疼痛或处理。另一个组则不受干扰。所有的老鼠随后都被用于 3 天的条件性恐惧训练来测试它们对威胁的处理能力，以及用于测量机械和热阈值的感觉来测试它们的躯体感觉。结果表明，与未受干扰的对照组相比，经历母婴分离和疼痛的老鼠在青春期时表现出更强的恐惧条件反射，并且在触觉上表现出与年龄无关的轻度超敏反应。这些数据表明，经历新生儿疼痛和母婴分离的双重压力可能会导致潜在的易感性，使其对随后的应激源产生反应。
