Loneliness affects group-living mammals triggering a cascade of stress-dependent physiological disorders. Indeed, social isolation stress is a major risk factor for several neuropsychiatric disorders including anxiety and depression. Furthermore, social isolation has a negative impact on health and fitness. However, the neurobiological consequences of long-term chronic social isolation stress (LTCSIS) manifested during the adulthood of affected individuals are not fully understood. Our study assessed the impact of LTCSIS and social buffering (re-socialization) on the behavioural performance and social-affective brain-related proteins in diurnal, social, and long-lived Octodon degus (degus). Thereby, anxiety-like and social behaviour, and social recognition memory were assessed in male and female animals subjected to a variety of stress-inducing treatments applied from post-natal and post-weaning until their adulthood. Additionally, we evaluated the relationship among LTCSIS, Oxytocin levels (OXT), and OXT-Ca²⁺-signalling proteins in the hypothalamus, the hippocampus, and the prefrontal cortex. Our findings suggest that LTCSIS induces anxiety like-behaviour and impairs social novelty preference whereas sociability is unaffected. On the other hand, re-socialization can revert both isolation-induced anxiety and social memory impairment. However, OXT and its signalling remained reduced in the abovementioned brain areas, suggesting that the observed changes in OXT-Ca²⁺ pathway proteins were permanent in male and female degus. Based on these findings, we conclude degus experience social stress differently, suggesting the existence of sex-related mechanisms to cope with specific adaptive challenges.

孤独感会影响群体生活的哺乳动物，引发一系列与压力相关的生理疾病。事实上，社会孤立压力是包括焦虑和抑郁在内的多种神经精神疾病的主要危险因素。此外，社会孤立会对健康和健身产生负面影响。然而，受影响个体成年期间表现出的长期慢性社会隔离压力（LTCSIS）的神经生物学后果尚不完全清楚。我们的研究评估了 LTCSIS 和社会缓冲（再社会化）对昼夜性、社会性和长寿八齿八齿鼠(degus) 的行为表现和社会情感大脑相关蛋白的影响。因此，对雄性和雌性动物的焦虑样行为和社会行为以及社会认知记忆进行了评估，这些动物接受了从产后和断奶后直至成年的各种应激诱导治疗。此外，我们还评估了下丘脑、海马和前额皮质中 LTCSIS、催产素水平 (OXT) 和 OXT-Ca ²⁺信号蛋白之间的关系。我们的研究结果表明，LTCSIS 会诱发类似焦虑的行为，并损害社交新奇偏好，而社交能力则不受影响。另一方面，重新社会化可以恢复孤立引起的焦虑和社会记忆损伤。然而，OXT 及其信号传导在上述大脑区域中仍然减少，这表明观察到的 OXT-Ca ²⁺通路蛋白的变化在雄性和雌性八齿鼠中是永久性的。基于这些发现，我们得出结论，八齿鼠经历的社会压力不同，这表明存在与性别相关的机制来应对特定的适应性挑战。