Abstract：
Sleep fragmentation (SF) is a common sleep problem experienced during the perioperative period by older adults, and is associated with postoperative cognitive dysfunction (POCD). Increasing evidence indicates that delta-wave activity during non-rapid eye movement (NREM) sleep is involved in sleep-dependent memory consolidation and that hippocampal theta oscillations are related to spatial exploratory memory. Recovery sleep (RS), a self-regulated state of sleep homeostasis, enhances delta-wave power and memory performance in sleep-deprived older mice. However, it remains unclear whether RS therapy has a positive effect on cognitive changes following SF in older mouse models. Therefore, this study aimed to explore whether preoperative RS can alleviate cognitive deficits in aged mice with SF. A model of preoperative 24-h SF combined with exploratory laparotomy-induced POCD was established in 18-month-old mice. Aged mice were treated with preoperative 6-h RS following SF and postoperative 6-h RS following surgery, respectively. The changes in hippocampus-dependent cognitive function were investigated using behavioral tests, electroencephalography (EEG), local field potential (LFP), magnetic resonance imaging, and neuromorphology. Mice that underwent 24-h SF combined with surgery exhibited severe spatial memory impairment; impaired cognitive performance could be alleviated by preoperative RS treatment. In addition, preoperative RS increased NREM sleep; enhanced EEG delta-wave activity and LFP theta oscillation in the hippocampal CA1; and improved hippocampal perfusion, microstructural integrity, and neuronal damage. Taken together, these results provide evidence that preoperative RS may ameliorate the severity of POCD aggravated by SF by enhancing delta slow-wave activity and hippocampal theta oscillation, and by ameliorating the reduction in regional cerebral blood flow and white matter microstructure integrity in the hippocampus.
摘要：
睡眠碎片（SF）是老年人围手术期常见的睡眠问题，并与术后认知功能障碍（POCD）有关。越来越多的证据表明，非快速眼动（NREM）睡眠期间的delta波活动与睡眠依赖性记忆巩固有关，海马theta振荡与空间探索性记忆有关。恢复睡眠（RS），自我调节的睡眠稳态，增强睡眠剥夺的老年小鼠的三角波功率和记忆性能。然而,目前尚不清楚RS治疗对老年小鼠模型SF后认知改变是否有积极作用.因此,本研究旨在探讨术前RS是否可以减轻老年SF小鼠的认知障碍。在18月龄小鼠中建立了术前24hSF联合剖腹探查术诱导的POCD模型。老年小鼠在SF后接受术前6小时RS治疗，手术后6小时RS治疗，分别。海马依赖性认知功能的变化采用行为测试，脑电图（EEG），局部场电位(LFP),磁共振成像，和神经形态学。接受24小时SF联合手术的小鼠表现出严重的空间记忆障碍；术前RS治疗可以减轻认知能力的损害。此外,术前RS增加NREM睡眠；增强海马CA1区EEGδ波活动和LFPθ振荡；改善海马灌注，微观结构完整性，和神经元损伤。一起来看,这些结果提供了证据，表明术前RS可能通过增强δ慢波活动和海马theta振荡来改善SF加重的POCD的严重程度，并通过改善海马局部脑血流量和白质微结构完整性的减少。
