Département Neurosciences & Contraintes Opérationnelles, Institut de Recherche Biomédicale des Armées (IRBA), Brétigny-sur-Orge, France.
Université Paris Cité, INSERM, U1124, Paris, France.
Sleep. 2023 Jul 11;46(7). doi: 10.1093/sleep/zsad068.
Stress can push individuals close to the threshold to depression. An individual's intrinsic vulnerability before a stressful event determines how close they come to the threshold of depression. Identification of vulnerability biomarkers at early (before the stressful event) and late (close to the threshold after the stressful event) stages would allow for corrective actions. Social defeat is a stressful event that triggers vulnerability to depression in half of exposed rats. We analyzed the sleep properties of rats before (baseline) and after (recovery) social defeat by telemetry electroencephalogram recordings. Using Gaussian partitioning, we identified three non-rapid eye movement stages (N-S1, N-S2, and N-S3) in rats based on a sleep depth index (relative δ power) and a cortical activity index (fractal dimension). We found (1) that, at baseline, N-S3 lability and high-θ relative power in wake identified, with 82% accuracy, the population of rats that will become vulnerable to depression after social defeat, and (2) that, at recovery, N-S1 instability identified vulnerable rats with 83% accuracy. Thus, our study identified early and late sleep biomarkers of vulnerability to depression, opening the way to the development of treatments at a prodromal stage for high sensitivity to stress, and for stress-induced vulnerability to depression.
压力可能会使个体接近抑郁的门槛。个体在面临压力事件之前的内在脆弱性决定了他们接近抑郁门槛的程度。在早期（压力事件之前）和晚期（压力事件后接近门槛）识别脆弱性生物标志物将允许采取纠正措施。社会挫败是一种压力事件，会使一半暴露于其中的大鼠易患抑郁症。我们通过遥测脑电图记录分析了大鼠在社会挫败之前（基线）和之后（恢复）的睡眠特性。使用高斯分区，我们根据睡眠深度指数（相对 δ 功率）和皮质活动指数（分形维数），在大鼠中确定了三个非快速眼动阶段（N-S1、N-S2 和 N-S3）。我们发现：（1）在基线时，清醒时的 N-S3 不稳定性和高θ相对功率以 82%的准确率识别出了在社会挫败后易患抑郁症的大鼠群体，（2）在恢复时，N-S1 不稳定性以 83%的准确率识别出了易患大鼠。因此，我们的研究确定了易患抑郁症的早期和晚期睡眠生物标志物，为在高压力敏感的前驱阶段和应激引起的易患抑郁症阶段开发治疗方法开辟了道路。
