The relationship between circadian rhythms and mood disorders has been established. Circadian dysregulations are believed to exacerbate the severity of mood disorders and vice versa. Although many studies on diurnal changes of clock genes in animal model of depression have been performed from the RNA level, only a few studies have been carried out from the protein level. In this study, we investigated the diurnal changes induced by chronic unpredictable stress (CUS) using free-running wheel test and Western Blotting (WB). Besides, we examined the depression-like behaviors of rats by sucrose preference test (SPT) and forced swim test (FST). We found that CUS induced significant reductions in the quantity of free-running wheel activity and rhythmic disruptions of clock proteins in hippocampus. Furthermore, we found that the amplitude of PER1 in CA1 was positively related to the severity of depression-like behaviors. These results suggest that CUS results in both changes in diurnal rhythms and in depression-like behaviors and that it is suggested that these changes are related.

昼夜节律和情绪障碍之间的关系已经确立。昼夜节律失调被认为会加剧情绪障碍的严重程度，反之亦然。尽管从RNA水平对抑郁症动物模型中生物钟基因昼夜变化的研究很多，但从蛋白质水平进行的研究却很少。在这项研究中，我们使用自由轮试验和蛋白质印迹法 (WB)研究了由慢性不可预测应力 (CUS) 引起的昼夜变化。此外，我们通过蔗糖偏好试验（SPT）和强迫游泳试验（FST）检测了大鼠的抑郁样行为。我们发现 CUS 显着减少了自由运行的数量海马体时钟蛋白的轮活动和节律性破坏。此外，我们发现 CA1 中 PER1 的幅度与抑郁样行为的严重程度呈正相关。这些结果表明 CUS 导致昼夜节律和抑郁样行为的变化，并且表明这些变化是相关的。