2.5. CUMS Protocol

The CUMS protocol is shown in Figure 1. The major depressive-like behaviors of this mouse model were induced by CUMS. The CUMS protocol was based on other studies [19]. After habituation, mice were exposed to unpredictable mild stressors for 21 d in this protocol; we used 14 diverse stressors and two stressors were applied per day. The stressors included day and night reversal, fasting, binding, removing water, tilting, empty cage, ice water swimming, noise, shaking, humidity, thermal stimulation, peculiar smell, clipping, and foreign body. Mice in the control group were handled without any stress.

Flow chart depicting the procedural order used in this experiment (a). Chronic unpredictable mild stress protocol (b). Description of stressors (c).