Effects of Understory Panax ginseng Extract on Depression-like Behavior and HPA Axis of Chronic Unpredictable Mild Stress Model Mice

Objective: To explore the effect of understory Panax ginseng extract (UGPE) on depression-like behavior and hypothalamic-pituitary-adrenal (HPA) axis of chronic unpredictable mild stress (CUMS) model mice. Methods: Ultra-high performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) were used to detect the contents of ginsenosides. Totally 60 male Kunming mice were randomly divided into four groups: Control, model, positive venlafaxine (10 mg·kg⁻¹ Ven) and UGPE group (100 mg·kg⁻¹ UPGE). The depression model was induced by CUMS in mice except for those in the control group, they were received corresponding drug by intragastric administration for 21 days. The sucrose preference test, open field test and Morris water maze experiments were conducted to analyze their behavioral changes. The contents of corticotropin-releasing hormone (CRH), adrenocorticotropic hormone (ACTH) and corticosterone (CORT) in plasma were measured by enzyme linked immunosorbent assay (ELISA). Hematoxylin-Eosin (HE) staining was used to investigate the pathological changes of neurons in the CA1 and CA3 area of hippocampus. The apoptosis of hippocampal neurons was observed by terminal-deoxynucleoitidyl transferase mediated nick end labeling (TUNEL) method. Results: UPGE contained 16 ginsenosides. Compared with the model group, the UPGE group significantly improved sugar-water preference (P<0.01), increased horizontal movement distance, and increased vertical standing times in the absenteeism experiment (P<0.05, P<0.01). Shortened the escape latency in Morris water maze test (P<0.05). Increased the target quadrant residence time and the platform crossing times in Morris water maze test (P<0.05, P<0.01). UPGE would alleviate hippocampal neuron injury. The levels of ACTH, CORT and CRH in plasma were decreased (P<0.05), the apoptosis of hippocampal cells was decreased (P<0.05, P<0.01). Conclusion: The UGPE would improve antidepressant behavior of CUMS mice, and its mechanism might be related to the regulation of HPA axis function.