Evaluating the Anti-depression Effect of Xiaoyaosan on Chronically-stressed Mice

Summary

Here, we present a protocol to establish the mouse depressive model, observe the behavior changes associated with chronic unpredictable mild stress (CUMS), and evaluate the anti-depression effect of Xiaoyaosan.

Abstract

In addition to the standardized use of antidepressant medications and psychotherapy, the usage of traditional Chinese medicine has lead to an overall improvement of patients with major depressive disorder (MDD). Therefore, the purpose of this study was to establish the mouse depressive model, observe the behavior changes associated with chronic unpredictable mild stress (CUMS), and then evaluate the anti-depression effect of Xiaoyaosan. Mice were randomly divided into four groups: a control group, a model group, a treatment group with Xiaoyaosan, and a treatment group with fluoxetine. All mice were individually kept in cages, and depression was induced in the mice by exposing them to several designed manipulations of CUMS for 21 days, as described in the protocol. Mice in the control group and model group received 0.5 mL of distilled water, while mice in the treatment groups received either Xiaoyaosan (0.25 g/kg/day) or fluoxetine (2.6 mg/kg/day). The drugs used in the study were given intragastrically daily during the entire three weeks. To estimate the depressive-like behaviors, a series of parameters including the coat state, body weight, open field test score, and sucrose preference test score were recorded. Data analysis showed that behaviors of model mice were significantly changed compared to behaviors of mice in the control group, which were improved by the treatment of Xiaoyaosan and fluoxetine. The current findings demonstrated the anti-depression effects of Xiaoyaosan on the behaviors of CUMS-induced mice and revealed that compounds from the Xiaoyaosan prescription may be worthwhile for treating depression, considering their beneficial effects on depressive-like behaviors.

Introduction

MDD is a chronic, highly recurrent mental disease that presents with persistent low mood, depression, low self-esteem, mental retardation, loss of interest, sleep disorders, profoundly pessimistic or suicidal tendencies; it has caused great harm to human health and social stabilization¹. It has become one of the world's primary cause of disability, and it may be one of the main leading causes of disease burden by 2030 according to the World Health Organization^2,3. Currently, antidepressant medications and psychotherapy are considered to be the first choice to treat MDD. Nevertheless....

Protocol

This protocol was approved by the Animal Ethics Committee of Beijing University of Chinese Medicine and was in accordance with all guidelines for the Care and Use of Laboratory Animals of China. There was no accidental death situation during the experimental procedure, and no animals needed to be euthanized in this study.

1. Preparing Drugs for the Experiment

NOTE: The Chinese herbs were purchased and then authenticated by Dr. B. Liu of the Beijing University of .......

Discussion

The CUMS model used in this study is a common method to establish the stress diathesis model of depression²⁴. Most manifestations of CUMS can be restored by antidepressant drugs, which indicated that this model method has a strong predictive validity²⁵. By this method, animals receive chronic unpredictable stressful stimuli and develop core symptoms of major depression, including decreased place preference conditioning, anhedonia, and impaired emotion-like behaviors

Materials

Name	Company	Catalog Number	Comments
Chinese Herbs	Tongrentang (Bozhou, AnHui) Decoction Pieces Limited Company	-	The drugs were extracted by the Chinese medicine preparation room of the China-Japan Friendship Hospital, distilled water was used to prepare the suspension of Xiaoyaosan, and the dose was 0.25 g/kg/d.
Fluoxetine	PATHEON FRANCE	5545A	The distilled water was used to prepare the suspension of fluoxetine, and the dose 2.6 mg/kg/d.
C57BL/6j mice	Beijing Vital River of the Charles River Company	SCXK 2011-0004	60 healthy male C57BL/6J mice aged 12 weeks were purchased from Beijing Vital River of the Charles River Company.
Mouse cage	Styling Biotechnology	34853016	318×202×135 mm
Distilled Water	-	-	The water was used througout the experiment.
Sucrose	Sigma	-	The sucrose was used in the sucrose preference test to prepare 1% sucrose solution.
ACS-2EAS Electronic Balance	Beijing Hengzhongheng Electronic Technology Co., Ltd.	-	It was used to weigh the avoirdupois of mice at different stages.
Wooden Black Lusterless Box	-	-	(40 cm x 40 cm x 15 cm), divided into 25 equal squares by blue lines.
WV-CP470 Camera	Panasonic, Japan	-	A HD digital camera which was used for recording the whole process of the open field test.
Etho Vision 3.0 Software	Noldus, Wageningen, Holland	-	A video-tracking system which was used to evaluate the locomotor function and emotionality of mice.
SPSS Statistics 21.0 Software	IBM	-	SPSS 21.0 software was used to analyze the data, one-way ANOVA or non-parametric test was used for general data based on normality test and homogeneity test for variance, and LSD method was adopted for the comparisons between groups.
Graphpad Prism 6.0 Software	Graphpad Software,Inc.USA	-	Graphpad Prism 6.0 software was used to draw statistical graphs.