Chronic Unpredictable Mild Stress in Rats based on the Mongolian medicine

Summary

This protocol outlines a chronic unpredictable mild stress (CUMS) model for depression based on Mongolian medical theory, along with methods for validating behavioral tests.

Abstract

Depression is a prevalent affective disorder and constitutes a leading cause of global disability. The limitations of current pharmacological interventions contribute to the substantial health burden attributed to this condition. There is a pressing need for a deeper understanding of the underlying mechanisms of depression, making pre-clinical models with translational potential highly valuable. Mongolian medicine, a subset of traditional medicine, posits that disease occurrence is closely tied to the equilibrium of wind, bile, and Phlegm. In this study, we introduce a protocol for the chronic unpredictable mild stress (CUMS) method in rats. Within this framework, rats are subjected to a series of fluctuating, mild stressors to induce a depression-like phenotype, mimicking the pathogenesis of human depression. Behavioral assays employed in this protocol include the sucrose preference test (SPT), indicative of anhedonia-a core symptom of depression; the open field test (OFT), which measures anxiety levels; and the Morris water maze test (MWM), which evaluates spatial memory and learning abilities. The CUMS method demonstrates the capability to induce anhedonia and to cause long-term behavioral deficits. Furthermore, this protocol is more aligned with Mongolian medical theory than other animal models designed to elicit depression-like behavior. The development of this animal model and subsequent research provide a robust foundation for future innovative studies in the realm of Mongolian medicine.

Introduction

Major depressive disorder (MDD) is a prevalent mental illness, ranking as the third leading cause of disability globally and affecting over 300 million people^1,2,3. Notably, it is estimated that at least half of the affected individuals do not receive adequate treatment⁴. Given this gap, animal models serve as a crucial tool for investigating the etiology of depression. To date, more than 20 different animal models for depression exist⁵. Among these, the chronic unpredictable mild stress (CUMS) model, refined by Paul Winer in 19....

Protocol

The experimental protocols received approval from the Ethics of Animal Experiment Care Committee of Inner Mongolia Medical University (YKD202301172) and adhered to the National Institutes of Health guidelines for animal care and ethics. The license number for our animal center is NO.110324230102364187. Twenty-four male Sprague-Dawley (SD) rats, each 8 weeks old (200 g ± 20 g), were acquired and housed in a controlled environment with a temperature of 22°C ± 2°C and humidity of 55% ± 15%. Feed the.......

Discussion

Depression is a mental disorder characterized by symptoms such as low mood, lack of pleasure, and reduced energy³⁰. In the field of depression research, the establishment of a reliable animal model is crucial for advancing therapeutic interventions. Among various animal models, the CUMS model is particularly noteworthy for its high reliability, validity, and its congruence with the characteristics of human depression³¹. It is well-suited to mimic the cumulative effects of l.......

Materials

Name	Company	Catalog Number	Comments
1.5 mL centrifuge tube	service Biotechnology Co., Ltd	EP-150-M
1000 µL Pipette	service Biotechnology Co., Ltd	IC021198160223
10 µL pipette tip	service Biotechnology Co., Ltd	IC012395160823
10 µL pipette tip	service Biotechnology Co., Ltd	TP-10
1250 µL pipette tip	service Biotechnology Co., Ltd	TP-1250
2 mL centrifuge tube	service Biotechnology Co., Ltd	EP-200-M
200 µL pipette tip	service Biotechnology Co., Ltd	TP-200
200 µL pipette tip	service Biotechnology Co., Ltd	IC021029160323
300 µL Multi-Channel Pipette	service Biotechnology Co., Ltd	IC091006161022
50 µL Pipette	service Biotechnology Co., Ltd	DS35110
Automatic plate washing machine	rayto Life Sciences Co., Ltd	RT-3100
Benchtop High-Speed Freezing Centrifuge	dalong construction Co., Ltd	D3024R
electronic balance	Mettler Toledo International Trade (Shanghai) Co., Ltd	ME203E/02
Electrothermal blast drying oven	Labotery Experimental Instrument Equipment Co., Ltd	GEL-70
Enzyme Label Detector	BioTeK Co., Ltd	Epoch
High Speed Tissue Grinder	service Biotechnology Co., Ltd	KZ--F
Horizontal Freezer	Mellow Group Co., Ltd	BCD-318AT
Laboratory Ultrapure Water Machine	Jinan Aiken Environmental Protection Technology Co., Ltd	AK-RO-C2
Morris water maze video trail analysing system	Tai Meng Tech Co., Ltd	WMT-200
Rat 5-HT ELISA Kit	Lian Ke bio Co., Ltd,China	96T/48T
SPF grade Sprague Dawley (SD) rats	SPF (Beijing) Biotechnology Co	SCXK(JING)2019-0010
Sprague Dawley rats	Beijing Biotechnology Co., Ltd, China	SCXK (JING) 2019-0010
Vertical Refrigerated Display Cabinet	Xingx Group Co., Ltd	LSC-316C
video tracking system	Tai Meng Tech Co., Ltd	ZH-ZFT
vortex mixer	Servicebio technology Co., Ltd	MV-100