Stress-induced myelin damage in the hippocampal formation in a rat model of depression
Related Experiment Video
Updated: Aug 27, 2025
A Chronic Immobilization Stress Protocol for Inducing Depression-Like Behavior in Mice
Published on: May 15, 2019
Chun-Xia Huang1, Qian Xiao2, Lei Zhang3
1Department of Physiology, Faculty of Basic Medical Sciences, Chongqing Medical University, Chongqing, PR China; Laboratory of Stem Cell and Tissue Engineering, Faculty of Basic Medical Sciences, Chongqing Medical University, Chongqing, PR China.
Background:
According to previous studies, myelin damage may be involved in the occurrence of depression. However, to date, no study has quantitatively investigated the changes in myelinated fibers and myelin sheaths in the hippocampal formation (HF) and hippocampal subfields in the context of depression.
Methods:
Male Sprague-Dawley (SD) rats (aged 4-5 weeks) were evenly divided into the control group and chronic unpredictable stress (CUS) group. Behavioral tests were performed, and then changes in myelinated fibers and myelin ultrastructure in hippocampal subfields in depression model rats were investigated using modern stereological methods and transmission electron microscopy techniques.
Results:
After a four-week CUS protocol, CUS rats showed depressive-like and anxiety-like behaviors. The total length and total volume of myelinated fibers were reduced in the CA1 region and DG in the CUS group compared with the control group. The total volumes of myelin sheaths and axons in the CA1 region but not in the DG were significantly lower in the CUS group than in the control group. The decrease in the total length of myelinated nerve fibers in the CA1 region in CUS rats was mainly due to a decrease in the length of myelinated fibers with a myelin sheath thickness of 0.15 μm-0.20 μm.
Limitations:
The exact relationship between the degeneration of myelin sheaths and depression-like, anxiety-like behaviors needs to be further investigated.
Conclusions:
CUS induces depression- and anxiety-like behaviors, and the demyelination in the CA1 region induced by 4 weeks of CUS might be an important structural basis for these behaviors.
