Time-Dependent Progression of Demyelination and Axonal Pathology in MP4-Induced Experimental Autoimmune
Johanna Prinz1, Aylin Karacivi1, Eva R Stormanns1
1Department of Anatomy I, University of Cologne, Cologne, Germany.
Background:
Multiple sclerosis (MS) is an autoimmune disease of the central nervous system (CNS) characterized by inflammation, demyelination and axonal pathology. Myelin basic protein/proteolipid protein (MBP-PLP) fusion protein MP4 is capable of inducing chronic experimental autoimmune encephalomyelitis (EAE) in susceptible mouse strains mirroring diverse histopathological and immunological hallmarks of MS. Lack of human tissue underscores the importance of animal models to study the pathology of MS.
Methods:
Twenty-two female C57BL/6 (B6) mice were immunized with MP4 and the clinical development of experimental autoimmune encephalomyelitis (EAE) was observed. Methylene blue-stained semi-thin and ultra-thin sections of the lumbar spinal cord were assessed at the peak of acute EAE, three months (chronic EAE) and six months after onset of EAE (long-term EAE). The extent of lesional area and inflammation were analyzed in semi-thin sections on a light microscopic level. The magnitude of demyelination and axonal damage were determined using electron microscopy. Emphasis was put on the ventrolateral tract (VLT) of the spinal cord.
Results:
B6 mice demonstrated increasing demyelination and severe axonal pathology in the course of MP4-induced EAE. Additionally, mitochondrial swelling and a decrease in the nearest neighbor neurofilament distance (NNND) as early signs of axonal damage were evident with the onset of EAE. In semi-thin sections we observed the maximum of lesional area in the chronic state of EAE while inflammation was found to a similar extent in acute and chronic EAE. In contrast to the well-established myelin oligodendrocyte glycoprotein (MOG) model, disease stages of MP4-induced EAE could not be distinguished by assessing the extent of parenchymal edema or the grade of inflammation.
Conclusions:
Our results complement our previous ultrastructural studies of B6 EAE models and suggest that B6 mice immunized with different antigens constitute useful instruments to study the diverse histopathological aspects of MS.
Insights
This study shows that MP4-induced experimental autoimmune encephalomyelitis (EAE) in mice models multiple sclerosis (MS) pathology, revealing progressive demyelination and axonal damage over time. These findings highlight the utility of this mouse model for MS research.
Area of Science:
- Neuroscience
- Immunology
- Pathology
Background:
- Multiple sclerosis (MS) is a central nervous system autoimmune disease.
- MP4 fusion protein induces experimental autoimmune encephalomyelitis (EAE) in mice, mimicking MS hallmarks.
- Animal models are crucial for studying MS pathology due to limited human tissue availability.
Purpose of the Study:
- To investigate the histopathological and immunological changes in MP4-induced EAE in C57BL/6 mice.
- To assess demyelination and axonal damage at different stages of EAE.
- To evaluate the utility of this model for MS research.
Main Methods:
- C57BL/6 mice were immunized with MP4 to induce EAE.
- Spinal cord tissues were analyzed using light and electron microscopy at acute, chronic, and long-term EAE stages.
- Lesional area, inflammation, demyelination, and axonal damage were quantified.
Main Results:
- MP4-induced EAE in mice showed progressive demyelination and severe axonal pathology.
- Early signs of axonal damage included mitochondrial swelling and decreased neurofilament distance.
- Lesional area peaked in chronic EAE, with inflammation consistent across acute and chronic stages.
Conclusions:
- MP4-induced EAE in B6 mice exhibits key MS histopathological features.
- This model complements existing EAE models for studying MS.
- B6 mice immunized with different antigens are valuable tools for MS research.
