In vivo dynamic MR imaging of MBP-induced acute experimental allergic encephalomyelitis in Lewis rat
Related Experiment Videos
I J Namer1, J Steibel, P Poulet
1Institut de Physique Biologique, Faculté de Médecine, Strasbourg, France.
Abstract:
A dynamic in vivo study by MRI consisting of the measurement of relaxation times and in the visualization of the BBB permeability by Gd-DOTA was performed in an MBP-induced acute EAE model of Lewis rat. Fourteen rats were immunized with an MBP/CFA mixture, eight by CFA alone, and three control rats were used to test the harmless effect of repeatedly performed MRI examinations. Beginning on the 8th or 9th days and in parallel with the emergence of clinical signs, rats immunized by the MBP/CFA mixture showed slight increases of relaxation times and of the BBB permeability. These abnormalities, which always remain localized in the periventricular regions, become more pronounced toward the 10th and 11th days, just before (or at the same time) as paraplegia manifestations. After a plateau of a few days, they diminish with the clinical signs. This close correlation found in vivo establishes the essential role of BBB in the pathogenesis of clinical signs of this EAE model.
Insights
This study shows that increased blood-brain barrier (BBB) permeability correlates with clinical signs in an experimental autoimmune encephalomyelitis (EAE) model. These BBB changes, visualized by MRI, are crucial in the development of EAE symptoms.
Area of Science:
- Neuroscience
- Immunology
- Radiology
Background:
- Experimental autoimmune encephalomyelitis (EAE) is a model for multiple sclerosis.
- The role of blood-brain barrier (BBB) dysfunction in EAE pathogenesis requires further in vivo investigation.
Purpose of the Study:
- To dynamically assess BBB permeability and relaxation times using MRI in an MBP-induced EAE rat model.
- To correlate in vivo MRI findings with the clinical progression of EAE.
Main Methods:
- Lewis rats were induced with EAE using myelin basic protein (MBP) and complete Freund's adjuvant (CFA).
- Magnetic resonance imaging (MRI) was used to measure relaxation times and visualize BBB permeability with Gd-DOTA.
- Control groups included CFA-only immunization and non-invasive MRI examination controls.
Main Results:
- MBP-immunized rats showed increased relaxation times and BBB permeability starting around days 8-9, coinciding with clinical signs.
- These abnormalities were localized to periventricular regions and intensified before paraplegia onset.
- BBB changes diminished as clinical signs resolved, demonstrating a strong correlation.
Conclusions:
- In vivo MRI can dynamically visualize BBB permeability changes during EAE.
- BBB disruption plays an essential role in the pathogenesis of clinical manifestations in this EAE model.
- These findings highlight BBB integrity as a critical factor in EAE progression.