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The distribution of myelin basic protein in central nervous system lesions of multiple sclerosis and acute
Abstract:
To obtain more information about early events in central nervous system myelin injury in multiple sclerosis (MS), a comparative study was conducted of the distribution of myelin basic protein (BP) in tissue lesions of both MS and experimental allergic encephalomyelitis (EAE). Sixteen postmortem specimens containing lesions from 4 persons with MS and the brains of 14 guinea pigs with acute EAE induced with BP were studied. Cryostat sections of quick-frozen material were fixed, treated with rabbit antibody to BP, and processed by immunoperoxidase techniques. The reaction of antibody to BP was reduced or absent in MS lesions but normal in uninvolved surrounding tissue. Alterations in BP generally paralleled changes in staining of myelin by histological methods. Marked diminution of reactivity with anti-BP occurred in early lesions of MS and extended far beyond any identifiable inflammatory elements. In both parenchyma and perivascular areas, lipid-laden macrophages in MS plaques frequently contained BP material in addition to a variable amount of endogenous peroxidatic activity. Compared with MS, BP was relatively well preserved in brains of guinea pigs with EAE. At the light microscopy level, normal-appearing patterns of BP existed adjacent to the perivascular cellular infiltrates, and macrophages containing BP material were rare. The results of this study suggest differences between MS and acute EAE in both removal of BP from the central nervous system and its subsequent disposal.
Insights
This study reveals myelin basic protein (BP) is significantly reduced in multiple sclerosis (MS) lesions, unlike in experimental allergic encephalomyelitis (EAE). Macrophages in MS plaques contain BP, suggesting different clearance mechanisms in these central nervous system diseases.
Area of Science:
- Neuroscience
- Immunology
- Pathology
Background:
- Multiple sclerosis (MS) involves central nervous system (CNS) myelin injury.
- Understanding early myelin damage is crucial for MS research.
- Experimental allergic encephalomyelitis (EAE) serves as an animal model for demyelinating diseases.
Purpose of the Study:
- To compare the distribution of myelin basic protein (BP) in CNS lesions of MS and EAE.
- To investigate early events in myelin injury in MS.
Main Methods:
- Comparative analysis of postmortem MS brain tissue and EAE guinea pig brains.
- Immunoperoxidase staining using rabbit anti-BP antibody on cryostat sections.
- Histological examination of myelin and inflammatory cell infiltration.
Main Results:
- Myelin basic protein (BP) reactivity was reduced or absent in MS lesions, contrasting with normal levels in surrounding tissue.
- BP alterations in MS lesions paralleled general myelin staining changes and extended beyond inflammatory cells.
- Lipid-laden macrophages in MS plaques contained BP material.
- In EAE, BP was relatively preserved, with rare macrophages containing BP and normal BP patterns adjacent to infiltrates.
Conclusions:
- Significant differences exist between MS and acute EAE in the removal and disposal of myelin basic protein (BP) from the CNS.
- Early myelin injury in MS involves substantial BP degradation and macrophage-mediated clearance.