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An electron microscopic study of MPTP-induced inclusion bodies in an old monkey
L S Forno1, J W Langston, L E DeLanney
1Veterans Administration Medical Center, Palo Alto, CA 94304.
Abstract:
Eosinophilic inclusion bodies have recently been found in the nerve cells of the substantia nigra in aged primates with 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP)-induced parkinsonism. This report describes the ultrastructure of the inclusion-bearing nerve cells in the substantia nigra from one of these animals. By electron microscopy the inclusions were less well demarcated and less conspicuous than those seen in hematoxylin-eosin stained paraffin sections. The bodies corresponded to portions of the nerve cell that were devoid of Nissl substance, but contained an increased number of randomly oriented, thick filamentous or tubular structures with some resemblance to neurotubules. The inclusion bodies were compared to Pick bodies: argentophilic inclusions in Pick's disease, a rare form of dementia, and to Lewy bodies: the inclusions characteristically present in Parkinson's disease. The MPTP-induced inclusions differed from both Pick bodies and Lewy bodies, but could represent immature Lewy bodies, similar to Lewy bodies in the cerebral cortex. The mechanism of formation of these structures, their relationship to Parkinson's disease and the reason why they appear to require the substrate of an aged nervous system, remain to be determined.
Insights
New eosinophilic inclusion bodies found in aged primates with MPTP-induced parkinsonism. These structures differ from Lewy bodies and Pick bodies, potentially representing immature Lewy bodies.
Area of Science:
- Neuroscience
- Cell Biology
- Pathology
Background:
- Eosinophilic inclusion bodies have been observed in aged primates exhibiting 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP)-induced parkinsonism.
- These inclusions are located within the nerve cells of the substantia nigra, a critical brain region affected in Parkinson's disease.
Purpose of the Study:
- To describe the ultrastructure of these novel inclusion bodies.
- To compare these inclusions with known pathological markers like Lewy bodies and Pick bodies.
Main Methods:
- Electron microscopy was employed to examine the ultrastructure of inclusion-bearing nerve cells.
- Inclusions were analyzed for their ultrastructural characteristics and compared to existing literature on neuronal inclusions.
Main Results:
- The MPTP-induced inclusion bodies were less defined than those observed in paraffin sections.
- Ultrastructurally, these bodies lacked Nissl substance and contained abundant, randomly oriented filamentous or tubular structures resembling neurotubules.
- The inclusions differed morphologically from both Pick bodies and characteristic Lewy bodies.
Conclusions:
- The observed inclusion bodies represent a novel finding in MPTP-induced parkinsonism in aged primates.
- These structures may represent an immature form of Lewy bodies, potentially similar to those found in the cerebral cortex.
- Further research is needed to elucidate the formation mechanism, relationship to Parkinson's disease, and the role of aging in their development.