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Degeneration of Pick bodies visualized by methenamine-silver staining and immunohistochemistry
Toshinari Odawara1, Eizo Iseki, Yoshiko Furukawa
1Department of Psychiatry, Yokohama City University School of Medicine, Yokohama, Japan. odaw1913@med.yokohama-cu.ac.jp
Abstract:
The degeneration process of Pick's bodies (PB) was investigated using methenamine-silver (MS) staining and immunohistochemistry. Methenamine-silver staining sensitively detected extracellular PB as well as intracellular PB in the granular cell layer of the dentate gyrus. Extracellular PB appeared as granular masses with ill-defined boundaries in the neuropil. For MS electron microscopy, the extracellular PB were composed of randomly oriented fibrillary components measuring 9-12 nm in diameter with astroglial processes and degenerated organelles. Tau immunoreactivity of extracellular PB was reduced or abolished. These findings indicate that MS staining is a convenient method for detecting extracellular PB. In addition, it was shown that microglial involvement was associated with PB-bearing neurons at the late stage of the degeneration process and that extracellular PB remained in the neuropil with astroglial reaction.
Insights
Methenamine-silver staining effectively detects Pick
Area of Science:
- Neuroscience
- Neuropathology
Background:
- Pick's bodies (PB) are pathological hallmarks in neurodegenerative diseases.
- Understanding the degeneration process of PB is crucial for disease research.
Purpose of the Study:
- To investigate the degeneration process of Pick's bodies (PB).
- To evaluate the utility of methenamine-silver (MS) staining for PB detection.
- To characterize the cellular and ultrastructural features of degenerating PB.
Main Methods:
- Methenamine-silver (MS) staining.
- Immunohistochemistry.
- Electron microscopy.
Main Results:
- MS staining sensitively detected both intracellular and extracellular PB.
- Extracellular PB showed ill-defined boundaries, fibrillary components, and were associated with astroglial processes and degenerated organelles.
- Tau immunoreactivity was reduced in extracellular PB, and microglial involvement was observed in late-stage degeneration.
Conclusions:
- MS staining is a convenient method for detecting extracellular PB.
- Extracellular PB persist in the neuropil with astroglial reactions during degeneration.
- Microglial activation is associated with PB-bearing neurons in later stages.