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Periodic acid-Schiff (PAS)-positive, granular structures increase in the brain of senescence accelerated mouse (SAM)
Abstract:
Abnormal granular structures, which stained positively with periodic acid-Schiff (PAS-positive granular structures; PGS), were observed in the brain of senescence accelerated mouse (SAM). They were small, round to ovoid, homogeneous structures measuring up to 5 microns in diameter and usually grouped in clusters. PGS were localized in the hippocampus, piriform cortices, olfactory tubercle, nucleus of the trapezoid body, and cerebellar cortices. Quantitative analysis revealed that PGS remarkably increased in the hippocampus of SAM-P/8, a substrain of SAM, with advancing age, although a few PGS also appeared in the aged control mice, SAM-R/1 and DDD. Their histochemical nature, morphological features and distribution pattern were different from those of corpora amylacea and other similar bodies. A close anatomical relationship between PGS and glial fibrillary acidic protein-positive astrocytes was inferred from immunohistochemical studies. PGS is considered to be one of the morphological manifestations of senescence in mice brains, and are found to occur more numerously in the brains of learning or memory deficit mice, SAM-P/8.
Insights
Periodic acid-Schiff positive granular structures (PGS) were found in the brains of aging mice. These structures increased with age, particularly in learning and memory deficit mice.
Area of Science:
- Neuroscience
- Aging Research
- Histopathology
Background:
- Senescence accelerated mouse (SAM) models exhibit age-related brain changes.
- Periodic acid-Schiff positive granular structures (PGS) are abnormal cellular accumulations.
- Understanding brain aging markers is crucial for neurodegenerative disease research.
Purpose of the Study:
- To characterize the morphology, distribution, and prevalence of PGS in the aging mouse brain.
- To investigate the relationship between PGS and senescence in different SAM substrains.
- To explore the potential link between PGS and cognitive decline.
Main Methods:
- Histochemical staining using periodic acid-Schiff (PAS) to identify PGS.
- Immunohistochemical analysis to assess glial fibrillary acidic protein (GFAP) and astrocyte association.
- Quantitative analysis of PGS in various brain regions across different aged SAM substrains (SAM-P/8, SAM-R/1, DDD).
Main Results:
- PGS were observed in multiple brain regions, including the hippocampus and cerebellum.
- PGS significantly increased in the hippocampus of SAM-P/8 mice with advancing age.
- PGS exhibited distinct morphological and distribution patterns compared to other brain inclusions.
- A correlation between PGS presence and glial fibrillary acidic protein-positive astrocytes was noted.
Conclusions:
- PGS are a novel morphological manifestation of senescence in the mouse brain.
- The increased prevalence of PGS in SAM-P/8 mice suggests a role in age-related cognitive deficits.
- PGS represent a potential biomarker for brain aging and associated functional decline.