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Cerebral β-Amyloidosis in Mice Investigated by Ultramicroscopy.

Jährling N, Becker K, Wegenast-Braun BM, Grathwohl SA, Jucker M, Dodt HU - PLoS ONE (2015)

Bottom Line: Alzheimer´s disease (AD) is the most common neurodegenerative disorder.Ultramicroscopy makes this possible by replacing mechanical slicing in standard histology by optical sectioning.This in turn is the basis to study neural network degeneration upon cerebral β-amyloidosis and to assess Aβ-targeting therapeutics.

View Article: PubMed Central - PubMed

Affiliation: Department of Bioelectronics, FKE, Vienna University of Technology, Vienna, Austria; Section of Bioelectronics, Center for Brain Research (MUW), Vienna, Austria.

ABSTRACT
Alzheimer´s disease (AD) is the most common neurodegenerative disorder. AD neuropathology is characterized by intracellular neurofibrillary tangles and extracellular β-amyloid deposits in the brain. To elucidate the complexity of AD pathogenesis a variety of transgenic mouse models have been generated. An ideal imaging system for monitoring β-amyloid plaque deposition in the brain of these animals should allow 3D-reconstructions of β-amyloid plaques via a single scan of an uncropped brain. Ultramicroscopy makes this possible by replacing mechanical slicing in standard histology by optical sectioning. It allows a time efficient analysis of the amyloid plaque distribution in the entire mouse brain with 3D cellular resolution. We herein labeled β-amyloid deposits in a transgenic mouse model of cerebral β-amyloidosis (APPPS1 transgenic mice) with two intraperitoneal injections of the amyloid-binding fluorescent dye methoxy-X04. Upon postmortem analysis the total number of β-amyloid plaques, the β-amyloid load (volume percent) and the amyloid plaque size distributions were measured in the frontal cortex of two age groups (2.5 versus 7-8.5 month old mice). Applying ultramicroscopy we found in a proof-of-principle study that the number of β-amyloid plaques increases with age. In our experiments we further observed an increase of large plaques in the older age group of mice. We demonstrate that ultramicroscopy is a fast, and accurate analysis technique for studying β-amyloid lesions in transgenic mice allowing the 3D staging of β-amyloid plaque development. This in turn is the basis to study neural network degeneration upon cerebral β-amyloidosis and to assess Aβ-targeting therapeutics.

No MeSH data available.


Related in: MedlinePlus

Location of measured test-cubes.β-Amyloid plaques (yellow dots) in the right hemisphere of the frontal cortex in the APPPS1 mouse model, side view: example from the young (2.7 month-old) group (A) and the adult (7.8 month-old) group (B). Positioning of the six cubed-shaped areas (purple color) in the frontal cortex for measuring the β-amyloid plaque volumes by applying a threshold segmentation technique. C-D) Top view of the frontal cortex: example from the young group (C) and old group (D). After segmentation amyloid plaque volumes of the six cubed shaped areas are represented in various colors. Scale bar 500 μm.
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pone.0125418.g004: Location of measured test-cubes.β-Amyloid plaques (yellow dots) in the right hemisphere of the frontal cortex in the APPPS1 mouse model, side view: example from the young (2.7 month-old) group (A) and the adult (7.8 month-old) group (B). Positioning of the six cubed-shaped areas (purple color) in the frontal cortex for measuring the β-amyloid plaque volumes by applying a threshold segmentation technique. C-D) Top view of the frontal cortex: example from the young group (C) and old group (D). After segmentation amyloid plaque volumes of the six cubed shaped areas are represented in various colors. Scale bar 500 μm.

Mentions: The β-amyloidosis in the frontal cortex of the brains was quantitatively analyzed. The brain volumes of individual animals vary. Hence, the volume of each cortex was determined by segmentation (raw data based on data recorded with the 2-fold objective). There was no significant difference in the cortex volume between the age groups. The total β-amyloid plaque number and the volume of amyloid plaques was measured within cubed shaped blocks placed at different regions of the frontal cortex (raw data based on data recorded with the 4-fold objective). Fig 4 shows how six of these cubes were positioned in the frontal cortex in each brain hemisphere. To adjust for potential differences due to tissue processing, the volume of each test cube was fixed to 0.1% of the determined cortex volume. There was no significant difference in the cube shaped block volume between the age groups (S1 Table). Labeled amyloid plaques were segmented based on intensity, using a manual threshold on Amira 5.2 visualization software.


Cerebral β-Amyloidosis in Mice Investigated by Ultramicroscopy.

Jährling N, Becker K, Wegenast-Braun BM, Grathwohl SA, Jucker M, Dodt HU - PLoS ONE (2015)

Location of measured test-cubes.β-Amyloid plaques (yellow dots) in the right hemisphere of the frontal cortex in the APPPS1 mouse model, side view: example from the young (2.7 month-old) group (A) and the adult (7.8 month-old) group (B). Positioning of the six cubed-shaped areas (purple color) in the frontal cortex for measuring the β-amyloid plaque volumes by applying a threshold segmentation technique. C-D) Top view of the frontal cortex: example from the young group (C) and old group (D). After segmentation amyloid plaque volumes of the six cubed shaped areas are represented in various colors. Scale bar 500 μm.
© Copyright Policy
Related In: Results  -  Collection

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Show All Figures
getmorefigures.php?uid=PMC4446269&req=5

pone.0125418.g004: Location of measured test-cubes.β-Amyloid plaques (yellow dots) in the right hemisphere of the frontal cortex in the APPPS1 mouse model, side view: example from the young (2.7 month-old) group (A) and the adult (7.8 month-old) group (B). Positioning of the six cubed-shaped areas (purple color) in the frontal cortex for measuring the β-amyloid plaque volumes by applying a threshold segmentation technique. C-D) Top view of the frontal cortex: example from the young group (C) and old group (D). After segmentation amyloid plaque volumes of the six cubed shaped areas are represented in various colors. Scale bar 500 μm.
Mentions: The β-amyloidosis in the frontal cortex of the brains was quantitatively analyzed. The brain volumes of individual animals vary. Hence, the volume of each cortex was determined by segmentation (raw data based on data recorded with the 2-fold objective). There was no significant difference in the cortex volume between the age groups. The total β-amyloid plaque number and the volume of amyloid plaques was measured within cubed shaped blocks placed at different regions of the frontal cortex (raw data based on data recorded with the 4-fold objective). Fig 4 shows how six of these cubes were positioned in the frontal cortex in each brain hemisphere. To adjust for potential differences due to tissue processing, the volume of each test cube was fixed to 0.1% of the determined cortex volume. There was no significant difference in the cube shaped block volume between the age groups (S1 Table). Labeled amyloid plaques were segmented based on intensity, using a manual threshold on Amira 5.2 visualization software.

Bottom Line: Alzheimer´s disease (AD) is the most common neurodegenerative disorder.Ultramicroscopy makes this possible by replacing mechanical slicing in standard histology by optical sectioning.This in turn is the basis to study neural network degeneration upon cerebral β-amyloidosis and to assess Aβ-targeting therapeutics.

View Article: PubMed Central - PubMed

Affiliation: Department of Bioelectronics, FKE, Vienna University of Technology, Vienna, Austria; Section of Bioelectronics, Center for Brain Research (MUW), Vienna, Austria.

ABSTRACT
Alzheimer´s disease (AD) is the most common neurodegenerative disorder. AD neuropathology is characterized by intracellular neurofibrillary tangles and extracellular β-amyloid deposits in the brain. To elucidate the complexity of AD pathogenesis a variety of transgenic mouse models have been generated. An ideal imaging system for monitoring β-amyloid plaque deposition in the brain of these animals should allow 3D-reconstructions of β-amyloid plaques via a single scan of an uncropped brain. Ultramicroscopy makes this possible by replacing mechanical slicing in standard histology by optical sectioning. It allows a time efficient analysis of the amyloid plaque distribution in the entire mouse brain with 3D cellular resolution. We herein labeled β-amyloid deposits in a transgenic mouse model of cerebral β-amyloidosis (APPPS1 transgenic mice) with two intraperitoneal injections of the amyloid-binding fluorescent dye methoxy-X04. Upon postmortem analysis the total number of β-amyloid plaques, the β-amyloid load (volume percent) and the amyloid plaque size distributions were measured in the frontal cortex of two age groups (2.5 versus 7-8.5 month old mice). Applying ultramicroscopy we found in a proof-of-principle study that the number of β-amyloid plaques increases with age. In our experiments we further observed an increase of large plaques in the older age group of mice. We demonstrate that ultramicroscopy is a fast, and accurate analysis technique for studying β-amyloid lesions in transgenic mice allowing the 3D staging of β-amyloid plaque development. This in turn is the basis to study neural network degeneration upon cerebral β-amyloidosis and to assess Aβ-targeting therapeutics.

No MeSH data available.


Related in: MedlinePlus