帕金森病模型

As can be seen in this microscopy image, there is substantial loss of TH-positive dopaminergic neurons in the ipsilateral SNc compared to the contralateral hemisphere. For reference, an illustration with atlas labels for this brain level is provided below.

Using our PERMITS^TM quantitative analysis software, we have quantified the TH staining in the SNc. The plots below show a highly significant reduction in the ipsilateral hemisphere.

We have found significant brain atrophy in the SNc by generating regional volume data from in vivo anatomical MRI scans, which corresponds well with the loss of TH-positive neurons. MR images were acquired from mice injected with different doses of AAV-Synuclein at 4 weeks post-inoculation using a 7T animal MRI scanner.

This microscopy image shows the contralateral (right hemisphere) SNc which shows unaffected TH-positive cell bodies and processes in red. The DAPI-counterstained nuclei are shown in blue.

This microscopy image shows the ipsilateral (left hemisphere) SNc, which demonstrates a substantial reduction of TH-positive cell bodies and processes (in red) compared to the contralateral hemisphere. The DAPI-counterstained nuclei are shown in blue.

This microscopy image show severe dopaminergic denervation of the ipsilateral (left hemisphere) caudate-putamen (loss of TH-positive terminals). For reference, an illustration with atlas labels for this approximate brain level is provided below.

Using our PERMITS^TM quantitative analysis software, we have quantified the TH staining in the Caudate-Putamen. The plot below shows a highly significant reduction in the ipsilateral hemisphere.

This loss of dopaminergic innervation corresponds well with unilateral motor deficits in these mice, including a highly significant increase in use of the ipsilateral paw during the Cylinder Test, decreased latency to fall in the Rotarod Test, and increased swings to the contralateral side in the Tail Suspension Swing Test (TSST).

This high magnification view shows the severe extent of loss of dopaminergic (TH-positive) terminals in the ipsilateral striatum. There are some remaining (albeit dystrophic) axons present.

Similar to our findings in the SNc, we have observed brain atrophy in the caudate-putamen by quantitative analysis of high-resolution anatomical MRI scans, which establishes an in vivo-ex vivo relationship between neuroimaging and IF measures.

In this low magnification image, one can readily appreciate the higher density of Iba-1 staining microglia in the ipsilateral hemisphere (indicated by the box) relative to the contralateral hemisphere in an AAV-Syn injected mouse brain.

The plots below show the Iba-1 stain density in various brain regions, with highly significant increased staining in the AAV-Syn mice.

We have performed a morphological analysis of microglia using a novel computer vision & machine learning approach developed by our team. This fully-automated algorithm classifies non-activated (ramified) and activated (non-ramified) microglia.

The plots below show the microglial activation in various brain regions, with highly significant increased microglial activation in the AAV-Syn mice.

This high magnification view shows the increased density of Iba-1-stained microglia in areas with phosphorylated α-synuclein aggregates.

This low magnification microscopy image show a higher density of GFAP-positive astrocytes in the ipsilateral hemisphere (indicated by the box) of an AAV-Syn injected mouse brain. The plots below show the GFAP stain density in various brain regions.

This high magnification microscopy image shows a high level of Iba-1-positive microglia and GFAP-positive astrocytes in the ipsilateral hemisphere. Note the “activated” morphology of these neuroinflammatory cells.

The AAV A53T α-syn mouse model recapitulates many of the hallmark features of Parkinson’s disease. This model demonstrates progressive development of asymmetric motor dysfunction (due to unilateral injection), and associated loss of TH-positive SNc neurons and striatal TH expression.

AAV A53T α-synuclein locally increases brain atrophy, microglial density and activation levels, and astrocyte density and hypertrophy. Studies are planned to further interrogate the spatial relationships between microglial activation, astrocyte hypertrophy, and α-synuclein aggregation.

The AAV A53T α-synuclein mouse model is well-suited for drug development given the quantitative in-life and ex vivo readouts. It also has advantages over other models as a screening tool for novel disease-modifying therapeutics targeting α-synuclein related pathology, including the relatively short timeframe required to perform preclinical studies in this model.

Please feel free to further explore the microscopy image in the viewer.

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