Visualization of a Mouse Brain Choroid Plexus Using Scanning Electron Microscopy
JoVE Encyclopedia of Experiments
Neuroscience
0 views • 2:23 min • June 17th, 2025
Take the choroid plexus from a mouse brain in a specimen basket.
The tissue, located within the brain ventricles, contains a layer of epithelial cells featuring microvilli on their apical surface.
Incubate the tissue in a fixative solution to preserve its cellular architecture.
Wash with a buffer to remove excess fixative and stabilize the pH.
Incubate the tissue with osmium tetroxide that binds to cell membrane lipids, preserving membrane stability, then rinse off excess reagent.
Dehydrate the tissue using increasing alcohol concentrations to prevent tissue distortion during imaging.
Dry the tissue, secure it onto a carbon-coated specimen mount, then coat it with a conductive platinum layer.
Using scanning electron microscopy, focus an electron beam onto the surface. The platinum layer dissipates electrons, preventing charge buildup and minimizing imaging artifacts.
A detector captures the electrons backscattered from the surface, producing an image of the tissue exhibiting epithelial cells with microvilli.
To perform the sample preparation for SEM, transfer the freshly isolated choroid plexus into freshly made fixation solution, and incubate overnight at 4 degrees Celsius. Once done, wash the sample three times using 3 to 5 milliliters of 0.1 molar sodium cacodylate buffer for five minutes each.
Post-fix the samples in 3 to 5 milliliters of 2% osmium tetroxide in 0.1 molar sodium cacodylate buffer for 30 minutes. Then wash the samples three times for five minutes each using 3 to 5 milliliters of ultrapure water. Next, dehydrate the samples in an increasing series of ice-cold ethyl alcohol concentrations with 15 minutes per ethyl alcohol solution. Use a critical point dryer to dry the sample properly. Position the sample carefully on a specimen mount with a carbon sticker, and visualize the choroid plexus samples using SEM.
Overview
This article details a protocol for the microdissection and whole mount scanning electron microscopy (SEM) visualization of the mouse choroid plexus. The method enables high-resolution imaging of the tissue's epithelial cell layer and its microvilli, providing structural insights into this specialized brain region.
Key Study Components
Area of Science
- Neuroscience
- Electron Microscopy
- Tissue Preparation
Background
- The choroid plexus is located within the brain ventricles and is composed of epithelial cells with apical microvilli.
- Detailed visualization of these structures is essential for understanding their function and pathology.
- SEM offers high-resolution surface imaging, making it suitable for studying microvilli and cellular architecture.
- Proper sample preparation is critical to preserve tissue morphology and prevent imaging artifacts.
Purpose of Study
- To demonstrate a reliable protocol for isolating and preparing mouse choroid plexus tissue for SEM analysis.
- To visualize the ultrastructural features of choroid plexus epithelial cells, particularly their microvilli.
- To provide a step-by-step guide for researchers interested in SEM imaging of delicate brain tissues.
Methods Used
- Microdissection of choroid plexus from mouse brain ventricles.
- Fixation of tissue in a fixative solution overnight at 4°C.
- Buffer washes to remove excess fixative and stabilize pH.
- Post-fixation with osmium tetroxide to preserve membrane lipids.
- Dehydration through a graded series of ice-cold ethyl alcohol concentrations.
- Critical point drying to prevent tissue distortion.
- Mounting on carbon-coated specimen mounts and coating with a conductive platinum layer.
- Imaging with scanning electron microscopy to capture detailed surface structures.
Main Results
- SEM imaging revealed well-preserved epithelial cells with prominent microvilli on the choroid plexus surface.
- The platinum coating minimized charging and imaging artifacts, resulting in high-quality images.
- The protocol maintained tissue integrity and cellular architecture throughout preparation and imaging.
- Detailed visualization of microvilli and cell surfaces was achieved.
Conclusions
- This protocol enables reliable preparation and SEM imaging of mouse choroid plexus tissue.
- The method preserves fine structural details, such as microvilli, essential for morphological studies.
- It provides a valuable resource for researchers studying brain barrier tissues and their ultrastructure.
Frequently Asked Questions
Executive Industry Relevance
High-resolution visualization of the mouse choroid plexus using scanning electron microscopy (SEM) enables detailed assessment of epithelial cell architecture and microvilli, supporting mechanistic studies of brain barrier tissues. This capability is critical for early discovery teams seeking to clarify tissue-specific morphology and de-risk biological hypotheses in neuropharma pipelines. Reliable ultrastructural imaging informs target validation and translational research by providing quantitative morphological benchmarks.
Strategic Applications in Biopharma R&D
Early Discovery & Target Validation
- Enables precise morphological characterization of choroid plexus epithelial cells and microvilli.
- Supports biological de-risking by confirming tissue integrity and cellular architecture.
- Provides structural benchmarks for evaluating disease models and target engagement.
Screening & Assay Development
- Facilitates preparation of validated tissue samples for downstream imaging workflows.
- Ensures reproducibility and standardization in sample processing and imaging outputs.
- Delivers quantitative surface morphology data for comparative analysis.
Translational & Preclinical Research
- Aligns morphological findings with disease-relevant brain barrier models.
- Enables continuity from discovery imaging to preclinical tissue validation.
- Supports risk-adjusted advancement by providing ultrastructural evidence of tissue health.
Pipeline & Workflow Integration
This SEM-based protocol integrates into the discovery-to-preclinical continuum by providing robust morphological data for hypothesis testing and model validation.
- Discovery Biology: Confirms cellular and subcellular features critical for mechanistic studies.
- Screening: Standardizes imaging outputs for cross-condition comparison.
- Analytics: Generates high-resolution images enabling quantitative assessment of microvilli density and epithelial integrity.
- Translational Research: Bridges morphological data from basic research to disease modeling.
- Enterprise Reuse: Establishes a reproducible imaging workflow applicable across neuropharma projects.
Operational & Enterprise Impact
- Scientific Value: Increases predictive confidence in tissue-based target validation.
- Operational Value: Delivers standardized, reproducible imaging protocols for enterprise-wide adoption.
- Strategic Value: Reduces mechanistic ambiguity and supports informed go/no-go decisions.
- Portfolio Impact: Enables risk-adjusted prioritization of neuropharma assets based on robust morphological data.
Implementation Considerations
- Requires expertise in tissue microdissection and electron microscopy sample preparation.
- Demands access to SEM instrumentation and critical point drying infrastructure.
- Necessitates cross-team standardization of fixation, dehydration, and coating protocols.
- Adaptation may be needed for different brain regions or disease models.
- Sample integrity and imaging quality depend on precise execution of each preparation step.
Biopharma FAQs
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Last updated: 29 August 2026