Analysis of Immune Cells in Single Sciatic Nerves and Dorsal Root Ganglion from a Single Mouse Using Flow Cytometry
December 6th, 2017
11.4K views
Quantitative analysis of cell content within the murine sciatic nerve is difficult due to the scarcity of the tissue. This protocol describes a method for tissue digestion and preparation that provides sufficient cells for flow cytometry analysis of immune cell populations from nerves of individual mice.
Overview
This study presents a method for obtaining viable cells from the murine sciatic nerve and dorsal root ganglions for flow cytometry analysis. It addresses the challenges of debris generation during tissue digestion and showcases a protocol that allows for the simultaneous use of several markers to identify various immune cell populations.
Key Study Components
Area of Science
- Neuroscience
- Immunology
- Cell Biology
Background
- Isolation of cells from peripheral nerves is crucial for studying inflammation and immunopathology.
- Murine models provide insight into nerve and immune interactions.
- The dissection process is complex due to the limited tissue material.
- Digestion of neuronal material can produce significant debris, complicating cell isolation.
Purpose of Study
- To develop a reliable protocol for cell extraction from sciatic nerves and dorsal root ganglions.
- To facilitate flow cytometry analysis for studying immune cell profiles.
- To apply this method to other species potentially, such as humans and pigs.
Methods Used
- Ex vivo dissection and digestion of murine sciatic nerves and dorsal root ganglions.
- Flow cytometry analysis for immunophenotyping of isolated cells.
- Emphasis on careful dissection techniques to minimize tissue damage.
- Inclusion of critical steps like incubation and filtration to enhance cell viability.
Main Results
- Successfully isolated a sufficient number of cells for flow cytometry analysis.
- Identified multiple immune cell types using various markers through the described method.
- The protocol demonstrated adaptability for potential use in other organisms.
Conclusions
- This method enables detailed immunological studies of peripheral nerves in murine models.
- The cellular insights gleaned from this approach can enhance understanding of neuroinflammatory conditions.
Frequently Asked Questions
What are the advantages of this dissection method?
This method allows simultaneous analysis of multiple immune cell types, which aids in comprehensive immunological studies.
How is cell extraction from the sciatic nerve conducted?
Cells are extracted by carefully dissecting the sciatic nerve and dorsal root ganglions, followed by a digestion protocol to prepare for flow cytometry.
What types of data can be obtained using this technique?
The technique allows for detailed profiling of immune cell populations via flow cytometry, capturing various phenotypic characteristics.
Can this method be adapted for other species?
Yes, with minor modifications, this protocol can be applied to human and pig nerve tissues.
What limitations exist with this method?
One limitation is the potential for cell loss during the digestion process, which can affect the accuracy of flow cytometry results.
How does the method help in understanding neuropathies?
By providing insights into immune cell involvement in peripheral nerve inflammation, this method aids in studying conditions like neuropathy.
Executive Industry Relevance
This flow cytometry method enables quantitative profiling of immune cells in peripheral nervous tissue, addressing a key gap in neuroinflammatory research. By providing reproducible, multi-parametric data from individual mouse sciatic nerves and dorsal root ganglia, it supports target validation and mechanistic de-risking in preclinical models of neuropathy and diabetes. The approach enhances predictive confidence in early discovery by linking immune phenotypes to neuronal integrity and regeneration capacity.
Strategic Applications in Biopharma R&D
Early Discovery & Target Validation
- Scientific Value: Enables interrogation of therapeutic hypotheses regarding leukocyte infiltration and microglial-like cell activation in PNS.
- Operational Value: Provides quantitative CD45+ leukocyte frequencies (~5% in sciatic nerve, 5-10% in DRG) as a biomarker for immune engagement.
- Strategic Value: Supports target validation by correlating immune cell phenotypes with nerve injury, disease models, or genetic perturbations.
Screening & Assay Development
- Scientific Value: Allows simultaneous detection of surface and intracellular markers (e.g., CD68, CD206, MHC class II) for immune subset characterization.
- Operational Value: Generates ≥30,000 singlet events from sciatic nerves and >200,000 from DRG per mouse, enabling robust statistical analysis.
- Translational Value: Facilitates assay standardization across neurotoxicology, diabetic neuropathy, and genetic model studies.
Translational & Preclinical Research
- Scientific Value: Connects immune cell profiles in PNS to functional outcomes like neuronal integrity and regeneration.
- Operational Value: Enables longitudinal tracking of immune changes in chronic disease models (e.g., streptozotocin-induced diabetes).
- Translational Value: Supports biomarker alignment by identifying CD68+CD206+ macrophage subsets in sciatic nerves (60-80% of CD68+ cells).
Pipeline & Workflow Integration
The method fits within the discovery continuum from target validation to preclinical profiling, particularly for neuroimmunology and metabolic disease programs.
- Discovery Biology: Tests hypotheses about immune cell recruitment and phenotype in PNS using multi-parameter flow cytometry.
- Screening: Delivers reproducible, high-content immune profiling with defined singlet thresholds for assay acceptance.
- Analytics: Provides quantitative readouts (e.g., %CD45+, MFI of MHC class II) to compare conditions and guide go/no-go decisions.
- Translational Research: Links immune findings in murine DRG and sciatic nerve to models of neuropathy and diabetes.
- Enterprise Reuse: Establishes a standardized workflow for immune profiling across PNS disease areas, reducing method redevelopment.
Operational & Enterprise Impact
- Scientific Value: Reduces mechanistic ambiguity in neuroimmune interactions through quantitative, multi-marker immune phenotyping.
- Operational Value: Ensures reproducibility via standardized digestion, filtration, and gating strategies to minimize debris interference.
- Strategic Value: Improves go/no-go decisions by providing immune-mediated risk metrics early in discovery.
- Portfolio Impact: Enables risk-adjusted prioritization of targets based on immune engagement in PNS disease models.
Implementation Considerations
- Requires expertise in murine peripheral nerve dissection and enzymatic tissue dissociation.
- Dependent on flow cytometry instrumentation capable of multi-parameter detection and debris exclusion.
- Necessitates standardized gating strategies (e.g., DAPI+ singlet gating) across laboratories for data comparability.
- Must account for variability in immune cell yields between sciatic nerve and dorsal root ganglion tissues.
- Limited by tissue availability per mouse, necessitating careful experimental design for group sizes.
Biopharma FAQs
Why is CD45 expression measured in sciatic nerve and DRG?
CD45 expression identifies leukocytes of hematopoietic origin, with approximately 5% of singlets positive in sciatic nerves and 5-10% in dorsal root ganglia, providing a quantitative metric for immune cell infiltration.
How does isolating DAPI+ singlets improve flow cytometry accuracy?
Gating on DAPI+ events excludes non-nucleated debris and incompletely digested tissue, ensuring analysis focuses on viable single cells and increasing data reliability.
What enables simultaneous detection of multiple immune markers?
The protocol uses multi-color flow cytometry to detect surface and intracellular proteins (e.g., CD68, CD206, MHC class II) on the same cell, allowing comprehensive immune subset profiling.
Why are replication requirements important for immune profiling?
Consistent cell yields (>30,000 singlets from sciatic nerves, >200,000 from DRG) and reproducible leukocyte frequencies are required for cross-study comparison and target validation confidence.
What statistical outputs support immune phenotype comparison?
The method generates mean fluorescent intensity and event counts for selected fluorophores, enabling quantitative comparison of marker expression between experimental conditions.
Chapters in this video
0:05
Title
1:28
Dissection of Sciatic Nerve and Dorsal Root Ganglion
4:02
Digestion of Sciatic Nerve and Dorsal Root Ganglion
6:36
Setup and Flow Cytometry and Running of Samples
10:00
Results: Flow Cytometry Analysis of Surface Expressed Markers on Singlets from the Sciatic Nerve and Dorsal Root Ganglion
11:46
Conclusion
