Transmission Electron Microscopy of the Peripheral Nervous System: Methods, Sample Preparation, and Case Studies

Area of Science:

• Neuroscience
• Pathology
• Microscopy

Background:

• Peripheral nerves and ganglia are crucial for evaluating drug safety.
• Standardized methods for their ultrastructural analysis are essential for accurate pathology assessment.
• Emerging pharmaceutical modalities require robust nonclinical safety data.

Purpose of the Study:

• To provide practical recommendations for peripheral nerve and ganglion sample processing.
• To illustrate the utility and limitations of transmission electron microscopy (TEM) in nonclinical safety evaluations.
• To identify common artifacts and findings in nerve and ganglion ultrastructure.

Main Methods:

• Detailed protocols for sample collection, fixation, and resin embedding.
• Light microscopy and transmission electron microscopy (TEM) techniques for ultrastructural evaluation.
• Case studies using control and test article-dosed nonclinical samples.

Main Results:

• Established best practices for high-quality ultrastructural preservation.
• Demonstrated common artifacts (e.g., swelling, myelin defects) and pathological findings.
• Highlighted the value of TEM in detecting subtle nerve and ganglion changes.

Conclusions:

• Standardized sample preparation enhances the reliability of ultrastructural pathology.
• TEM is a valuable tool for nonclinical safety assessment of peripheral nerves and ganglia.
• Understanding artifacts is critical for accurate interpretation of TEM findings in drug development.