A Technical Guide to Sampling the Beagle Dog Nervous System for General Toxicity and Neurotoxicity Studies

Area of Science:

• Veterinary Pathology
• Neuroscience
• Toxicology

Background:

• Beagle dogs are crucial nonrodent models in biomedical product safety evaluations.
• Existing Society of Toxicologic Pathology (STP) guidelines for nervous system sampling in nonrodents lack specific adaptation for Beagle dogs.
• Standardized protocols are needed to ensure comprehensive neuroanatomic evaluation in canine toxicity studies.

Purpose of the Study:

• To present two distinct brain trimming schemes tailored for Beagle dogs in nonclinical toxicity studies.
• To align nervous system sampling with STP 'best practices' for both general and targeted neurotoxicity assessments.
• To provide practical guidance on collecting central and peripheral nervous system tissues, including less common sites.

Main Methods:

• Developed two coronal brain sectioning schemes for Beagle dogs: a 7-level scheme for general toxicity studies (Tier 1) and a 14-level scheme for neurotoxicity studies (Tier 2).
• Ensured the Tier 1 scheme aligns with STP recommendations for nonrodent nervous system sampling.
• Incorporated guidance for collecting spinal cord, ganglia, and peripheral nerves, referencing established STP protocols.

Main Results:

• The proposed trimming schemes provide a framework for evaluating unique canine neuroanatomy in toxicity studies.
• The Tier 1 scheme facilitates broad screening for potential neurotoxic effects.
• The Tier 2 scheme allows for in-depth investigation when the brain is a suspected target organ.

Conclusions:

• These adaptable trimming schemes enhance the evaluation of Beagle dogs in nonclinical safety studies.
• The protocols support consistent and thorough nervous system sampling according to STP guidelines.
• This guide offers practical solutions for optimizing neuroanatomic assessments in canine toxicology.