Spontaneous Pathology and Routine Clinical Pathology Parameters in Aging Beagle Dogs: A Comparison With Adolescent...

Area of Science:

• Veterinary Pathology
• Toxicology
• Preclinical Research

Background:

• Routine preclinical toxicology studies typically use Beagle dogs up to 24 months of age.
• A lack of age-matched historical control data exists for older Beagle dogs (25-37 months).
• Age-related spontaneous findings may confound the interpretation of toxicology study results.

Purpose of the Study:

• To generate age-matched clinical pathology and histopathology data in older Beagle dogs.
• To assess age-related differences in spontaneous findings in Beagle dogs aged 25-37 months.
• To support the use of older Beagle dogs in routine preclinical toxicology studies.

Main Methods:

• A bespoke study was conducted on a cohort of Beagle dogs aged 25-37 months.
• Clinical pathology and histopathology data were collected and analyzed.
• Findings were compared to expected data from younger adult dogs (<24 months).

Main Results:

• Most histopathology findings showed similar prevalence to younger dogs.
• Observed differences in thymus (involution), bone marrow (adiposity), testes (degeneration), and lung (fibrosis, hyperplasia) were noted.
• Minor, low-magnitude differences in hemoglobin, alkaline phosphatase, and reticulocytes were observed.

Conclusions:

• Specific age-related changes in older Beagle dogs were identified.
• These changes could be misinterpreted as test article effects in toxicology studies.
• The generated data supports the appropriate use and interpretation of studies involving older Beagle dogs.