Validation of a geropathology grading system for aging mouse studies

Area of Science:

• Gerontology
• Pathology
• Animal Models

Background:

• Understanding aging mechanisms requires evaluating pre-frailty changes.
• Histopathology in aging mouse studies complements molecular and physiological data.
• Standardized scoring criteria for age-related lesions are currently lacking.

Purpose of the Study:

• Validate a geropathology grading platform (GGP) for scoring age-related lesions in mice.
• Establish a composite lesion score (CLS) for comparing histological findings.
• Assess the reproducibility and reliability of the GGP system.

Main Methods:

• Multiple veterinary pathologists independently scored histological slides from mouse hearts, lungs, livers, and kidneys.
• Mice from two strains (C57BL/6 and CB6F1) were analyzed at ages 8, 16, 24, and 32 months.
• The geropathology grading platform (GGP) generated a composite lesion score (CLS).

Main Results:

• Moderate to high agreement was observed among pathologists, especially within a 1-point range.
• Composite lesion scores (CLS) were significantly higher in older mice compared to younger mice across all organs.
• The GGP system demonstrated reliability in detecting age-related pathology in mice.

Conclusions:

• The validated geropathology grading platform (GGP) guidelines reliably distinguish between younger and older mice.
• The GGP system is accurate for differentiating experimental groups based on age-related pathology.
• This standardized approach enhances the utility of histopathology in aging research.