Pathology of aging B6;129 mice

Area of Science:

• Comparative Pathology
• Aging Research
• Mouse Models of Disease

Background:

• The B6;129 mouse strain is widely used in research.
• Understanding age-related pathologies in mouse models is crucial for human disease research.
• Longitudinal studies on aging mouse strains are essential for characterizing spontaneous lesions.

Purpose of the Study:

• To characterize the age-related pathology of the B6;129 mouse strain up to 2 years of age.
• To identify common neoplastic and non-neoplastic lesions in aged B6;129 mice.
• To compare the incidence of specific pathologies between male and female mice.

Main Methods:

• Longitudinal maintenance of 50 male and 49 female B6;129 mice until 104-105 weeks of age.
• Necropsy and histopathological examination to identify and classify lesions.
• Immunohistochemistry and IgH gene rearrangement analysis to characterize lymphomas.

Main Results:

• High incidence of lymphoma in both sexes (males 42%, females 67%), predominantly in mesenteric lymph nodes, Peyer's patches, and spleen.
• Lymphomas showed B-cell origin (IgH rearrangement) with T-cell infiltration, resembling human T-cell rich B-cell lymphomas.
• Other common tumors included lung, liver, and ovarian/endometrial tumors; frequent non-neoplastic lesions included nasal amyloid, otitis media, and glomerulonephritis.

Conclusions:

• The B6;129 mouse strain exhibits a high incidence of lymphoma, a characteristic aging lesion, particularly in females.
• This strain presents a spectrum of age-related pathologies, making it a valuable model for aging research.
• The observed lymphomas share similarities with human lymphomas, suggesting potential translational relevance.