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Aging changes in CD-1 HaM/ICR mice reared under standard laboratory conditions
Journal of the National Cancer Institute
|July 1, 1975
Summary
This 2-year study observed 300 mice, finding high tumor incidence (54% males, 75% females) and amyloidosis in half. Lung tumors were most common, highlighting the need for large sample sizes in mouse research.
Area of Science:
- Toxicologic pathology
- Animal models in research
Background:
- Long-term toxicological studies in mice are crucial for understanding aging and disease.
- CD-1 HaM/ICR mice are a common strain used in preclinical research.
Purpose of the Study:
- To document the incidence and types of spontaneous neoplasms and age-related diseases in CD-1 HaM/ICR mice over a 2-year period.
- To assess the impact of age on mortality and disease prevalence in this mouse model.
Main Methods:
- Observation of 300 CD-1 HaM/ICR mice for 2 years.
- Necropsy and histopathological examination of 99 male and 102 female mice.
- Recording of mortality rates, tumor incidence, tumor types, and presence of amyloidosis.
Main Results:
- Mortality reached 50% at 16 months (males) and 18 months (females).
- Tumor incidence was 54% in males and 75% in females, primarily occurring after 18 months.
- Most frequent tumors included lung adenomas/adenocarcinomas, lymphoreticular tumors, and hepatomas. Amyloidosis affected approximately 50% of mice.
- Significant variability in tumor incidence was noted, emphasizing the need for adequate sample sizes.
Conclusions:
- CD-1 HaM/ICR mice exhibit a high incidence of spontaneous tumors and amyloidosis with age.
- Lung neoplasms are the most prevalent, followed by lymphoreticular and vascular tumors.
- The study underscores the importance of robust experimental design with sufficient sample sizes to account for biological variability in mouse studies.