Inbred C57BL/6J and C57BL/6N mice exhibit differential vascular dysfunction compared with outbred UM-HET3 mice

Area of Science:

• Cardiovascular Research
• Animal Models in Biomedical Research
• Vascular Physiology

Background:

• Inbred C57BL/6 mice are standard in research, with C57BL/6J and C57BL/6N substrains often used interchangeably.
• Subtle genetic differences between C57BL/6 substrains can impact experimental outcomes, particularly in vascular studies.
• Understanding these differences is crucial for accurate interpretation of research findings.

Purpose of the Study:

• To compare vascular function between C57BL/6J and C57BL/6N mouse substrains.
• To evaluate the impact of inbreeding on vascular function by comparing C57BL/6 substrains with the outbred UM-HET3 mice.
• To assess the suitability of UM-HET3 mice as an alternative to inbred C57BL/6 mice in biomedical research.

Main Methods:

• Vascular function assessment in C57BL/6J, C57BL/6N, and UM-HET3 mice.
• Measurements included systolic blood pressure, aortic stiffness, vasodilation responses (acetylcholine-mediated and flow-mediated), and aortic structural characteristics.
• Comparison of vascular parameters and measurement variability across the different mouse strains.

Main Results:

• C57BL/6N mice exhibited lower systolic blood pressure and aortic stiffness compared to C57BL/6J mice.
• Flow-mediated vasodilation was greater in C57BL/6N mice than in C57BL/6J mice.
• UM-HET3 mice demonstrated generally superior vascular function compared to both C57BL/6 substrains, with no increase in measurement variability.

Conclusions:

• Significant differences in vascular function exist between C57BL/6J and C57BL/6N substrains, with C57BL/6N showing better vascular health.
• Outbred UM-HET3 mice possess enhanced vascular function compared to inbred C57BL/6 mice.
• UM-HET3 mice represent a viable alternative to inbred strains in biomedical research due to their superior vascular function and comparable measurement variability.