C57BL/6J and C57BL/6N mice show distinct aging-associated behavioral alterations.

Aging affects emotional, cognitive, and social functions, increasing susceptibility to neuropsychiatric conditions. C57BL/6 mice are commonly used to study aging mechanisms, yet differences between C57BL/6J and C57BL/6N substrains remain underexplored. This study compared aging-related behavioral changes in these substrains. Aging reduced exploratory activity and heightened anxiety in C57BL/6J, but not C57BL/6N, mice. Conversely, aging reduced social novelty preference in C57BL/6N, but not C57BL/6J, mice. Male mice of both substrains exhibited increased female urine sniffing with age. These findings highlight substrain-specific aging effects, underscoring the importance of substrain selection in behavioral studies of aged mice for drug development.
Competing Interests: Declaration of competing interest The authors declare that there are no conflicts of interest associated with this manuscript.
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