A model for studying cutaneous wound healing and resilience to aging: Ear punch biopsy in old mice

Abstract

Resilience to aging is a biological event that precedes age-related decline in physiological function and is defined as an organism's ability to respond to physical stress with increasing age. There is a need to identify factors that may predict resilience for enhancing and maintaining healthy aging. Older people often experience delayed wound healing beause of compromised tissue repair and immune response. Therefore preclincal models may be of value to investigate the relationship between cutaneous wound healing and resilience to aging. This brief report descibes an ear punch biopsy model of cutaneous wound healing in aging mice and shows that mice with biopsy ear wounds that heal more quickly have better cognition, increased strength and better running endurance later in life.

Keywords: Resilience to aging; aging mice; ear punch biopsy; wound healing.

Figure 1.. Ear biopsy procedure.

A. A 2 mm ear punch biopsy instrument (VWR) was used for B. creating a through and through biopsy opening in the central part of each ear.

Figure 2.

C57BL/6 female mice, 20 months of age, had close to a 50 percent closure after two weeks following an ear punch biopsy. N = 20 mice. There was no difference in closure in either ear at any time point up to five weeks.

Figure 3.

Mice that had increased closure of an ear punch biopsy after two weeks (fast healers) were: A. Better at finding an escape hole in a spatial navigation learning task (box maze), B. Had similar times staying on a rotating rod, C. Had increased grip strength, and D. Ran further over three days on a slanted wheel, compared to mice with a decreased ear biopsy closure (slow healers). All performance tests were conducted three months after the ear biopsy. N = 8–10 mice per cohort. * P ≤ 0.05.