Older mice show a weaker cell response to skin wounds
Connective-tissue cells that had stopped dividing made up 1.7% of profiled wound cells in older mice versus 4.1% in younger mice.
Limit: Cell profiling pooled only three male mice per age group
Edited by Boris Djordjevic · AgingResearch.News
Male C57BL/6 mice aged 2 or 24 months received a single 1-centimeter, full-thickness skin wound on their backs in an animal experiment. Researchers assessed tissue at four time points through day 24, using at least five mice per age group at each point. Nearly all young mice’s wounds closed by day 18; most older mice’s wounds closed between days 22 and 24.
Young mice showed a temporary rise in signs of senescence, a state in which cells stop dividing. This response was markedly weaker in older mice. Gene activity measured in individual cells on day 6 identified senescent fibroblasts, cells that build connective tissue. In young wounds, these cells showed a profile associated with making and remodeling tissue’s supporting framework. In older wounds, their profile shifted toward inflammation, which the authors suggested could contribute to delayed healing.
Why it matters
Temporary senescence can help tissue repair. Understanding how aging changes this response may help clarify why older skin heals less efficiently.
Caveats
The age-group comparison did not establish whether altered senescence caused slower healing. The day-6 cell analysis pooled cells from three male mice per age group.
