Wound repair in mice as influenced by age and antimacrophage serum

The closure of bilateral, full-thickness cutaneous wounds made over the back with a sharp paper punch was measured with calipers and assessed histologically in C57BL/6J male mice for 10 days after wounding. Young (6 months) mice exhibited a significantly more rapid rate of wound closure and repair than did mature (15 months) or aged (26 or 27 months) mice. The repair rate in mature and aged mice did not differ. Young mice, injected subcutaneously at the wound sites with rabbit antimouse macrophage serum (RAMMS) 5 min before wounding and on days 1 and 3 after wounding, exhibited slow delayed closure of cutaneous wounds during days 1 to 4 after wounding, similar to that of untreated aged mice. The early closure rate of mice injected with normal rabbit serum or physiological saline was rapid, resembling that of untreated young mice. The results suggest that cutaneous wound repair in mice is another physiological phenomenon whose rate of change is age related, but not necessarily progressive to senescence. The results also imply that macrophage functional decline may contribute to the slowing of wound repair in middle-aged and aged mice compared to young mice.