Impaired wound healing but unaltered colonic healing with increasing age: an experimental study in rats.

Age-related differences in the healing of left colonic anastomoses and abdominal incisional wounds were compared between young and old rats. Immediately after surgery the anastomotic strength (suture-binding capacity) was 67% higher in old rats corresponding to a 107% higher collagen content per unit length of left colon compared to young rats. After 2 and 4 days of healing there was no difference in the breaking strength of the anastomoses between young and old rats, although the increase in collagen content of the anastomosed segment was 100% in the young rats and only 35% in the old rats from day 2 to day 4. The healing of the abdominal incisional wounds was, however, impaired in old rats compared to young rats, since the tensile strength and the energy absorption on the 4th postoperative day was 67 and 57% lower, respectively. In conclusion, old rats have impaired skin healing, whereas colonic healing is not affected by age.