Maturation of Collagen in healing Wounds in Young and Old Rats

Abstract

The thermal reactivity of collagen in incisional wounds and adjacent skin was studied in young (2.5-3.0 months) and old (18-23 months) rats at days 8 and 21 of healing. Twenty-five micron thick sections of the wound areas were mounted on a heating microscope stage, and the denaturing temperature was assessed by determining the loss of birefringence in the collagen. Wound collagen became denatured at lower temperatures than collagen in adjacent skin. At day 8 the collagen in wounds of old animals was less mature than in wounds of young. From the 8th to the 21st day only a slight increase in denaturing temperature occurred in wounds of young rats. In the old rats, however, a more marked increase took place. This finding indicates that the rate of maturation of wound collagen is greater in old than in young rats. In the old rats a decrease in the denaturing temperature for the collagen in skin adjacent to the wound was recorded. It is suggested that this change represents a “distant collagen response” to wounding in these animals.