[The course of healing of cutaneous wounds in young and old rats]

Healing of cutaneous wounds produced on the backs of young and old rats has been compared at ten various intervals between days 3 and 28. The only differences disclosed pertained to the exsudative and proliferative phases between days 3 and 5, which were found to develop more rapidly in young rats. The phase of the (predominantly afibrillar) connection of the wound stumps was reduced to less than 5 days. The exact nature of the "sticking" intercellular substance has not been clarified; most probably the substance represents nonfibrillar collagen. In the group of old rats neoformation of fibrillary neocollagen was somewhat more marked during days 7 to 9 than in yound rats, in whom a rather pronounced exsudative component was found during that period. No significant differences between the two groups were disclosed during the later stages of the experiment. Fibroblasts participated in collagen phagocytosis during the definitive reconstruction of the provisional, imperfectly oriented fibrillar connection of the wound edges.