Inhibition of connective tissue proliferation by dermal extract

Following the subcutaneous injection of a water soluble dermal extract (DE) of neonatal rat skin into young adult male rats, depression of nuclear labeling (DNA synthesis) was observed in proliferating connective tissue in several wound sites. At 16--20 hr following DE injection, DNA synthesis was depressed most in back wounds (57--87%) and maxillary palatal wounds (45--68%), and least in ear wounds (24--29%). Epithelium in the wound margins of back, ear and palate did not show a similar depression in DE-injected animals. This study suggests that a chalone-like negative feedback mechanism may be partially responsible for in vivo control of fibroblastic proliferation in wound healing.