Skin stretching and epidermopoiesis.

In order to determine whether the heightened epidermopoiesis seen over dermal expansile lesions is due to stretch, attempts were made to induce similar degrees of skin stretching by implanting Silastic materials in the dermis of guinea-pigs. Silastic elastomer produced mild inflammation and thus, this model could not be used to evaluate the effects of stretch alone. Silastic testicular implants caused no inflammation and were found to initially stimulate a rise in thymidine autoradiographic labelling index, but no increase in epidermal thickness during the experiment. It is suggested that there is an increase in the germinative pool size caused by stretch but that the epidermal hyperplasia seen over dermal lesions is due to some other process.