Mouse epidermal cell proliferation after a single application of dimethyl sulphoxide (DMSO).

Hairless mouse epidermis was treated topically with a single application of undiluted DMSO. Epidermal cell proliferation during the following 72 hr was examined by means of DNA flow cytometry, [3H]TdR autoradiography, and a stathmokinetic method with colcemid. Topical application of DMSO was followed by perturbations in the epidermal cell proliferation that were in general similar to those observed in epidermal regeneration due to sudden cell loss. In contrast to such regenerative reactions, no hyperplasia could be detected after DMSO treatment, in spite of a consistently increased mitotic rate the first 3 days after DMSO treatment. The augmented epidermal cell production following exposure to DMSO therefore appears to be balanced by a correspondingly increased cell loss.