[Epidermal proliferation rate after skin expansion in the dog model]

The aim of this study was to evaluate the time course of the epidermal proliferation under the influence of skin expansion. Therefore 99 expanders were implanted in 18 beagles. The expansion times were between 2 hours and 4 months. Cells in the S-phase were marked by in vivo application of bromodesoxyuridine (BrdU). The tissue specimens were immunohistochemically stained and positive nuclei counted. The proliferation index increased markedly about 32 hours after the onset of the expansion and decreased afterwards slowly during the first week. Because the dog is the most appropriate species for experimental expansion studies (4,5) it can be assumed that skin expansion leads to a stimulation of the epidermal proliferation during the first few days also under clinical conditions. Nevertheless, the amount of skin that can be surgically used depends not only on the characteristics of the epidermal layer, but also on the dermis with its strong fibre system. Own studies published elsewhere (8) have shown that the dermal fibres react much slower to the expansion stimulus, so that even though there is an early epidermal proliferation increase new surgically applicable skin can only be produced by long-term expansion.