Repopulation of guinea-pig skin by melanocytes during wound healing: a morphometric study.

Epidermal keratinocytes and melanocytes have a close functional interrelationship. In order to study this relationship we used computer-assisted three-dimensional morphometry (CAM) to investigate the shape and size changes of the cutaneous melanocyte in healing guinea-pig skin. The combination of CAM with osmium iodide staining and resin embedding of tissue gave excellent results and allowed qualitative and quantitative morphometric assessment of melanocytes in vertical epidermal sections. The changes in melanocytes and keratinocytes during healing of a standard 1 cm full thickness wound in the guinea-pig were studied. After an initial decrease, more melanocytes per mm2 of epidermis were seen (from 36 days). These were smaller in volume with shorter, less branched dendrites compared to controls. An unexpected finding was a late phase of melanocyte proliferation, at the end of our study period (99 days). Clearly, the complex changes in the melanocyte-keratinocyte relationship during wound healing continue throughout and beyond the period of our study.