Repigmentation after burn injury in the guinea-pig.

The normal process of repigmentation of small partial- and full-thickness burn wounds in the guinea-pig has been studied visually, and by light microscopy and transmission electron microscopy of biopsy material, at various stages of healing. Repigmentation proceeded apace with re-epithelialization and occurred progressively from the periphery to the centre of the wound or scar. There was an initial lag period of 1 to 2 weeks post burn during which the melanocytes and melanin content of the regenerated epithelium were below or around normal control levels. Thereafter, the melanocytes and melanin were above normal levels and correlated with hyperpigmentation of the scar epithelium. Electron microscopy at 6 and 7 weeks post burn also confirmed the increased melanogenic and cytochrine activity of the melanocytes during this phase of burn healing.