Metallothioneins: potential therapeutic aids for wound healing in the skin.

Metallothioneins are a family of low molecular weight proteins containing approximately 30 % cysteine. Expression of the metallothionein gene is up-regulated in the skin following topical application of zinc and copper, and in wound margins particularly in regions of high mitotic activity. This induction of metallothionein in the wound margin may reflect its role in promoting cell proliferation and reepithelialiation. The action of metallothioneins in these processes may result from the large number of Zinc-dependent and copper-dependent enzymes required for cell proliferation and matrix remodeling. In addition, selected growth factors may modulate metallothionein gene expression and hence the ability of cells to proliferate. Recent studies suggest that metallothioneins may be an attractive target for development as vulnerary agents.