Gelatinase activity during wound healing.

The two known mammalian gelatinases, 72- and 92-kDa gelatinase, are extracellular matrix metalloproteinases (MMPs) with a potential role in wound healing. The gelatinase activity as a function of wound age was analysed in tissue extracts of partial- and full-thickness wounds in the skin of pigs, using two assay systems. Total gelatinase activity, assessed using a 3H-labelled gelatin assay, was highest in the early healing phases and then decreased as healing proceeded in both wound types. Gelatin zymography, which distinguishes the activities of the two gelatinases, showed that the 92-kDa (MMP-9) gelatinase essentially followed the same pattern as that of total gelatinase activity, whereas the activity of the 72-kDa gelatinase (MMP-2) remained fairly stable, although it was higher than in uninjured skin, over the experimental period, irrespective of wound type. In conclusion, the two gelatinases appear to have different functions in the wound healing process. The 72-kDa gelatinase (MMP-2) is important during the prolonged remodelling phase, whereas the 92-kDa gelatinase (MMP-9) is linked to the epithelialization process and early repair events.