OBJECTIVETo study the effect of vacuum-assisted closure (V.A.C) on the expression of Urokinase-type plasminogen activator (uPA) and Urokinase-type plasminogen activator receptor(uPAR) protein in margin tissue of pigs with acute wounds and patients with chronic wounds.

METHODSAcute wounds were created on the two side of five male pigs' back, the experiment wounds on one side received V. A. C treatment and the control side received traditional treatment. Punch biopsies were taken from margin tissue of the wounds in 0, 1, 3, 6, 9, 12, 18, 25 days after the V.A.C treatment. The uPA and uPAR positive cells were stained with immunohistochemical technique . Six human chronic wounds were also treated with the V. A. C treatment, and the samples of extravasate from those wounds were collected in 0, 1, 3, 5, 7 days after the treatment, and the levels of uPA and uPAR expression were examined by enzyme-linked immunosorbent assay (ELISA).

RESULTSThe expression of uPA and uPAR protein in margin tissues of pigs with acute wounds increased and peaked in 3 days after the treatment with V. A. C, then it presented rapidly downtrend, but the expression and staining in the experiment group were obviously higher than that of the control group. In the six chronic wounds, the high level expression of uPA and uPAR protein was decreased after the treatment with V. A. C.

CONCLUSIONThe V. A. C may increase the expression of uPA and uPAR protein in acute wound keratinocytes and decrease the high expression of uPA and uPAR in chronic wounds.