Tissue plasminogen activator reduces intraperitoneal adhesion after intestinal resection in rats

We investigated whether tissue plasminogen activator (tPA), a plasma serine protease that catalyzes the initial and rate-limiting step in fibrinolysis, inhibits postoperative intraperitoneal adhesion formation in rats. Male Wistar rats weighing 200 to 250 g underwent laparotomy with a 15-cm intestinal resection and reanastomosis; the intestinal serosa was scratched to induce adhesion formation. The rats were divided into three groups: the control group received no medication; the normal saline group received peritoneal irrigation with 6 mL normal saline intraoperatively; and the tPA group received peritoneal irrigation with 6 mL tPA solution (5 mg/L) intraoperatively. The rats were killed 7 or 14 days later. The scores (severity of adhesion, 0-3 point scale), strength, and extent of fibrous bands were recorded on the day the rats were killed. Wound strength was measured using an Instron tensionmeter immediately after the rats were killed. The concentrations of plasma tPA and plasminogen activator inhibitor (PAI)-1 and -2 were measured. The scores and strength of fibrous bands in the tPA group were lower than those in the control and saline groups whereas wound strength was similar in all groups. The plasma tPA concentration was significantly higher and the plasma PAI-1 and PAI-2 concentrations were significantly lower in the tPA group than in the control and saline groups on the 7th and 14th postoperative days. Our findings suggest that tPA can reduce the incidence of postoperative intraperitoneal adhesions without impairing wound healing.