Effects of the treatment with glibenclamide, an ATP-sensitive potassium channel blocker, on intestinal ischemia and reperfusion injury

Intestinal ischemia and reperfusion injury is dependent on the recruitment and activation of neutrophils. Glibenclamide, an ATP-sensitive potassium channel (K(ATP)) blocker, has been shown to suppress neutrophil migration and chemotaxis during acute inflammatory responses by a mechanism dependent on its K(ATP) channel blocking activity. In the present study, we evaluated whether the treatment with glibenclamide prevented local, remote and systemic injury following reperfusion of the ischemic superior mesenteric artery in rats. The artery was made ischemic for a period of 30 or 120 min followed by 30 (mild I/R) or 120 (severe I/R) min of reperfusion, respectively. Glibenclamide (0.8 to 20 mg/kg) or vehicle was administered subcutaneously 40 min prior to the reperfusion. Glibenclamide dose-dependently inhibited the reperfusion-associated increase in vascular permeability and neutrophil accumulation in mild I/R. In the severe injury model, glibenclamide inhibited inflammatory parameters, as assessed by Evans blue extravasation, neutrophil influx and haemoglobin content, and the increase in TNF-alpha (tumor necrose factor-alpha) and IL (interleukin)-6 levels in the intestine and lung. The drug did not affect the increase in IL-1beta and IL-10 levels. TEA, a nonselective potassium channel blocker, also inhibited reperfusion injury in both intestine and lungs of animals submitted to mild and severe I/R. Our experiments suggest a role for K(ATP) channels in mediating neutrophil influx and consequent reperfusion-associated injury in rats. The lack of effect of these drugs on the reperfusion-associated hypotension and lethality may limit their usefulness after severe reperfusion injury.