AMELIORATION OF POSTISCHEMIC REPERFUSION INJURY BY ANTIARRHYTHMIC DRUGS IN ISOLATED-PERFUSED RAT LUNG

Antiarrhythmic drugs, such as lidocaine, quinidine, and procainamide, have been shown to be effective against postischemic reperfusion injur y in isolated rat lungs. Rat lungs were perfused at a constant flow wi th Krebs-Henseilet buffer supplemented with 4% bovine serum albumin an d ventilated with air containing 5% CO2. The lungs were subjected to i schemia by slopping perfusion and ventilation for 60 min followed by 3 0 min of reperfusion. Lung injury was determined by measuring the incr ease in wet-to-dry lung weight ratio, while pulmonary arterial pressur e and peak airway pressure were calculated from the pre- and postische mic differences, Lidocaine, quinidine, and procainamide al doses of 5, 10, and 20 mg/kg body weight, respectively, were found to attenuate t he postischemic lung injury significantly (p<0.0001). The formation of cyclooxygenase products, which were elevated during reperfusion, was also significantly (p<0.0001) inhibited by these drugs. Since these an tiarrhythmic agents are found to be powerful scavengers of hydroxyl ra dicals and can prevent membrane lipid peroxidation, these findings sug gest that the antioxidant properties of these drugs may, in part, be r esponsible for protecting the lungs against reperfusion injury.