THE INFLUENCE OF OXYGEN-FREE RADICAL SCAVENGERS ON THE REDUCTION OF MEMBRANE-ROUND NA-K+-ATPASE ACTIVITY-INDUCED BY ISCHEMIA-REPERFUSION INJURY IN THE CANINE KIDNEY()

The present study was designed to determine whether the administration of free radical scavengers, superoxide dismutase (SOD), catalase or d imethylsulfoxide (DMSO) is able to ameliorate ischemia/reperfusion inj ury in the canine kidney and also ascertain whether or not a relations hip exists between oxygen free radicals and membrane-bound Na+-K+-ATPa se activity. In 23 dogs, the vascular pedicle of the left kidney was c lamped for 75 min at room temperature. The experimental animals receiv ed free radical scavengers for 30 min starting at 2 min prior to reper fusion. Renal tissue specimens were enzyme-histochemically examined re garding the activity of membrane-bound Na+-K+-ATPase, and a marked red uction just before reperfusion was revealed. The SOD- and the DMSO-tre ated groups showed a marked recovery of the membrane-bound Na+-K+-ATPa se activity; however, the untreated and the catalase-treated groups st ill demonstrated a marked reduction 1 day after reperfusion. At the sa me time, widespread acute tubular necrosis in the cortex was observed in the untreated and catalase groups in comparison with the SOD and th e DMSO groups. In addition, the SOD and the DMSO groups significantly preserved better renal function. Based on these findings, it was thus concluded that free radical scavengers ameliorate the recovery of depr essed membrane-bound Na+-K+-ATPase activity and ischemia/reperfusion i njury in the canine kidney.