[Controlled reperfusion of ischemic extremity musculature to prevent free radical induced lesions]

Tissue injury following reperfusion represents an essential problem of reconstructive vascular surgery. Pathogenetically toxic oxygen radicals are considered to play a pivotal role. Pharmacotherapeutical approaches are based particularly on antioxidants and vasodilators. However, a standardized regimen is not yet clinically introduced. In 48 adult Lewis-rats lower limb ischemia was induced by aortal cross-clamping. Following 3.5 hours of ischemia intravascular flushing perfusion via the distal aorta with a heparinized electrolyte solution (group B). Group C received additionally oxypurinol, group D alprostadil and group E sodium selenite into the flushing solution. At 4 hours recirculation was established. After 10 min, 30 min and 24 hours of reperfusion we determined lactate, creatine kinase, lactate dehydrogenase, urea, malondialdehyde and the laser Doppler flux. At the end of the experiments biopsies were taken from M. tibialis anterior. In comparison to control animals (group A) we observed an attenuation of reperfusion injury in the groups treated with flushing perfusion. Free oxygen radical reactions measured by malondialdehyde release were significantly reduced (30 min: A-209.1 +/- 45.4, B-127.3 +/- 36.9, C-113.2 +/- 14.1, D-99.6 +/- 24.5, E-123.6 +/- 11.2 mmol/l, p < 0.05). The laser Doppler flux measurements corresponded with the biochemical analyses (30 min: A-52.4 +/- 11.1, B-48.0 +/- 11.0, C-72.6 +/- 12.0, D-74.4 +/- 13.3, E-62.6 +/- 10.8% of baseline). Histologically, treatment with alprostadil (PGE1) and oxypurinol revealed superior results. Standardized intraarterial flushing perfusion with antioxidants and vasodilators reduces reperfusion injury. Clinical trials are urgently required to confirm the experimental findings and to optimize the therapy of extremity ischemia/reperfusion injury in humans.