Graded postischemic reoxygenation reduces lipid peroxidation and reperfusion injury in the rabbit spinal cord

The effect of graded postischemic reoxygenation on lipid peroxidation, neurological recovery and the degree of spinal cord damage after 20 min abdominal aorta ligature was tested in the rabbit. In comparison with normoxic recirculation, the graded postischemic reoxygenation (GPIR) during early phase of reperfusion (30 min) significantly reduced the level of lipid peroxidation products (LPP) in vivo and in vitro after 1 h survival. Neuropathological changes in animals with normoxic reperfusion showed gradual deterioration ranging from appearance of heavy argyrophilic neurons after 1 h reperfusion followed by neuronal necroses after 12 h survival to the development of an extensive spongy lesion reaching ventral horn and intermediate zone 2 days postoperatively. The neuroprotective effect of graded postischemic reoxygenation was evident even after 2 days survival with preserved structural integrity of the gray matter as confirmed by light and electron microscopy. The results indicate that graded postischemic reoxygenation during 1 h reperfusion can reduce lipid peroxidation and suppress irreversible neuronal damage using developing during the early reperfusion phase.