Tolerization against loss of neuronal function after ischemia–reperfusion injury

To investigate whether sublethal ischemia preserves neuronal function otherwise lost after stroke, anesthesized rabbits were subjected to clamping of abdominal aorta to cause lumbar spinal cord ischemia. An occlusion period of 12.5 min was followed 12 or 48 h later by a second occlusion for 30 min. When scored 24 h later for hindlimb function on a 0-6 scale, the rabbits that underwent tolerizing ischemia 12 h before infarction had better motor function (n = 7; 4.29 ± 0.21, p < 0.0001) than sham-operated controls (n = 7; 1.00 ± 0.27), but those infarcted at 48 h had mixed outcomes (n = 5; 2.20 ± 0.21, ns). In correlation, the proportion of neurons with histological evidence of damage was lower in the tolerized rabbits (0.15 ± 0.04) than in sham-operated controls (0.74 ± 0.09, p < 0.001). We conclude that ischemic tolerance also improves neurological function of infarcted spinal cord and could be studied for clinical application.