Preoperative stress conditioning prevents paralysis after experimental aortic surgery: Increased heat shock protein content is associated with ischemic tolerance of the spinal cord

Background: All forms of surgical therapy are stressful and injurious. The problems of paralysis, renal dysfunction, and colonic ischemia associated with aortic occlusion are due to acute ischemia-reperfusion injury at the cellular level. Acute-anterior spinal cord ischemia is the most devastating outcome of these iatrogenic-ischemic events. The majority of surgical procedures are performed electively and therefore provide an opportunity to preoperatively condition the patient to minimize these ischemia-related morbidities. Objectives: We sought to determine whether acute spinal cord injury associated with aortic occlusion can be prevented by induction of the cellular stress response by means of preoperative administration of whole-body hyperthermia or stannous chloride. Methods: The study consisted of an experimental rabbit model of infrarenal aortic occlusion for 20 minutes at normothermic body temperature. Results: Control rabbits experienced an 88% (7/8) incidence of paralysis after spinal cord ischemia induced by 20 minutes of aortic occlusion, whereas animals treated preoperatively with either whole-body hyperthermia (0/9) or stannous chloride (0/4) never became paralyzed (P