Ischemic preconditioning protects against paraplegia after transient aortic occlusion in the rat

Background. Paraplegia can result from operations requiring transient occlusion of the thoracic aorta. A rat model of paraplegia with the characteristics of delayed paraplegia and transient ischemic dysfunction was developed to determine whether ischemic preconditioning (IPC) improved neurologic outcome. Methods. Rats underwent balloon occlusion of the upper descending thoracic aorta. One group (2 minute IPC, n = 19) underwent 2 minutes of IPC and a second group (5 minute IPC, n = 19) had 5 minutes of IPC 48 hours before 10 minutes of occlusion. The control group (n = 31) had no IPC prior to 10 minutes of occlusion. Results. Paraplegia occurred in 68% of the control animals (21 of 31 paraplegic: 6 delayed and 15 immediate paraplegia). Both the 2-minute IPC and 5-minute IPC groups had a decreased incidence of paraplegia when compared to controls (32%, p = 0.011 and 26%, p = 0.009, respectively). Conclusions. A rat model of spinal cord ischemia demonstrating both delayed paraplegia and transient ischemic dysfunction was characterized. Both 2-minute and 5-minute periods of IPC were found to protect against paraplegia. (C) 2000 by The Society of Thoracic Surgeons.