Co-application of ischemic preconditioning and postconditioning provides additive neuroprotection against spinal cord ischemia in rabbits

Postconditioning can induce cardioprotection against ischemia. However, the data on postconditioning of the spinal cord is very limited. We investigated here whether co-application of ischemic preconditioning (IPC) and postconditioning can provide additive neuroprotection against prolonged spinal cord ischemia. Spinal cord ischemia was produced in rabbits by infrarenal aortic occlusion with a balloon catheter for 30 min. The four treatment groups were control (n = 10): no intervention; IPC (n = 10): a 5-minute aortic occlusion was performed 20 min before the prolonged ischemia; Postcon (n = 10): postconditioning comprised of four cycles of 1-minute occlusion/1-minute reperfusion was applied one minute after the start of reperfusion. IPC + postcon (n = 11): both IPC and postconditioning were applied. Functional evaluation with Tarlov score was performed during a 14-day observation period. Neurologic impairment was noticeably attenuated in the IPC + postcon group (compared with the control group, P < 0.01, at day 1, day 2, day 7 and day 14, respectively), but not in either the IPC or Postcon group. Plasma malondialdehyde levels after reperfusion were significantly decreased to a similar extent in the IPC, Postcon and IPC + Postcon groups (compared with the control group (P < 0.01). In the IPC + Postcon group, many more large motor neurons were preserved than in the control group (P < 0.05) and white matter injury was also markedly attenuated as evidenced by reduction of the vacuolation area of the white matter (P < 0.01) and decreased amyloid precursor protein immunoreactivity (P < 0.01). From this, we conclude that the combination of IPC and postconditioning induces additive neuroprotective effects for spinal cord against ischemia and reperfusion injuries.