Attenuation of spinal cord ischemia and reperfusion injury by erythropoietin.

Background: Paraplegia remains a devastating complication for patients undergoing thoracic aortic procedures. Although surgical adjuncts have evolved to reduce the risk of paraplegia, no pharmacologic therapies have proven efficacious in attenuating spinal cord ischemia-reperfusion injury. Effects of erythropoietin in spinal cord ischemia-reperfusion injury, however, have not yet been elucidated. We hypothesized that pretreatment with erythropoietin would attenuate functional and cytoarchitectural spinal cord injury related to high-risk aortic procedures.

Methods: Adult male mice were subjected to ischemia-reperfusion. Aortic arch and proximal left subclavian arteries were clamped for 5 minutes; animals were observed for 48 hours. Neurologic scores of hind limb function were assessed every 12 hours. Experimental groups consisted of treatment with erythropoietin 4 hours before crossclamping (n = 7), ischemic controls (n = 7), and sham ischemia (operation without crossclamping, n = 6). Thoracolumbar sections of spinal cord were removed after 48 hours and preserved for cytoarchitectural analysis.

Results: Mice pretreated with erythropoietin exhibited significant preservation of hind limb motor function. All mice without pretreatment were paralyzed at 48 hours. Mice with erythropoietin pretreatment had improved motor function; 3 had no measurable neurologic deficit at 48 hours. Histologic analysis in mice treated with erythropoietin showed markedly reduced neuronal cell injury.

Conclusions: Erythropoeitin preserves both function and histologic appearance in mice undergoing spinal cord ischemia-reperfusion. With further elucidation of mechanisms of protection and optimal administration, erythropoietin could become an important adjunct in reducing the incidence and severity of spinal cord injury related to aortic interventions.