Additive effect of tetramethylpyrazine and deferoxamine in the treatment of spinal cord injury caused by aortic cross-clamping in rats

Study design: Tetramethylpyrazine and deferoxamine are effective agents for nerve injury. Experiments in a Sprague-Dawley rat model of spinal cord injury were performed. Objectives: This study investigated the effects of tetramethylpyrazine and deferoxamine on neurological outcome and spinal cord hisotpathology after transient spinal cord ischemia in rats. Setting: Chongqing Medical University and Third Military Medical University, Chongqing, China. Methods: Spinal cord ischemia was induced in Sprague-Dawley rats by infrarenal aortic occlusion for 30 min followed by 72 h of reperfusion. Animals were divided into a sham group with a sham procedure; control group with aortic occlusion, but no pharmacological intervention applied; and treatment group with aortic occlusion, treated with tetramethylpyrazine and deferoxamine. After 72 h of reperfusion, neurological status was evaluated in the animals. A histopathological study of spinal cords was performed, and glutamate level and metabotropic glutamate receptor-1 (mGluR1) mRNA expression were determined. Results: All animals in the control group were completely paraplegic with 0% recovery. Tarlov criteria were significantly better in the animals treated with tetramethylpyrazine and deferoxamine than that in the control group (P<0.05). Functional parameters were fully correlated with the morphological findings. Glutamate level was elevated in the control group, whereas it was significantly supressed in animals treated with tetramethylpyrazine and deferoxamine treatment. The infrarenal artery occlusion significantly elevated the expression of mGluR-1 mRNA, whereas tetramethylpyrazine and deferoxamine greatly supressed the expression of mGluR-1 mRNA. Conclusion: The combination of tetramethylpyrazine and deferoxamine significantly reduced the incidence of paraplegia induced by spinal cord ischemia/reperfusion. Spinal Cord (2011) 49, 302-306; doi: 10.1038/sc.2010.113; published online 14 September 2010