Tetramethylpyrazine attenuates spinal cord ischemic injury due to aortic cross-clamping in rabbits.
BACKGROUND
Lower limb paralysis occurs in 11% of patients after surgical procedure of thoracic or thoracoabdominal aneurysms and is an unpredictable and distressful complication. The aim of this study was to investigate the effects of tetramethylpyrazine (TMP), an intravenous drug made from traditional Chinese herbs, on the neurologic outcome and histopathology after transient spinal cord ischemia in rabbits.


METHODS
Forty-five male New Zealand white rabbits were anesthetized with isoflurane and spinal cord ischemia was induced for 20 min by infrarenal aortic occlusion. Animals were randomly allocated to one of five groups (n = 8 each). Group C received no pharmacologic intervention. Group P received intravenous infusion of 30 mg x kg(-1) TMP within 30 min before aortic occlusion. Group T1, Group T2 and Group T3 received intravenous infusion of 15, 30 and 60 mg x kg(-1) TMP respectively within 30 min after reperfusion. In the sham group (n = 5), the animals underwent the same procedures as the control group except infrarental aortic unocclusion. Neurologic status was scored by using the Tarlov criteria (in which 4 is normal and 0 is paraplegia) at 4 h, 8 h, 12 h, 24 h, and 48 h after reperfusion. All animals were sacrificed at 48 h after reperfusion and the spinal cords (L5) were removed immediately for histopathologic study.


RESULTS
All animals in the control group became paraplegic. Neurologic status and histopathology (48 h) in the Groups P, T2 and T3 were significantly better than those in the control group (P < 0.05). There was a strong correlation between the final neurologic scores and the number of normal neurons in the anterior spinal cord (r = 0.776, P < 0.01).


CONCLUSIONS
Tetramethylpyrazine significantly reduces neurologic injury related to spinal cord ischemia and reperfusion after aortic occlusion within a certain range of dose.
Chen
Shaoyang
S
Department of Anesthesiology, Xijing Hospital, Fourth Military Medical University, Xi'an ShaanXi, 710032, China. chensy@fmmu.edu.cn
Xiong
Lize
L
Wang
Qiang
Q
Sang
Hanfei
H
Zhu
Zhenhua
Z
Dong
Hailong
H
Lu
Zhihong
Z
D000818:Animals; D000894:Anti-Inflammatory Agents, Non-Steroidal / Q000494:pharmacology; D001011:Aorta / Q000502:physiology; D002452:Cell Count; D003250:Constriction; D004195:Disease Models, Animal; D004305:Dose-Response Relationship, Drug; D008297:Male; D009043:Motor Activity / Q000187:drug effects; D009460:Neurologic Examination; D009474:Neurons / Q000187:drug effects / Q000473:pathology; D010264:Paraplegia / Q000209:etiology / Q000517:prevention & control; D011719:Pyrazines / Q000494:pharmacology*; D011817:Rabbits; D013116:Spinal Cord / Q000098:blood supply / Q000187:drug effects* / Q000473:pathology; D020760:Spinal Cord Ischemia / Q000188:drug therapy* / Q000209:etiology / Q000473:pathology; D019616:Thoracic Surgical Procedures / Q000009:adverse effects; D016896:Treatment Outcome
D000894:Anti-Inflammatory Agents, Non-Steroidal; D011719:Pyrazines; C017953:tetramethylpyrazine