Protective Effect of Etomidate on Spinal Cord Ischemia–Reperfusion Injury Induced by Aortic Occlusion in Rabbits

We conducted a randomized controlled study on the neuroprotective effect of a commonly used anesthetic, etomidate, in an ischemia-reperfusion (IR) injury rabbit model.We studied 24 white adult Japanese rabbits at the animal facility at the Medical College of Wuhan University. Rabbits were randomly assigned into a sham-operation group (group I), an IR group (group II), and an etomidate-treated IR group (group III). Rabbits in groups II and III were subjected to 45 min of infrarenal aortic cross-clamping to induce spinal cord ischemia, while group I rabbits received the sham operation as a control. Following an initial single-dose intravenous injection at 0.6 mg/kg 10 min before aortic clamping, etomidate was infused intravenously at 3mg/(kg . hr) in group III rabbits until unclamping, while 0.9% saline was given as the control in group II.Changes in neurological function scores, histopathology, electromyography, malondialdehyde levels, superoxide dismutase activities, and the concentrations of Ca(2+), Mg(2+), Cu(2+), and Zn(2+) ions were measured. Compared with the sham-operation group, group II showed significant IR injury-associated changes in all parameters evaluated (p<0.01), whereas these unfavorable changes were significantly reversed in etomidate-treated animals (p<0.05 or p<0.01). No significant differences were observed between group I and group III animals in all parameters.Etomidate displayed a potent neuroprotective effect against IR-induced spinal cord injuries. We propose that this effect may be associated with the ability of etomidate to enhance the activities of endogenous antioxidants and maintain the ion balance in IR-affected tissues.