Effect of dexmedetomidine on cell apoptosis during spinal cord ischemia-reperfusion in rats / 中华麻醉学杂志

ABSTRACT

Objective To evaluate the effect of dexmedetomidine on cell apoptosis during spinal cord ischemia-reperfusion(I∕R)in rats. Methods Forty-eight adult male Wister rats, weighing 200-260 g, were divided into 4 groups(n=12 each)using a random number table sham operation group (Sham group), I∕R group, prophylactic dexmedetomidine use group(DPro group)and dexmedetomidine postconditioning group(DPost group). The model of spinal cord I∕R was established by temporary occlu-sion of the abdominal aorta using the modified Zivin′s method. Dexmedetomidine 5 μg·kg-1·h-1was in-travenously infused at 1 h before occlusion of the abdominal aorta in group DPro. Dexmedetomidine 5 μg·kg-1·h-1was intravenously infused for 1 h starting from the time point immediately after beginning of reperfusion in group DPost. The equal volume of normal saline was given instead in Sham and I∕R groups. The motor nerve function of the hindlimb was assessed and scored at 4, 12 and 24 h of reperfusion. The rats were sacrificed at 24 h of reperfusion, and L2-5segments of the spinal cords were removed for microscopic examination and for determination of Bcl-2 and Bax positive cells(by immuno-histochemistry)and cell ap-optosis(by flow cytometry). The apoptosis rate was calculated. Results Compared with group Sham, motor nerve function scores were significantly decreased at 4-12 h of reperfusion, and the apoptosis rate of nerve cells and Bcl-2 and Bax positive cells were increased in group I∕R, and motor nerve function scores were significantly decreased at 4 h of reperfusion, and the apoptosis rate of nerve cells and Bcl-2 and Bax positive cells were increased in DPro and DPost groups(P<005 or 001). Motor nerve function scores were significantly higher, and the apoptosis rate of nerve cells was lower, Bcl-2 positive cells were higher, and Bcl-2 and Bax positive cells were lower in DPro and DPost groups than in group I∕R(P<005 or 001). Conclusion The mechanism by which dexmedetomidine reduces spinal cord I∕R injury is related to inhibiting cell apoptosis in rats.