不同后处理方式对脊髓缺血再灌注损伤保护作用的比较

Comparison of neuroprotective effect of two postconditioning methods on spinal cord ischemia- reperfusion injury in rats

目的比较机械后处理与他克莫司后处理对大鼠脊髓缺血再灌注损伤保护作用的差异。方法将雄性sD大鼠45只随机分为3组：缺血再灌注（IR）组、机械后处理（MP）组和他克莫司后处理（TP）组。IR组在脊髓缺血20min后行再灌注；MP组在再灌注即刻行30S再灌注／30S缺血，3个循环，余操作同IR组；TP组在再灌注即刻经左颈总动脉一次性注射他克莫司0．5ms／kg，余操作同IR组。再灌注1、3、7d应用Tarlov评分评价后肢运动功能，采用Westernblot法检测脊髓组织半胱氨酰天冬氨酸特异性蛋白酶（Caspase）．3表达变化。结果再灌注1、3、7dMP组运动功能评分值分别为1．75±0．23、2．67±0．35和3．06±0．27，TP组分别为1．62±0．41、2．46±0．33和3．09±0．22，均显著高于IR组（P〈0．05）；再灌注7d时TP组评分值高于MP组，但各时间点两组评分值之间差异无统计学意义（P〉0．05）。MP组和TP组脊髓组织Caspase．3蛋白表达在再灌注1、3、7d时分别为0．26±0．03、0．29±0．04、0．28±0．07和0．27±0．02、0．30±0．07、0．28±0．03，均明显低于IR组（P〈0．05）；各时间点TP组Caspase-3表达与MP组比较差异无统计学意义（P〉0．05）。结论两种后处理方式均可有效减轻大鼠脊髓缺血再灌注损伤，且他克莫司后处理具有与经典机械后处理相当的神经保护作用。

Objective To compare neuroprotective effect of mechanical postconditioning （MP） vs. tacrolimus postconditioning （TP） on spinal cord ischemia-reperfusion （IR） injury in rats. Methods Forty-five male SD rats were randomly divided into IR group, MP group and TP group. The model of spinal cord ischemia was established by means of catheterization through femoral artery and balloon dilatation. IR group underwent 20-min reperfusion after spinal cord ischemia. MP group received 3 cycles of 30-s reperfu- sioa/30-s ischemia at the onset of reperfusion. TP group experienced a single injection of taerolimus （0. 5 mg/kg） through the left common carotid artery at the onset of reperfusion. Tarlov scale was conduc- ted to evaluate hindlimb motor function, and Western blotting was applied to determine the expression of Caspase-3 in spinal cord at 1st, 3rd, and 7th day after reperfusion. Results The motor function scores of both MP and TP groups were significantly higher than those of IR group with 1.75 ±0. 23 and 1.62 ±0. 41 vs. 0.33±0.47 at lstday, 2. 67±0.35 and 2.46±0.33 vs. 1.53±0.44 at3rdday, and 3.06±0.27 and 3.09 ±0. 22 vs. 2. 54 ±0. 31 at 7th day respectively after reperfusion （P 〈0. 05）. There were no sig- nificant differences in the motor function scores between MP and TP groups at all observational time points （P 〉0.05） , though the score in TP group was higher than that in MP group at 7th day after reperfusion. The expression of Caspase-3 in spinal cord of both MP and TP groups was significantly lower than that of IR group with 0. 26 ± 0.03 and 0. 27 ± 0. 02 vs. 0. 32 ± 0. 06 at 1 st day, 0. 29 ± 0. 04 and 0. 30 ± 0. 07 vs. 0.40 ±0. 08 at 3rd day, 0. 28±0. 07 and 0. 28 ±0. 03 vs. 0. 39 ±0. 10 at 7th day respectively after reper- fusion （ P 〈 0. 05 ）. There were no significant differences in the Caspase-3 expression between MP and TP group at all observational time points （ P 〉 0. 05 ）. Conclusion Tacrolimus postconditioning possesses neuroprotective effect comparative to classic mechanical postconditioning, and both postconditioning meth- ods can alleviate spinal cord ischemia-reperfusion injury in rats.