甘草酸二铵对大鼠脊髓缺血再灌注损伤后运动神经元Caspase-3表达的影响

The effect of diammonium glycyrrhizinate on the expression of caspase-3 in rat spinal cord after ischemia-reperfusion injury

目的:观察甘草酸二铵(DG)对大鼠脊髓缺血再灌注损伤后脊髓前角运动神经元Caspase-3表达的影响。方法:60只大鼠随机分为3组,每组20只。两组采用手术夹闭大鼠左右肾动脉之间的腹主动脉30min致脊髓缺血,然后松开再灌注,其中一组在缺血前10min舌下静脉注射DG20mg/kg(DG干预组),一组仅造成脊髓缺血损伤(损伤组);另一组打开腹腔后即关腹,不进行缺血再灌注(正常对照组)。分别于术后3、24、72、16 8h处死大鼠取腰段脊髓行免疫组化染色,观察脊髓前角Caspase-3光密度变化情况;72、168h处死动物前先采用Behrmann 5点评分法评定大鼠后肢功能。结果:损伤组与干预组72h时后肢功能评分分别为4.2±0.45分、5.8±1.1分;168h时分别为5±0分、6.2±1.3分,两组相同时间比较有显著性差异。Caspase-3表达位于脊髓前角运动神经元胞浆。术后3、24、72、168h,正常对照组前角运动神经元的平均光密度为0.13±0.04、0.15±0.06、0.13±0.06、0.15±0.06,损伤组为0.18±0.04、0.18±0.03、0.20±0.04、0.20±0.05,DG干预组为0.17±0.06、0.15±0.02、0.16±0.04、0.15±0.02,损伤组各时间点与对照比较均有显著性差异,DG干预组在24、72、168h与损伤组比较差异有显著性。结论:DG可下调凋亡信号转导通路中Caspase-3的表达水平,从而抑制脊髓前角神经元凋亡的发生。

Objective：To investigate the effect of diammonium glycyrrhizinate（DG） on expression of caspase- 3 in rat eomuanterius medullae spinalis using isehemia reperfusion injury model.Method：60 rats were divided into blank group,control group and DG treated group,each group contains 20 rats.The protocol was estab- lished by intercepting rat abdominal aorta between right and left renal alter branches for 30rain.The animals in DG treated group were injected DG 20mg/kg 10min via Vena suhlingualis prior to isehemia start,the con- trol group received nothing for ischemia-reperfusion injury,while the blank group received the procedure of open abdomen without introduction of ischemia-reperfusion injury.The expression of caspase-3 optical density in comuanterius medullae spinalis were measured at 3th ,24th,72th ,168th hour time-point respectively,and the socre of limb function at 72th,168th hour were evaluated using Behrmann method prior to testing the caspase-3 expression.Result：The mean score of limb function were 4.2±0.45 and 5±0 for blank group and DG intervention group at 72th hours time point , 5.8 ±l .1 and 6.2±1.3 at 168th hour time pointrespectively, which had significant difference.Caspase-3 was expressed in cytolymph of motor neuron at 3th ,24th,72th and 168th time point respectively.At 3th,24th,72th and 168th time point,the average level of caspase-3 optical density in blank group were 0.13±0.04,0.15±0.06,0.13±0.06,0.15±0.06,while 0.18±0.04,0.18±0.03,0.20±0.04, 0.20±0.05 in control group,and 0.17±0.06,0.15±0.03,0.16±0.04 in DG intervention group.There was statistical significance between groups at each time point.Conclusion：DG can down-regulate the level of easpase -3 in signal transduction pathway,which is useful in protecting the spinal cord in isehemia-reperfusion.