人参皂甙对大鼠急性脊髓损伤的保护作用及其机制

Study on the mechanism underlying neuroprotective effect of Ginsenosides in rats after spinal cord injury

目的探讨人参皂甙(Ginsenodides,Gs)对急性脊髓损伤的保护作用及其机制。方法采用改良Allen’s重物打击法制作急性脊髓损伤模型。大鼠随机分为对照组、损伤组和Gs治疗组。每组36只,分别于术后6h、12h、1d、3d、7d、14d完整取大鼠T9脊髓段。斜板实验和BBB行为学评分评价大鼠脊髓功能的恢复情况;TUNEL法标记脊髓组织凋亡细胞;Western blot方法检测B细胞淋巴瘤/白血病基因-2(Bcl-2)和Bcl伴随蛋白x(Bax)蛋白表达;RT-PCR方法检测半胱氨酸基天冬氨酸-特异性蛋白酶-3(Caspase-3)mRNA表达。结果损伤组和Gs组大鼠术后14d内脊髓功能均有不同程度恢复,Gs组恢复优于损伤组(P<0.05或P<0.01);损伤组大鼠脊髓TUNEL标记的阳性细胞数于术后3d达高峰,Gs组于相应各时间点均低于损伤组(P<0.01);术后各时间点Gs组大鼠脊髓Bcl-2蛋白表达高于损伤组(P<0.01),术后12h、1d、3d、7d、14dGs组大鼠脊髓Bax蛋白表达均低于损伤组(P<0.05或P<0.01);术后各时间点Gs组大鼠脊髓Caspase-3 mRNA表达低于损伤组(P<0.01)。结论通过提高Bcl-2/Bax比值并抑制Caspase-3 mRNA表达减少脊髓损伤后神经元凋亡是Gs对脊髓损伤后具有保护作用的可能机制之一。

Objective To study the effect of Ginsenosides on protecting the neuron after spinal cord injury. Methods Modified Allen impaction methods were used to establish spinal cord injury model in rats. Rats were randomly divided into three groups： control group, injury group and Ginsenosides group, 36 rats per each group. The rats were sacrificed at 6h, 12h, ld, 3d, 7d and 14d, and T9 spinal cord specimen was obtained. Parallel tilt plate test and BBB evaluation were performed to observe the outcome of neural functional recovery; TUNEL methods was used to detect the apoptosis cells in spinal cord; Western blot was used to detect the expression level of Bcl - 2 and Bax protein; RT - PCR was performed to detect the mRNA expression of Caspase - 3 in spinal cord. Results Some degree of neural functional recovery was found in injury group and Gs group during the 14 days observation, scores of Gs group were significantly higher than that of injury group （ P 〈 0.05 or P 〈 0.01 ） ; The TUNEL - positive ceils showed a maximum presence at 3d after surgery, and decreased significantly at every time point in Gs group compared with injury group （ P 〈 0.01 ） ; At every time point after surgery, the expression of Bcl protein in Gs group was higher than that in injury group （ P 〈0.01）, 12h,1d,3d,7d,14d after surgery, the expression of Bax protein in Gs group was lower than that in injury group （ P 〈 0.05 or P 〈 0.01 ） ; The mRNA expression of Caspase - 3 in Gs group were lower than that in injury group at every time point after surgery （ P 〈 0.01 ）. Conclusion Gs has the neuroprotective effect after spinal cord injury. Inhibiting apoptosis of neuron after spinal cord injury via enhancing the rate of Bcl - 2/Bax and impressing the mRNA expression of Caspase - 3 may be one of possible mechanisms.