黄芪对大鼠实验性脊髓损伤的神经保护作用

Neuro-protective effect of astragalus root on experimental injury of spinal cord in rats

目的:观察黄芪对脊髓损伤后脂质过氧化的抑制作用,探讨黄芪对大鼠脊髓损伤的影响。方法:实验于2004-03/2004-05在吉林大学第二医院中心实验室完成。采用改良Allen’s法制作脊髓损伤模型,40只SD大鼠随机分为两组:对照组(n=20)为单纯脊髓损伤,术后腹腔注入适量生理盐水;实验组(n=20)为脊髓损伤加黄芪注射液(成都地奥九鸿制药厂产品,黄芪含量为2g/mL)腹腔注射,注射后4h、8h、24h每组随机取3只动物切取损伤区1cm脊髓节段,分别采用黄嘌呤氧化法和硫代巴比妥酸化学发光法测定线粒体超氧化物歧化酶活性和丙二醛浓度;于损伤后4周,将动物麻醉后处死,以40g/L多聚甲醛行心室-主动脉灌注,取脊髓损伤区7μm标本,光镜观察损伤脊髓的组织病理学改变;同时进行神经功能评分(神经功能恢复率=评分/正常分×100%)和斜板实验评估用药后黄芪对运动功能的影响。结果:40只SD大鼠,均进入结果分析。①对照组大鼠脊髓内丙二醛的浓度不断升高,超氧化物歧化酶活性急剧下降,实验组腹腔注射黄芪注射液后脊髓内丙二醛浓度降低,超氧化物歧化酶活性升高。实验组与对照组之间在伤后各时相点(4,8,24h)的丙二醛浓度和超氧化物歧化酶活性均存在显著性差异(t=6.256,8.212,9.254;3.215,8.721,10.324;P<0.01)。②脊髓损伤后两组大鼠神经功能恢复率逐渐升高,到3周末实验组和对照组之间神经功能恢复率具有显著性差异犤(42.2±18.5)%,(18.5±6.3)%,t=12.243,P<0.05犦。③脊髓损伤3周后,实验组同对照组之间的斜板试验结果差异存在显著性犤(58.6±5.2)°,(50.5±6.8)°,t=5.872,P<0.05犦。④实验组和对照组损伤脊髓的组织病理切片均可见神经细胞坏死,炎性细胞浸润,微小空腔形成。但实验组较对照组的水肿减轻,坏死区范围减小。结论:黄芪可以抑制脊髓损伤后的脂质过氧化反应,减轻脊髓继发性损害,促进脊髓损伤后的神经功能恢复,从而发挥神经保护作用。

AIM： To observe the effect of astragalus root （AR） on lipid peroxidation after spinal cord injury （SCI） and investigate the neuro-protective effect of AR on the spinal cord injury in rats. METHODS： The experiment was completed at the CentralLaboratory of the Second Hospital of Jilin University from March to May 2004. By the modified Allen＇s method, the model of SCI was established, and 40 SD rats were divided randomly into control group （n=20） and experimental group （n =20）. Rats in control group were pure SCI and injected intraperitoneal with proper saline after treatment; but rats in experimental group were SCI and injected intraperitoneal with AR parenteral solution （provided by Chengdu Di＇ao Jiuhong Pharmacy Factory, 2 g/mL AR）. Four, 8 and 24 hours after injection, 3 rats were randomly selected from each group to cut off 1 cm segment of spinal cord in injured area; meanwhile, activity of supercxide dismutase （SOD） and concentration of ma/ondialdehyde （MDA） of the spinal cord tissue were measured with xanthine oxidation method and TBA chemiluminescence method. Four weeks after injury, rats were sacrificed under anesthesia and perfused with 40 g/L citromint through first aorta of ventricle to obtain 7 μm sample in SCI area. The pathological changes were observed with light microscope; meanwhile, nerve function score （nerve functional recovery rate=score/ normal socre×100%） and inclined plane test were performed. RESULTS： Totally 40 rats entered the final analysis, ①The concentration of MDA in the injured tissue was increased in control group, and the activity of SOD was decreased. In experimental group, the concentration of MDA in the injured tissue was decreased, but the activity of SOD was increased. It was significant difference that the concentration of MDA and activity of SOD at different time point （4, 8 and 24 hours） after injury between experimental group and control group （t=6.256, 8,212, 9.254; 3.215, 8.721, 10.324, P 〈 0.01）.② The nerve function recovery rates of two groups were increased gradually, at three week end after injury, there was significant difference between experimental group and control group [（42.2±18.5）%, （18.5±6.3）%, t=12.243, P 〈 0.05]. ③The angle of inclined test of two groups was increased gradually, at three week end -after injury, there was significant difference between experimental group and control group [（58.6±5.2）° （50.5±6.8）°, t=5.872, P 〈 0.05]. ④ Nerve cell necrosis, inflammatory cell infiltration and mierocyst could be observed in two groups, but the edema degree and injured zone in experiment group was less than those in control group. CONCLUSION： Astragalus root can inhibit the lipid peroxidation after spinal cord injury, alleviate the second injury of spinal cord, improve the nerve function and thus showes a promising neuro-protective effect.