丹参注射液对急性脊髓损伤大鼠脊髓灰质GDNF mRNA的提高作用及其机制

目的观察丹参注射液对急性脊髓损伤（spinal cord injury，SCI）大鼠的脊髓灰质胶源性神经营养因子（glial cell line-derived neurotrophic factor，GDNF）的作用，并探讨其机制。方法将144只SD雄性大鼠制作成SCI模型，随机分为治疗组、对照组及SCI组（每组各48只），其中治疗组给予腹腔注射丹参注射液1．78mL，（kg·天）]，对照组腹腔注射大剂量甲基强地松龙30mg／（kg·23h），45min后按5．4mg／（kg·h）计算23h总量，分4次注射]，SCI组不予干预，此外另选48只SD雄性大鼠为假手术组（不损伤脊髓），进行伤后1、3、7及14天各组脊髓运动功能评估，检测以上时间点脊髓灰质GDNFmRNA表达。结果本实验造模成功率80．54％，脊髓损伤后14天内，治疗组出血、水肿以及神经元坏死等表现明显少于SCI组，与对照组没有明显区别。SCI组损伤后1、3、7、14天斜板试验临界角均低于假手术组同期（P〈0．01），GDNFmRNA阳性产物吸光度值高于假手术组同期（P〈0．01）；损伤后1天，治疗组斜板试验临界角低于治疗前（P〈0．01），治疗组斜板试验临界角及GDNFmRNA阳性产物吸光度值低于对照组同期（P〈0．05），高于SCI组同期（P〈0．01）；损伤后3天，治疗组GDNFmRNA阳性产物吸光度值高于损伤后1天及SCI组同期（尸〈0．01，P〈0．05），低于对照组同期（P〈0．05）；损伤后7天，治疗组斜板试验临界角高于损伤后3天及SCI组同期（P〈0．01），低于对照组（P〈0．05），治疗组GDNFmRNA阳性产物吸光度值高于SCI组同期（P〈0．01）；损伤后14天，治疗组斜板试验临界角高于损伤后7天（P〈0．01，P〈0．05），治疗组斜板试验临界角高及GDNFmRNA阳性产物吸光度值高于SCI组同期（P〈0．01）。结论丹参能减轻大鼠损伤脊髓的水肿、出血，改善脊髓微循环，从而提高SCI鼠脊髓灰质GDNFmRNA，是SCI早期理想的治疗药物。

Effects of Danshen Injection on Glial Cell Line derived Neurotrophic Factor mRNA of Acute Spinal Cord Injury Rats and Its Mechanisms

Objective To observe effects of Danshen Injection （DSI） on glial cell line-derived neu- rotrophic factor （GDNF） in the gray matter of acute spinal cord injury （SCI） rats and to discuss its mechanisms. Methods Totally 144 male SD rats were used to prepare the SCI model, and then they were randomly divided into three groups, i.e., the treatment group, the control group, and the SCI group, 48 in each group. Rats in the treatment group were intraperitoneally injected with DSI （at the daily dose of 1.78 mL/ kg）, those in the control group were intraperitoneally injected with methylprednisolone （at the dose of 30 mg/kg in 23 h, the 23-h total dose calculated according to 5.4 mg/kg per hour 45 min later; injected in 4 times）, but rats in the SCI group were not intervened. Besides, another 48 male SD rats were recruited as the sham-operation group （no injury of their spinal cords）. The spinal motor functions were assessed on the first day, the third day, the 7th day, and the 14th day after SCI. Their expressions of GDNF mRNA were detected at the aforesaid time points. Results The successful rate of modeling was 80.54% in this experiment. Within 14 days after SCI, bleeding, edema, and neuronal necrosis were obviously less in the treatment group than in the SCI group, but with no significant difference when compared with those of the control group. Compared with the sham-operation group at the same time points, the critical angle in the tiltboard test was smaller in the SCI group on the first day, the third day, the 7th day, and the 14th day after SCI. The density of GDNF mRNA immunoreactivity was higher in the SCI group than in the sham-operation group at the same time points （P 〈0.01 ）. On the 1st day after SCI, the critical angle in the tiltboard test was smal- ler in the treatment group after treatment than before treatment （P 〈0.01 ）. The critical angle and the densi- ty of GDNF mRNA immunoreactivity were lower in the treatment group than in the control group at the same time points （P 〈0.05）, but they were higher in the treatment group than in the SCI group at the same time points （P 〈0.01 ）. The density of GDNF mRNA immunoreactivity was higher in the treatment group on the 3rd day after SCI than on the 1st day after SCI, and than in the SCI group on the 3rd day after SCI （P 〈 0.01, P 〈0.05）. It was lower in the treatment group than in the control group on the 3rd day after SCI （P 〈 0.05）. The critical angle in the tiltboard test was higher in the treatment group on the 7th day after SCI than on the 3rd day after SCI, and than the SCI group on the 7th day after SCI （P 〈0.01 ）, but lower than the con- trol group （P 〈0.05）. The density of GDNF mRNA immunoreactivity was higher in the treatment group than in the SCI group on the 7th day after SCI （P 〈0.01 ）. The critical angle in the tiltboard test was higher in the treatment group on the 14th day after SCI than on the 7th day after SCI （P 〈0.01, P 〈0.05）. The critical an- gle and the density of GDNF mRNA immunoreactivity were higher in the treatment group than in the SCI group on the 14th day （P 〈0.01 ）. Conclusions Salvia miltiorrhiza could attenuate edema and bleeding in the gray matter of SCI rats, and improve the microcirculation of the spinal cord, thus elevating the GDNF mRNA expression in the gray matter of acute SCI rats. It was an ideal drug for treating early SCI.