IGF-1抑制SCI大鼠脊髓前角神经元凋亡的体内实验

Inhibitory effect of IGF-1 gene on motoneurons apoptosis in anterior horn after acute spinal cord injury in adult rats

目的:研究脂质体介导的胰岛素样生长因子-1(IGF-1)体内转基因对急性脊髓损伤神经细胞凋亡的干预作用。方法:雄性Wistar大鼠36只,使用半横断法制造脊髓损伤模型,随机分为IGF-1治疗组、模型组、空白对照组。将阳性脂质体LipofectAmine同重组质粒pcDNA-hIGF-1混合注入治疗组大鼠脊髓病灶,模型组大鼠在损伤区域注射pcDNA3.1、LipfectAmine和生理盐水混合液。利用免疫组化方法观察IGF-1蛋白表达,通过TUNEL染色进行凋亡细胞组织定量分析。BBB法进行动物肢体功能评分。结果:同模型组和空白对照组比较,治疗组神经细胞中IGF-1在伤后1和4周蛋白表达明显增加(P<0.05);TUNEL染色结果显示,治疗组神经细胞凋亡数目明显减少(P<0.05)。BBB评分结果显示,肢体功能BBB评分伤后1和4周时,治疗组(7.00±0.53、11.20±0.56)恢复明显优于对照组(4.40±0.49、8.70±0.44)(P<0.05)。结论:IGF-1体内转基因可减少急性脊髓损伤大鼠的神经细胞凋亡,对急性损伤后的脊髓具有保护作用。

Objective To identify the effect of insulin-like growth factor-1 （IGF-1） gene transfer on motoneurons apoptosis in anterior horn after acute spinal cord injury in adult rats. Methods Thirty-six male Wistar rats were randomly divided into 3 groups： IGF-1 group, model group and control group. The SCI models were made by cutting half spinal cord of rats on the T8 segment by ophthalmogy scissors. Lipofectamine and recombinant plasmid pcDNA-hIGF-1 complexes were injected into the injury spinal cord by microinjector in IGF-1 group while pcDNA3.1, LipfectAmine and saline were administered in model group. The expression of IGF-1 was detected by immunohistochemistry method, the apoptosis of the motoneurons in anterior horn was detected by TLINEL, and moting function of hindlimhs was evaluated hy BBB locomotor scale. Results Compared with model group and control group, the expression of IGF-1 was increased significantly （P〈0. 05）, the apoptotic cells were decreased significantly （P〈0. 05） in IGF-1 group. The BBB score in IGF-1 group at 1 week （7. 00±0. 53） and 4 week （11.20±0. 56） after spinal cord injury were higher than that in model group （4.40±0. 49, 8. 70±0.44） （P〈 0. 05）. Conclusion IGF-1 gene could reduce the motoneurons apoptosis in anterior horn after acute spinal cord injury in adult rats and protect the spinal cord of SCI rats.