人神经生长因子基因修饰的许旺细胞治疗脊髓损伤的实验研究

The experimental study of human nerve growth factor gene modified schwann cells for therapy of spinal cord injury

目的:观察神经生长因子(nerve growth factor,NGF)基因修饰的许旺细胞(Schwann cells,SCs)对大鼠脊髓损伤后运动功能恢复及GAP-43的表达情况,探讨其对脊髓损伤修复的作用机制。方法:清洁级SD大鼠52只,随机分为EGFP-N1-NGF转染许旺移植组16只(A组),许旺细胞移植组16只(B组),PBS对照组12只(C组)和假手术组8只(D组),用改良Allen法制造大鼠脊髓损伤模型。分别于术后7,14,21,28d用BBB评分法观察动物行为学的变化,用肌电图检测动物中枢传导速度和波幅;然后处死动物,取损伤区1cm范围脊髓节段,常规石蜡包埋,组织切片,GAP-43免疫组织染色观察脊髓损伤的组织学变化。结果:BBB评分结果D组>A组>B组>C组;肌电图检测结果显示中枢传导速度A、B、C组间差别有统计学意义P<0.05,D组明显高于其它三组;GAP-43免疫组化检测结果提示A>B>C组,D组仅有少量表达。结论:本研究证实NGF基因修饰的许旺细胞能够促进脊髓损伤的恢复,可能是促进神经轴突的生长有关。

Objective Nerve growth factor can promote the repair of peripheral nerve injury.Schwann cells may provide appropriate microenvrionment for repairing central nerve system. Object Schwann cells （SCs） which were modified by human nerve growth factor gene were injected into the injured spinal cord, the aim was to observe the functional recovery of hind limb and the expression of GAP-43 after spinal cord injury, and to explore the mechanism of SCs on the spinal cord injury. Methods 52 SD rats were divided into four groups randomly：EGFP-N1-NGF transfected SCs transplantation group （group A） 16 rats, SCs transplantation group （group B） 16 rats, PBS control group （group C） 12 rats and sham group（group D） 8 rats. The modified Allen method was used to make spinal coed injury（SCI） model.BBB scores were used to evaluate the behavior improvement and EMG to detect the velocity of the central nerve at 7 d,14 d,21 d and 28 d, respectively. Then the animals were killed and the SCI areas were embedded by paraffin, tissue section and immunostaining of GAP-43 to evaluate the histology recovery after spinal cord injury. Results The result of BBB scores is group D 〉 group A 〉 group B 〉 group C ; There is significantly difference between group A, B and C, but it were longer than group D for the velocity of the central nerve of EMG, the p value is lower than 0.05. Conclusion The immunostaining of GAP-43 showed that group A 〉 group B 〉 group C, the group D have little expression.Our study confirmed that NGF gene modified SCs could promote the recovery of spinal cord injury, probably by promoting the growth of the nerve axon.