神经干细胞移植对大鼠脊髓损伤后Caspase-3和c-fos表达的影响

Effects of neural stem cell transplantation on expressions of Caspase-3 and c-fos after injury of rat spinal cord

目的研究神经干细胞移植对大鼠脊髓损伤后Caspase-3和c-fos表达的影响。方法 SD大鼠45只,随机分成3组(n=15):假手术组、脊髓损伤模型组(模型组)和神经干细胞移植组。假手术组仅打开锥板但不离断脊髓;模型组动物锥板打开后横向断开脊髓,止血并逐层缝合;神经干细胞移植组椎板打开后横向断开脊髓,止血并注入神经干细胞悬液,再逐层缝合。手术后1、2、3和14 d对大鼠进行神经功能评分(BBB评分)。14 d后处死动物,取脊髓组织,部分用于制备切片并进行TUNEL标记,检测神经细胞(神经元)的凋亡;对另一部分脊髓组织进行蛋白提取,Western blotting检测Caspase-3和c-fos蛋白的表达。结果与假手术组相比,模型组和神经干细胞移植组BBB评分均显著下降(P<0.05);但神经干细胞移植组神经功能改善情况好于模型组(P<0.05)。模型组和神经干细胞移植组的细胞凋亡率均显著高于假手术组(P<0.05);神经干细胞移植组细胞凋亡率明显低于模型组(P<0.05)。Western blotting检测结果显示,模型组和神经干细胞移植组大鼠脊髓组织中Caspase-3和c-fos的表达量显著高于假手术组(P<0.05);神经干细胞移植组大鼠脊髓组织中Caspase-3和c-fos的表达量显著低于模型组(P<0.05)。结论在大鼠脊髓损伤后,神经干细胞移植能够加快大鼠损伤后的恢复并降低细胞凋亡率,使Caspase-3和c-fos的表达量减少,对大鼠脊髓损伤具有治疗作用。

Objective To investigate the effects of neural stem cell transplantation on Caspase-3 and c-fos expressions after injury of rat spinal cord. Methods A total of 45 SD rats were randomly divided into 3 groups（ n= 15）, i. e. the sham operation group, spinal cord injury model group（ model group）, and neural stem cell transplantation group. The cone plate of the sham group was opened without transecting the spinal cord. The cone plate of the model group was opened; the spinal cord was transected; and suture was conducted layer by layer after hemostasis. The cone plate of the neural stem cell transplantation group was opened; the spinal cord was transected;and suture was conducted layer by layer after hemostasis and injection of the neural stem cell suspension. BBB rating was performed for rats 1, 2, 3, and 14 d after surgery. Rats were sacrificed 14 d after surgery and spinal cord tissues were removed. TUNEL labeling was conducted for sections of spinal cord tissue and the neuronal apoptosis was detected. Protein extraction was performed for spinal cord tissues and the expressions of Caspase-3 and c-fos proteins were detected by the Western blotting. Results The scores of BBB rating of the model group and neural stem cell transplantation group were significantly lower than that of the sham operation group（ P〈0. 05）, while the improvement of neural function of neural stem cell transplantation group was better than that of the model group（ P〈0. 05）. The apoptotic rates of the model group and neural stem cell transplantation group were significantly higher than that of the sham operation group（ P〈0. 05）. The apoptotic rate of the neural stem cell transplantation group was significantly lower than that of the model group（ P〈0. 05）. The results of Western-blotting showed that the expressions of Caspase-3 and c-fos in the spinal cord tissue of the model group and neural stem cell transplantation group were significantly higher than those of the sham operation group（ P〈0. 05）, while the expressions of Caspase-3 and c-fos in the spinal cord tissue of the neural stem cell transplantation group were significantly lower than those of the model group（ P〈0. 05）. Conclusion Neural stem cell transplantation can accelerate the recovery; decrease the apoptotic rate; down-regulate the expressions of Caspase-3 and c-fos after the spinal cord of rat is injured; and has the therapeutic effect on spinal cord injury of rats.