不同移植时间对胚胎脊髓源性神经干细胞体内分化为神经元影响的实验研究

The effect of different transplantation time for spinal cord-derived neural stem cells differentiating into neurons： a pilot study in vivo

目的探讨不同移植时间对胚胎脊髓源性神经干细胞体内分化为神经元影响，为胚胎脊髓源性神经干细胞移植防治骨骼肌失神经萎缩的最佳移植时间点的选择提供实验依据。方法从孕龄14dSD大鼠胚胎脊髓组织中分离、获得并鉴定脊髓源性神经干细胞。90只SD大鼠分为9组，分别于胫神经切断后0、1、2、3、4、6、8、12及16周，移植胚胎脊髓源性神经干细胞至切断胫神经远端神经外膜下，移植后4周取胫神经冰冻切片行免疫组化方法计数神经元数量并进行图像分析。结果损伤后1周移植时，神经元数量最多，其次为损伤后6周，损伤后16周组无神经元存在。结论对胚胎脊髓源性神经干细胞体内移植后分化为神经元影响最小的时间点是损伤后1周，因此我们可以推断胚胎脊髓源性神经干细胞移植防治骨骼肌失神经萎缩的最佳移植时间点是损伤后1周。

Objective In order to determine the optimal time of spinal cord-derived neural stem cell transplantation for preventing skeletal muscle denervation atrophy, we investigated the effect of different transplantation time on the differentiation of spinal cord-derived neural stem cells into neurons. Methods The spinal cord-derived neural stem cells of 14-day SD fetal rats were isolated and cultivated in serum-free media. They were then identified by cellular immunoeytoehemistry. A total of 90 SD rats were divided into 9 groups （ 10/ group）. The spinal cord-derived neural stem cells were transplanted into epineurium of the tibia/nerves 0, 1, 2, 3, 4, 6, 8, 12 and 16 week（s） after nerve transection respectively. Four weeks after the transplantation, the tibial nerves were harvested. The neurons were counted with frozen section and cellular immunoeytoehemistry. The images were analyzed by Leiea Q-win software. Results There were the most neurons in the group that the spinal cord-derived neural stem cells were transplanted into the epineurium of tibial nerves 1 week after nerve transection. The second most was the group in which they were transplanted 6 weeks after tibial nerve transection. There were no neurons in the group in which they were transplanted 16 weeks after tibial nerve transection. Conclusion Transplantation of spinal cord-derived neural stem coils 1 week after tibial nerve transection has the least impact on differentiation of the stem cells into neurons. Therefore the optimal time of spinal cord-derived neural stem cell transplantion for preventing skeletal muscle denervation atrophy is 1 week following nerve transection.