嗅鞘细胞移植对坐骨神经切断后神经元的作用

目的研究嗅鞘细胞(olfactory ensheathing cells,OECs)移植对周围神经切断后脊髓及神经节内神经元的保护作用。方法SD大鼠55只,随机分为3个组:空白组5只、实验组及对照组各25只。行右侧坐骨神经切断,近端断端行肌肉内包埋,实验组和对照组分别予OECs及细胞培养液,空白组暴露神经后不作任何处理。术后1、2、3、7和14d,分批处死,行组织学观察及TUNEL标记观察神经元的改变。结果空白组术后14d均无阳性变化。大鼠坐骨神经切断后,脊髓及神经节内均有神经元凋亡发生。术后1、2、3d实验组细胞存活率分别为98.4%±6.5%、97.6%±6.5%及95.2%±6.7%,对照组分别为97.8%±6.7%、97.4%±6.4%及94.3%±6.8%,比较差异无统计学意义(P>0.05);7、14d实验组细胞存活率分别为92.4%±8.9%、87.7%±9.4%,较对照组87.4%±8.6%、83.4%±8.5%高,差异有统计学意义(P<0.05)。术后1、2d实验组及对照组脊髓前角运动神经元无细胞凋亡;3、7、14d实验组脊髓前角运动神经元凋亡指数分别为1.2±0.8、1.4±0.6及4.1±1.3,较对照组2.1±1.1、3.1±1.1、6.1±1.8低,差异有统计学意义(P<0.05)。术后1、2、3d神经节内细胞无凋亡;7d实验组神经节内的凋亡指数2.10±0.32,较对照组4.40±0.56低,差异有统计学意义(P<0.05);14d实验组神经节内的凋亡指数4.3±1.80与对照组6.70±2.50比较,差异无统计学意义(P>0.05)。结论周围神经损伤后脊髓及神经节内神经元有神经元凋亡发生,OECs移植对神经元凋亡有保护作用。

EFFECT OF OLFACTORY ENSHEATHING CELLS TRANSPLANTATION ON PROTECTING SPINAL CORD AND NEURONS AFTER PERIPHERAL NERVE INJURY

OBJECTIVE: To study the effect of olfactory ensheathing cells (OECs) transplantation on protecting spinal cord and neurons after peripheral nerve injury. METHODS: Fifty-five SD rats were randomly divided into blank group (n = 5), experimental group (n = 25) and control group (n = 25). The right sciatic nerves of all the rats were transected. The proximal end was embedded in muscle and treated with OECs (experimental group) and DMEM (control group). No treatment was given to the blank group. The rats were sacrificed 1, 2, 3, 7, and 14 days after the transplantation, the related neurons were observed with histological and TUNEL methods. RESULTS: After sciatic nerves were transected, death of neurons occurred in spinal cord and ganglion. One, 2, 3 days after treatment, the neuron survival rate in experimental group was 98.4% +/- 6.5%, 97.6% +/- 6.5%, 95.2% +/- 6.7% respectively. The neuron survival rate in control group was 97.8% +/- 6.7%, 97.4% +/- 6.4%, 94.3% +/- 6.8% 1, 2, and 3 days after treatment respectively. There was no significant difference between experimental group and control group. Seven and 14 days after treatment, the neuron survival rate in experimental group was 92.4% +/- 8.9%, 87.7% +/- 9.4% respectively. The neuron survival rate in control group was 87.4% +/- 8.6%, 83.4% +/- 8.5% 7 and 14 days after treatment respectively. There was significant difference between experimental group and control group. On 1st and 2nd day, no apoptosis was seen in spinal cord anterior horn of the rats in both experimental group and control group. On 3rd, 7th, and 14th day, the apoptosis index of spinal cord anterior horn motoneuron in experimental rats were lower (1.2+/-0.8, 1.4 +/- 0. 6, 4.1 +/- 1. 3) than that in the control group (2.1 +/- 1.1, 3.1 +/- 1.1, 6.1 +/- 1.8) (P < 0.05). One, 2, and 3 days after the operation, no ganglion neurons apoptosis was observed in all rats. On 7th day the apoptosis index of ganglion neurons in experimental group(2.10 +/- 0.32) were lower than that in control group (4.40+/-0.56) (P<0.05). On 14th day there was no significant difference in the apoptosis index of ganglion neurons between experimental group (4.30+/-1.80) and control group (6.70 +/- 2.50) (P<0.05). CONCLUSION: Apoptosis of neurons occur after peripheral nerve injury in spinal cord and ganglion. OECs transplantation is effective in preventing apoptosis.