嗅鞘细胞移植结合步行训练对脊髓挫伤大鼠神经功能的影响

The effect of olfactory ensheathing cell transplantation combined with walking training on neurofunction recovery in rats after spinal cord contusion

目的 探讨嗅鞘细胞移植结合步行训练对脊髓挫伤大鼠神经功能的影响.方法 （75±1）d雌性SD大鼠40只分为A、B、C、D 4组,制作脊髓挫伤模型后,A组行嗅鞘细胞移植结合步训练,B组行嗅鞘细胞移植,C组行步行训练结合改良Eagle培养基（DMEM）注射,D组行 DMEM注射.细胞移植和DMEM注射在造模后2周进行,步行训练利用大鼠活动平板进行,自伤后1周开始,每周5 d,每天1次,每次15～30 min,共训练10周.造模后每周利用BBB评分观察大鼠后肢运动功能,移植后9周取材,取脊髓行相关指标的免疫化学染色.结果 ①与D组比较,A组和C组大鼠后肢BBB评分自伤后第4周始出现明显改善,B组仅在伤后第5～8周出现明显改善;伤后第11周末时,A、B、C、D组大鼠后肢BBB评分分别为（13.14±0.24）、（11.64±0.56）、（12.29±0.64）和（11.07±0.84）,A组较其它三组明显增高.②各组腰段脊髓切片TH阳性神经元计数差异无统计学意义（P＞0.05）,但A组和C组横切片上Ⅶ～Ⅸ层可见胞体较大和较小、轮廓清楚的两种TH阳性神经元,而B组和D组则仅出现胞体较小的神经元.结论 嗅鞘细胞移植结合步行训练可明显改善脊髓挫伤大鼠神经功能.

Objective To explore the effect of olfactory ensheathing cell （OEC） transplantation combined with walking training on neurofunction recovery in rats after spinal cord contusion. Methods Forty adult female rats aged （75 ± 1 ） days were subjected to experimental spinal cord contusion at the T10 level using a New York University impactor at a height of 25 mm. They were then divided into 4 groups： （ 1 ） an OEC transplantation combined with walking training （OEC-walking training） group, （2） an OEC transplantation （OEC） group, （3） a walking training combined with Dulbecco＇s modified Eagle medium injection （DMEM） （walking training-DMEM） group, and （4） aDMEM injection （SCI-DMEM） group. The OEC transplants and DMEM injections were performed 2 weeks post-injury. Walking training began at the 7th day post-injury and consisted of daily sessions （once daily, 5 days a week for 10 weeks） of quadrupedal treadmill training, starting from 15 min and gradually increasing to 30 min daily, at speeds starting from 3 m/min and gradually increasing in accordance to the condition of the rats. Locomotor function recovery of the rats＇ hindlimbs was evaluated weekly using the Basso, Beattie and Bresnahan （BBB） locomotor rating scale.The expression of tyrosine hydroxylase （ TH ） was detected in the injured region of the lumbar spinal cord. Results The BBB scores of rats in the OEC-walking training group and the walking training-DMEM group improved significantly from the 4th week post-injury compared to the SCI-DMEM injection group. Rats in the OEC transplantation group had a significant improvement in BBB scores at the 5th to 8th weeks post-injury. At the end of the 11th week post-injury, the average BBB scores were 13.14 ± 0.24 in the OEC-walking training group, 11. 64 ± 0.56 in the OEC transplantation group, 12.29 ±0.64 in the walking training-DMEM group and 11.07 ± 0.84 in the SCI-DMEM group.The OEC-walking training group scored significantly higher than the other 3 groups. Although the number of TH-positive neurons in the lumbar spinal cord was not significantly different among the groups, the morphology of TH-positiveneurons in the OEC-walking training group and the walking training-DMEM group was different from those in the OEC transplantation group and the SCI-DMEM group. Conclusions OEC transplantation combined with walking training can effectively promote the functional recovery of the hindlimb. The plasticity of the descending TH system and of motoneurons of the ventral horn of the lumbar spinal cord might mediate the changes.