步行训练对不完全性脊髓损伤大鼠损伤部位周围组织可塑性的影响

Spinal cord plasticity and the effect of step training on functional recovery after incomplete spinal cord injury

目的 探讨步行训练对不完全性脊髓损伤大鼠损伤部位周围组织可塑性的影响.方法 将雌性SD大鼠24只分为步行训练组和对照组,每组12只,制作第10胸椎段脊髓损伤模型.步行训练组在制作脊髓损伤模型后1周开始进行步行训练,共训练9周;对照组不接受干预.制作模型后每周利用BBB评分评定后肢运动功能,8周后取材进行免疫荧光染色、Western blotting和轴突示踪分析.结果 后肢运动功能：步行训练组在伤后4周（步行训练3周）时,BBB评分较对照组出现明显改善（P〈0.05）,一直持续到实验结束（伤后第10周,P〈0.01）.损伤部位神经丝（NF）免疫荧光染色分析：对照组胶质瘢痕中可见许多排列比较规则、与脊髓纵轴方向一致的NF阳性纤维穿行,步行训练组除了可见少量NF阳性纤维在胶质瘢痕中穿越,还可见较多的NF阳性纤维围绕空洞边缘延伸,其NF阳性纤维数量明显高于对照组（P〈0.05）.损伤部位生长相关蛋白-43（GAP-43）表达：2组损伤部位周围均可见呈红色的排列凌乱的GAP-43表达,步行训练组GAP-43＋组织免疫荧光灰度值较对照组高（P〈0.05）.皮质脊髓束再生：2组损伤部位尾侧均未见生物素化葡聚糖胺（BDA）标记的纤维.结论 步行训练能明显增强脊髓损伤大鼠后肢损伤部位组织的可塑性,促进大鼠后肢运动功能恢复,但未能促进皮质脊髓束的再生.

Objective To explore neural plasticity around an injured region of the spinal cord and the effects of step training on functional recovery after incomplete spinal cord injury （SCI）. Methods Adult female Sprague-Dawley rats （ n = 24） were induced with spinal cord contusion at T10 and divided into a step training group and a control group （ 12 rats in each）. Training started from the 7th day post-injury and lasted for （20 ± 10）min per day, 5 days per week, for 9 weeks. Treadmill speeds were 3 m/min at the beginning, and adjusted daily according to each rat＇s tolerance up to 11 m/min or more. The functional recovery was measured weekly with the open-field locomotor rating scale of Basso, Beattie and Bresnahan （BBB score）. The expression of glial fibrillary acidic protein （GFAP）, neurofilament protein （NF） and growth-associated protein-43 （GAP-43） in the spinal cord around the injured region were detected. Results After 70 days of step training, the average BBB score of the step training group reached （ 12.86 ± 0.94 ）, significantly higher than that of the control group （ 10.71 ± 0.95 ）. The expression of NF and GAP-43 around the injured region increased significantly more in the step training group than among the controls. Conclusions Step training can promote functional recovery and neural plasticity in rats after incomplete SCI.