运动训练对脊髓损伤后痉挛大鼠脊髓内钾-氯离子协同转运体2表达的影响

关键词：运动训练  脊髓损伤  痉挛  钾-氯离子协同转运体2

Keywords:exercise training  spinal cord injury  spasticity  potassium-chloride cotransporter-2

摘要：

      摘要 目的：研究运动训练对脊髓损伤（SCI）后痉挛大鼠行为学表现及脊髓内钾-氯离子协同转运体2（KCC2）表达的影响，探讨KCC2在运动训练的解痉效应中的作用。 方法：将30只雌性SD大鼠随机分为假手术组、对照组、实验组。采用改良 Allen 撞击法建立脊髓损伤后痉挛模型，使用BBB评分、Ashworth评分来评估三组大鼠术后行为学变化，并于术后5周用免疫组化技术检测各组大鼠损伤远段脊髓KCC2表达。 结果：假手术组术后行为学评分一直保持正常。术后1d—5周，对照组和实验组的BBB评分均持续升高，且2组组内不同时间点的BBB评分差异均有显著性意义（P<0.05）。术后2—5周，实验组评分均高于对照组，且差异均有显著性意义（P<0.05）。对照组和实验组在术后1周左右出现痉挛，后痉挛程度逐渐加重，至术后5周左右降低，2组组内不同时间点的Ashworth评定结果差异均有显著性意义（P<0.05）。术后3—5周，对照组评定等级均高于实验组，差异有显著性意义（P<0.05）。三组大鼠脊髓运动神经元胞膜上KCC2表达水平比较，组间差异有显著性意义（P<0.05）。与假手术组相比，其余两组大鼠 KCC2蛋白表达下调（P<0.05）；与对照组相比，实验组能够明显上调 KCC2 蛋白的表达（P<0.05），但仍低于假手术组（P<0.05）。 结论：运动训练可以促进脊髓损伤后运动功能恢复，有效缓解痉挛，并可抑制KCC2表达的下调，运动训练的解痉效应可能是通过增加KCC2表达实现的。

Abstract:

      Abstract Objective: To investigate the effect of exercise training on the behaviors and expression of potassium-chloride cotransporter-2 (KCC2) in injured spinal cord of spastic rats and explore the role of KCC2 in the antispasmodic effect of exercise training. Method: Thirty female SD rats were randomly divided into three groups: sham operation group, control group, and experimental group. The spastic rat model with spinal cord injury (SCI) was induced by modified Allen's method, the change of behavior after operation was evaluated with the Ashworth scale and BBB scale. The expression of KCC2 in injured spinal cord was examined by immunohistochemistry at the 5th week post injury. Result:The behavior of sham operation group didn’t change. From the first day to fifth week after the operation, the BBB values of control group and experimental group both increased, and each group showed statistically significant in the scales at different time after the operation (P<0.05). At the 2nd-5th week, the BBB values of experimental group were higher than control group, and the differences between the 2 groups were statistical significant (P<0.05). Spasticity occurred about one week after the operation in control group and experimental group, and gradually aggravated afterwards. About 5 weeks after the operation, spasticity was somewhat alleviated. the Ashworth values was statistical significant at different time after the operation in each group (P<0.05). At the 3rd-5th week, the Ashworth values of control group were higher than those of experimental group, and the differences showed statistically significant (P<0.05). Immunohistochemistry results showed that there was significant differencant in the KCC2 expression among 3 groups (P<0.05). Furthermore, compared with the sham operation group, the KCC2 expression upregulated in the other 2 group，compared with the control group, the KCC2 expression of the experimental group upregulated (P<0.05), but lower than sham operation group (P<0.05). Conclusion: Exercise training might improve motor function and alleviate spasticity by promoting the KCC2 expression in injured spinal cord of rats with SCI.