重复经颅磁刺激不同干预时机对脊髓半横断损伤大鼠运动功能的影响

Effects of repetitive transcranial magnetic stimulation at different intervention time on motor function recovery after spinal cord hemisection in rats

中文关键词:  脊髓损伤  经颅磁刺激  脊髓半横断损伤  运动功能  大鼠

英文关键词:Spinal cord injury  Repetitive transcranial magnetic stimulation  Spinal cord hemisection  Functional recovery  Rat

中文摘要:

  【摘要】　目的：观察重复经颅磁刺激不同干预时机对脊髓半横断损伤大鼠运动功能的影响。方法：将42只SD大鼠随机分为正常对照组（n=6）、假手术组（n=6）、脊髓损伤组（SCI组，n=10）、急性期刺激组（ArTMS组，n=10）和亚急性期刺激组（SrTMS组，n=10），SCI组、ArTMS组和SrTMS组大鼠建立T10脊髓右半侧横断损伤模型，假手术组仅行椎板切开，不横断脊髓，正常对照组不行手术处理。ArTMS组和SrTMS组大鼠分别于术后4d和18d开始重复经颅磁刺激治疗，刺激强度为最大输出强度的35%，刺激频率为10Hz，每序列5s，间歇2min，连续10个序列，每日1次，每周5d，连续2周；正常对照组、假手术组和SCI组不行经颅磁刺激治疗。大鼠术前与术后3d、10d、17d、24d、31d和38d分别进行BBB评分和水平梯子实验评价右后肢运动功能；术后38d取右后肢胫前肌，采用ATP酶法（pH 4.6）行肌肉病理染色，观察肌肉形态并测量不同类型肌纤维直径。结果：5组大鼠术前BBB评分均为21分，水平梯子实验步态正确率均为100%。假手术组术后各时间点BBB评分和水平梯子实验步态正确率与术前比较无变化。SCI组、ArTMS组、SrTMS组术后３ｄ BBB评分和水平梯子实验步态正确率明显下降，与术前比较差异显著。SCI组和SrTMS组术后31ｄ和38ｄ BBB评分有所恢复，与术后３ｄ和10ｄ比较差异显著（P<0.05），SCI组和SrTMS组术后24d、31d、38d水平梯子实验步态正确率与术后３ｄ和10ｄ比较差异显著（P<0.05）。ArTMS组术后17d、24ｄ、31d、38d时的BBB评分和水平梯子实验步态正确率明显高于术后3d和10d（P<0.05）。SCI组和SrTMS组术后3~38d各时间点BBB评分、水平梯子实验步态正确率组间比较无显著性差异（P＞0.05）；ArTMS组术后3d和10d BBB评分、水平梯子实验步态正确率与SCI组和SrTMS组比较无显著性差异（P＞0.05）。ArTMS组术后17d、24d、31d、38d BBB评分明显高于SCI组和SrTMS组（P<0.05）；术后17d、24d、31d、38d水平梯子实验步态正确率明显高于SCI组（P<0.05）；术后24d、31d、38d水平梯子实验步态正确率明显高于SrTMS组（P<0.05）。术后38d时，SCI组大鼠右后肢胫前肌１型、2A型、2B型肌纤维直径与正常对照组和假手术组比较均明显变小（P<0.05）；ArTMS组2A型肌纤维直径与正常对照组和假手术组比较变小（P<0.05），2A型和2B型肌纤维较SCI组明显增粗（P<0.05），1型与SCI组比较无显著性差异（P＞0.05）；SrTMS组大鼠2A型和2B型肌纤维与正常对照组和假手术组比较变细（P<0.05），2B型肌纤维与ArTMS组比较明显变细（P<0.05）。结论：重复经颅磁刺激早期干预可促进脊髓半横断损伤大鼠运动功能恢复，改善部分肌肉萎缩，急性期治疗效果明显优于亚急性期治疗的效果。

英文摘要:

  【Abstract】 Objectives: To observe the effect of repetitive transcranial magnetic stimulation(rTMS) on motor function recovery at different intervention time after spinal cord hemisection in rats. Methods: 42 SD rats were separated into five groups randomly, including normal control group(n=6),　sham group(n=6), SCI group(n=10), ArTMS group(n=10) and SrTMS group(n=10). T10 spinal cord hemisection model was made in SCI group, ArTMS group and SrTMS group. In sham group, the vertebral laminae of rats were removed while keeping spinal cord intact. The rats in normal control group did not receive any surgery.　RTMS(10×5sec bursts of 10Hz at 35% maximal stimulator output,　each burst separated by a 2min interval) was delivered daily 5 days per week for 2 weeks.　The treatment began at 4 days after surgery for acute group(ArTMS group) and 18 days after surgery for subacute group(SrTMS group). The rats in normal control group, sham group and SCI group did not receive any intervention. Motor functional recovery was assessed by using BBB locomotor rating scale and the Horizontal Ladder Scale before surgery and at 3 days, 10 days, 17 days, 24 days,　31 days,　38 days after surgery. The tibialis anterior was surgically removed for observing muscle shape, and diameters of different muscle types were merssured by ATPase staining(pH 4.6) at 38 days after surgery. Results: The BBB score(21) and the percentage of correct steps of Horizontal Ladder Scale(100%) were normal in normal control group, sham gourp and SCI group, ArTMS group, SrTMS group before surgery, which remianed unchangeed in sham group after surgery compared with those before surgery. The BBB score and the percentage of correct steps in SCI group, ArTMS group and SrTMS group at 3 days after surgery decreased significantly compared with those before surgery. The BBB score of SCI group and SrTMS group at 31 days and 38 days after surgery and the percentage of correct steps at 24 days, 31 day, 38 days after surgery improved significantly compared with those at 3 days and 10 days after surgery(P<0.05). In ArTMS group, the BBB score increased significantly at 17 days, 24 days, 31 days, 38 days after surgery compared with those at 3 days and 10 days（P<0.05）. The BBB score and the percentage of correct steps between SCI group and SrTMS group showed no difference from 3 days to 38 days after surgery. The BBB score and the percentage of correct steps in ArTMS group at 3 days and 10 days after surgery showed no significant difference compared with those in SCI group and SrTMS group. The BBB score of ArTMS group at 17 days, 24 days, 31 days and 38 days after surgery improved significantly compared with those in SCI group and SrTMS. The Horizontal Ladder Scale of ArTMS group was significantly higher at 17 days, 24 days, 31 days, 38 days after surgery than SCI group and was higher at 24 days, 31 days, 38 days after surgery than SrTMS group（P<0.05）. ATPase staining of paralysis tibialis anterior of right low limb showed the diameters of Ⅰ, 2A, 2B type muscle fibers in SCI group decreased compared with normal control group and sham group（P<0.05）. The diameters of type 2A muscle fibers decreased in ArTMS group than in normal control group and sham group（P<0.05）. The diameters of type 2A and 2B muscle fibers were significantly greater in ArTMS group than those in SCI group（P<0.05）, but for 1 type muscle fibers there was no significant difference between ArTMS group and SCI group. In SrTMS group, the diameters of 2A and 2B muscle fibers significantly decreased compared with normal control group and sham group（P<0.05）, and 2B muscle fibers decreased significantly than those of ArTMS group（P<0.05）. Conclusions:　rTMS in acute stage of SCI improves the functional recovery and alleviate muscle atrophy partially after spinal cord hemisection in rats, which shows better effect than subacute stage.