摘要
目的 观察高强度超声(HIU)作用于兔坐骨神经干后,不同时间(1周、2周、1个月、3个月、6个月)胫神经、腓浅神经动作电位幅度、神经传导速度的变化、展趾功能的变化,为高强度超声用于顽固性疼痛的治疗提供实验依据。方法80只新西兰大白兔随机分为4组(0 s、15 s、25 s、50 s组),每组20只,以不同的HIU剂量(强度×时间)辐照兔坐骨神经干。结果 0s组:各时间点胫神经、腓浅神经的动作电位峰值、神经传导速度、潜伏期及神经纤维均无明显改变。15 s组:胫神经动作电位峰值略有下降,但很快恢复;腓浅神经动作电位峰值明显下降,1个月恢复正常;胫神经传导速度、潜伏期无明显改变;腓浅神经2周内传导速度略有减慢,潜伏期略有延长,1个月时已恢复。1周时神经纤维轻微脱髓鞘,髓鞘断裂、脱失、轴突空泡、变性,细胞器结构消失,2周后基本恢复。25 s组:胫神经动作电位峰值明显下降,3个月恢复,腓浅神经动作电位峰值明显下降,6个月恢复正常;胫神经传导速度减慢、潜伏期延长,1个月基本恢复;腓浅神经传导速度明显减慢,潜伏期明显延长,3个月时恢复。1周时部分神经纤维轴突断裂、变性,细胞明显坏死,2周时出现增生细胞。50 s组:各时间点动作电位均未引出。1周时大部分神经纤维凝固性坏死,2周时见有肉芽增生,1个月时增生明显。
Objective To determine the changes in action potential peak value and maximal nerve conduction velocity of rabbit sciatic nerve after being exposed to different doses of high intensity ultrasound (HIU) and establish the experimental basis for the use of HIU in patients with refractory pain. Methods Eighty New Zealand white rabbits of either sex weighing 2.0-2.5 kg, aged 5-10 months were randomly divided into four groups with 20 rabbits in each group :group Ⅰ 0 second;group Ⅱ 15 seconds;group Ⅲ 25 seconds and group Ⅳ 50 seconds. The animals were anesthetized and placed in the prone position. Sciatic nerves were exposed to 4 different doses of HIU (7.1 MHz, 40 W/cm2 f55 0 s, 15 s, 25 s, 50 s) in the four groups. The animals were allowed to recover. At 5 intervals (1 and 2 weeks, 1, 3 and 6 months) after exposure to HIU, 4 animals in each group were anesthetized and recording electrodes were placed on sciatic nerves at 2 cm distal to the site of HIU radiation, tibial and sural cutaneous nerves. The amplitude (peak value) and latency of action potential and maximal conduction velocity of the nerves were recorded. Sciatic nerves were obtained from one of the four animals for light and electron microscopic examination. Results The larger was the dose of HIU, the more time was needed for the injuried nerve to recover. In group Ⅰ (0 s) there were no significant changes in action potential peak value and maximal nerve conduction velocity at any interval after exposure to HIU;in group Ⅱ (15 s) there were slight changes in the electrophysiological parameters and the changes recorded on tibial nerve returned to normal soon while those recorded on sural cutaneous nerve returned to normal one month later; in group Ⅲ (25 s) there were significant changes in the electrophysiological parameters and it took 3 months for tibial nerve but 6 months for sural cutaneous nerve to recover;in group Ⅳ (50s) the nerves were completely blocked, no action potential was recorded and no recovery was observed after 6 months. Light and electron microscopic examination showed that in group 1 no significant changes of nerves were observed; in group Ⅱ there was slight deformation of myelin sheath which returned to normal 2 weeks later; in group Ⅲ sheath was broken or lost, and axon degeneration was observed at 1 week after exposure to HIU and the changes disappeared 1 month later; in group Ⅳ necrosis of the nerve was observed and no recovery was observed 6 months later. Conclusion HIU can be used for the treatment of refractory pain. Analgesia can be achieved with loss of only part of motor function. The nerve can be permanently blocked by HIU if necessary.
出处
《中华麻醉学杂志》
CAS
CSCD
北大核心
2004年第3期198-202,共5页
Chinese Journal of Anesthesiology
基金
国家"九五"重点科技攻关项目专题(NO.969050201)
重庆市卫生局青年科研项目(NO.99-3010)
