植入微型刺激器对大鼠神经损伤后自残及神经再生的影响

本实验利用大鼠坐骨神经钳夹损伤模型，观察了电针（Ａ组）、直流刺激器（Ｂ组）及双向平衡电脉冲刺激器（Ｃ组）对神经损伤后自残及神经再生的影响，Ｄ组为对照。结果：（１）术后１７ｄ，Ｃ组的右后足趾自残率为１３％，而Ａ、Ｂ及Ｄ组分别为４６％、５３％及８０％，Ｃ组的自残率显著低于其它各组（Ｐ＜０．００１）；（２）右侧屈肌反射阈：当刺激强度为３５±５Ｖ（Ｃ组）、４５±５Ｖ（Ａ和Ｂ组）时，可引出短潜伏期（４５～１５０ｍｓ）的Ａ类及长潜伏期（１２５～５２５ｍｓ）Ｃ类传入纤维反应，而当刺激强度增至６５±５Ｖ时，于Ｄ组仅见长潜伏期（１９０～６００ｍｓ）的Ｃ类传入纤维反应；（３）术后１７ｄ脊神经节的标记细胞百分享分别为１１．１％（Ｃ组）、５．７％（Ｂ组）、５．２％（Ａ组）及１．１％（Ｄ组）；脊髓前角的标记细胞百分率分别为１６．６％（Ｃ组）、８．１％（８组）、７．４％（Ａ组）及１．９％（Ｄ组）。上述结果表明：双向平衡电脉冲刺激器在抑制神经损伤后自残及促进周围神经再生等方面具有更显著的生理功效。

APPLICATION OF ELECTRICAL STIMULATION TO REDUCE AUTOTOMY FOLLOWING SCIATIC NERVE LESION IN RATS

In order to evaluate the effect of three kinds of electrical stimulation in relieving the neuropathic pain and in promoting the regeneration of peripheral nerves, an animal model of autotomy following sciatic nerve lesion was used in this study. 65 adult male Wistar rats were divided into 4(A, B, C and D) groups and the sciatic nerve of right side were crushed. 3days after operation, group A were treated with electroacupuncture(EA, 30 min/day, 10 Hz, 0.4 mA). group B with directcurrent(DC, 24h/day, 0.6 μA), group C with pulse current(MS, 24h/day, 10 Hz, 8μA)and group D as control. The anodic electrode of electrical stimulation in Huantiao (+) point and the cathode in Sanyinchiao(-) point. 17 days after operation.autotomy were checked first, then following experiment on bilateral side : (1)Saphenous nerve were transected;(2)The medial and lateral gastrocnemius were placed in recording electrode, the paw pad were placed in stimulating electrode, the pain threshold of the flexion reflex were observed ; (3) HRP injected into the gastrocnemius and the hypodermis of the paw pad, the labeled cells in the ganglion spinal (L4～L6) and cornu ventrale of spinal cord (L4～L6) were checked. (1)The percentage of autotomy in group C was 13%, 46% in group A, 53% in group B, 80% in group D; (2) The electromyographs(EMGs) from medial and latetal gastrocnemius on left side were evoked by both A-afferent fibers with a short latency (12ms) and C-afferent fibers with a longer latency(87 ms), the threshold of the flexion reflexis 4±0.5V. The stimulus strength from 35±5V (for group C) to 45±5V (for group A and B), the flexion reflex on right side were evoked by both A-afferent fibers with a short latency(45-150 ms)and C-afferent fibers with a longer latency(125-525 ms). Increasing the stimulus strength to 65±5V only produced a long latency (190～600ms) with a very long after-discharge in the gastrocnemius on right side of group D; (3) The small round labeled cells with heavy stain and the big round ones with light stain were observed in the right ganglion spinals of group C. The big triangular and stellate-like labeled cells with heavy stain were observed in the cornu ventrale of group A, B and C. The percentages of labeled cells (right side/left side)in the ganglion spinals were 11. 1% (gruup C), 5.2% (group A), 5.7% (group B)and 1.1% (group D);but in the cornu ventrale were 16.6% (group C), 7.4%(group A), 8.1% (group B)and 1.9% (group D). MS has better effect than DC or EA on reducing the autotomy and promoting there generation of the peripheral nerves.