Objective: To evaluate the efficacy and safety of electrical stimulation at the rabbit sciatic nerve trunk with the body-insulated acupuncture needle whose body is painted with insulating material.
Methods: Eighteen male New Zealand rabbits were randomized into the body-insulated acupuncture needle (BIAN), the general acupuncture needle (GAN), and the blank control groups，with 6 rabbits in each group. The rats'sciatic nerve trunks in BIAN and GAN groups were stimulated by electroacupuncture with the body-insulated acupuncture needle (only allowing the uncoated needle handle and tip to conduct electricity) and the general acupuncture needle, separately. The current intensity was recorded when regular plantarflexion reflexes (sciatic nerve effector reflexes) were observed in the rabbit's foot. The pathological changes of the sciatic nerve at the acupuncture site were observed by H.E. staining, and the ultrastructural changes of the sciatic nerve trunk were observed by transmission electron microscope.
Results: The intensity of the current causing the regular plantar flexion reflection in BIAN group (［0.29±0.07］ mA) was significantly lower than that in the GAN group(［0.86±0.08］ mA, P<0.01). H.E. staining revealed nerve axon degeneration, forming eosinophilic bodies, nerve fiber edema, and focal loss of myelin sheath in the GAN group. While the nerve fiber damage was not obvious, and axons were only degenerated in a few areas in the BIAN group. Transmission electron microscopy observations showed that the nerve myelin sheath structure was separated, the layers were arranged disorderly and bubbled in the GAN group. while the nerve myelin sheath structure of the BIAN group was normal, and it presents a concentric circle-like light and dark lamellar structure, with fewer myelin vacuoles and fissures, only a small part of the mitochondria, microfilaments, and microtubules of the nerve axons were abnormal, and the overall vacuole-like degeneration was significantly reduced, with few of the myelinated fibers were slightly degenerated, and axonal disease was not obvious.
Conclusion: Insulated acupuncture needle is more accurate and safer than ordinary acupuncture needle for electrical stimulation of rabbit sciatic nerve trunk, and the required electric current intensity is smaller.
目的：初步评价针身绝缘针灸针对家兔坐骨神经刺激的有效性与安全性。方法：将18只新西兰雄兔，随机分为空白对照组、普通针组、绝缘针组，每组6只。空白对照组无干预措施，仅用于神经取材对比评价安全性；绝缘针组与普通针组于家兔暴露的左下肢坐骨神经干处分别以涂层针灸针或传统针灸针针刺，并连接电刺激仪与隔离器。当观察到家兔足部出现规律性跖反射(坐骨神经效应器反射)时记录电流强度。针刺结束后，HE染色法观察坐骨神经损伤程度，透射电镜观察坐骨神经干的超微结构变化。结果：绝缘针组引发规律跖反射的电流强度为(0.29±0.07)mA，普通针组为(0.86±0.08)mA，绝缘针组明显低于普通针组(P<0.01)。HE染色结果显示，普通针组轴突变性，形成嗜酸性小体，神经纤维水肿，局灶性髓鞘丢失；绝缘针组神经纤维损伤不明显，且轴突仅在少数区域变性。透射电镜观察结果显示，普通针组神经髓鞘板层结构分离，各层间排列杂乱，层间可见大量空泡及裂隙，神经轴索萎缩，轴浆及线粒体肿胀、空泡化；绝缘针组神经髓鞘结构正常，且呈现同心圆样明暗相间的板层结构，髓鞘空泡及裂隙较少，神经轴索仅小部分线粒体、微丝、微管结构异常，整体空泡样变性明显少于普通针组，仅部分有髓纤维轻微变性，轴索病变不明显。结论：针身绝缘针灸针对家兔坐骨神经干的电刺激较普通针灸针的刺激更精准，安全性更好，所需电流强度更小。.
Keywords: Body-insulated needle; Electroacupuncture; Micron coating; Sciatic nerve trunk.