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.