Effects Of Electroacupuncture On Schwann Cell Morphology And Ciliary Neurotrophic Factor Expression In A Rabbit Model Of Facial Nerve Injury

Objective: This study aims to investigate the biological mechanisms of acupuncture therapy in rabbit models of facial paralysis. Methods: 42 healthy adult Japanese big-ear rabbits were randomly divided into the normal control (n = 6), model (n = 18) and electroacupuncture (EA; n = 18) groups. Rabbit models of facial nerve injury were established by clamping the right facial nerve. Electron microscopy, light microscopy and immunohistochemistry were performed to observe the morphology of injured facial nerves and detect the expression of ciliary neurotrophic factor (CNTF). Results: Compared with the normal control group, the majority of myelin sheaths were damaged in the model group. There were significant differences in the number of myelinated nerve fibers, the thickness of myelin sheath, and axonal area between the model and normal control groups on days 10 and 15 after injury (P < 0.01 or P < 0.05). CNTF expression in the model group was significantly greater than that in the control group on days 5, 10 and 15 after injury (P < 0.01). Compared with the model group, the extent of demyelination was less severe, and there was a greater number of intact organelles in the EA group. CNTF expression in the EA group was significantly lower than that in the model group on days 5 after injury (P < 0.05). Subsequently, CNTF expression in the EA group increased and was significantly different from that in the model group on day 15 after injury (P < 0.01). In the EA group, demyelination was milder on day 5 after injury than on days 10 or 15 after injury, and was associated with the duration of low CNTF expression. Conclusions: EA rapidly promotes the repair of injured facial nerves and improves the morphology of Schwann cells during the initial stage of facial nerve injury. It may be disadvantageous to the recovery of injured facial nerve fibers and Schwann cells during the later stages of the repair process.