Effect of direct current electrical stimulation on the recovery of facial nerve crush injury

This study aimed to evaluate the effect of noninvasive electrical stimulation (ES) using transcutaneous direct current on facial nerve crush injury by assessing in vitro cellular responses including proliferation and differentiation using PC12 cells as well as by performing in vivo functional and morphological assessments. Compared to the non-treated cells, the cells subjected to ES treatment showed clear in vitro neurite outgrowth and enhanced expression of differentiation genes. In this animal model, functional assessment of recovery was performed using vibrissa movement orientation and electrically stimulated muscle action potential. Moreover, histological observation was performed using a transmission electron microscope. A higher score of recovered vibrissa movement and more significant reduction of the threshold of electrically evoked muscle action potential were observed in the ES group than in the control group. Furthermore, histomorphometric evaluation showed that the experimental group had statistically significantly higher axon counts than did the control group. Regenerative nerve fibers were prominent in the distal segments of the ES group.