Effect of Electroacupuncture on the Expression of Oligodendrocyte Precursor Cells in Rats with Compressed Spinal Cord Injury

Objective To investigate the effect of electroacupuncture on the expression of oligodendrocyte precursor cells in rats with compressed spinal cord injury (CSCI) and to explore the mechanism of remyelinization. Methods Thirty-six SD rats were randomly divided into a control group and three treatment groups with 3 d, 7 d and 14 d of treatment respectively. Acupuncture was given to rats in the treatment groups through jiaji point, double zusanli (ST36), and double taixi (KI3). Electroacupuncture (continuous wave, 2 Hz/1.5 V, 30 min) was applied for the double zusanli (ST36) and double taixi (KI3). Ethological alterations of the rats were observed with quantitative assessment of neurologic function. The ultrastructure changes of nerve fibers in white matter were determined under electronic microscope. Expressions of NG2 protein, an OPC marker, was observed by Western blot. Results No significant changes in neurologic function and G-ratio were observed after three days and seven days of electroacupuncture treatment (P>0.05). However, 14 d of electroacupuncture treatment made a significant change compared to the 7 d treatment group and the control group (P<0.05). The electronic microscope showed axons with varied degree of swollen, degenerated and lost cell organelle in axoplasm, edema in myelin sheaths, disordered, thickened and even broken layers of myelin sheaths in the rats with CSCI. The rats in the treatment groups had milder swollen axons and more compacted layers of myelin sheaths compared to their controls. Western blot showed that the expression of NG2 was increased with time and the differences among the three treatment groups were statistically significant (P<0.05). The rats in the treatment groups also had higher expressions of NG2 than their controls at 7 d and 14 d (P<0.05). Conclusion Electroacupuncture can improve inflammation and edema in the injured nerve fibers and up-regulate NG2 expression and remyelination of the injured nerve fibers in rats with CSCI.