[Effect of electroacupuncture at "Jiaji" (EX-B 2) points on the proliferation and differentiation of oligodendrocyte precursor cells in rats with acute spinal cord injury]

Objective: To observe the effect of electroacupuncture (EA) at "Jiaji" (EX-B 2) points on the proliferation and differentiation of oligodendrocyte precursor cells in rats with acute incomplete spinal cord injury, and to explore the mechanism of EA on improving motor function of spinal cord injury.

Methods: A total of 72 male SPF SD rats were randomly divided into a sham operation group, a model group, an EA group and a medication group, 18 rats in each group. Each group was further divided into 1-day subgroup, 7-day subgroup and 14-day subgroup, 6 rats in each subgroup. The T₁₀ acute incomplete spinal cord injury model was established by modified Allen's method in the model group, EA group and medication group. The rats in each group received intraperitoneal injection of 5-bromodeoxyuridine (BrdU, 50 mg/kg), once a day, and each subgroup received continuous injection for 1, 7, 14 times for cell proliferation labeling. The rats in the EA group were treated with EA at "Jiaji" (EX-B 2) points 3-4 mm next the spinous process of the upper and lower segments of the injured spinal cord (T₉, T₁₁) with a frequency of 2 Hz/100 Hz and intensity of 1-2 mA. The muscle twitch at the treatment site was taken as the degree. The treatment was given 20 min each time, once a day. In the medication group, monosialogangliosides (GM1) was injected intraperitoneally (10 mg/kg), once a day. The subgroups of EA group and medication group were treated for 1, 7, 14 times. The score of Basso Beattie Bresnahan (BBB) was used to evaluate the motor function of hind limbs. The co-expression of BrdU/NG2 positive cells was detected by immunofluorescence, and the expression of Olig2 and Sox10 was detected by Western blot.

Results: Compared with the sham operation group, the BBB score was decreased 1 day, 7 days and 14 days after operation in the model group (P<0.05), the expression of Olig2 and Sox10 was increased (P<0.05), and the co-expression of BrdU/NG2 positive cells was increased 7 days and 14 days after operation (P<0.05). Seven days and 14 days after operation, the BBB score in the EA group and medication group was higher than that in the model group (P<0.05), and the co-expression of BrdU/NG2 in the medication group was higher than that in the model group (P<0.05). Fourteen days after operation, the co-expression of BrdU/NG2 in the EA group was higher than that in the model group (P<0.05); 1 day, 7 days and 14 days after operation, the expression of Olig2 and Sox10 in the EA group and medication group was higher than that in the model group (P<0.05). Compared with the medication group, the co-expression of BrdU/NG2 positive cells in the EA group 14 days after operation was decreased (P<0.05); 1 day, 7 days and 14 days after operation, the expression of Olig2 and Sox10 in the EA group was decreased (P<0.05).

Conclusion: EA at "Jiaji" (EX-B 2) points could promote the expression of Olig2 and Sox10 after spinal cord injury, which has similar effects with GM1. It could promote the proliferation and differentiation of oligodendrocyte precursor cells into oligodendrocytes, so as to promote the recovery of motor function of rats.