Objective To observe the effect of electroacupuncture(EA)on locomotor activity and the expression of high-mobility group box-1(HMGB1) and Toll-like receptor 4(TLR4) in mice with spinal cord injury(SCI)

so as to explore its mechanisms underlying improvement of SCI at the acute stage. Methods Forty-eight female C57 BL/6 mice were equally randomized into 3 groups: sham operation

model and EA. The SCI model was established by clamping the spinal cord with a serrefine after laminectomy at the 1

(st)

lumbar vertebra(L1). EA(1.5 Hz/7.5 Hz

1.0 mA) was applied to "Jiaji"(EXH-B2) for 10 min

once a day for 5 and 14 days

separately. The hindlimb locomotor function was assessed by Basso

Beattie

Bresnahan Locomotor Rating Scale(BBB). Histopathological changes of the injured area of the spinal cord were determined by H.E. staining. The expression levels of spinal HMGB1

TLR4

ionized calcium binding adaptor molecule 1(Iba1) proteins were detected by Western blot

and the Iba1-positive microglial cells and HMGB1 and Iba1 co-labelled microglia were displayed by immunofluorescence staining.Results After SCI

the BBB scores on day 5 and 14 were obviously decreased(P

<

0.05)

and the expression of HMGB1 on day 14

TLR4 on day 5 and 14

the number of Iba1-positive microglia as well as the co-expressed HMGB1/Iba1-positive microglia on day 5 and 14 were significantly increased in the model group relevant to the sham operation group(P

<

0.05

P

<

0.01). In the EA intervention group

SCI-induced reduction of BBB scores on day 5 and 14

and increases of the expression of HMGB1 and Iba1 on day 14

and TLR4 on day 5 and 14

and the number of Iba1-positive cells as well as the co-expressed HMGB1/Iba1-positive microglia on day 14 were reversed relevant to the model group(P

<

0.05

P

<

0.01). H.E. staining showed a structural disorder with lots of cavities

severe inflammatory infiltration with a large quantity of inflammatory cells

and a reduction of normal neurons in the injured spinal cord tissue in the model group

which was relatively milder

with lower activation of microglia in the EA group. Conclusion EA can significantly improve locomotor function in SCI mice

which is associated with its effects in suppressing the expression of inflammatory factors such as HMGB1

TLR4

Iba1 and the over-activation of microglia.