Objective To observe the effect of electroacupuncture(EA) on motor function

calpain and calpastatin expression in rats with spinal cord injury

so as to explore the mechanism of EA underlying improvement of acute spinal cord injury. Methods Thirty male SD rats were randomly divided into sham operation group

model group and EA group

with 10 rats in each group. The acute moderate spinal cord injury model was established by using a NYU spinal cord impactor. EA was applied to "Jizhong"(GV6) and "Mingmen"(GV4) for 30 min

once daily for 28 d. The Basso

Beattie and Bresnahan(BBB) rating scale(0 to 21 points) was used to assess changes of locomotor function. Histopathological changes of the injured spinal cord were observed after sectioning and Nissl staining

and the expression levels of calpain1

calpain2 and calpastatin mRNA and protein in the spinal cord tissues were detected by using quantitative real-time PCR and Western blot

respectively. Results The BBB score of the model group was significantly lower than that of the sham operation group(P

<

0.01)

and was significantly higher in the EA group than that of the model group on 14

(th)

and 28(th) and 28

(th)

day(P

<

0.01). Compared with the sham operation group

the number of neurons in the model group decreased

and Nissl body stained cells decreased or even disappeared

which was evidently milder in the EA group. Compared with the sham operation group

the expression levels of calpain1 mRNA and protein in the spinal cord of the model group were significantly increased(P

<

0.01)

while the expression levels of calpastatin mRNA and protein were significantly reduced(P

<

0.01). Following EA intervention

in contrast to the model group

the expression levels of calpain1 mRNA and protein in the EA group were significant down-regulated(P

<

0.01)

calpastatin mRNA and protein expression levels were significantly up-regulated(P

<

0.01). There was no significant difference in calpain2 mRNA and protein expression among the 3 groups(P

>

0.05). Conclusion EA can improve the locomotor function of rats with spinal cord injury

which may be related to its effect in inhibiting the activity of calpain in the injured spinal cord.