Objective To observe the influence of eletroacupuncture(EA)at"Dazhui"(EX-B2)and"Mingmen"(GV4)on expression of NR2 Bsubunit of N-methyl-D-aspartate receptor(NMDA)in the injured anterior horn(AH)area of rats with acute spinal cord injury(SCI)

so as to explore its mechanisms underlying improvement of neural repair.Methods A total of 96 male Sprague-Dawley(SD)rats were randomly and equally divided into four groups:sham operation(sham)

model

medication(Methyl-prednisone

MP)and EA(n=24 in each group).The acute SCI model was established by using a MASCIS spinal cord impactor.EA(2 Hz

0.5 mA)was applied to EX-B2 and GV4 for 30 min

once at 0.5 h

12 and 24 hafter SCI.Rats of the medication group were treated by tail intravenous injection of MP 30 mg/kg within 15 min(impact therapy)and 5.4 mg·kg

(-1)

·h-1(maintaining treatment)45 min thereafter for 23 h.The Basso

Beattie and Bresnahan(BBB)rating scale(0 to 21 points)was used to assess changes of locomotor function 6

24 and 48 hafter SCI.Histopathological changes of the injured spinal cord AH region were observed after sectioning and hematoxylin-eosin(H.E.)staining

and the expression levels of NR2 BmRNA and protein of AH were measured by quantitative real-time PCR

Western blot and immunofluorescence

respectively.Results After SCI

the BBB scores at 6

24 and 48 hwere significantly decreased in the model group compared with those of the sham group(P

<

0.001)

but had no remarkable changes in both medication and EA groups after the intervention in comparison with those of the model group(P

>

0.05).After modeling

the histopathological changes(blurred border of the grey-white matter

cellular karyopyknosis

deepening of the cytoplasmic red stain

and rupture

dissolution and disordered arrangement of myelinated nerve fibers)in the injury area of the spinal cord in the model group were apparent

the number of NR2 Bpositive neurons and the relative expression levels of NR2 BmRNA and protein were significantly increased in the model group relevant to the sham group(P

<

0.05).In contrast to the model group

the injured severity of the spinal cord AH region was relatively milder

and the expression levels of NR2 BmRNA and protein were considerably down-regulated in both EA and MP groups(P

<

0.05).However

there were no significant differences between the EA and MP groups in the expression levels of NR2 BmRNA and protein(P

>

0.05).Conclusion EA at EX-B2 and GV4 may inhibit the expression of NR2 BmRNA and protein in acute SCI rats

which may contribute to its action in promoting nerve repair of the injured ventricolumna area of the thoracic spinal cord.