Objective To observe the effect of electroacupuncture (EA) at "Ciliao" (BL 32) on detrusor hyperreflexia and c-fos expression in the sacral segment of spinal cord in rats with spinal cord injury (SCI). Methods Thirty-seven adult female Sprague-Dawley rats were randomized into normal control (n=5)

SCI model (n=16) and EA (n=16) groups. EA(20 Hz

3 mA) was applied to bilateral BL 32 for 2 hours

once daily for 14 days. Intravesical pressure was detected by using a pressure transducer and a bioelectric amplifier. The expression of c-fos gene was detected by immunohistochemistry. Results In comparison with normal control group

the maximum intravesical pressure (MIVP)raised significantly in model group (P<0.05)

and the compliance of the bladder decreased remarkably (P<0.05). While compared with model group

MIVP decreased significantly in SCI rats of EA group after EA intervention (P<0.05)

and the vesical compliance increased obviously (P<0.05). In comparison with normal control group

the mean optical density (OD) value of c-fos immuno-reaction (IR) positive products increased significantly in the sacral cord after SCI in model group (P<0.05)

while compared with model group

the mean OD value of c-fos IR positive products in EA group declined evidently but still being higher than that of normal control group (P<0.05)

displaying a downregulation of c-fos expression after EA. Conclusion Electroacupuncture at "Ciliao" (BL 32) can inhibit the over-activity of bladder in SCI rats and reduce the c-fos expression in the sacral cord

suggesting that the declined C-fibers' activity after EA may be one of its mechanism underlying improving detrusor hyperreflexia in spinal cord injury.