Objective To observe the effect of electroacupuncture(EA) at "Ciliao"(BL32) and "Huiyang"(BL35) on the expression of extracellular signal-regulated kinase 1/2(p-ERK1/2) and cellular oncogene fos(c-fos) phosphorylated of spinal dorsal horn in rats with interstitial cystitis(IC). Methods Eighteen female Wistar rats were randomly divided into control

model and EA groups

with 6 rats in each group. The IC model was established by intraperitoneal injection of cyclophosphamide(150 mg/kg). EA(30 Hz

1 mA) was applied to bilateral BL32 and BL35 for 20 min

once daily for 3 consecutive days. The bladder pain was measured by using a Von Frey at 48 h after modeling and 24 h after EA. The expression levels of p-ERK1/2 and c-fos protein in L6-S1 segment of spinal cord were detected by Western blot

and the expression of p-ERK1/2 and c-fos in the right spinal dorsal horn were displayed by immunofluorescence staining. Results After modeling

the bladder mechanical pain threshold(PT) was significantly decreased(P<0.05)

the protein expression of p-ERK1/2 and c-fos in the spinal cord was increased(P<0.05) and the immunofluorescence surface density of p-ERK1/2 and c-fos in the right dorsal horn of spinal cord was increased(P<0.05) in the model group relevant to the control group. After EA intervention

IC-induced reduction of PT

and increases of the expression of p-ERK1/2 and c-fos as well as immunofluorescence surface density of p-ERK1/2 and c-fos were reversed in the EA group relevant to the model group(P<0.05). Conclusion EA at BL 32 and BL 35 has an analgesic effect in IC rats

which may be related to its effect in down-regulating the expression of p-ERK1/2 and c-fos in spinal dorsal horn.