Effect of electroacupuncture on expression of p-ERK1/2 and c-fos in spinal dorsal horn in rats with interstitial cystitis

Abstract

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). 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. 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). 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.