Objective: To elucidate the effect of electroacupuncture (EA) on arthritic flexion pain scores

pathological reaction and IL-1β mRNA and IL-1ra mRNA expression of the skin tissue of the pain focus in adjunvant monoarthritis rats. Methods: 39 SD rats were randomized into control group (n=13)

inflammation group (n=13) and EA group (n=13). Arthritis model was established by subcutaneously injection of 50 μL complete Freund’s adjuvant (CFA) into unilateral rat’s hind-paw. EA (0.5～1.5 V

4～16 Hz) was applied to “Huantiao”(GB 30) and “Yanglingquan” (GB 34) for 30 minfollowing injection of CFA. Arthritic flexion pain scores were given everyday and continuously for 7 days. At the end of the experiments

the focal skin tissue was taken to be stained by hematoxylin eosin (HE) method for detecting the inflammatory cell number (in 100×100 μm2 section)

and the expression of interleulin (IL)-1β mRNA and IL-1 receptor antagonist (IL-1ra) mRNA was detected by RT-PCR. Results: ① After EA treatment

compared with inflammation group

the arthritic flexion pain scores of EA group reduced significantly (P<0.01); ② The inflammatory cells of the focus induced by CFA in EA group (45.71±5.92) were significantly fewer than those of inflammation group (95.66±6.53

P<0.01); ③ The IL-1β mRNA expression of EA group was significantly lower than that of inflammation group (P<0.01)

while IL-1ra mRNA expression of EA group considerably higher than that of inflammation group (P<0.01)

and IL-1ra/IL-1β of EA group (1.723± 0.049) was also significantly higher than that of inflammation group (0.948±0.034

P<0.01). Conclusion: EA can regulate the balance between IL-1β and IL-1ra to inhibit the activation of the immune cells in the pain focus

thus exert the effect of analgesia.