Objective To observe the effect of electroacupuncture(EA)of "Zusanli"(ST 36)and "Sanyinjiao"(SP 6)on collagen-induced arthritis(CIA)and its underlying mechanism in regulating the secretory function of knee-joint synovial cells in CIA rats.Methods Thirty-six Wistar rats were equally randomized into control

model and EA groups.CIA model(rheumatoid arthritis)was duplicated by intradermal injection of Bovine type Ⅱ collagen into the back of the anesthetized rats.EA(2 Hz

2 mA)was applied to "Zusanli"(ST 36)and "Sanyinjiao"(SP 6)for 30 min

once a day for 30 days.The paw volume was measured by using a Plethysmometer and hot water tail-flick tests(50 ℃)were conducted for detecting the rats' pain threshold(PT)before and after the treatment.The contents of PGE2

IL-1β and TNF-α in supernatant of the cultured joint synoviocytes were detected by enzyme linked immunosorbent assay(ELISA).Results In comparison with control group

the swelled paw volume

the declined PT

PGE2

TNF-α and IL-1β contents in knee-joint synoviocyte supernatant were significantly higher in model group(P<0.05).Compared with model group

PT increased obviously(P<0.05);paw volume

supernatant PGE2

TNF-α and IL-1β contents decreased obviously(P<0.05)in EA group.Conclusion EA of ST 36 and SP 6 has a pronounced therapeutic effect in relieving knee joint pain and inflammation in CIA rats

which may be related to its effect in regulating the secretory function of the knee-joint synoviocytes.