Objective: To observe the effect of electroacupuncture (EA) intervention on inflammatory reactions and articular synovial nuclear factor kappa B (NF-κB) and TNF-α converting enzyme (TACE) protein expression in rheumatoid arthritis (RA) rats, so as to elucidate its anti-inflammatory mechanism.
Methods: Forty Sprague-Dawley (SD) rats were randomly divided into normal control, model, EA, and non-acupoint groups, with 10 rats in each group. The RA model was established by intradermal injection of bovine type Ⅱ collagen emulsified in incomplete Freund's adjuvant for 21 days. EA (2 Hz, 1 mA) was applied to bilateral "Zusanli" (ST 36), "Xuanzhong" (GB 39) and "Shenshu" (BL 23) for 15 min, once daily for 19 days, starting from the third day on after modeling. The sham acupoints (5 mm lateral to the above-mentioned acupoints) received the same stimulation to EA group. Paw swelling volume was detected using a water-filled glass mug, the serum C-reactive protein (CRP) and rheumatoid factor (RF) contents were assayed using velocity scatter turbidimetric method, and the plasma erythrocyte sedimentation rate (ESR) was assayed with Westergren method and VES-MATIC 20 ESR auto-analyzer and the expression levels of TACE and NF-κB proteins in the synovial tissue of knee joint were detected by Western blot.
Results: After RA modeling, the hind-paw volume was significantly bigger in the RA rats than in the normal rats (P<0.01), and remarkably lower in the EA group (not in the non-acupoint group) than in the model group (P<0.05). In addition, the plasma ESR, serum CRP and RF contents and the expression levels of NF-κB and TACE proteins in the synovial tissues were significantly increased in the model group compared with those in the normal group (P<0.01), and were obviously down-regulated in the EA group (P<0.05), but not in the non-acupoint group (P>0.05).
Conclusions: EA can effectively improve the severity of articular inflammatory swelling and lo-wer ESR, serum CRP and RF contents and suppress synovial TACE/NF-κB protein signaling in RA rats.