Shuangtengbitong tincture treatment of collagen-induced arthritis via downregulation of the expression of IL-6, IL-8, TNF-α and NF-κB

Abstract

Rheumatoid arthritis (RA) is a chronic, systemic autoimmune disease and may lead to joint damage, synovial membrane destruction and cartilage and bone damage. RA is closely associated with increased expression of interleukin (IL)-6, IL-8, tumor necrosis factor-α (TNF-α) and nuclear transcription factor-κB (NF-κB). Therefore, inhibition of the expression of IL-6, IL-8, TNF-α and NF-κB is a promising strategy for the development of novel anti-RA therapies. The aim of this study was to investigate the effect of shuangtengbitong tincture (STBT) on the expression of IL-6, IL-8, TNF-α and NF-κB in synovial tissues of rats with collagen-induced arthritis (CIA). STBT as a clinical prescription created at Fujian University of Traditional Chinese Medicines (TCM) Affiliated People's Hospital has been shown to be clinically effective in the treatment of RA. The model of Wistar rats with CIA was created using bovine type II collagen. The two treatment groups with CIA were administered STBT (1 ml per time) or Votalin (∼1 cm per time) for ∼1 month continuously. Following treatment, STBT suppressed paw swelling significantly (P<0.05) compared with the model group. STBT also improved pathological changes, STBT-treated rats showed a significant improvement in synovial hyperplasia, inflammatory infiltration, cartilage and bone destruction and other symptoms. The protein expression levels of IL-6, IL-8, TNF-α and NF-κB were markedly suppressed in synovial tissues of STBT-treated and Votalin-treated rats. Our findings demonstrate for the first time that STBT markedly reduces paw swelling, improves pathological changes and increases the expression of IL-6, IL-8, TNF-α and NF-κB in synovial tissues of CIA rats, which may partially explain the anti-RA activity of STBT.

Keywords: interleukin-6; interleukin-8; nuclear transcription factor-κB; rheumatoid arthritis; shuangtengbitong tincture; tumor necrosis factor-α.

Figure 1.

HPLC of target analytes in the STBT sample. Inset: HPLC of target analytes standard mixture. In liquid chromatograms 1 is triptolide and 2 is sinomenine. STBT, shuangtengbitong tincture; HPLC, high-performance liquid chromatography.

Figure 2.

Histological changes in CIA rats. Representative lesions using HE stain of hind knee joint from rats are shown (magnification, ×100). CIA, collagen-induced arthritis; HE, hematoxylin and eosin; STBT, shuangtengbitong tincture.

Figure 3.

Immunohistochemical determination of protein expression. Representative images of staining for TNF-α are shown (magnification, ×10). TNF, tumor necrosis factor; STBT, shuangtengbitong tincture.

Figure 4.

Determination of mRNA expression of TNF-α and NF-κB. The levels of TNF-α and NF-κB in synovial tissues were determined by RT-PCR analysis. GAPDH was used as the internal control. TNF-α, tumor necrosis factor-α; NF-κB, nuclear transcription factor-κB; GAPDH, glyceraldehyde-3-phosphate dehydrogenase.