Effect and mechanism of Shao-Yao Gan-Cao Tang on adjuvant-induced arthritis in rats

Abstract

Shaoyaogancao-tang (SGT) is a widely used traditional medical formula to relieve different types of pain in China. Here, we investigated the suppressive effect of SGT on rat adjuvant-induced arthritis (AA) and the underlying mechanism. Paw swelling and histological score were calculated during or after SGT treatment. Levels of tumor necrosis factor-α (TNF-α), interleukin-1β (IL-1β) and prostaglandin E2 (PGE2) in serum were analyzed by enzyme-linked immunosorbent assay, and nitric oxide (NO) in serum were analyzed by Griess reaction method. Cyclooxygenase-2 (COX-2) and inducible nitric oxide synthase (iNOS) proteins expression in synovial tissues were detected by Western blot assay. SGT markedly relieved the paw swelling and lowered the histological score. SGT also notably decreased the levels of TNF-α, IL-1β, PGE2 and NO in serum. In addition, SGT significantly suppressed the expression of COX-2 and iNOS proteins in synovial tissues. These findings suggest that SGT have pronounced anti-arthritic effect on AA in rats through inhibiting the production of inflammatory mediators, and indicate that SGT would be a promising candidate as a novel anti-rheumatic drug for further investigation. Key words: Shaoyaogancao-tang, adjuvant-induced arthritis, rheumatoid arthritis, traditional Chinese medicine, inflammation.