Reduction of urate crystal-induced inflammation by root extracts from traditional oriental medicinal plants: elevation of prostaglandin D2 levels

• Published in: Arthritis research & therapy 2007-01, Vol.9 (4), p.R64-R64
• Main Authors: Jung, Sung Mun, Schumacher, H Ralph, Kim, Hocheol, Kim, Miyeon, Lee, Seoung Hoon, Pessler, Frank
• Format: Article
• Language: English
• Subjects: Animals; Anti-Inflammatory Agents - therapeutic use; Arthritis, Gouty - drug therapy; Arthritis, Gouty - metabolism; Arthritis, Gouty - pathology; Dinoprostone - genetics; Dinoprostone - metabolism; Disease Models, Animal; Eleutherococcus - chemistry; Exudates and Transudates - drug effects; Exudates and Transudates - metabolism; Female; Gene Expression - drug effects; Interleukin-6 - genetics; Interleukin-6 - metabolism; Leukocyte Count; Medicine, East Asian Traditional; Mice; Mice, Inbred BALB C; Neutrophils - drug effects; Neutrophils - pathology; Plant Extracts - therapeutic use; Plant Roots - chemistry; Plants, Medicinal - chemistry; Prostaglandin D2 - genetics; Prostaglandin D2 - metabolism; RNA, Messenger - metabolism; Tumor Necrosis Factor-alpha - genetics; Tumor Necrosis Factor-alpha - metabolism; Uric Acid
• ISSN: 1478-6354; 1478-6362
• DOI: 10.1186/ar2222

Dried roots of the plants Acanthopanax senticosus, Angelica sinensis and Scutellaria baicalensis are used in traditional oriental medicine and reportedly possess anti-inflammatory properties. Using the murine air pouch model of inflammation, we investigated the efficacy and mode of action of an extract from these three plants in crystal-induced inflammation. Air pouches were raised on the backs of 8-week-old BALB/c mice. Mice were fed 100 mg/kg body weight of root extracts (A. senticosus:A. sinensis:S. baicalensis mixed in a ratio of 5:4:1 by weight) or vehicle only on days 3-6. Inflammation was elicited on day 6 by injecting 2 mg of monosodium urate (MSU) crystals into the pouch. Neutrophil density and IL-6 and TNF-alpha mRNA levels were determined in the pouch membrane, and the leukocyte count and IL-6, prostaglandin E2 (PGE2) and prostaglandin D2 (PGD2) levels were determined in the pouch exudate. Treatment with the root extracts led to a reduction in all inflammatory parameters: the leukocyte count in the pouch exudate decreased by 82%; the neutrophil density in the pouch membrane decreased by 68%; IL-6 and TNF-alpha mRNA levels in the pouch membrane decreased by 100%; the IL-6 concentration in the pouch fluid decreased by 50%; and the PGE2 concentration in the pouch fluid decreased by 69%. Remarkably, the concentration of the potentially anti-inflammatory PGD2 rose 5.2-fold in the pouch exudate (p < 0.005), which led to a normalization of the PGD2:PGE2 ratio. A 3.7-fold rise in hematopoietic PGD synthase (h-PGDS) mRNA paralleled this rise in PGD2 (p = 0.01). Thus, the root extracts diminished MSU crystal-induced inflammation by reducing neutrophil recruitment and expression of pro-inflammatory factors and increasing the level of the potentially anti-inflammatory PGD2. These results support a need for further studies of the efficacy of these extracts in the treatment of inflammatory arthropathies and suggest elevation of PGD2 levels as a novel mechanism for an anti-inflammatory agent.