Suppression of carrageenan-induced inflammation in vivo by an extract of the Chinese herbal remedy Tripterygium wilfordii Hook F

Objective and Design: The current studies investigated the effect of subacute administration of an ethyl acetate extract of the Chinese herbal remedy, Tripterygium wilfordii Hook F (TWHF) on the inflammatory response induced by carrageenan in the rat. Materials and Subjects: F344 rats were randomly divided into 3 groups of seven animals. Treatment: The rats were treated orally for 5 days with either vehicle or an ethyl acetate extract of TWHF at a dose of 270mg/kg, equivalent to 1/5 of the dose causing death in 50% of the animals. Methods: Air pouches were induced subcutaneously on the backs of rats and injected with carrageenan on the last day of treatment. Sixteen hours after carrageenan challenge, the air pouches were removed and analyzed. Student's t-test was employed for statistical analysis. Results: The number of exudate cells and the concentration of PGE(2), nitrite and TNF-alpha in the exudate obtained from TWHF-treated animals were significantly reduced (by 69%, 78%, 57% and 77%, respectively) compared to that from vehicle-treated animals, mRNA for cyclooxygenase-2 was markedly suppressed in the air pouch lining tissue of TWHF treated rats (p<0.001). In contrast, PGE(2) content of the kidney and stomach and the production of PGE(2), nitrite and TNF-alpha by spleen cells was not affected by treatment with TWHF. Conclusions: These results indicate that TWHF exerts a significant anti-inflammatory activity in vivo.