Tao X, Schulze-Koops H, Ma L, Cai J, Mao Y, Lipsky P E
University of Texas Southwestern Medical Center at Dallas, 75235-8884, USA.
Arthritis Rheum. 1998 Jan;41(1):130-8. doi: 10.1002/1529-0131(199801)41:1<130::AID-ART16>3.0.CO;2-4.
Extracts of the Chinese herbal remedy Tripterygium wilfordii Hook F (TWHF) have been reported to be effective in the treatment of patients with a variety of inflammatory and autoimmune diseases, but the mechanism of this therapeutic effect has not been completely delineated. The present study was designed to assess the effects of TWHF on the in vitro synthesis of prostaglandin E2 (PGE2) and on the expression of the cyclooxygenase isoforms, COX-1 and COX-2, in various human cell types.
Monocytes from human peripheral blood (HM), fibroblasts from rheumatoid arthritis synovial tissue (RASF), human neonatal foreskin fibroblasts (HFF), and the histiocytic cell line U937 were cultured for designated time periods with or without lipopolysaccharide (LPS), and in the presence or absence of varying concentrations of the following inhibitors: the methanol/chloroform (T2) extract of TWHF, the ethyl acetate (EA) extract of TWHF, a purified diterpenoid component of TWHF (triptolide), dexamethasone, and indomethacin. Culture supernatants were harvested for PGE2 content assays. Total RNA was extracted from the cells and analyzed for COX-1 and COX-2 messenger RNA (mRNA) expression using reverse transcriptase-polymerase chain reaction or Northern blotting.
Both the T2 and EA extracts inhibited PGE2 synthesis in the LPS-stimulated HM, RASF, and HFF cells, which was reflected by a marked suppression in the levels of mRNA for COX-2. In contrast, neither extract inhibited PGE2 production in U937 cells that did not express COX-2. Triptolide also inhibited LPS-stimulated induction of COX-2 mRNA and synthesis of PGE2, at the same inhibitory concentration as seen with the EA extract. The effects of T2, EA, and triptolide paralleled the inhibitory action of dexamethasone.
The data indicate that both the T2 and EA extracts of TWHF, as well as the triptolide component, inhibit PGE2 production in a variety of human cells by blocking the up-regulation of COX-2.
据报道，中药雷公藤多苷（TWHF）提取物对多种炎症和自身免疫性疾病患者的治疗有效，但其治疗作用机制尚未完全阐明。本研究旨在评估TWHF对不同人类细胞类型中前列腺素E2（PGE2）体外合成以及环氧化酶同工型COX-1和COX-2表达的影响。
将人外周血单核细胞（HM）、类风湿性关节炎滑膜组织成纤维细胞（RASF）、人新生儿包皮成纤维细胞（HFF）以及组织细胞系U937在有或无脂多糖（LPS）的情况下培养指定时间段，并在有或无不同浓度的以下抑制剂存在的情况下培养：TWHF的甲醇/氯仿（T2）提取物、TWHF的乙酸乙酯（EA）提取物、TWHF的纯化二萜类成分（雷公藤内酯醇）、地塞米松和吲哚美辛。收集培养上清液进行PGE2含量测定。从细胞中提取总RNA，并使用逆转录聚合酶链反应或Northern印迹分析COX-1和COX-2信使核糖核酸（mRNA）表达。
T2和EA提取物均抑制LPS刺激的HM、RASF和HFF细胞中PGE2的合成，这表现为COX-2 mRNA水平的显著抑制。相反，两种提取物均未抑制不表达COX-2的U937细胞中PGE2的产生。雷公藤内酯醇在与EA提取物相同的抑制浓度下也抑制LPS刺激的COX-2 mRNA诱导和PGE2合成。T2、EA和雷公藤内酯醇的作用与地塞米松的抑制作用相似。
数据表明，TWHF的T2和EA提取物以及雷公藤内酯醇成分通过阻断COX-2的上调来抑制多种人类细胞中PGE2的产生。
