青藤碱抗炎机理——青藤碱对人外周血单个核细胞环氧化酶活性及其基因表达的影响

目的 :研究青藤碱对人环氧化酶 (COX)活性及其基因表达的影响 ,深入探讨青藤碱的抗炎药理机制。方法 :应用细胞培养 ,放射免疫测定 ,RT-PCR等方法 ,观察青藤碱等药物对LPS刺激和非LPS刺激的体外培养的人外周血单个核细胞 (PBMC)产生前列腺素E₂ CPGE₂ C的影响 ,并深入研究其对COX-1和COX-2基因表达的作用。结果 :青藤碱对LPS刺激状态下正常人外周血单个核细胞PGE₂ 合成的抑制作用明显高于不加LPS的状态 ,间接反映青藤碱对COX-2的抑制作用较强。RT-PCR结果表明青藤碱对人COX-1及COX-2的基因表达无明显影响。结论 :青藤碱对COX-2活性具有一定的选择性抑制作用 ,并可能主要是通过对COX酶活性的直接作用来实现。

The Effect of Sinomenine on Cyclooxygenase Activity and the Expression of COX-1 and COX-2 mRNA in Human Peripheral Monocytes

OBJECTIVE: To observe in vitro the effect of Sinomenine, a pure alkaloid extracted from the chinese medical plant Sinomenium acutum on the activity of cyclooxygenase (COX-1 and COX-2) and the expression of COX-1 and COX-2 mRNA. METHOD: Mononuclear leukocytes were obtained from healthy adults. Isolated mononuclear leucocytes from human peripheral blood (PBMC) were incubated (1 x 10(6).mL-1) with or without sinomenine (or indomethacin), after incubated for 24 hours at 37 degrees C with 5% CO2; the media were assayed for the PGE2 by radioimmunoassay (RIA). LPS was used to stimulate the monocytes at a concentration of 5 micrograms.mL-1. And by RT-PCR, both COX-1 and COX-2 mRNAs were detected in Mononuclear leukocytes after incubation for different hours with drug (sinomenine or indomethacin) or not. RESULT: LPS (stimulated) induced the production of PGE2 in PBMC increasing with high expression of COX-2 mRNA; sinomenine reduced PGE2 production in LPS stimulated human monocytes more than in non-stimulated human monocytes. In comparative experiments, indomethacin, a non selective COX inhibitor, reduced the production of PGE2 equally in both states. Meanwhile, neither sinomenine(0.1-1 mmol.L-1) nor indomethacin(0.5-10 mumol.L-1) inhibited the expression of both COX-1 and COX-2 mRNAs by RT-PCR with beta-actin as reference. CONCLUSION: In contrast with indomethacin, Sinomenine shows a preferential inhibitory effect on COX-2 over COX-1, These results suggest that Sinomenine is a selective COX-2 inhibitor, which may be directly related to suppressing cyclooxygenase activity.