| 摘要: | 發炎反應是血管及細胞受到傷害及感染所產生的反應。巨噬細胞的活化是這些發炎開始及增幅的主要關鍵。巨噬細胞受到傷害或是病理刺激時會釋放一氧化氮(NO)、PGE2、TNF-a、IL-1b、IL-6及IL-12；另外，T細胞會分泌IFN-g及其他的促發炎細胞激素，這些因子可增加抵抗外來的入侵物。發炎訊號分子的產生也與釵h發炎疾病有關連性。因此，抑制過量的發炎訊號分子產生是新藥物開發的一個重要目標。
香茹，Glossogyne tenuifolia，是清熱解毒的民間常用生藥。之前本研究室已經利用RAW264.7小鼠巨噬細胞株，發現香茹乙醇萃取物可抑制促發炎訊號分子的釋放。因此，本論文之研究，想要更進一步探討香茹乙醇萃取物對於活化後的BALB/c小鼠腹腔巨噬細胞和脾臟細胞，以及人類全血和周邊血單核細胞(PBMC)之抗發炎的幼躉P分子藥理機轉，研究結果顯示，香茹乙醇萃取物可以減少經由LPS活化的小鼠腹腔巨噬細胞和經由PHA刺激的脾臟細胞所產生的促發炎訊號分子的量，包括NO、PGE2、IL-1b、IL-6和IL-12，以及IFN-g。香茹乙醇萃取物也可以減少經LPS或是PHA刺激人類全血及周邊單核細胞(PBMC)所產生的促發炎細胞激素，包括TNF-a，IL-6及IFN-g。此論文接著探討香茹乙醇萃取物抑制LPS引起訊息傳導的機轉。本論文研究發現香茹乙醇萃取物，可抑制小鼠腹腔巨噬細胞的iNOS及COX-2啟動子活性，因此抑制NO及PGE2的釋放。另外，香茹乙醇萃取物可能是經由後轉錄作用，而非轉錄來抑制小鼠巨噬細胞株RAW264.7的促發炎細胞激素的產生。接著，本論文繼續探討香茹抑制發炎的上游調控機轉，包括nuclear factor-kB的活化及mitogen-activated protein kinases (MAPKs)的活化。本論文利用電泳膠體位移分析(EMSA)證實香茹乙醇萃取物在小鼠巨噬細胞株RAW264.7、小鼠腹腔巨噬細胞及小鼠脾臟細胞中，可減弱LPS或是PHA引起的kB DNA結合活性。進一步利用西方墨點法分析結果顯示，香茹乙醇萃取物可抑制活化之小鼠巨噬細胞株RAW264.7的p38 MAPK、JNK及ERK的磷酸化，及活化的小鼠腹腔巨噬細胞的p38、JNK及ERK的磷酸化。因此，本論文結果證實了香茹乙醇萃取物可影響一些受NF-kB及MAPK調控的基因之表現，因此抑制發炎訊號分子的釋放。
Inflammatory response is typically represented by a cascade of vascular and cellular reactions caused by injury and infection. The activation of macrophages is a key event for the initiation and propagation of these defensive reactions. When stimulated with pathologic stimuli or injury, macrophages release nitric oxide, PGE2, TNF-a, IL-1b, IL-6 and IL-12. In addition, T cells secret IFN-g and other pro-inflammatory cytokines that augment defense against invasion. The sustained inflammatory mediator production has been implicated associated with the pathologic process of inflammatory disease. Thus, the inhibition of over production of inflammatory mediators stands as an important therapeutic goal for drug development.
Glossogyne tenuifolia (Hsiang-Ju) is an anti-pyretic herb in Chinese medicine.
In previons investigation, the ethanol extract from Glossogyne tenuifolia (GT) inhibits pro-inflammatory mediators release in murine macrophage-like cell line, RAW 264.7 cells. In this study, in order to further investigate the anti-inflammatory effects and mechanisms of ethanol extract of G. tenuifolia Cassini (GT) on LPS-stimulated BALB/c mouse peritoneal macrophages and spleen cells as well as human whole blood and peripheral blood mononuclear cells (PBMC).
In the present study demonstrated the production of pro-inflammatory mediators, NO, PGE2, IL-1b, IL-6 and IL-12 as well as IFN-g, were attenuated by the ethanol extract of G. tenuifolia (GT) in LPS-activated mouse peritoneal macrophages and PHA-stimulated mouse splenocytes, respectively. GT also attenuates inflammatory cytokines synthesis in human whole blood and PBMC. To determine the mechanism by which GT inhibits LPS signaling, this study results showed GT downregulates iNOS and COX-2 promoter activity, thus inhibiting NO and PGE2 release in LPS-activated mouse peritoneal macrophages. In addition, GT exerted inhibition of the LPS-stimulated expression of the proinflammatory cytokines through post-transcriptional mechanisms. Moreover, we focused on nuclear factor-kB (NF-kB) activation and mitogen-activated protein kinases (MAPKs). The electrophoretic mobility shift assay (EMSA) demonstrated that GT attenuated LPS-mediated kB DNA binding activity in RAW264.7 cells, peritoneal macrophages, and spleen cells. Moreover, Western blot analysis revealed that GT inhibited the phosphorylation of p38 MAPK, JNK and ERK in activated RAW 264.7 cells; and the phosphorylation of p38, JNK and ERK in activated peritoneal macrophages. Our result demonstrated that GT interferes NF-kB- and MAPK-mediated gene expression therefore inhibits inflammatory mediators release. |
