| 摘要: | 根據世界衛生組織十大死因的統計資料顯示，心血管疾病一直被視為頭號殺手，研究指出不正常的血小板活化不僅造成血栓形成，同時也是心血管疾病的主因。因此開發有效預防血栓疾病的抗血小板藥物極為重要。近年來，研究發現許多中草藥或天然物對於抗血栓具有很大的潛力。Rutaecarpine (Rut) 是從Evodia rutaecarpa植物中分離出來的一種生物鹼，具有抗發炎、抗癌、抗氧化及血管舒張等作用。研究已證實，Rut能抑制collagen、ADP以及arachidonic acid (AA) 所造成的血小板凝集反應。然而，Rut對於抑制血小板的活化機制仍尚未明瞭。因此本篇論文將探討Rut在人類血小板中的作用機轉。本研究中發現，2.5-5 µM Rut皆可以抑制由collagen誘導的血小板凝集反應以及降低ATP、鈣離子釋出反應和P-selectin的表現量，且對於這些反應的抑制效果都具有濃度依賴性。在乳酸去氫酶 (lactate dehydrogenase assay) 的毒性試驗下，證實Rut對血小板不會產生細胞毒性。在collagen所誘導的血小板活化訊息傳遞路徑中，Rut可以減少PLCγ2、p47、Akt、ERK1/2、JNK1/2及p38 MAPK蛋白磷酸化的表現量但不是直接透過p47 蛋白質或cGMP或cAMP pathway來抑制血小板活化。而Rut在動物實驗中發現可抑制血栓的形成。本篇研究結果顯示，Rut 透過抑制PLCγ2/PKC、Akt以及MAPKs pathway來阻止經由collagen所誘導的血小板凝集作用以及抑制血栓的形成，Rut未來可能作為心血管疾病的臨床用藥。
According to statistics from the World Health Organization’s top ten causes of death, the leading cause of death was cardiovascular disease. Research reported that abnormal platelet activation not only causes thrombosis also is a major cause of cardiovascular disease. Therefore, it is extremely important to develop anti-platelet drugs that can effectively prevent thrombotic diseases. In recent years, studies have found that many herbs or natural products have the potential for anti-thrombosis. Rutaecarpine (Rut) is a kind of alkaloid extracted from Evodia rutaecarpa, which has been found to exhibit anti-inflammation, anti-tumor, anti-oxidative stress, and vasodilatory effects. It has been demonstrated that Rut can inhibit platelet aggregation reaction by agonists including collagen, ADP, and arachidonic acid (AA). However, the mechanisms of Rut anti-human platelet aggregation are still unclear. Therefore, this study will explore the mechanism of Rut in human platelets. Results showed that 2.5-5 µM Rut can inhibit collagen-stimulated platelet aggregation, ATP release, intracellular Ca2+ mobilization and P-selectin expression in a concentration-dependent manner. In the platelet toxicity test (lactate dehydrogenase assay), Rut does not produce cytotoxicity. Rut can reduce the expression of PLCγ2, p47, Akt, ERK1/2, JNK1/2, and p38 MAPK protein phosphorylation but not directly through p47 protein or cGMP or cAMP pathway to inhibit platelet aggregation. Rut markedly inhibited thrombus formation in vivo. In summary, Rut repressed collagen-stimulated platelet aggregation through the inhibition of PLCγ2/PKC, Akt, and MAPKs pathways, and prevented thrombus formation. Rut may be used as a clinical drug for cardiovascular disease in the future. |
