| 摘要: | 黃芩?元對內皮細胞生長及附著等生物效應機轉之探討 研究生 謝昀志 中國醫藥學院中國藥學研究所 藥理學組 中文摘要 心臟血管病變及癌症是人類重要致死疾病，許多醫學、藥學研究者，期望能研發治療此類疾病的有效方法。而尋找新的治療心臟血管疾病及新的抗癌藥物是熱門的研究方向之一。在台灣目前政府正大力推動以現代化科學化的理論為基礎，進行傳統中藥的研究。本研究以黃芩?元(baicalein) （中藥黃芩Scutellaria baicalensis GEORGI有效成分之一），探討其對老鼠心臟內皮細胞的生物活性作用。在實驗室中我們以黃芩?元處理培養的老鼠心臟內皮細胞，發現處理黃芩?元之內皮細胞其生長幾乎完全停滯。細胞週期分析顯示黃芩?元可使內皮細胞停止在G1及G2/M期。進一步分析黃芩?元造成細胞生長之抑制，是否由於細胞週期調控基因之調控，西方轉漬法分析結果發現經黃芩?元處理後之內皮細胞Cdk1、Cdk2、cyclin A及cyclin D2等基因之蛋白質表現及其相關激?活性均有明顯下降之趨勢，但p15INK4B, p21CIP1/WAF1, p53 和 cyclin E 等蛋白質表現量會增加。然而黃芩?元對cyclins D1, D3, A or B, Cdk3, Cdk4, p16INK4A, p27KIP1, pRb1 等蛋白質在內皮細胞之表現沒有明顯影響。由本研究之結果我們可以推論黃芩?元之所以能抑制老鼠心臟內皮細胞之生長，主要原因是使促進細胞生長之分子，如Cdk1、Cdk2、cyclin A及cyclin D2等之表現受到抑制，降低了週期調控激?之活性，使內皮細胞之生長減緩甚至停滯。此外，本論文之研究結果亦發現黃芩?元可改變actin蛋白在內皮細胞內的分佈位置，同時也具有抑制內皮細胞移位的能力；但是在預處理黃芩?元時，內皮細胞的移位與血管形成能力反有增加之趨勢。由此結果我們可以推論黃芩?元具有抑制內皮細胞生長及抑制新血管形成之作用，有關黃芩?元抑制細胞生長之分子機轉，本論文已證實是經由對一些細胞週期基因Cdk1、Cdk2等分子之表現抑制作用造成。但有關黃芩?元促進內皮細胞形成新血管之作用分子機轉，尚待我們進一步探討; Effects of Baicalein on Proliferation and Adhesion of Cultured Rat Heart Endothelial Cells Yun-Chih Hsieh Institute of Chinese Pharmaceutical Science China Medical College Abstract Baicalein, a flavonoid present in the root of Scutellaria baicalensis GEORGI, has been reported to inhibit cell proliferation in various types of cells antagonize platelet aggregation. In this study, the effect of baicalein on cell growth was examined in primary cultured rat heart endothelial cells(RHECs). We have observed that baicalein mediated the dose- and time-dependent growth arrest in primary cultured endothelial cells at both G1 and G2/M phases. 100μM baicalein treatment caused a nearly complete inhibition of cell proliferation after three to five days of incubation. Furthermore, the baicalein-mediated growth arrest accompanied by the down-regulation of the cyclin D2, cyclin A, cyclin-dependent kinase 1 (Cdk1) and cyclin-dependent kinase 2 (Cdk2) proteins and up-regulation of p15INK4B, p21CIP1/WAF1, p53 and cyclin E proteins. However, baicalein had no effect on the levels of cyclins D1, D3, A or B, or on Cdk3, Cdk4, p16INK4A, p27KIP1, pRb1 proteins in rat endothelial cells. Evaluation of the kinase activity of cyclin-Cdk complexes showed that baicalein decreases Cdk1, Cdk2, cyclin D2 and cyclin A protein expression in rat endothelial cells and results to the markely reduced Cdk/cyclin-associated kinase activities. These results suggest that reduction of Cdk1, Cdk2, cyclin D2 and cyclin A proteins expression could prevent the entry into the S-phase in baicalein-treated endothelial cells. In addition, baicalein induced the reorganization of cytoskeletal actin and decreased the migration activity of RHECs. Furthermore, in functional studies, pretreatment of baicalein induced the adhesion of RHECs to vitronectin and increased the capillary-like tube formation on Matrigel. In conclusion, baicalein inhibits the cell proliferation and migration of RHECs in culture, whereas induces angiogenesis in vitro. |
