氣球擴張術經常應用於治療冠狀動脈粥狀硬化疾病引起之血管阻塞。然而，大約有30 %~50 %左右曾經接受過氣球擴張術治療的病患，於半年內會有血管再阻塞(restenosis)的不良情況發生。因此，血管再阻塞的情形即成為氣球擴張術這項技術應用上的最大缺點。一般相信，血管結構在遭受氣球擴張術破壞後，會促使血管內平滑肌細胞的增生和遷移作用，進而產生新生內膜(neointima)成為血管再阻塞的主要原因。所以，本篇研究的目的在利用actinomycin D當作治療藥物，在大鼠的頸動脈動物模式中探討actinomycin D是否具有預防氣球擴張術引起的內膜增生並探討其可能之作用機轉。在體外的(in vitro)細胞培養方面，分別給予A10細胞株不同濃度的actinomycin D (各為0.1 ?m/ml、1 ?g/ml和10 ?g/ml)處理後，抽取蛋白質進行西方點墨法分析。研究的結果顯示許多與調節細胞週期相關的蛋白質(例如：PCNA、FAK、Raf)表現量與正對照組(positive control)相比較皆有下降的趨勢，且藥物的抑制作用呈現劑量依附特性。此外，應用BrdU崁入法 (bromodeoxyuridine incorporation) 分析細胞增生的結果顯示，A10細胞經由actinomycin D處理後與正對照組比較具有明顯抑制細胞增生的情形(p< 0.01)。在動物體內(in vivo)實驗方面，將actinomycin D溶於30% (w/v)的pluronic F-127 gel中(藥物最終濃度為100 ?g/ml)，並將此膠狀物包覆於經過氣球擴張術處理的血管外圍。組織切片結果顯示濃度100 ?g/ml的actinomycin D相較於假手術組(sham controls)，可以明顯抑制氣球擴張術後的血管再阻塞情形。綜合本篇研究的結果發現，以actinomycin D來預防經氣球擴張術破壞後血管再阻塞的情形，應屬不錯的藥物治療選擇。; Percutaneous coronary angioplasty (PTCA) is usually indicated for atherosclerosis-induced coronary obstruction. However, there are approximately 30% to 50% of patients receiving PTCA suffered from restenosis within 6 months. Therefore, restenosis has been regarded as a major limitation for this procedure. It is generally believed that the proliferation and migration of vascular smooth muscle cells (VSMCs) were involved in the development of restenosis by balloon injury. Thus, the present study was to examine whether actinomycin D as a pharmacological remedy could prevent balloon injury-induced restenosis in rat carotid arteries. In the in vitro study, total protein extracted from A10 cells treated with 0.1, 1 and 10 ug/ml of actinomycin D was subjected to western blot analysis. Our results showed that several cell-cycle regulators such as PCNA, FAK, Raf were down- regulated as compared to the positive controls. The down-regulation effects of actinomycin D on these proteins were in a dose-dependent manner. In addition, bromodeoxyuridine (BrdU) incorporation analysis demonstrated that actinomycin D significantly reduced proliferation of A10 cells as compared to the positive controls (p<0.01). In the in vivo study, 100 ug/ml of actinomycin D resuspended in 30% (w/v) of pluronic F-127 gel was coated on the periphery of balloon-injury carotid artery. Our in vivo results showed that the balloon injury-induced restenosis can be significantly inhibited by 100 ug/ml of actinomycin D as compared to the sham controls. The finding of the present study suggested that actinomycin D can be a potential candidate as the pharmacological approach to prevent PTCA-mediated restenosis
