Investigation of Focused Ultrasound with Contrast Agent on Normal and Tumor Vascular Permeability in Mice

現今腫瘤治療的方法大部分是採用化學治療，希望增加藥物在腫瘤中的濃度，達到控制腫瘤的效果；降低在身體其他部位的濃度，減少正常組織中的副作用。在化療的藥物遞送上，依腫瘤血管與正常血管之間不同的特性，使得高分子藥物載體會傾向遞送到腫瘤組織。但高分子藥物載體從血管中遞送到腫瘤組織的過程仍遭遇到許多的阻礙。有文獻指出超音波搭配超音波顯影劑具有促進藥物遞送的能力，或許這方法可用來提升高分子藥物載體滲透出腫瘤血管的能力。 我們利用代糖螢光劑當作高分子藥物載體的模式，搭配雙光子顯微技術活體且動態觀察小鼠背部皮膚的正常血管與腫瘤血管中代糖的滲透情形。利用聚焦式超音波頻率1MHz，最大負聲壓0.6MPa，脈衝長度10ms，搭配超音波顯影劑，探討小鼠背部皮膚正常血管與腫瘤血管所造成代糖滲透的影響。實驗結果觀察到在正常血管中注射超音波顯影劑後不施打超音波和注射顯影劑後施打超音波並沒有明顯的差異，在腫瘤血管中注射超音波顯影劑後不施打超音波和注射顯影劑後施打超音波有明顯的差異，發現腫瘤血管有施打超音波後，血管外代糖的累積量有增加的情形發生。後續的研究期望找到最佳參數與技術，進而讓高分子藥物載體，在腫瘤中有更好的滲透性、有較多的累積量以及有較遠的穿透距離，進而使腫瘤藥物遞送達到最好的效果。In recent years, the development of drug delivery to the tumor has been greatly extended to achieve successful cancer chemotherapy by using various carrier systems targeted to the tumor. The purpose of the site-specific control of drug delivery is to increase the concentration in the target tissues and on the other hands, to minimize the side effects in normal tissues. In the aspect of chemotherapeutic drug delivery, due to the significant differences between normal blood vessels and tumor blood vessels, macromolecular drug carriers tend to deliver the drug to tumor tissues, however, there are lots of barriers on the way of delivery. It has been shown that through the combination of ultrasound contrast agent and ultrasound, we can improve drug delivery and by applying this method, the effects of extravasation of macromolecular drug carriers across the tumor blood vessels could be enhanced. We use dextran rhodamine as macromolecular drug carriers, together with two-photon microscope to observe the permeability of dextran in both the normal blood vessels and the tumor blood vessels in dorsal skin of mice in vivo. Besides, we also use focused ultrasound at the frequency of 1 MHz, the peak of negative pressure of 0.6 MPa, and the burst length of 10 ms, combining with ultrasound contrast agent to investigate their effects. Our results suggest that in normal blood vessels, there is no significant difference between exposure to ultrasound or not after injection of ultrasound contrast agent. On the other hand, it is significantly different when our samples are exposed to ultrasound after injection of ultrasound contrast agent in the tumor blood vessels. The accumulation of dextran outside the blood vessels is increased in the tumor blood vessels. Our long term goal is to find out the best parameter and technology to raise the permeability, to increase the amount of accumulation and to extend distance of penetration of macromolecular drug carriers in the tumor to optimize the effects of tumor drug delivery.誌謝 I要 IIbstract III錄 IV目錄 V 1 章 緒論 1-1 腫瘤 1-2 藥物遞送(Drug Delivery) 2-3 腫瘤血管的特性 3-4 高分子藥物載體(Macromolecular Drug Carriers) 5-5 超音波機械力的特性 5-6 超音波促進藥物遞送原理 7-7 研究目的 8 2 章 實驗設備與材料方法 11-1 腫瘤細胞株 11-2 實驗動物 11-3 皮膚固定裝置 11-4 雙光子顯微系統 12-5 超音波設備 13-6 超音波參數 14-7 螢光代糖(Dextran) 14-8 血管內外影像分析 14-9 實驗流程 15 3 章 結果 23-1 柱狀型聚焦式超音波探頭特性 23-2 小鼠正常血管三維造影 23-3 小鼠正常血管時間間隔影像(Time-Lapse) 24-4 正常血管內外代糖70 kDa的螢光劑隨著時間的變化情形 24-5 正常血管內外代糖70 kDa與2 MDa的螢光劑隨著時間的變化情形 25-6 小鼠腫瘤血管三維造影 25-7 小鼠腫瘤血管時間間隔影像(Time-Lapse) 25-8 腫瘤血管內外代糖2 MDa的螢光劑隨著時間的變化情形 26 4 章 討論 44 5 章 結論與未來工作 47amp;#21442;考文獻 4