以溫感型透明質酸膠體作為控制藥物釋放載體評估急性缺血性腦中風之保護潛力

Abstract

腦中風是指腦部發生急性的血管病變，而本研究所探討之缺血性腦中風佔了 所有中風的 87%，是由於腦部因血栓阻塞而造成局部血液循環不足、供氧減少而 對細胞產生傷害。而病人常因為中風後留下的嚴重後遺症，造成長期失能，因此 在急性期給予病人有效的治療，減少因為中風而造成的神經學症狀是一個相當重 要的議題，而現今臨床診療指引所提供的靜脈血栓溶解治療及血管內取栓術，則 因為適應症規範嚴格，少有患者能使用，意即現行治療只在腦中風初期直接注射 讓血栓溶解的藥物，而後就沒有其他介入治療方式。 因此本研究開發一個材料作為一個藥物載體，利用膠體測試不同中風階段的 有效藥物，輔助臨床研究進而找到適合的藥物。本研究主要聚焦於在腦組織受傷 前期，藉由降低發炎反應幫助後面神經功能的傷後組織功能恢復更容易形成。將 設計溫感型透明質酸(HA)膠體搭載藥物藉由硬腦膜下腔注射填入中風的空腔， 而搭載的藥物則具有抗發炎、抗氧化、組織修復和再生能力的表沒食子兒茶素沒 食子酸酯(EGCG)。 本研究以 FTIR 和 1H-NMR 檢驗交聯官能基的改變與交聯程度，再鑑定膠體 流變性質以及模擬體外降解，測定降解速率，以及體外藥物釋放速率;細胞實驗 的部分，使用 WST-1 測定細胞材料毒性，Live/Dead 染色觀察細胞活性;動物實 驗，利用光栓塞(photothrombosis stroke)造成小鼠產生缺血性中風並注入本實驗之 溫感型膠。最後，行為實驗及組織切片分析，顯示本實驗材料 HXP 確實可以於 動物模型中風後初期階段搭載 EGCG 藥物注射至中風空腔，且可加速組織修復。

Stroke is one of the leading causes of mortality and disability worldwide. This study focuses on ischemic stroke, which accounts for about 87 % of all strokes. Ischemic stroke happens when a vessel supplying blood to the brain is obstructed. Considered the clinical guideline, tissue plasminogen activator, tPA, is the gold standard for treating ischemic stroke. However, many people couldn’t meet the indication criterias to receive the medication. Besides, current treatment only focuses on dissolving the clot in the early stage of stroke onset; there is no other following treatment to facilitate the tissue-repairing process. To assist current clinical research, we develop a hyaluronate-based thermosensitive gel, “HXP” for decreasing the initial inflammatory response, facilitating the following proliferation and remodeling process in the early stage of ischemic stroke. We expected to minimize the stress and death of the tissue around the stroke site and reduce the inflammatory response. We used FTIR and 'H-NMR to ensure the cross-linking reaction between Pluronic F127and HA. We also measured rheological properties, release profile and degradation rate of our materials. For the in vitro study, WST-1 assay and Live/Dead staining were used to test cytotoxicity and biocompatibility. For the in vivo study, we conducted photothrombotic stroke on mice to induce ischemic stroke. In sum, EGCG-loaded HXP was found to be effective in mice behavioral tests and histology analysis. Also, HXP gel exhibits the potential to help the clinical study of different stages in acute ischemic stroke.