開發微流道系統晶片分析剪應力與缺氧刺激對於內皮細胞產生活性氧化物與一氧化氮之影響

Abstract

心血管疾病是全球最大死因之一，研究心血管的各式反應變得十分重要。本研究中我們開發出一個微流道系統用以建立得以模擬人體內的氧氣及剪應力環境。我們利用四個平行但寬度不同的微流道製造出來的剪應力分別為2.5, 5, 10, 20dyne/cm2，同時我們也一個建立了一個介於2.8 %-12 % 的氧氣濃度梯度。我們在這些微流道中培養人類臍靜脈血管內皮細胞，使這些內皮細胞同時受到剪應力以及氧氣梯度的刺激模擬在人體內的條件。我們使用相位差顯微鏡以及螢光染劑來分析細胞的型態、活性氧化物種以及一氧化氮的胞內表現。我們初步發現細胞沿著流體方向排列的速度較不存在缺氧條件的細胞快，我們更發現間歇性缺氧卻沒有如同缺氧促進細胞轉向的效果。而活性氧化物的分泌量則在一小時的實驗中受到缺氧而有所抑制，最後在六小時的實驗中，一氧化氮表現量並沒有發現明顯變化。這項研究有助於了解內皮細胞在各式心血管疾病、腫瘤以及人體運動時的反應，開發的微流道平台更有助於後人運用研究更複雜的生理條件。

Cardiovascular diseases are the leading cause of death worldwide, making the study of various cardiovascular responses critically important. In this study, we developed a microfluidic system designed to simulate the oxygen and shear stress environments within the human body. Using four parallel microchannels of different widths, we generated shear stresses of 2.5, 5, 10, and 20 dyne/cm2. Additionally, we established an oxygen concentration gradient ranging from 2.8 % to 12 %. Human umbilical vein endothelial cells were cultured within these channels, exposing them to both shear stress and the oxygen gradient to simulate in vivo conditions. We employed phase-contrast microscopy and fluorescent dyes to analyze cell morphology, reactive oxygen species, and nitric oxide production. Preliminary findings revealed that in hypoxic conditions, cell alignment along the flow direction was faster compared to normoxic conditions. We also found that cyclic hypoxia did not enhance cell reorientation. ROS production was suppressed under hypoxia within one hour, while NO production showed no significant changes over a six-hour period. This study enhances our understanding of endothelial cell responses in various cardiovascular diseases, tumors, and during physical exercise. Furthermore, this developed platform can also be a powerful tool for researchers studying complicated physiological conditions.