利用螢光共軛焦顯微術監控循血綠在小鼠活體肝臟中的代謝

Abstract

循血綠是一種近紅外光的螢光染劑已經被使用在醫學和生物影像領域數十年，吸收峰值約在780奈米，螢光峰值約在805奈米。在臨床醫學上，醫師會給病患注射循血綠，循血綠會經由肝門靜脈進入肝臟，然後被肝細胞代謝經由膽管排出，所以醫師會在注射後15分鐘抽血，量測血液中殘餘的循血綠濃度，用以診斷病患的肝功能。根據組織學，肝腺泡依據功能被區分為三個區域，區域一、區域二和區域三，區域一最接近肝門靜脈最先得到來自腸道的養分，區域三最靠近中央靜脈最遠離腸道養分供給，區域二介於二者之間，在本研究中，我們利用循血綠的特性和反射式共軛焦顯微鏡隨時間拍攝肝腺泡中不同區域的影像。藉由分析這些影像資料，我們發現影像因為光漂白造成強度與對比下降。因此轉而定性上的討論肝細胞排出ICG的速率；更進一步分析肝細胞核與細胞質排出ICG的速率。區域一肝細胞排出ICG的速率最快，區域二次之，區域三最慢。細胞核排出ICG速率大於細胞質排出ICG速率，與區域無關。

Indocyanine green (ICG) is a near-infrared fluorescent dye which absorption peak about 780 nm and emission peak about 805 nm. ICG has been used for decades on medical and bio-image field. For example, doctor diagnose a patient’s hepatic function by injecting ICG into the patient and monitor its excretion with time. Since ICG is processed by hepatocytes from portal vein then excreted into the bile duct, diagnosis can be performed by drawing blood from the patient 15 minutes following ICG injection. In this study, we studied ICG metabolism within the liver acinus which is classified into three zones: zone I, zone II, and zone III. Epi-illuminated confocal fluorescence microscope is used with a liver imaging chamber to observe ICG metabolism in vivo. By analyzing ICG liver images found that ICG fluorescence was degraded by excitation light. We discussed ICG excretion rate of hepatocytes to proceed qualitative analysis in three zones. Further, studying nucleus and cytoplasm of individual hepatocyte separately because of the image contrast between nucleus and cytoplasm. In an acinus, zone I hepatocytes excrete ICG fastest. Nucleus excretes ICG fast than cytoplasm independent of zone classified.