Maréchal X, Mordon S, Devoisselle J M, Bégu S, Guery B, Nevière R, Buys B, Dhelin G, Lesage J C, Mathieu D, Chopin C
INSERM (French National Institute of Health and Medical Research), University Hospital, Lille, France.
Photochem Photobiol. 1999 Nov;70(5):813-9.
Measurement of gastrointestinal intramucosal pH (pHim) has been recognized as an important factor in the detection of hypoxia-induced dysfunctions. However, current pH measurement techniques are limited in terms of time and spatial resolutions. A major advance in accurate pH measurement was the development of the ratiometric fluorescent indicator dye, 2',7'-bis(carboxyethyl)-5,6-carboxyfluorescein (BCECF). This study aimed to set up and validate a fluorescence imaging technique to measure in vivo the intramucosal pH (pHim) of the intestine. The intestine was inserted into an optical chamber placed under a microscope. Animals were injected intravenously with the pH-sensitive fluorescent dye BCECF. Fluorescence was visualized by illuminating the intestine alternately at 490 and 470 nm. The emitted fluorescence was directed to an intensified camera. The ratio of emitted fluorescence at excitation wavelengths of 490 and 470 nm was measured, corrected and converted to pHim by constructing a calibration curve. The pHim controls were performed with a pH microelectrode and were correlated with venous blood gas sampling. Results show that pHim is determined with an accuracy of +/- 0.07 pH units and a response time of 1 min. In conclusion pHim mapping of rat intestine can be obtained by fluorescence imaging using BCECF. This technology could be easily adapted for endoscopic pH measurements.
胃肠道黏膜内pH值（pHim）的测量已被公认为检测缺氧诱导功能障碍的一个重要因素。然而，目前的pH测量技术在时间和空间分辨率方面存在局限性。准确pH测量的一项重大进展是比率荧光指示剂染料2',7'-双（羧乙基）-5,6-羧基荧光素（BCECF）的开发。本研究旨在建立并验证一种荧光成像技术，用于在体内测量肠道黏膜内pH值（pHim）。将肠道插入置于显微镜下的光学腔室中。给动物静脉注射对pH敏感的荧光染料BCECF。通过在490和470 nm交替照射肠道来观察荧光。发射的荧光被导向增强型相机。测量在490和470 nm激发波长下发射荧光的比率，通过构建校准曲线进行校正并转换为pHim。用pH微电极进行pHim对照，并与静脉血气采样相关联。结果表明，pHim的测定精度为±0.07 pH单位，响应时间为1分钟。总之，使用BCECF通过荧光成像可以获得大鼠肠道的pHim图谱。这项技术可以很容易地应用于内镜pH测量。
