NADH fluorescence/UV reflectance ratio provides a semi-quantitative measure for NADH fluorometry of blood-perfused rat heart

摘要

A procedure for semi-quantitative analysis of NADH fluorescence image is presented which enables non-invasive monitoring of the metabolic state of tissue in vivo. In blood perfused tissue, the NADH fluorescence intensity can be disturbed by movement and by hemodynamic and oximetric effects. These factors alter the tissue absorbance of UV excitation light and thereby the NADH fluorescence excitation efficiency. Combination of the theories of front- face fluorimetry and Kubelka and Munk for description of NADH fluorescence (F$-NADH$/) and UV reflectance (R$- 365$/$+d$/) of optically thick samples, predicts that the F$-NADH$//R$-365$/$+d$/ ratio provides adequate compensation for changes in tissue absorbance. The validity of this correction procedure is verified in tissue phantoms, in Langendorff perfused rat hearts and for rat hearts in vivo. Movement artifacts were eliminated using a CCD video camera with a biprism configuration for simultaneous measurement of fluorescence and reflectance images. Therefore, the F$-NADH$//R$+d$/ ratio can be used to monitor the metabolic state of blood perfused tissue.