Endogenous Fluorescence Dissimilarity Assessment of Four Potential Biomarkers of Early Liver Fibrosis by Preservation Media Effect.

Build-up of extracellular matrix in liver fibrosis results in changes on endogenous molecules expression that may be studied through the fluorescence characterization of ex vivo liver samples. To the best of our knowledge, no investigations have provided in-depth evidence and discussion on the changes of the endogenous fluorescence in ex vivo tissue due to the effects of the preservation media. In this work, we contrast and analyze the endogenous fluorescence from tryptophan, vitamin A, hydroxyproline and elastin cross-links potential biomarkers of the liver fibrosis, in in vivo measurements and liver samples preserved on formaldehyde, and two standard preservation media. As it is known, chemical changes in tissue, caused by formaldehyde fixation, alter the endogenous fluorescence spectra. We propose the use of phosphate-buffered saline (PBS), and Iscove's Modified Dulbecco's Medium (IMDM) to elude the fluorescence changes. PBS and IMDM showed to maintain the endogenous fluorescence characteristics similar to in vivo conditions. The results of this work point the way for a more reliable assessment of endogenous fluorescence in ex vivo hepatic studies.