Molecular determination of liver fibrosis by synchrotron infrared microspectroscopy

Liver fibrosis is an adaptive response to various injuries and may eventually progress to cirrhosis. Although there are several non-invasive methods available to monitor the progression of liver fibrogenesis, they cannot reliably detect fibrosis in its early stages, when the process can be stopped or reversed by removing or eliminating the underlying etiological agent that cause the hepatic injury. In this study, early fibrosis alterations were characterized biochemically, morphologically, and spectroscopically in a rat bile duct ligation (BDL) model. Progressive elevations in serum alanine transaminase (ALT), aspartate transaminase (AST), and bilirubin levels in the BDL rats were found indicating the dynamic deterioration of hepatocellular function. Immunofluorescence microscopy using monoclonal anti-collagen III antibody further revealed abnormal intertwined networks of collagen fibres surrounding the portal areas and extending into the lobules towards the central veins in all BDL samples starting from week one. Synchrotron infrared microspectroscopy of liver sections was exploited to generate false color spectral maps based upon a unique and strong collagen absorption at 1340 cm− 1, revealing a collagen distribution that correlated very well with corresponding images provided by immunofluorescence imaging. We therefore suggest that infrared microspectroscopy may provide an additional and sensitive means for the early detection of liver fibrosis.