Interrogation of the Liver During Regeneration by Fluorescence Lifetime Imaging and Mass Spectrometry

We studied the structural and functional state of liver tissue during the regeneration process using multiphoton microscopy in combination with fluorescence lifetime imaging (FLIM) and second-harmonic generation microscopy, supplementing our findings with a mass spectrometry analysis. The regeneration process was induced by 30% or 70% partial hepatectomy (PH) of rats. The multiphoton microscopy and FLIM were used to evaluate the structure of the liver tissue and to assess the metabolic state of the hepatocytes, respectively. As a result, there was a statistically significant increase in the contribution of the bound forms of NAD(P)H during liver regeneration, indicating a metabolic shift towards oxidative phosphorylation and an increase in the intensity of biosynthesis processes in hepatocytes. Time-of-flight secondary ion mass spectrometry was used to study changes in the lipid and amino acid composition of liver tissue during regeneration. The approach used in the present work is effective for analyzing the dynamics of changes in the structural and functional state of liver tissue during the regeneration process. These results can be useful for the further development of criteria for the assessment of the regenerative potential of the liver and for predicting the dynamics of its recovery after the resection.