Label-free lipid droplet imaging for rapid nonalcoholic-fatty-liver-disease (NAFLD) analysis using dynamic full-field optical coherence tomography

Nonalcoholic fatty liver disease (NAFLD) is one of the most prevalent chronic liver diseases globally. Hepatic steatosis, characterized by the accumulation of lipid droplets (LDs), is a hallmark of NAFLD. Traditional pathology and specific fluorescent dye imaging have difficulty in observing LDs in their natural state within hepatocytes rapidly. In this study, a customized dynamic full-field optical coherence tomography (D-FFOCT) system was applied for label-free visualization of LDs and rapid ex vivo assessment of NAFLD. Two groups of mice fed the methionine choline-deficient (MCD) diet for one week and two weeks, respectively, underwent dual-mode FF-OCT imaging and comparative quantitative analysis. The subcellular structures — including nuclei and small LDs — were clearly observed. Quantitative analysis of D-FFOCT results revealed significant quantitative profiles in LD characteristics across various NAFLD stages. Furthermore, imaging of a nonalcoholic steatohepatitis (NASH) mouse model fed a high-fat diet for 14 weeks provided insights into the identification of inflammatory cells via D-FFOCT. These results indicate that D-FFOCT can effectively resolve the subcellular structure and quantify LDs in NAFLD models across varying severities, thereby demonstrating its potential for rapid NAFLD assessment and pharmaceutical development applications.