Mechanism-Oriented Model Selection in MASH Research: Insights from the iHFC Diet and TSOD/TSNO Mice

Metabolic dysfunction-associated steatohepatitis (MASH) represents a systems-level disorder driven by the interplay of metabolic stress, bile acid dysregulation, gut microbiota remodeling, and immune activation. Because no single experimental platform recapitulates the full spectrum of human disease—from steatosis and fibrosis to spontaneous hepatocellular carcinoma (HCC)—model selection must be guided by the dominant biological mechanism under investigation rather than by phenotypic similarity alone. This review proposes a mechanism-oriented framework for model selection, illustrated by representative experimental systems, including the intensified high-fat/high-cholesterol diet supplemented with cholate (iHFC diet) and Tsumura–Suzuki obese diabetic (TSOD) and non-obese (TSNO) mouse models. The iHFC diet provides a reproducible platform for interrogating the bile acid–microbiota–macrophage axis in fibro-inflammatory progression, whereas TSOD mice represent a valuable system in which spontaneous MASH–HCC development can emerge under chronic metabolic imbalance without engineered oncogenic triggers. TSNO mice serve as a controlled background for dissecting bile acid-dependent susceptibility. We further integrate hepatocyte mitochondrial dysfunction, immune remodeling, and stellate cell activation into this triadic framework and position additional diet-induced, genetic, and in vitro models within a complementary translational landscape. Together, this mechanism-centered framework provides a practical roadmap for rational model selection and enhanced translational precision in MASH and metabolic hepatocarcinogenesis research.