FRG mice are obtained by crossing Fah KO mice (Catalog No.: C001273) with B6RG mice (Rag2 and Il2rg double knockout mice, Catalog No.: C001367). Research shows that FRG mice (triple knockout of Fah, Rag, and Il2rg), developed by mating Fah KO mice with Rag2 KO and Il2rg KO mice, can be used to study human hepatocyte regeneration. After transplantation of human hepatocytes, these mice can develop "humanized livers", which are of significant importance for research in liver biology, stem cells, infectious diseases, metabolism, and gene therapy.