Mice used in this study were age-matched Cyp2e1-null mice on 129/Svj background [13] and WT mice [stock number 002448 from Jackson Laboratory (Bar harbor, ME, USA)]. Male mice were randomly assigned to four groups fed on solid LFD (10% energy-derived calories) or HFD (60% energy-derived calories) (Research Diets, New Brunswick NJ, USA) for 10 weeks: (1) wild-type fed LFD (WT-LFD) (n=4); (2) wild-type fed HFD (WT-HFD) (n=5); (3) Cyp2e1-null fed LFD (null-LFD) (n=4); and (4) Cyp2e1-null fed HFD (null-HFD) (n=4). Weight of each mouse was recorded before the start of LFD/HFD regimen, once every week, and at the time of euthanasia. Tissue preparation for histological examination and tissue maintenance were performed as previously described [11]. The NAFLD histological scoring system (NAS) [14] was also used to evaluate the samples blindly. NASH was defined in the cases of NAS of ≥5. All animal experiments were performed in accordance with the National Institutes of Health guidelines and approved by the Institutional Animal Care and Use Committee.
