Fig. 4: The therapeutic efficacy of AAV_{MUSE-ΔhFGF21}-mediated gene therapy in diet-induced NAFLD model mice.

a Schematic representation of the experimental procedure and schedule for AAV_MUSE-mediated ΔhFGF21 expression (AAV_{MUSE-ΔhFGF21}) in NAFLD model mice. At 10 weeks after starting the HFFCD diet, NAFLD model mice were transduced with AAV_{MUSE-ΔhFGF21}or transduced with control AAV_Luc via tail vein. One week after AAV injection, the transduced NAFLD model mice were exposed to nebulized muscone for 4 h once each week until week 31 or were exposed to a vehicle (a mixture of castor oil and ddH₂O). The HFFCD diet was continued for an additional 21 weeks, and a battery of metabolic parameters in mice were measured at the indicated time points. i.v., intravenous. b The ΔhFGF21 levels in plasma were quantified 4 h after muscone exposure every two weeks over 21 weeks. c, d The fat mass and lean mass were measured by magnetic resonance imaging at 29 weeks after starting the HFFCD diet. e–h Indirect calorimetry was performed 27 weeks after starting the HFFCD diet in NAFLD model mice. e Volume of O₂ (VO₂) consumption. f Area under the curve for O₂ consumption. g Volume of CO₂ (VCO₂) expiration. h Area under the curve for CO₂ expiration. i The body weight of NAFLD model mice were monitored every week over 31 weeks. j Representative images of the NAFLD model mice 31 weeks after starting the HFFCD diet. Representative pictures of dissected livers (k) and epididymal adipose tissues (m); the weight of liver tissues (l) and epididymal adipose tissues (n) were determined 31 weeks after starting the HFFCD diet. o Representative H&E is staining, and Sirius red staining of liver sections. The images represent typical results from three independent measurements. Scale bars, 50 µm. Data in (b–i, l and n) are presented as means ± SEM (e–h, n = 4 mice; b–d, i, l and n, n = 5 mice). P values were obtained from two-tailed unpaired t tests. *P < 0.05, **P < 0.01, ***P < 0.001, ****P < 0.0001. Source data are provided as a Source Data file.