Therapeutic efficacy of MSC-ex in the HFD-induced NAFLD model.
(A) Representative result of NTAs of MSC-ex and HFL1-ex. (B) Representative results of nanosized vesicles (MSC-ex and HFL1-ex) photographed by TEM and AFM. Scale bar, 100 nm. (C) Exosome markers CD9, CD63, Alix, and TSG101 were positive in MSC-ex and HFL1-ex by immunoblotting. (D) C57BL/6 mice were fed a HFD (40%) for 10 weeks and then were i.v. administered PBS as a control or 10 mg/kg MSC-ex or 10 mg/kg HFL1-ex or deMSC-ex from the 10th week to the 14th week of HFD feeding. (E) Representative Images of gross liver appearance from mice. (F and G) Representative images of H&E (scale bars, 50 μm) (F) and Oil Red O (scale bars, 20 μm) staining (G) of liver sections from mice from each treatment group. (H) Liver contents of total TG and TC in each group. (I) Liver indexes (liver index = liver wet weight/body weight) and body weight changes of mice from each group. (J) i.p. ITTs evaluated individual insulin tolerance by injecting insulin at a dose of 0.75 IU/kg body weight; blood glucose levels were detected at 0, 30, 60, 90, and 120 min and compared with that at 0 min. Individual glucose tolerance was assessed by IPGTT; fasted mice were administered 1 g of glucose/kg body weight by i.p. injection, and blood glucose levels were determined at 0, 30, 60, 90, and 120 min. (K) Fasting glycaemia (after 16-h fast). (L and M) Serum insulin (L), and TG, TC, AST, and ALT (M) levels in each group. Data are represented as the mean ± SEM. Statistical analyses were performed by a one-way ANOVA (H–M). ∗p <0.05, ∗∗p <0.01, ∗∗∗p <0.001 vs. normal chow diet group; #p <0.05, ##p <0.01, ###p <0.001 vs. HFD group. AFM, atomic force microscopy; ALT, alanine transaminase; AST, aspartate transaminase; deMSC-ex, MSC-ex-free conditional medium supernatant; HFD, high-fat diet; HFL1, human lung fibroblast 1; HLF1-ex, foetal HFL1-derived exosomes; IPGT, i.p. glucose tolerance test; ITT, insulin tolerance test; MSC-ex, MSC-derived exosomes; MSC, mesenchymal stem cell; NAFLD, non-alcoholic fatty liver disease; NTA, nanoparticle tracking analysis; TC, total cholesterol; TFM, transmission electron microscopy; TG, triglycerides; TSG101, tumour susceptibility gene 101.