Abstract
To investigate the effects and potential mechanisms of human umbilical cord mesenchymal stem cells, exosomes, and their conditioned media on lipid storage in oleic acid (OA) and palmitic acid (PA) treated hepatocytes and high-fat methionine- choline deficient diet (HFMRCD) induced non-alcoholic steatohepatitis (NASH) mice. AML12 cells were stimulated with OA and PA to establish the lipid storage cell model. HucMSCs, exosomes, and culture medium were then co-cultured. At the same time, C57BL/6 mice were fed an HFMRCD for 6 or 8 weeks to establish a NASH mouse model. The effect of HucMSCs, exosomes, and culture medium on lipid droplet repair of hepatocytes or NASH mice was then assessed. The weight of hepatocytes or liver tissue, Oil Red O, hematoxylin-eosin staining, Masson staining, Western blot, and qPCR were used to detect the related IL-6, TNF-α, TGF-β1 andEI24/AMPK/mTOR pathway expression in hepatocytes and liver tissue. Compared with the model group, the effect of HucMSCs-Ex on inhibiting the accumulation of lipid droplets was more obvious at the cell level. In vivo study showed that HucMSCs-Ex reduces activity scores in NASH mice and improves liver tissue morphology by reducing vacuolar degeneration, fat deposition, and collagen deposition of liver tissue. Western blot and qPCR results showed that inflammatory factors and AMPK/mTOR or EI24-related autophagy pathways were altered before and after treatment. HucMSCs, HucMSC-Ex, and CM can promote autophagy in hepatocytes or NASH mice through the AMPK/mTOR or EI24-related autophagy pathway and alleviate injury associated with lipid deposition, collagen deposition or inflammation, reversing the progression of NASH.