ABSTRACT
The present study aimed to investigate the protective effects and mechanisms of Didymin from Mentha spicata on non-alcoholic fatty liver disease (NAFLD) induced by dexamethasone and high-fat diet (DEX/HFD) in C57BL/6J mice. Briefly, mice were acclimated for 5 days and then subjected to DEX/HFD from days 5 to 28; meanwhile, the animals were treated with Didymin or Silibinin from days 12 to 28. Key indicators of NAFLD were then detected, including the pathological changes of liver tissues, serum biochemical indicators, inflammation, oxidative stress, apoptosis and lipid metabolism. Besides, the expressions of pivotal genes and proteins of the TLR4/NF-κB and PI3K/Akt pathways were examined to further elucidate the mechanisms of Didymin. The results demonstrated that Didymin significantly extenuated hepatocyte damage and lipid disorder. Moreover, Didymin markedly decreased hepatocyte apoptosis by regulating the expressions of B-cell lymphoma-2 (Bcl-2) family and the expressions of the caspase family. Further study elucidated that Didymin decreased the expressions of toll-like receptor 4 (TLR4), as well as the phosphorylation of inhibitor of nuclear factor kappa-B (IκB) and nuclear factor kappa-B p65 (NF-κB p65), suggesting the inhibition of Didymin on the TLR4/NF-κB pathway. Similarly, the PI3K/Akt pathway was also inhibited by Didymin, as evidenced by the decrease in the phosphorylation levels of PI3K and Akt. In summary, this study indicates that Didymin mitigates NAFLD by alleviating lipidosis and suppressing the TLR4/NF-κB and PI3K/Akt pathways, which may be a potential natural medicine for the treatment of NAFLD.
Subject(s)
Flavonoids/therapeutic use , Glycosides/therapeutic use , NF-kappa B/metabolism , Non-alcoholic Fatty Liver Disease/chemically induced , Non-alcoholic Fatty Liver Disease/drug therapy , Phosphatidylinositol 3-Kinases/metabolism , Toll-Like Receptor 4/metabolism , Animals , Dexamethasone/toxicity , Gene Expression Regulation/drug effects , Lipid Peroxidation/drug effects , Male , Mice , Mice, Inbred C57BL , NF-kappa B/genetics , Oxidative Stress/drug effects , Phosphatidylinositol 3-Kinases/genetics , Proto-Oncogene Proteins c-akt/genetics , Proto-Oncogene Proteins c-akt/metabolism , Random Allocation , Toll-Like Receptor 4/geneticsABSTRACT
Endoplasmic reticulum stress (ERS), mutual crosstalk between autophagy and apoptosis-related signaling pathway, plays an important role in the process of acute liver injury (ALI). The present study was to investigate the effects and underlying mechanisms of Asiatic acid from Potentilla chinensis (AAPC) on ALI. The model of ALI in mice was induced by administration with Lipopolysaccharide/D-Galactosamine (LPS/D-GalN). The effects of AAPC on hepatic pathology and hepatocyte apoptosis were observed by hematoxylin-eosin (H&E) staining and TUNEL staining. Serum transaminases activities were measured using an automated biochemical analyzer. Moreover, ERS and autophagy were induced in LO2 cells, respectively. Cell cycle and apoptosis were analyzed using flow cytometry. In addition, ERS and autophagy-related pathways were detected in vivo and in vitro. The results showed that AAPC significantly ameliorated LPS/D-GalN-induced ALI in mice, as evidenced by the improvement of liver pathology and the decrease in serum alanine aminotransferase (ALT) and aspartate transaminase (AST) activities. Moreover, AAPC pre-treatment markedly inhibited thapsigargin-induced cell apoptosis, accompanied by cell cycle arrest at S/G1 phase in LO2 cells. AAPC notably inhibited the activation of the PERK/ATF6 and IRE1 pathway, alleviating the extent of ERS. Additionally, AAPC significantly promoted autophagy, as evidenced by the increase in the formation of autophagic vacuoles and the number of autophagosomes as well as the increased expressions of LC3II/I, Beclin-1, Atg5 and Atg7. In summary, our results indicate that AAPC significantly ameliorates ALI by inhibiting the ERS pathway and promoting hepatocyte autophagy.
