Didymin ameliorates dexamethasone-induced non-alcoholic fatty liver disease by inhibiting TLR4/NF-κB and PI3K/Akt pathways in C57BL/6J mice

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.