Total Saponins of Dioscorea Mitigate Nonalcoholic Steatohepatitis in Mice by Regulating AMPK/SREBP-1c/ACC Signaling Pathway / 中国实验方剂学杂志

ABSTRACT

ObjectiveTo investigate the role and mechanism of total saponins of Dioscorea （TSD） in mitigating nonalcoholic steatohepatitis （NASH） in mice. MethodForty-eight C57BL/6J mice were randomized into a normal group and a modeling group. The mice for modeling were fed with a high-fat and high-cholesterol diet + 20% fructose solution for 16 weeks and randomized into model， atorvastatin （4 mg·kg-1·d-1）， and high-， medium-， and low-dose （200， 60， and 20 mg·kg-1·d-1） TSD groups. The mice were administrated with corresponding doses of drugs by gavage for 8 weeks. The mouse activity， liver index， levels of total cholesterol （TC）， triglycerides （TG）， and free fatty acids （FFAs） in the liver， and levels of TC， TG， aspartate aminotransferase （AST）， alanine aminotransferase （ALT）， γ-glutamyl transferase （GGT）， interleukin-1β （IL-1β）， and tumor necrosis factor-α （TNF-α） in the serum were measured. Hematoxylin-eosin staining， Masson staining， oil red O staining， and transmission electron microscopy were employed to observe the pathological changes， lipid accumulation， and morphological changes of liver ultrastructure. Western blot was employed to determine the protein levels of AMP-activated protein kinase （AMPK）， sterol regulatory element-binding protein-1c （SREBP-1c）， acetyl-CoA carboxylase （ACC）， and phosphorylated ACC （p-ACC） in the liver tissue. ResultCompared with the normal group, the activity of mice in the model group decreased(P<0.05， P<0.01), the levels of TC, TG, FFA and serum TC, TG, ALT, AST, GGT, IL-1β and TNF-α, liver coefficient and liver pathology scores were significantly increased, the expression of p-AMPK/AMPK and p-ACC proteins in liver tissues was significantly reduced, and the expressions of SREBP-1c and ACC proteins were significantly increased (P<0.01). Compared with the model group， atorvastatin increased the mouse activity （P<0.05）， while each dose of TSD caused no significant changed in the mouse activity. The levels of TC, TG, FFA in liver and serum TC, TG, ALT, AST, GGT, IL-1β, TNF-α, liver coefficient and liver pathological score in TSD and atorvastatin groups were significantly decreased, and the expressions of p-AMPK/AMPK and p-ACC in liver tissue were significantly increased. The expressions of SREBP-1c and ACC were significantly decreased (P<0.05,P<0.01). ConclusionTSD may alleviate NASH in mice by regulating the AMPK/SREBP-1c/ACC signaling pathway to reduce lipid synthesis.