Tao-Hong-Si-Wu-Tang protects against methionine- and choline-deficient diet-induced hepatic steatosis in rats and is associated with inhibition of oxidative stress, inflammation, apoptosis, and pyroptosis.

BACKGROUND

Non-alcoholic fatty liver disease (NAFLD), which is the most prevalent chronic liver disease, affects more than 30% of the adult population worldwide. Lifestyle interventions and management of metabolic comorbidities are the current main treatments. Thus, it is urgent to find candidate drugs for NAFLD. Traditional Chinese medicine (TCM) formulas have been extensively applied to treat NAFLD in China. Tao-Hong-Si-Wu-Tang (THSWT), a classic TCM formula with anti-oxidation, anti-inflammation, and anti-apoptosis, has emerged as an important formula for hepatoprotection. Based on its biological actions, we speculate that THSWT may have the therapeutic effect on NAFLD.

METHODS

For dose exploration, the rats were randomly divided into six groups (n = 3-4 in each group): a control group, a model group, and four treatment groups receiving different doses of THSWT (0.5 g/kg, 2.5 g/kg, 5.0 g/kg, 7.5 g/kg; gavage). NAFLD rat model was established by feeding a methionine- and choline-deficient (MCD) diet for two weeks. On day 8 of MCD diet feeding, THSWT treatment was initiated and continued for seven days, with tissue collection performed on day 15. The effect of THSWT on MCD diet-induced hepatic steatosis was evaluated by haematoxylin and eosin (H&E) staining and hepatic steatosis grade scores. The best dosage of THSWT was used to further confirm the protection of THSWT on MCD diet-induced hepatic steatosis in rats. Therefore, a new batch of animals was randomly divided into three groups: a control group, a model group, and a THSWT treatment group (n = 7 in each group). The MCD modelling and THSWT treatment protocols were the same as above. H&E, Oil Red O, and Masson's trichrome staining, qPCR for lipid metabolism-related genes, immunoblot for Collagen I and II, and the commercially available kits for hepatic triglycerides (TG) and hydroxyproline (HYP) and serum alanine aminotransferase (ALT) and aspartate aminotransferase (AST) levels were used to evaluate the effects of THSWT on hepatic steatosis. Furthermore, immunofluorescence staining and immunoblot were performed to examine the key proteins expression and activation involved in the protection of THSWT on NAFLD.

RESULTS

THSWT (2.5 g/kg/day) treatment can alleviate MCD diet-induced hepatic steatosis (including slight fibrosis) in rats. Mechanistically, THSWT treatment is associated with diminishing hepatic reactive oxygen species (ROS), 3-nitrotyrosine (3-NT) and malondialdehyde (MDA) levels, while increasing hepatic GSH levels; inhibiting TLR4/9-IKK-NF-κB-TNF-α/IL-1β/IL-18 innate immune signalling; suppressing JNK and Caspase-3 apoptosis signalling, and Caspase-1/11/8-Gasdermin D (GSDMD) and Caspase-3-GSDME pyroptosis signalling in the liver of rats feeding a MCD diet.

CONCLUSIONS

THSWT alleviated MCD diet-induced hepatic steatosis in rats possibly via inhibiting hepatic oxidative stress, pro-inflammatory cytokines expression, apoptosis, and pyroptosis. THSWT is a classic prescription worth exploring for treating hepatic steatosis in future.