Hepatic protective effects of Shenling Baizhu powder, a herbal compound, against inflammatory damage via TLR4/NLRP3 signalling pathway in rats with nonalcoholic fatty liver disease

Objective: High-fat diet (HFD) and inflammation are two key contributors to nonalcoholic fatty liver disease (NAFLD). Shenling Baizhu powder (SLBZP), a classical herbal compound, has been successfully used to alleviate NAFLD. However, its specific mechanisms are not fully understood. In this study, we assessed the anti-NAFLD effect of SLBZP in vivo.

Methods: Rats were fed an HFD with or without SLBZP or with probiotics. At the end of week 16, an echo magnetic resonance imaging (EchoMRI) body composition analyser was used to quantitatively analyse body composition; a micro-computed tomography (micro-CT) imaging system was used to evaluate whole body and liver fat; and the Moor full-field laser perfusion imager 2 was used to assess liver microcirculation, after which, all rats were sacrificed. Then, biochemical indicators in the blood and the ultrastructure of rat livers were evaluated. Protein expression related to the liver Toll-like receptor 4 (TLR4)/Nod-like receptor family pyrin domain-containing 3 (NLRP3) signalling pathway was assessed using Western blot analysis. Further, high-throughput screening of 29 related inflammatory factors in liver tissue was performed using a cytokine array.

Results: SLBZP supplementation reduced body weight, serum free fatty acid, and insulin resistance index (P < 0.05). It also ameliorated liver microcirculation and ultrastructural abnormalities. EchoMRI and micro-CT quantitative analyses showed that treatment with SLBZP reduced fat mass and visceral fat (P < 0.05 and P < 0.01, respectively). In addition, SLBZP decreased the expression of lipopolysaccharide (LPS)-activated TLR4/NLRP3 signalling pathway-related proteins and altered the expression levels of some inflammatory cytokines in liver tissues.

Conclusion: SLBZP can inhibit NLRP3 inflammasome activation and interleukin-1β release by suppressing LPS-induced TLR4 expression in rats with HFD-induced NAFLD. Thus, SLBZP may be beneficial for the prevention and treatment of inflammatory damage and associated diseases.