Liver fibrosis, a disease characterized by the excessive accumulation of extracellular matrix originating from activated hepatic stellate cells (HSCs), is a common pathological response to chronic liver injury resulting from a variety of insults. However, drugs that effectively block the activation of HSCs have still not been adequately investigated. This study demonstrates that metformin decreased the number of activated-HSCs through induction of apoptosis, but did not impact numbers of hepatocytes. Metformin upregulated BAX activation with facilitation of BIM, BAD and PUMA; downregulated Bcl-2 and Bcl-xl, but did not affect Mcl-1. Additionally, metformin induced cytochrome c release from mitochondria into the cytoplasm, directly triggering caspase-9-mediated mitochondrial apoptosis. The decline in mitochondrial membrane potential (ΔΨm) and deposition of superoxide in mitochondria accelerated the destruction of the integrity of mitochondrial membrane. Moreover, we verified the therapeutic effect of metformin in our mouse model of liver fibrosis associated with nonalcoholic steatohepatitis (NASH) in which hepatic function, NASH lesions and fibrosis were improved by metformin. In conclusion, this study indicated that metformin has significant therapeutic value in NASH-derived liver fibrosis by inducing apoptosis in HSCs, but does not affect the proliferation of hepatocytes.

Objective. This study aims to evaluate the clinical effects of Ling Gui Zhu Gan formula (LGZG), a famous TCM formula, for the management of serum lipids and obesity and preliminarily elucidates the bioactive components and the potential mechanism. Methods. Cluster analysis was adopted to investigate the TCM herbs and their frequency of occurrence for treating hyperlipidemia and obesity in an academic experience database of Chinese famous TCM doctors (http://www.gjmlzy.com:83). Then, relevant randomized controlled trials (RCTs) about LGZG supplementation in improving lipid levels and obesity were retrieved and analyzed. Lastly, the integration of network pharmacology, as well as greedy algorithms, which are theoretically well founded for the set cover in computer science, was exploited to identify the bioactive components of LGZG and to reveal potential mechanisms for attenuation or reversal of hyperlipidemia and obesity. Results. Based on the cluster analysis of 104 cases in TCM academic experience database, four TCM herbs in LGZG showed high-use frequency for treating hyperlipidemia and obesity. Meta-analysis on 19 randomized controlled trials (RCTs) with 1716 participants indicated that LGZG supplementation significantly decreased the serum levels of total triglycerides, total cholesterol, low-density lipoprotein cholesterol, BMI, and body weight and increased high-density lipoprotein cholesterol, compared with clinical control groups. No serious adverse effect was detected in all studies. Twenty-one bioactive components of LGZG, mainly flavonoids (i.e., naringenin, kaempferol, and kumatakenin), saponins (i.e., hederagenin), and fatty acids (i.e., eicosenoic acid), had the potential benefits possibly by regulating multiple targets such as PTPN1, CYP19A1, and ESR2, as well as a few complex pathways including the TNF signaling pathway, PPAR signaling pathway, arachidonic acid metabolism, fat digestion, and absorption. Conclusion. The present study has proved the clinical value of LGZG as a complementary treatment for attenuation or reversal of hyperlipidemia and obesity. More high-quality clinical and experimental studies in the future are demanded to verify its effects and the precise mechanism of action.