icaritin and Non-alcoholic-Fatty-Liver-Disease

Non-alcoholic fatty liver disease (NAFLD) is one of the most serious global public health concerns. However, there are currently no effective drugs for treatment of this disease. Icariin (ICA), a small-molecule natural product extracted from Epimedium brevicornu Maxim, offers various pharmacological activities. In the present work, we wondered whether ICA can attenuate NAFLD in db/db mice treated with ICA for 8 weeks and how ICA exerts an influence on NAFLD. In db/db mice, ICA treatment had a robust effect on inhibition of lipogenesis associated with NAFLD amelioration by decreasing liver lipid deposition, together with ameliorating insulin sensitivity, glucose tolerance, and fasting serum glucose. Of note, ICA-treated rats showed a much higher concentration of icaritin (ICT) in plasma, a major metabolite of ICA, about 2000 times higher than that of ICA by liquid chromatography mass spectrometry (LC-MS). Interestingly, ICT, rather than ICA, can dramatically decrease hepatic lipogenesis-related markers in oleate acid/palmitate acid (OA/PA)-induced steatosis in primary hepatocytes (PH) and HepG2 cells, and hepatic lipid accumulation in db/db mice, demonstrating the inhibitory effect of ICT on lipogenesis. Mechanistically, we found that anti-lipogenic activities of ICT were related to reducing endoplasmic reticulum (ER) stress as evidenced by Western blot, qPCR, and other assays in thapsigargin (THP) induced-ER stress models. To our knowledge, this is the first report showing the unexpected and key role for ICT on the prevention of NAFLD in db/db mice through an ER stress mechanism.

Topics: Animals; Glucose; Hep G2 Cells; Humans; Lipid Metabolism; Lipids; Lipogenesis; Mice; Non-alcoholic Fatty Liver Disease; Rats

This study aimed to reveal the effects of icaritin (ICT) on lipotoxicity induced by palmitate (PA) in hepatic cells and steatosis in high-fat diet (HFD)-fed mice as well as exploring the potential mechanisms.. Primary mouse hepatocytes and human hepatoma Huh7 cells were used to evaluate ICT effect in vitro. HFD-fed mice were used to evaluate the ICT effect in vivo.. In vitro study indicated that ICT significantly rescued PA-induced steatosis, mainly through a combination of robust increased mitochondrial respiration, fatty acid oxidation and mildly decreased synthesis of fatty acid. An HFD-fed mouse model with 8 weeks HFD-fed showed metabolic disorders, while ICT application significantly reduced the weight, serum glucose levels, insulin resistance, hepatic steatosis level and adipose contents. In consistent with the observations in cell lines, ICT rescued the HFD-impaired functions and contents of key factors related to fatty acid β-oxidation through elevated expression of peroxisome proliferator-activated receptor α (PPARα). Meanwhile, it also reversed the decreased phosphoryl levels of AKT and glucogen synthase kinase 3 (GSK3β), leading to the improvement of insulin resistance.. ICT administration had a therapeutic effect on PA- or HFD-induced hepatic steatosis and metabolic disorders. It may provide a novel strategy to construct preventive and therapeutic means for hepatic steatosis.

Topics: Adenosine Triphosphate; Animals; Diet, High-Fat; Fatty Acids; Flavonoids; Glycogen Synthase Kinase 3 beta; Hepatocytes; Humans; Insulin Resistance; Male; Mice, Inbred C57BL; Non-alcoholic Fatty Liver Disease; Overweight; Oxidation-Reduction; Palmitates; Proto-Oncogene Proteins c-akt; Reactive Oxygen Species; Triglycerides