Eugenol alleviated nonalcoholic fatty liver disease in rat via a gut-brain-liver axis involving glucagon-like Peptide-1.

Eugenol, an active ingredient of many medicinal aromatic plants, has been proved to have the hypolipidemic effect, but its potential mechanism of action is still unknown. This study aimed to investigate whether eugenol regulates liver lipid accumulation in high-fat diet (HFD) induced nonalcoholic fatty liver disease (NAFLD) rats via the gut-brain-liver axis involving glucagon-like peptide-1 (GLP-1). Hepatic vagotomy was performed in NAFLD rats to determine the role of eugenol in regulating hepatic lipid accumulation via vagus nerve. The results showed that after eight weeks of eugenol administration in NAFLD rats, serum total cholesterol (TC), triglyceride (TG) and hepatic TG decreased. However, eugenol showed no significant effect on the increased food intakes and weight gain caused by the HFD. Eugenol promoted the secretion of GLP-1 into the blood, increased GLP-1 receptor (GLP-1R) expression in the duodenum, liver, arcuate nucleus (ARC) and paraventricular nucleus (PVN), increased c-fos expression in the nucleus tractus solitarii (NTS), and promoted ZO-1 and occludin expression in duodenum. Furthermore, steatosis and lipid accumulation were significantly alleviated. Hepatic vagotomy partially attenuated the improvement of eugenol in hepatic lipid accumulation in NAFLD rats. In conclusion, eugenol regulates hepatic lipid metabolism via a gut-brain-liver axis involving in GLP-1, providing a new strategy for the treatment of NAFLD.

Atractylodes chinensis volatile oil up-regulated IGF-1 to improve diabetic gastroparesis in rats.

Objectives: Diabetic gastroparesis (DGP) is one of the main complications of diabetes, and more than half of diabetes cases are accompanied by gastroparesis. This study aims to explore the effect of Atractylodes chinensis volatile oil (ACVO) on DGP rats. Materials and Methods: The rats were injected with STZ combined with a high-sugar and high-fat diet in an irregular manner to establish the DGP model. ACVO at different doses (9.11 mg/kg, 18.23 mg/kg, and 36.45 mg/kg) were given by intragastric administration. A mixture of cisapride and metformin was used as the positive control. At the end of the experiment, gastric emptying and intestinal propulsion were determined. Then the tissue samples and blood were taken from each group for serum analysis, western blot and immunopathological examination. Results: After treatment with ACVO, body weight increased and blood glucose decreased when compared with rats in the DGP group. Gastric emptying and intestinal propulsion were accelerated, and gastric acid secretion increased. The serum insulin-like growth factor-1 (IGF-1) level was increased. Protein expressions and positive cells of IGF-1 receptor (IGF-1R), acetylcholine transferase (CHAT), and stem cell factors (SCF) in the stomach were significantly increased determined by western blot and immunofluorescence staining. The morphology and the number of interstitial cells of Cajal (ICCs) in the stomach were restored, determined by hematoxylin and eosin staining and immunohistochemical staining, respectively. Conclusion: ACVO effectively alleviated DGP in rats, and its mechanism may be related to the up-regulation of IGF-1/IGF-1R signaling.