Objective:To investigate the ameliorative effects of N-acetyl-D-mannosamine(ManNAc) on glucose and lipid metabolic disorders in obese mice.Methods:In vivo experiments were conducted using 21 four-week-old C57BL/6JGpt mice, randomly divided into three groups( n=7 per group): a normal control group, a high-fat diet(HFD) control grooup, and a ManNAc treatment group(400 mg·kg -1·d -1). The intervention lasted for 20 weeks. Body weight, food intake, and fasting blood glucose levels were monitored weekly. Glucose tolerance tests(GTT), insulin sensitivity tests(ITT), and respiratory metabolism monitoring were performed in the 17th, 18th, and 19th weeks, respectively. At the end of the experiment, whole-body fat distribution was assessed, and serum lipid profiles were measured. Liver and adipose tissue weights were recorded, and histological analyses including HE staining of liver, adipose and pancreatic tissues were performed. Liver transcriptome sequencing and quantitative real-time PCR(qPCR) were conducted to evaluate hepatic gene expression. In vitro, a hepatic steatosis model was established by inducing HepG2 cell with 0.4 mmol/L oleic acid, followed by treatment with 500 μg/mL ManNAc. Lipid accumulation was assessed using BODIPY staining, and the expression of lipid metabolism-related genes was quantified by qPCR. Results:ManNAc administration attenuated HFD-induced weight gain, reduced total body fat volume, and decreased liver and adipose tissue weights as well as intracellular lipid accumulation. Pancreatic islet numbers increased, while fasting blood glucose levels, glucose tolerance, and insulin sensitivity significantly improved. Serum levels of triglycerides, total cholesterol, and low-density lipoprotein levels were decreased, accompanied by enhanced energy expenditure. Additionally, hepatic expression of Cd36, Fabp3, and Scd1 was downregulated. In vitro, ManNAc significantly reduced lipid accumulation in HepG2 cells and downregulated the expression of Cd36, Fabp3, and Scd1 genes.Conclusion:ManNAc may improve glucose and lipid metabolism by modulating the PPARs-mediated fatty acid metabolic pathway, reducing lipogenesis, promoting fatty acid oxidation and energy expenditure, and enhancing insulin sensitivity, ultimately ameliorating disorders in obese mice.

Objective:To investigate the ameliorative effects of N-acetyl-D-mannosamine(ManNAc) on glucose and lipid metabolic disorders in obese mice.Methods:In vivo experiments were conducted using 21 four-week-old C57BL/6JGpt mice, randomly divided into three groups( n=7 per group): a normal control group, a high-fat diet(HFD) control grooup, and a ManNAc treatment group(400 mg·kg -1·d -1). The intervention lasted for 20 weeks. Body weight, food intake, and fasting blood glucose levels were monitored weekly. Glucose tolerance tests(GTT), insulin sensitivity tests(ITT), and respiratory metabolism monitoring were performed in the 17th, 18th, and 19th weeks, respectively. At the end of the experiment, whole-body fat distribution was assessed, and serum lipid profiles were measured. Liver and adipose tissue weights were recorded, and histological analyses including HE staining of liver, adipose and pancreatic tissues were performed. Liver transcriptome sequencing and quantitative real-time PCR(qPCR) were conducted to evaluate hepatic gene expression. In vitro, a hepatic steatosis model was established by inducing HepG2 cell with 0.4 mmol/L oleic acid, followed by treatment with 500 μg/mL ManNAc. Lipid accumulation was assessed using BODIPY staining, and the expression of lipid metabolism-related genes was quantified by qPCR. Results:ManNAc administration attenuated HFD-induced weight gain, reduced total body fat volume, and decreased liver and adipose tissue weights as well as intracellular lipid accumulation. Pancreatic islet numbers increased, while fasting blood glucose levels, glucose tolerance, and insulin sensitivity significantly improved. Serum levels of triglycerides, total cholesterol, and low-density lipoprotein levels were decreased, accompanied by enhanced energy expenditure. Additionally, hepatic expression of Cd36, Fabp3, and Scd1 was downregulated. In vitro, ManNAc significantly reduced lipid accumulation in HepG2 cells and downregulated the expression of Cd36, Fabp3, and Scd1 genes.Conclusion:ManNAc may improve glucose and lipid metabolism by modulating the PPARs-mediated fatty acid metabolic pathway, reducing lipogenesis, promoting fatty acid oxidation and energy expenditure, and enhancing insulin sensitivity, ultimately ameliorating disorders in obese mice.