Metabolomics-Based Study: Effects of Fructose, Glucose, and Mannose on Islet Cells and Change of Serum Markers in Streptozotocin-Induced Diabetic Rats

Introduction: experiment uses metabolomics to explore the effects of glucose, fructose, and mannose on the metabolism and pancreatic islet structure of rats, providing ideas and references for clinical and practical applications. Method: In this experiment, rats were randomly divided into four groups of 10 rats each: the normal control group, glucose group, fructose group, and mannose group. The sugar for each group was dissolved in water and freely ingested by the rats for 8 weeks. After 8 weeks, 5 rats were randomly selected from each group and injected intraperitoneally with STZ. After three days of observation, tissues were collected. Pathological tissue staining was performed to analyze the structure of rat pancreatic islets, and metabolomics analysis was conducted on rat serum. Based on the differential metabolites, predictive analysis of the metabolic pathways of the three monosaccharides was performed. Result: The results showed that glucose had a protective effect on rat pancreatic islet structure and reduced the degree of islet destruction caused by STZ. Fructose had a weaker protective effect than glucose but still demonstrated some protection. Mannose showed almost no protective effect on rat pancreatic islet function. Discussion: Serum metabolomics analysis suggested that the possible mechanisms underlying the effects of different monosaccharides on rats involved tyrosine metabolism, pentose phosphate metabolism, and Type 2 diabetes mellitus. In contrast, the potential mechanisms associated with STZ injection were related to arginine and proline metabolism, the mTOR signaling pathway, and amoebiasis. Conclusion: This experiment systematically revealed the differential effects of glucose, fructose, and mannose on the structural protection and metabolic pathways of rat pancreatic islets through metabolomics and histopathological analyses, providing an important theoretical basis for diabetic nutritional intervention and drug target development.