Tiantian Zhu - College of Pharmacy, Xinxiang Medical University, Xinxiang, China
Minghui Li - College of Pharmacy, Xinxiang Medical University, Xinxiang, China
Moli Zhu - College of Pharmacy, Xinxiang Medical University, Xinxiang, China
Xu Liu - College of Pharmacy, Xinxiang Medical University, Xinxiang, China
Keke Huang - College of Pharmacy, Xinxiang Medical University, Xinxiang, China
Wenru Li - College of Pharmacy, Xinxiang Medical University, Xinxiang, China
Shuang-Xi Wang - College of Pharmacy, Xinxiang Medical University, Xinxiang, China
Yaling Yin - Henan International Joint Laboratory of Cardiovascular Remodeling and Drug Intervention, Xinxiang, China
Peng Li - College of Pharmacy, Xinxiang Medical University, Xinxiang, China

Objective(s): Epigallocatechin-۳-gallate (EGCG) has a good therapeutic effect on type ۲ diabetes mellitus (T۲DM). This work was designed to explore EGCG’s effectiveness in insulin resistance (IR) and pancreas islet β-cell function in a rat model of T۲DM. Materials and Methods: Eight-week-old male Sprague Dawley rats were randomly divided into ۶ groups, including the Control (normal diet), Diabetes (high-sucrose high-fat [HSHF] diet combined with tail vein injection of streptozotocin [STZ] for T۲DM induction) and Treatment Diabetic rats which were treated with metformin [۵۰۰ mg/kg/d] or EGCG [۲۵, ۵۰ or ۱۰۰ mg/kg/d] intragastric administration for ۱۰ weeks. With the exception of control animals, the other groups were fed the HSHF diet.  EGCG’s effects on IR and insulin secretion were assessed by measuring body weights, and fasting blood glucose (FBG), postprandial blood glucose (PBG) and insulin levels. The morphological and molecular changes of pancreas islet β-cells were examined by hematoxylin-eosin (H&E) staining, transmission electron microscopy (TEM) and immunofluorescence.Results: Rats fed the HSHF diet combined with STZ treatment had increased body weights and blood glucose amounts, accompanied by IR and impaired β-cell function, induced T۲DM, and EGCG dose-dependently restored the above indicators. Additionally, EGCG upregulated the pancreatic transcription factors pancreatic duodenal homeobox protein-۱ (PDX-۱) and musculoaponeurotic fibrosarcoma oncogene homolog A (MafA).Conclusion: These results suggest that EGCG reduces blood glucose amounts, and improve IR and islet β-cell disorder in T۲DM.

Epigallocatechin-۳-gallate, insulin resistance, Insulin secretion, Pancreatic duodenal homeobox protein-۱, Type ۲ diabetes mellitus β-cell