Objective: To observe the effect of Camellia nitidissima polyphenols (CNP) on blood glucose and pancreas in type 2 diabetic rats

and explore the protective effect of CNP on pancreas.Method: A rat model of type 2 diabetes mellitus was established with high-glucose and high-fat diets combined with intraperitoneal injection of low-dose streptozotocin (STZ

30 mg · kg-1) for four weeks. The rats were divided into normal control group

high-fat control group

model control group

low-dose CNP group

medium-dose CNP group and high-dose CNP group. Each group was treated with CNP for 7 days

and then the fasting blood glucose (FBG) was measured by fast blood glucose meter. At the 1

2 and 3 day after modeling

pancreas were collected

made into paraffin sections and stained by hematoxylin-eosin (HE staining). The pathological changes of pancreatic tissues were observed. Immunohistochemistry (IHC) was used to label insulin secretion and measure the positive rate of insulin.Result: Compared with the normal control group and the high-fat control group

the FBG of the model control group increased significantly (P<0.05). Islet β cells had significant morphological changes

and islet cell positive rate was significantly reduced (P<0.05). Compared with the model control group

FBG of medium-dose and high-dose CNP groups decreased significantly (P<0.05)

with a certain dose dependence. Islet β cell damage was significantly reduced

and Islet cell positive rate significantly increased (P<0.05). There was no significant difference between low-dose CNP group and model control group.Conclusion: CNP can repair pancreatic injury

promote insulin secretion

effectively reduce fasting blood glucose and improve glucose tolerance

suggesting that CNP have a dose-dependent protective effect on pancreas.