金花茶多酚对2型糖尿病大鼠胰腺的保护作用

Protective Effect of Camellia nitidissima Polyphenols on Pancreas in Diabetic Rats

目的:观察金花茶多酚(Camellia nitidissima polyphenols,CNP)对2型糖尿病大鼠血糖和胰腺的影响,探讨CNP对胰腺的保护作用。方法:建立2型糖尿病大鼠模型的方法为高糖高脂饲料喂养4周结合腹腔注射小剂量链脲佐菌素(STZ,30 mg·kg-1)。将大鼠分为正常组,高脂组,模型组,CNP低、中、高剂量组。各CNP组预防给药7 d后造模,用快速血糖仪测定各组大鼠的空腹血糖值(FBG)。造模后分别于第1,2,3天摘取大鼠胰腺,制成石蜡切片,苏木精-伊红(HE)染色,观察胰腺组织病理变化;免疫组化法(immunohistochemistry,IHC)标记胰岛素分泌情况并统计胰岛细胞阳性率。结果:与正常组和高脂组比较,模型组大鼠FBG显著升高(P<0.05),胰岛β细胞有明显形态学改变,胰岛细胞阳性率明显降低(P<0.05)。与模型组比较,CNP中、高剂量组FBG显著降低(P<0.05),并且呈现一定程度的剂量相关性,胰岛β细胞损伤程度明显降低,胰岛细胞阳性率显著回升(P<0.05),CNP低剂量组无明显差异。结论:CNP能修复胰腺损伤,促进胰岛素分泌,有效降低空腹血糖、改善葡萄糖耐受,提示金花茶多酚对胰腺有剂量依赖性的保护作用。

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.