Title:Angiotensin-(1-7) Improves Islet Function in a Rat Model of Streptozotocin- Induced Diabetes Mellitus by Up-Regulating the Expression of Pdx1/Glut2
Volume: 21
Issue: 1
Author(s): Jingjing Li, Ruifang Zhu, Yalin Liu, Jinhui Yang, Xiaoyan Wang, Lisha Geng, Tingting Xu and Junhua He*
Affiliation:
- Department of Endocrinology, The Second Hospital of Shanxi Medical University, Taiyuan, Shanxi,China
Keywords:
Angiotensin (1-7), diabetes mellitus, rats, islet function, Pdx1, Glut2, Gk.
Abstract:
Objective: To observe the effects of angiotensin-(1-7) (Ang-(1-7)) on glucose metabolism,
islet function and insulin resistance in a rat model of streptozotocin-induced diabetes mellitus (DM)
and investigate its mechanism.
Methods: Thirty-four male Wistar rats were randomly divided into 3 groups: control group, which was
fed a standard diet, DM group, high-fat diet and injected with streptozotocin, and Ang-(1-7) group
receiving an injection of streptozotocin followed by Ang-(1-7) treatment. Blood glucose level, fasting
serum Ang II and insulin levels, and homeostasis model assessment of insulin resistance (HOMA-IR)
were measured. The pancreases were collected for histological examination, protein and gene expression
analysis.
Results: Compared with the control group, fasting blood glucose, serum angiotensin II level, and
HOMA-IR value increased, while serum insulin level decreased in the DM group. Moreover, islet
structure was damaged, β cells were irregularly arranged, the cytoplasm was loose in the DM group.
Expressions of Pancreatic duodenal homeobox-1 (Pdx1), glucose transporter-2 (Glut2) and glucokinase
(Gk) were significantly decreased in the DM group compared with the control group. However, the
DM-associated changes were dramatically reversed following Ang-(1-7) treatment.
Conclusion: Ang-(1-7) protects against streptozotocin-induced DM through the improvement of insulin
secretion, insulin resistance and islet fibrosis, which is associated with the upregulation of Pdx1,
Glut2 and Gk expressions.