【Animal Modeling】-The effect of exercise on pancreatic islets in diabetic rats and its mechanism

  Objective: To investigate the effect of aerobic exercise on pancreatic islets and β cells in type 2 diabetic rats and its mechanism.

  Methods: 30 Wistar rats were randomly selected as group C, and the remaining 20 rats were fed with streptozotocin combined with high-fat and high-sugar diet to establish a type 2 diabetic rat model. The 15 successful rats were kept and divided into two groups. , one group was DMC group (n=7); the other group was DME group (n=7, 1 died at the end of the experiment). The rats in the DME group exercised on the treadmill at an intensity of 20 m/min for 30 min every day, and rested for 1 d every 6 d for a total of 8 weeks. The rest of the rats were free to move in the cage. At the end of the experiment, blood was taken from the abdominal aorta to measure blood glucose and serum Ins content, and HOMA was calculated; the anterior third of the pancreas was cut for paraffin section, HE staining, and the morphology of the islet and β-cell structure were observed and photographed under a digital microscope; The perimeter and area of pancreatic islets were measured by Motic Images Advanced 3.1 image processing software under magnification field of view, and SF was calculated from this; the content of Ins, GK and trace total ATPase activity were measured after the remaining pancreas was homogenized.

  Results: Compared with the DMC group, the islet circumference and area of the DME group were significantly increased (P<0.05), but still lower than that of the C group, and the SF was significantly increased; Compared with the DMC group, the phenomenon was significantly improved; the blood glucose, Ins content, pancreatic GK and trace total ATPase activities in the DME group were significantly higher than those in the DMC group (P<0.05); SF and HOMA also changed significantly.

  Conclusion: Aerobic exercise can reduce the blood glucose concentration and improve the morphological structure of pancreatic islets and islet β cells in type 2 diabetic rats, which can be attributed to the increase of GK and ATP synthase activities and insulin sensitivity in pancreatic tissue.