Blood glucose meter

The oral glucose tolerance test (OGTT) was performed according to Kong et al. [19 (link)] with minor modifications. Sixteen, 8-week-old male KM mice, weighing 46.06 ± 1.66 g, were fasted overnight and divided into control and test groups (n = 8 per group). Each group was administered 2 g/kg body weight glucose into their stomach via oral administration with a proper gavage needle. The test group was simultaneously administrated, via intraperitoneal injection, a 1.0 mL dose of 0.1 mg/mL 6×mGLP-1 dissolved in physiological saline. The control group was administered an equivalent amount of physiological saline. Blood samples were taken from the tail vein of each mouse at 0, 10, 30, 60 and 120 min, and blood glucose levels were measured with a blood-glucose meter (Sinocare, Changsha, China).

To establish type 1 diabetes in mice using streptozotocin (STZ) (S0130, Sigma-Aldrich, USA), 6–8-week-old male C57BL/6 mice were first fasted for 6–8 h and then each mouse received intraperitoneal injection of STZ (10 mg/mL) at 50 mg/kg body weight. STZ treatment was performed daily for five consecutive days. One month after last STZ treatment, the blood glucose level was measured every 2 weeks using blood glucose meter (Sinocare, China). Mice with two consecutive readings of blood glucose levels above 16.7 mmol/L were considered diabetic. Mice will be used for further experiments 5–6 months after diagnosis of diabetes.

Right after 20 days of the treatment (Day 45 of life), Intraperitoneal(IP) glucose tolerance test (IPGTT) was performed [24 (link)]. The mice were fasted overnight (16 h) before the morning of the IPGTT. The mice were injected ip with glucose (2 g/kg as a 50% glucose stock solution). Glucose levels were measured by tail vein blood sampling using a blood glucose meter (Sinocare Inc., Changsha, China) immediately before the mice were injected intraperitoneally with glucose and then at 30, 60, 90, and 120 min after administration. Data were expressed as the absolute values of blood glucose concentrations. Total area under the curve of the glucose response (AUC) was calculated using GraphPad Prism 5.0 software.

Mice were fasted for 8 hours before the OGTT experiment. Glucose levels were measured by tail vein blood sampling using a blood glucose meter (Sinocare Inc., Changsha, China). After the fasting, the glucose levels were measured, then the mice were administered glucose (2 g/kg body weight) by oral gavage, and tail sampling was performed at the time point of 30, 60, 90and 120 minutes.

After treatment for 5 weeks, mice were fasted overnight and given 2 g/kg glucose by oral gavage. The blood glucose of mice was measured with a blood glucose meter (Sinocare, Shenzhen, China) after glucose administration for 0, 30, 60, 90, and 120 min. The area under the curve (AUC) was calculated to give the OGTT of mice.