Glucose loading test
Principle
The body's glucose level was measured by glucose meter at different time points through excessive glucose intake to assess the body's ability to absorb and metabolize glucose.
Appliance
Reflects the body's ability to regulate blood glucose concentration.
Operation method
Glucose Tolerance Testing Test (GTT)
Principle
The body's glucose level was measured by glucose meter at different time points through excessive glucose intake to assess the body's ability to absorb and metabolize glucose.
Materials and Instruments
Glucose powder (national medicine), saline, blood glucose meter
Glucose test strips and 1 mL syringe, surgical scissors
Move
1、Pre-experimental preparation:
Preparation of mice: The number of mice in each group is generally greater than or equal to 6 according to the experimental setup, and male mice in good physical condition are selected as the experimental subjects (if obese mice are used as the experimental subjects, it is necessary to test them after the high-fat diet induced to reach the obesity standard). At 5:00 p.m. on the day before the experiment, the mice were put into clean cages and fasted for 16 h until 9:00 a.m. on the following day. During the fasting period, the mice were allowed to maintain normal water intake.
2. Weigh each mouse and mark the serial number at the root of its tail with a marker so that the mice can be quickly identified during the experiment (alternatively, each mouse can be numbered by clipping its toes a few weeks before the experiment).
3. At 9:00 am on the following day, the glucose tolerance test will begin. Fasting basal blood glucose measurement: Take the mice out of the cage, gently place them on an iron mesh, cut off the end of their tails with scissors about 1~2 mm, gently squeeze the mice's tails along the tail vein, let the blood enrich into a single drop, and then discard the first drop of blood, and use the second drop of blood. Measure the fasting blood glucose with a glucometer and glucose test strips, and the measured value is the blood glucose value at 0 min by default.
4. After the mice are stabilized for a few moments, prepare for intraperitoneal glucose injection (IPGTT) or oral gavage of glucose (OGTT) (the corresponding volume of glucose solution can be aspirated according to the body weight of the mice in advance, and the corresponding syringe is numbered with the number of the mice). The glucose concentration for the general glucose tolerance test is 2 g/kg body weight, and 200 mg/ml of glucose solution is prepared in saline.
IP GTT: The mouse is gently picked up and injected with glucose solution using a 1 mL syringe according to standard intraperitoneal injection procedures. The volume injected is determined by the body weight of the mouse and is 0.01 mL per gram of body weight, and is timed from the time the injection is completed.
OGTT: The mouse is gently picked up and given the glucose solution using a 1 mL syringe attached to a gavage needle in accordance with standard gavage practices. The volume of glucose administered is determined by the body weight of the mouse, 0.01 mL per gram of body weight, and the time is counted from the completion of the gavage; under normal circumstances, each mouse is operated at an interval of 1 min, so that glucose measurements can be completed accurately and in accordance with the specified time for each mouse.
5. At 15 min, 30 min, 60 min, 90 min, and 120 min, the blood glucose value of each mouse at each time point was measured according to the procedure in step 3.
6. After completion of the experiment, feed each cage of mice and analyze the data.
Caveat
1、Ensure that all the experimental subjects can be detected within the specified time, and make sure that each mouse is detected at the point of time.
2、Operate as gently as possible during the process, so that the mice will not be overly shocked, resulting in excessive blood glucose in the mice.
3、Blood glucose meter pay attention to the battery power is sufficient, to avoid the use of the process of no electricity.
4、Blood glucose test paper pay attention to the preservation, can not be damp, pollution, so as to avoid data error.
Common Problems
1、Blood glucose meter can not measure the value?
A: There may be two situations. The first one is that the blood glucose level is too low, which basically does not occur in the GTT experiment.
However, it cannot be ruled out that the mice are very weak. The second is that the blood glucose level is too high, which is usually indicated by an H on the meter.
This is usually due to the fact that the mice have symptoms of diabetes and the blood glucose level is too high to be detected. In this case, the blood can be diluted with saline or PBS and then tested with the glucometer.
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