动物造模,药效评价,低温游泳脑缺血 z-bio 2024-07-25 393

　　1. Modeling material animals: ICR mice, half male and half female, weighing 18-22g.

　　2. Modeling method: Tie a rubber ball equivalent to 5% of body weight to the tail 2mm away from the tail root, swim in water at 10-10.5 ℃ for 5 minutes, and remove it. Quickly cut the head with large scissors and record the breathing time of the cut.

　　3. Modeling principle: Low temperature weight-bearing swimming leads to cerebral ischemia after decapitation. After decapitation of mice, due to the cessation of blood supply, the remaining energy can only sustain brain function for a relatively short period of time. When ATP rapidly decreases to a certain level, the transport ability of Na+- K+- ATPase on the nerve cell membrane is lost, Na+and K+exchange stops, and a large amount of Na+accumulates inside the cell. The concentration of K+outside the cell increases, the membrane potential changes, and the excitation and conduction functions of nerve cells are lost. Literature shows that after complete ischemia for 20 seconds, the bioelectric activity of the cerebral cortex in mice disappears. The muscles lose the stimulation of nerve excitation, and the breathing activity stops. Under low temperature conditions, the activity of various enzymes in the brain decreases, the energy metabolism rate decreases, and after decapitation, the consumption of residual energy slows down. The duration of neural function in the brain is prolonged, manifested as significantly prolonged wheezing time.

　　4. After modeling, the gasping time of mice after decapitation was (23.0 ± 5.94) seconds.

　　5. Precautions: In the experiment, if the average weight of the mice is light, the water temperature should be adjusted higher. If the average weight is heavy, the water temperature should be adjusted lower. Generally, the water temperature should be controlled within 8-12 ℃. After the water temperature is determined, it should be kept constant during the experiment to avoid fluctuations in the experimental results caused by changes. At room temperature of 22-26 ℃, a mouse can swim once and the water temperature can rise by about 0.5 ℃. Therefore, after swimming once, the water temperature should be adjusted with ice water. The temperature of ice water is constant. Based on pre testing, adding a certain amount of ice water can quickly restore the water temperature to the set value, which is convenient and fast. Throughout the experiment, the fluctuation of water temperature should be controlled within the range of 0.5 ℃.