微循环动物实验 z-bo 2020-10-14 357

　　(1) Animal anesthesia

　　In a microcirculation study in 1944, it was found that when pentobarbital sodium was injected into small animals, it was impossible to obtain vascular animals with an expected weight of more than 3 mg/100 g. There are also reports that rapid infusion of urethane can cause thrombosis. Therefore, the selection and dosage of animal anesthetics and the compatibility of anesthetics are important links in the experiment.

　　The compatibility and dosage of some animal anesthetics commonly used in microcirculation experiments:

　　1. Cat: 35 mg/kg body weight intraperitoneal injection of pentobarbital sodium: 70 mg/kg body weight chloralose or 700 mg/kg body weight carbamate intraperitoneal injection; 75 mg/kg body weight α-chloralose , Intravenous injection.

　　2. Golden hamster: 30 mg/kg pentopental sodium (25 mg/kg body weight to shorten the experiment time) was injected intraperitoneally.

　　3. Rabbit: 35-40 mg/kg body weight of pentopental sodium was injected intraperitoneally.

　　4. Rats, mice and other small animals: intraperitoneal or intramuscular injection of 25 mg/kg body weight of pentopental sodium, or intramuscular injection of urethane 130 mg/100 kg body weight. When the animal is under normal anesthesia, the corneal reflex is inhibited and stable chest breathing is maintained. If respiratory depression or deep abdominal breathing occurs, it indicates an overdose. The above amount of anesthesia can maintain good anesthesia for 2-3 hours. If you need to continue anesthesia, you can increase the original dose by one third.

　　Some experimental animals do not require anesthesia and can be performed awake, such as how to check the microcirculation of rabbit eyeballs.

　　(2) Constant temperature perfusion

　　Generally, the perfusion fluid of animal organs and tissues must be exactly the same as the composition and pH of the body fluid surrounding the organs and tissues. For example, the mesentery requires an intraperitoneal fluid environment, which is difficult to achieve.

　　Zweifach thinks as follows. No matter which perfusate is used, it must first be made into a colloid. That is, gelatin is added to the perfusion solution to make a 1% gelatin solution.

　　You need to pass the appropriate amount of oxygen and carbon dioxide through the perfusate. The pH of the perfusate should be adjusted to neutral with a buffer (pH 7.35). The temperature of the perfusate should be controlled by the controller within the animal's normal body temperature range. During the entire experiment, the perfusion fluid should be replaced slowly and continuously. Commonly used perfusate solutions include Ringer's solution, Tylord's solution, Kelda's solution and normal saline. The perfusion device and the observed animals should be placed in an adjustable constant temperature experimental observation box. This is especially important in winter. Adjust the temperature of the experimental observation box to a temperature close to the surface temperature of the experimental animal, preferably 25 to 30°C.

　　（3）Lighting equipment

　　The temperature of the lighting equipment usually cannot exceed the body temperature of the animal. It is best to keep it at 25-30°C. Otherwise it will cause vasodilation and abnormal blood flow. It is best not to light to change the natural shadow of blood. Otherwise, it will be difficult to distinguish blood oxygen saturation. The most ideal lighting equipment is a fiber optic beam cold light source, and experiments can be carried out without a cold light source lighting rod that can be inserted into the abdominal cavity, especially when observing the microcirculation of the liver, spleen, kidney and other organs. Difficult.

　　The light source used in the experiment must meet the three conditions of strong, concentrated and "cold". There are two commonly used lighting devices today. One is a high-pressure mercury lamp (220V, 80W). The advantages of this light source are strong light, less heat generation and strong contrast between blood vessels and background colors. The disadvantage is that the blood color is impractical and triggers the light source. slow. The other is a halogen tungsten lamp (5-12V, 40-100W). The latter has the advantages of small size, bright white light and fast start-up. The tungsten halogen lamp has a lens that can adjust the focal length to achieve the purpose of "condensing light" and can be replaced by a microscope lamp. Then add a blue-green insulating filter in front of the lamp to control the temperature of the light source. Relatively meet the "cold light" requirements. This kind of illumination source can provide a clear field of vision under a microscope in an ordinary room, and has little effect on the observation index. (4) Recording system

　　Microscopists often record transient changes in animal microcirculation. Choose microscopic equipment and corresponding phase cleaning equipment. To ensure successful shooting, all in-vivo photography should use split light sources, high-speed film (particle film above 24 degrees) photography. This is an important issue, but it can also improve contrast (using a green filter can enhance blood vessels and contrast the background color).

　　Camera is a commonly used recording tool. Only momentary images can be left. If possible, we recommend that you shoot movies and color video tapes.

　　When using an oscilloscope or multi-channel recorder to record the tube diameter scan curve, blood flow curve and micro pressure curve, it is ideal to be able to record and save the above signals in the microwave.