动物造模,冻伤动物模型 z-bio 2021-03-30 558

　　Frostbite is a group of symptoms in which certain parts of the body are affected by the cold, causing local damage. The freezing method includes immersing rabbit feet in -25°C, freezing with 80% to 95% ethanol, and freezing rabbit ears caused by solid carbon dioxide.

　　1 Alcohol-induced freezing model

　　First, cut the right hind paw of the rabbit, and intravenously inject 3% sodium pentobarbital from the ear of the rabbit at a dose of 1 ml/kg body weight for anesthesia, and then follow the nodular nodules. Freeze the line. Next, sterilize with 75% ethanol, insert a needle with a thermocouple into the surface of the palm from above the midpoint of the freezing line, and then insert it subcutaneously into the joint of the second and third meta knuckles, and record the temperature. Freezing area. Next, the rabbit feet were immersed in 95% ethanol and frozen at -25°C. After the temperature drops to -5°C and freezes for 7 minutes, take it out and put it in 20°C water, then reheat it until the tissue temperature reaches the water temperature. After one day of freezing, the frozen area of the rabbit's foot was significantly swollen, and the area of the frozen area was less than 25%.

　　2 Liquid nitrogen induced freezing model

　　(1) Copy method Fix the experimental rabbit with a fixed frame, close the skin with curved scissors, cut off the fur on both sides of the back of the experiment, and then set 10 applications. Use% sodium sulfide for further hair removal and wash thoroughly with warm water. The silver ring (diameter 39 mm) was immersed in liquid nitrogen at -196°C, cooled and removed, and then immediately attached to the experimental parts on both sides of the rabbit's back, causing local frostbite. (2) Model characteristics 24 hours after injury, skin histological observations showed that after animal frostbite, skin frostbite, inflammatory cell infiltration, epidermal vesicle formation, and animal frostbite, epidermal hair follicle necrosis (two frostbite)); exudation Hemorrhage, inflammatory cell infiltration, edema (from layer 11 to deep layer II) frostbite); local necrosis of the skin epidermis in frozen juvenile chilblains, massive inflammatory cell infiltration and edema in the superficial dermis, and coagulation and necrosis of surrounding fibrous tissue . Surface hair follicles. Inflammatory cells in the deep dermis infiltrate to form blisters, collagen fibers are degenerated, shortened, destroyed and disorderly arranged, and the striated muscle of the muscle layer becomes the base (layer 2 or more frostbite). (3) In comparative medicine, liquid nitrogen is used as a low-temperature source, and silver balls with high heat transfer performance are used to cause freezing. You can choose different damage times to create different frostbite animal models for different experimental purposes. After 5 seconds of freezing, even after 4 days, the skin of the frozen part of the model animal is still in the pathological changes of 2 degree deep frostbite, which is very suitable for the observation experiment of drug efficacy.