动物造模,药效评价,肺水肿 z-bio 2024-07-31 364

　　1、 Experimental purpose

　　1. Understand the basic principles and methods of replicating rat pulmonary edema models.

　　2. Further proficiency in basic experimental procedures for rats.

　　2、 Experimental equipment

　　1. One surgical scissors, one ophthalmic scissors, one medium-sized and one ophthalmic forceps, one balance, and three 2ml syringes.

　　2.0.1% adrenaline solution (1:1000), 6% ammonium chloride solution, 1 injection of adrenaline.

　　3. Three rats.

　　3、 Copy method

　　1. Weigh the weight of the rat

　　Weigh the rats in a paper box of known weight, deduct the box weight, and record the actual weight of the rats.

　　2. Medication administration

　　According to the body weight of the rats, three rats were given medication. The first rat was intravenously injected with 0.1ml adrenaline (0.1ml 0.1% adrenal solution) per 100g body weight; The second mouse was intraperitoneally injected with 0.6ml of 6% ammonium chloride per 100g body weight, and the third mouse was intramuscularly injected with 5mg of adrenaline.

　　3. Observation

　　Observe the changes of the animals after administration. After administration, the animals may have dyspnea, tachycardia first, then breathing upward, so that the respiratory rate slows down and the heart stops. Most animals can see pink foam like liquid flowing from the nose, and finally the whole body twitches and dies of heart failure. Usually surviving for tens of minutes. The above symptoms may vary depending on the medication administered, but they can all significantly cause pulmonary edema.

　　4. Result judgment

　　After the animal dies, take out the intact lungs (which can be ligated with sutures to the trachea and blood vessels) and weigh them. Calculate the lung weight to body weight ratio, and the pulmonary edema index=lung weight x 1000/body weight. It is generally believed that an index greater than 50 indicates the development of pulmonary edema. The indications for observing pulmonary edema are:

　　(1) Swelling in appearance, with bruising in the middle, and only inflated alveoli visible at the edges.

　　(2) Weight increases, lungs do not atrophy, and have toughness.

　　(3) There is water flowing out from the cut surface, with a concave middle and slightly protruding edges.

　　4、 Brief mechanism of replication

　　Toxic doses of adrenaline and iron amide can cause tachycardia, and the left ventricle cannot fully discharge the injected blood. The end diastolic pressure of the left ventricle gradually increases, which can cause an increase in pressure in the right atrium, leading to pulmonary vein congestion. Pulmonary capillary venous pressure also increases. Once it exceeds the plasma colloid osmotic pressure, it leads to an increase in tissue fluid formation, which cannot fully reflux the lymphatic system, resulting in pulmonary edema. Before death, foam like liquid flowed from the mouth of the animal, and after death, the dissected respiratory tract was also full of foam liquid, indicating that plasma entered the respiratory tract through the pulmonary vessels. Experimental evidence has shown that during the formation of pulmonary edema, there are indeed labeled proteins that penetrate blood vessels and alveolar membranes and enter alveoli and bronchioles. As plasma is rich in protein, it is easy to form foam and difficult to eliminate when gas flows through during respiration. Foam forms very quickly. A small amount of plasma can form a lot of foam, so that the respiratory tract is soon filled with white foam, seriously affecting gas exchange and causing death of animals. However, if the foam can be removed in time, the volume of liquid can be greatly reduced, thus reducing the obstruction of the respiratory tract, rapidly improving the hypoxia. With other measures, life can often be saved, and even the pulmonary function can be fully recovered.