Experiments on Execution and Necropsy Disposal of Laboratory Animals
Experiments on Execution and Necropsy Disposal of Laboratory Animals
The experimental method was obtained from the official website of the Fourth Military Medical University
Operation method
Experiments on Execution and Necropsy Disposal of Laboratory Animals Move I. Methods of Execution of Laboratory Animals 1. Execution methods for larger animals The following methods are applicable to guinea pigs, cats, rabbits, dogs and other larger or larger animals. (1) Air embolization method: Inject air into the vein of the animal to make it embolize and die soon. When the air is injected into the vein, the air can be mixed with the blood in the right heart with the beating of the heart so that the blood becomes foamy and circulates to the whole body with the blood. If it enters the pulmonary artery, it can block its branches and enter the coronary artery of the heart, resulting in coronary artery blockage, serious blood circulation disorders occur, and the animal will die soon. Generally, rabbits and cats need to be injected with 20-40 ml, and dogs need to be injected with 80-150 ml. This is the most commonly used method. (2) acute blood loss method: ① one-time extraction of a large amount of blood from the heart, can make the animal die quickly. ② Dogs can use femoral artery and vein bloodletting method. To the dog according to each kilogram of body weight intravenous injection of thiopental 20 ~ 30mg, the animal anesthesia, exposure of the femoral triangle, with a sharp knife in the femoral triangle to make a transverse incision of about 10cm, the femoral artery and vein cut off the whole, the blood is immediately sprayed out. Use a piece of wet gauze to constantly wipe away the blood and blood clots at the place around the femoral artery incision, and at the same time, constantly use tap water to flush the bleeding, so that the femoral artery incision is kept unobstructed, and the animal will die in 3~5min. (3) Destruction of the medulla oblongata method: If the brain has been exposed after the acute experiment, the medulla oblongata can be destroyed with instruments, resulting in the death of the animal. For rabbits, a mallet or a hand can be used to hit the back of the brain, damaging the medulla oblongata and causing death. (4) Open pneumothorax method: The animal's chest is opened, resulting in an open pneumothorax. At this time, the pressure in the pleural cavity is equal to the atmospheric pressure, and the lungs are compressed by the atmosphere, resulting in lung atrophy, mediastinal swing, and the animal suffocates to death. (5) The method of death by chemical drugs: injecting formalin solution into the vein of the animal, so that the protein in the blood coagulates, resulting in serious obstruction of blood circulation in the whole body and death by lack of oxygen. Adult dogs need to inject 10% formalin solution 20ml into the vein. 4% pentobarbital for intravenous injection (1mg/kg), or 20% ethyl carbamate (urethane or urethane for thoracic injection (5ml/kg) to the animal's vein injected with potassium chloride solution, so that the animal's cardiac muscle loss of contraction ability, acute dilatation of the heart, resulting in flaccid cardiac arrest and death. Adult rabbits should be injected 5-10ml of 10% KCl solution into the vein; adult dogs should be injected 20-30ml into the vein. 2. Methods of execution of small animals: The following methods are applicable to such small animals as rats and mice. (1) Spinal dislocation method: the animal's cervical vertebrae are dislocated and the spinal cord is disconnected to kill the animal. The thumb and forefinger of the left hand are pressed down hard on the head of the rat, and the right hand grabs the rat's tail and pulls it backward hard, and the rat will die immediately. This is the most commonly used method. (2) Acute blood loss method: the eyeballs can be removed, resulting in massive blood loss and death. (3) Striking method: the right hand grasps the rat's tail and lifts it up, striking its head with force, and the rat will die immediately after spasm. The rat will die immediately after spasm. Striking the rat's head with a mallet can also kill the rat. (4) Guillotine method: When guillotining a mouse, the left thumb and forefinger can be used to clamp the mouse's shoulder blade and fix it. The right hand holds the scissors and quickly cuts off the head. When guillotining a rat, the experimenter should wear cotton gloves, hold the rat's head with the right hand and the back with the left hand, exposing the neck, and the assistant should use scissors at the rat's neck to cut off the rat's head. (5) Cotton balls soaked with ether or chloroform may be anesthetized by sealing them in a glass container together with the small animal. 3. Frogs are often executed by inserting a metal probe into the foramen magnum of the occipital bone to destroy the cerebral spine. The left hand with a wet cloth to wrap the frog, exposing the head, and with the index finger to press the front of the head, thumb pressure on the back, so that the head is bent forward; the right hand holding the probe from the front of the head along the center line to the tail side of the piercing, and touched the depression that is the occipital foramen magnum is located. After entering the occipital foramen magnum, the tip of the probe is turned toward the head and probed forward into the cranial cavity, and then stirred in all directions to destroy the brain tissue. After the brain tissue is destroyed, the probe is withdrawn, and then pierced by the occipital foramen, turned to the tail side, and pierced into the spinal canal parallel to the spinal column, in order to destroy the spinal cord. After the muscles of the frog's limbs are completely relaxed, the probe is withdrawn and the needle hole is plugged with a dry cotton ball to prevent it from bleeding. For more product details, please visit Aladdin Scientific website.
If the execution is of a toad, prevent the secretion of the poisonous glands from being shot into the eyes during the operation. If shot into, immediately flush the eyes with large amounts of saline. Disposal of animal carcasses after the experiment 1. Animals that die from normal causes during the experiment, such as blood loss, trauma, etc., as well as those that are executed after the experiment, should be put into garbage bags and handed over to the School Animal Center for disposal. Note that experimental animals are forbidden to eat. 2. Animals dying of infectious diseases should be incinerated or buried (below 1m), or fixed and put into a cesspool to be used as fertilizer after rotting and fermenting.