Type I diabetes model

Type I diabetes model

Type I diabetes model: pancreatic islet beta cell destruction, absolute insulin deficiency. Streptozotocin STZ can selectively destroy islet β cells of certain species of animals and can induce diabetes in many animals. Generally, rats and mice are used to make animal models. Animal models of type I diabetes include animals that spontaneously produce autoimmune diabetes, and chemical ablation of pancreatic cells. There are many methods to establish T1D animal models, such as using anti insulin serum, pancreatectomy, glucose infusion, beta cytotoxic drugs, viruses, etc; The animal model reflecting human T1D is of great significance in both basic research and preclinical studies, which not only helps to understand the pathogenesis of T1D, but also helps to evaluate new therapies with therapeutic potential (monotherapy or combination therapy). There are five commonly used spontaneous models of type I diabetes, NOD mice and BB rats are widely used at present.

Experimental procedure:

Normal rats can be modeled after a single high-dose injection of streptozotocin STZ or multiple low-dose injections after 3 to 7 days; STZ causes the decrease of islet secretion and the rise of blood sugar, which shows the rise of blood sugar in diabetes.

Grasping and fixation methods for experimental animals

1. White mice are relatively gentle and generally do not bite people. They do not need to be caught with gloves. First, grab the tail of the mouse with your right hand, lift it up, and place it on a cage or experimental platform. Use the thumb, index finger, and middle finger of your left hand to grab the fur on the back of the mouse's ear and neck, and clamp the tail with your ring finger and little finger.

2. Rats have sharp teeth, so be careful not to be bitten when capturing them. When grabbing young rats from the cage, it is necessary to grasp the base of the rat's tail and not let the rat hang in the air for too long, otherwise it may anger the rat and cause the skin on the tail to fall off. When grabbing large rats, use your left hand to pinch from the center of your back to your chest, but do not use too much force. It is best to wear protective gloves, but the gloves should not be too thick.

If it is administered by gavage, intraperitoneal injection, intramuscular or subcutaneous injection, the mouse grasping technique can be used to adjust the posture of the rat in the hand before operation.

If tail vein blood collection or injection is required, the rat can be fixed in a fixator or placed in a inverted beaker according to the tail vein injection method of mice, and the tail of the rat can be left outside for operation.

3. Domestic rabbits are easy to tame and generally do not bite humans, but their claws are sharp. When grabbing, remember not to forcefully grab the rabbit's ears, waist, or limbs. When the rabbit quiets down in the cage, open the cage door, grab the fur and skin on the neck with your right hand, gently lift the animal, pull the rabbit to the cage door with its head facing outward, and then quickly use your left hand to lift the rabbit's buttocks, giving the rabbit a comfortable and secure feeling. According to the experimental requirements, it can be fixed by hand, rabbit table or rabbit box.

(1) Hand fixation: If oral administration is required, one should sit on a chair and grab the skin on the back of the rabbit's neck with one hand, while holding the two hind limbs between the thighs with the other hand. Grasp the rabbit's lower body with your thighs and use your empty hands to grab onto both front limbs to secure the rabbit in place. Grasp the hands on the neck and back while pinching both ears, preventing the head from moving, and then proceed with the operation.

(2) Rabbit table fixation: If neck, chest, or abdominal surgery is required or respiratory and blood pressure observation is needed, the limbs should be tied up after anesthesia (the hind limbs should be tied above the ankle joint, and the forelimbs should be tied above the wrist joint), and then fixed in a supine position on the rabbit table.

(3) Rabbit box fixation: If only ear vein injection or blood collection is required, rabbit box fixation can be used.

The first step in the dog experiment is to seal the dog's mouth and be careful not to be bitten. For tamed dogs, you can gently stroke the fur on their nape from the side, then quickly tie their mouth with a strap, tie a knot on the upper jaw, then loop back to the lower jaw to tie a second knot, and then lead them to the neck and nape to tie a third knot. For untamed dogs, use a dog headband to clamp their neck, press the dog to the ground, tie their mouth or administer intravenous anesthesia, and then remove the dog headband. Finally, place the dog on the experimental platform, fix its head first, and then fix its limbs (using the same fixation method as rabbits).

When conducting chronic experiments, if the experimenter personally feeds it daily and gradually tames it, the goal of full cooperation can be achieved during the experiment. For some non stimulating and painless experiments, dogs will also obey and cooperate.

When catching toads, frogs should not touch the venom glands on their ears to prevent venom from entering their eyes. Grasp the frog with your left hand, use your middle finger, ring finger, and little finger to press down on its left ventral side and hind limb, use your thumb and index finger to press down on your right and left forelimbs, and use your right hand to perform the operation. The frog can also be fixed to the frog board with fixing nails.