Experimental mice drug administration and blood collection method

1. Gavage

The gavage needle for mice is composed of a syringe and a feeding tube. The feeding tube is about 1 nm long. A small metal ball is welded to the tip of the feeding tube. The metal ball is hollow. The purpose is to prevent damage when the feeding tube is inserted. The metal ball is bent at a 20-degree angle to accommodate the bending between the mouth and esophagus. Connect the plug of the feeding tube tightly to the interface of the syringe and inhale a fixed amount of liquid medicine; hold the mouse in the left hand and pick up the prepared syringe in the right hand. Put the tip of the feeding tube needle into the oropharynx of the mouse, and gently push down along the back wall of the pharynx. The feeding tube will slide along the esophagus into the stomach of the mouse, and the insertion depth is about 3cm. Squeeze the syringe with the middle finger and thumb, and press the index finger slowly down the tip of the needle rod to infuse the liquid of the syringe into the stomach of the mouse. If resistance is encountered or 1/3 of the needle tube is visible during insertion, the Jiang feeding tube is removed and reinserted, because the stomach is not inserted into the stomach at this time.

2. Injection

(1) Subcutaneous injection

Subcutaneous injection administration is the process of pushing the drug solution into the subcutaneous connective tissue and absorbing it into the blood circulation through capillaries and lymphatic vessels. Subcutaneous injection is often used for skin on the back or inner thigh. During operation, the skin at the injection site is routinely disinfected, and then the skin is lifted. The injection needle is inserted into the skin at an obtuse angle, and the needle is gently swung to the left and right. Easy to swing means that it has been penetrated under the skin and then gently sucked if there is no blood return , The drug can be injected slowly under the skin. When pulling the needle, the left thumb and index finger pinch the needle into the needle for a moment to prevent leakage of the drug. The injection volume is about 0.1-0.3ml / 10g body weight.

(2) Intradermal injection

It is to inject the drug solution between the epidermis and the dermis of the skin, to observe the changes in the permeability of the blood vessels of the skin or the intradermal reaction. Inoculation and allergy tests are generally given as intradermal injections. First cut off the hair at the injection site and disinfect it locally. Hold the skin with the left thumb and index finger to tighten it. Between the two fingers, puncture the 4.5 needle with a tuberculin syringe. The needle enters the superficial layer of the skin and then upward. Prick the tip and pierce it, inject the liquid into the skin. After the injection, a small white skin mound appeared, and the pores on the skin were very obvious. The injection volume is 0.1 ml / time.

(3) Intramuscular injection

Mice are small in size and have few muscles, and intramuscular injections are rarely used. When mice are injected with drugs that are insoluble in water and suspended in oil or other solvents, intramuscular injection is used. During operation, one person Baoding the mouse, the other person grasps one hind limb of the mouse with the left hand, and the syringe is held with the right hand. Quickly insert the syringe at a 90 ° angle with the semitendinosus muscle and inject the drug solution. The dose should not exceed 0.1ml / 10g body weight.

(4) Intravenous administration

Place the mouse in a metal cage or mouse clip, pull the tail through the hole of the metal cage or mouse clip, and grasp the middle of the mouse tail with the left hand. The mouse has 2 arteries and 3 veins, and 2 arteries respectively On the dorsal and ventral sides of the tail, three veins are distributed in the shape of a character. Generally, two veins on the left and right are used. Pull out the hair that runs along the tail vein, and place the tail in 45-50 ℃ warm water for a few minutes or 75 % Alcohol cotton ball wipes the tail repeatedly to achieve the purpose of disinfecting and dilating the blood vessels of the tail and softening the epidermal keratin. When the tail vein is injected, pinch the mouse tail with the left thumb and index finger to make the vein more full, use the middle finger to remove Hold up the tail underneath, grasp the tip of the tail with the ring finger, hold the needle syringe with a size 4 needle on the right, make the needle parallel to the vein (less than 30 ° angle), enter the needle from the bottom 1/4 of the tail, and start to inject the drug slowly, Observe carefully that if there is no resistance and no white skin ridges appear, it means that the blood vessel has been penetrated and the drug can be officially injected. Some experiments require repeated tail vein injections every day. The injection site should start from the tail end as far as possible and follow the tail root in order. The part moves, and the position of the blood vessel is changed for injection. The injection volume is 0.05-0.1ml / 10g body weight. After pulling out the needle, press the injection site with your thumb and gently press for 1-2 minutes to prevent bleeding.

(5) Intraperitoneal injection

Lift and fix the mouse with the left hand so that the abdomen of the mouse is facing upwards, the head of the mouse is slightly lower than the tail. The right hand holds the syringe to puncture the needles in the lower abdomen near the white line of the abdomen. Pierce the abdominal muscles at a 45 ° angle to the skin, penetrate the abdominal muscles into the peritoneal cavity, and the resistance disappears when the needle tip passes through the abdominal muscles and enters the peritoneal cavity. Fix the needle, keep the tip of the needle fixed, and withdraw the needle plug. If there is no blood return, intestinal fluid and urine, you can inject the drug solution. The injection volume is 0.1-0.2ml / 10g body weight.

(2) Blood collection

1. Tail cut blood collection

The thumb and index finger of the left hand grabbed the skin of the neck of the mouse from the back, and the head of the mouse was face down. After the mouse was kept, the tail was soaked in 50 ° hot water for several minutes to fill the blood vessels in the tail. Dry the tail, and then use scissors or a blade to cut off the tip of the tail by 1-2mm, and use the test tube to take the blood out, and massage from the base of the tail to the tip of the tail. After taking the blood, use a cotton ball to compress the hemostasis and apply 6% liquid cotton glue to the wound to stop the bleeding. Each blood collection volume is 0.1mL.

2. Blood removal

Grab the skin on the neck of the mouse with the left hand, gently press it on the experimental table, take the lateral lying position, and press the skin around the eye of the mouse to the back of the neck as far as possible to make the eyeball protrude. Quickly clamp the eyeball with ophthalmologic curved forceps, turn the mouse upside down, and catch the outflowing blood with a vessel. Immediately after blood collection, use gauze to stop bleeding. Each blood collection volume is 0.6-0.1mL.

3. Heart blood collection

The mouse was fixed in the supine position, the hair in the chest area was cut off, after the skin was disinfected, the left heart index finger was used to touch the heart beat in the left 3-4 intercostal space, and the right hand was holding a syringe with a 4-5 gauge needle to select the heart The puncture is at the strongest stroke. When the heart is punctured, blood will automatically enter the syringe. Each blood collection is 0.5-0.6mL.

4. Decapitate blood collection

Cut the neck of the mouse approximately 1 / 2-4 / 5 with scissors in the right hand to allow blood to flow into the test tube. This method can collect blood 0.8-1.2mL.