【Animal Experiment】-Intravenous injection procedure in mice

  This is also a common operation, a little bit difficult, without guidance, you may feel a little at a loss at first. But it can be said with certainty that as long as the method is mastered, the tail vein injection of mice is still very easy.

  Steps:

  1. Fix the mouse first. The easiest way to fix the mouse is to put the mouse in the box, let its tail stick out of the lid, grab the mouse tail with your hand, and gently pull it out to fix it. The mice are gone. This kind of fixation method allows mice to move around in the box, and the fixation is not very firm, but as long as you are skilled in tail vein injection, it is enough for injection.

  Another fixing method is to use a small cylinder, preferably made of metal, (you can make it in a local blacksmith shop or buy a custom made in a white iron shop). First, the metal is relatively strong, and it can be used to fix it on an iron frame. , Easy to operate. A section of the cylinder has a lid that can be removed, and there is a small hole in the middle of the lid to allow the mouse's tail to stick out (the small hole in the middle can be wrapped with tape to prevent the sharp edge from cutting the mouse's tail). The other section can be made of a metal mesh, and the shape of the mesh can be made into the shape of the bullet head. The net-like structure allows light to penetrate closer, making it easier for mice to get into the cylinder. The length of the cylinder is about 10cm and the diameter is about 3~4cm. It can be a series of cylinders of length and diameter, suitable for mice of different sizes.

  2. After the mouse is fixed, it is ready to be injected. Generally, a disposable 1ml syringe is sufficient. A glass 1ml syringe can also be used, and a No. 4 needle is sufficient.

  3. Before injection, the blood vessels of the mice should be filled. You can use 75% alcohol cotton ball wipe method or use warm water soaking method. If the blood vessel of the mouse is very unclear, it is recommended to use warm water soaking method, the water temperature should not be hot. After soaking in warm water for 2 to 3 minutes, remove the tail of the mouse and wipe it with a dry cotton ball. Wait a while, after the blood vessels are filled, the needle can be inserted after rubbing with an alcohol cotton ball. If the blood vessels are still not full, you can soak in warm water repeatedly, and you must not risk injections, unless you are very skilled, another matter.

  4. There are four blood vessels in the tail of a mouse. It is generally believed that the two left and right veins are easier to inject. These two veins are often used for needle injection. Generally, the injection site is required to be close to the tail end of the mouse, so that if the injection fails, the injection point can be selected upwards. However, the needle should not be placed too far down, because the lower the vein, the thinner the vein and the more difficult the operation. Generally, it is better to place the lower third of the tail of the mouse.

  5. The most important thing is to get the needle. When inserting the needle, the operator's left index finger and thumb fixed the tail of the mouse, so that the tail of the mouse was bent down after passing the thumb, and the needle insertion point was close to the nail of the thumb. The needle and the blood vessel are at an angle of about 30°, the needle tip is inclined upward, and the needle is immediately parallel to the blood vessel after lightly piercing the skin. Generally, the needle can be inserted into the blood vessel at one time. You can pierce the needle into more than half of the blood vessel and gently shake the needle left and right. After confirming that the needle is in the blood vessel, the liquid medicine can be injected. Under normal circumstances, there should be no obvious resistance during the injection process and the blood vessel will not bulge. The action should be gentle when pushing the fluid. If the blood vessel is found to be bulging, it means that the needle has not penetrated into the blood vessel and the needle needs to be removed immediately.