How to give an injection to a rat? - briefly
Restrain the rat using an approved holder, locate a clean injection site such as the dorsal lumbar area, disinfect the skin, and insert a sterile needle at a shallow angle to deliver the dose slowly. Release the animal after confirming the injection was completed without immediate adverse effects.
How to give an injection to a rat? - in detail
Administering an injection to a laboratory rat requires precise preparation, proper restraint, and strict aseptic technique. The procedure is divided into equipment setup, animal handling, injection execution, and post‑procedure monitoring.
Essential supplies include a sterile syringe (1 ml or 0.5 ml depending on volume), appropriate gauge needle (27–30 G for subcutaneous or intraperitoneal delivery), disinfectant (70 % ethanol), sterile gauze, a warming pad, a restraining device (e.g., a plexiglass tube or manual grip), and personal protective equipment (gloves, lab coat, eye protection). All items must be inspected for integrity before use.
The rat should be acclimated to the handling environment for at least 10 minutes. Prior to injection, the animal’s fur over the chosen site is shaved or trimmed and the skin is swabbed with ethanol. Restraint can be achieved by:
- Holding the animal securely in a tube with the head protruding, allowing access to the flank.
- Using a gentle manual grip: thumb and forefinger on the scruff, other fingers supporting the torso.
Injection sites and corresponding routes:
- Subcutaneous (SC): Loose skin over the dorsal lumbar region.
- Intraperitoneal (IP): Right lower quadrant of the abdomen, avoiding the midline.
- Intramuscular (IM): Posterior thigh muscle (quadriceps) or the hind‑limb gastrocnemius.
Needle selection follows the route and volume: 27 G for volumes up to 0.5 ml, 30 G for smaller volumes. The needle length should be sufficient to reach the target tissue without penetrating deeper structures (e.g., ½ inch for SC, ⅝ inch for IP).
Steps for injection:
- Draw the calculated dose into the syringe, expel air bubbles, and verify the final volume.
- Attach the needle securely; confirm sterility.
- Position the rat according to the selected site and restraining method.
- Pinch the skin (SC) or insert the needle at a shallow angle (IP) to avoid organ damage; advance the needle to the appropriate depth.
- Depress the plunger steadily; withdraw the needle at the same angle of entry.
- Apply gentle pressure with sterile gauze to the entry point to prevent leakage.
After injection, place the rat on a warming pad for 5–10 minutes, observe for abnormal behavior, respiratory distress, or signs of pain. Record the date, time, dose, route, needle gauge, and any adverse reactions in the animal’s log. Dispose of sharps in a designated container and decontaminate surfaces with appropriate disinfectant.