How do you correctly give a rat an injection? - briefly
Use a sterile 27‑30 G needle on a 1 ml syringe, restrain the rat with a tail‑hold or plexiglass holder, locate the lower right abdominal quadrant, insert the needle bevel up at a 30–45° angle into the «intraperitoneal» space to a depth of 2–3 mm, deliver the prescribed volume slowly, then withdraw the needle, apply gentle pressure with sterile gauze and observe the animal for any adverse response.
How do you correctly give a rat an injection? - in detail
Administering an injection to a laboratory rat requires a systematic approach to ensure accuracy, animal welfare, and reproducibility.
First, gather sterile equipment: appropriate syringe (typically 1 ml), needle of suitable gauge (27–30 G for subcutaneous, 25–27 G for intraperitoneal), disinfectant, antiseptic swabs, and a restraining device such as a plexiglass tunnel or a soft cloth. Verify that the drug is prepared at the correct concentration and temperature; allow the solution to reach room temperature to avoid tissue irritation.
Second, restrain the animal securely but gently. Place the rat in a clean, well‑ventilated restrainer, or hold it with a thumb and forefinger on either side of the neck while supporting the body with the other hand. Avoid excessive pressure that could cause stress or injury. Confirm that the animal is calm before proceeding.
Third, select the injection site based on the intended route:
- Subcutaneous (SC): lift a fold of loose skin on the dorsal thoracic region, insert the needle bevel‑up at a shallow angle (≈10–20°), and deposit the volume slowly.
- Intraperitoneal (IP): locate the lower right quadrant of the abdomen, insert the needle bevel‑up at a 45° angle to avoid puncturing internal organs, and aspirate gently to confirm entry into the peritoneal cavity before delivering the dose.
- Intramuscular (IM): identify the hind‑limb quadriceps muscle, insert the needle perpendicular to the skin, and inject with minimal resistance.
Fourth, perform the injection with controlled pressure. Deliver the full volume within 5–10 seconds to prevent tissue damage. After injection, withdraw the needle smoothly, apply gentle pressure with a sterile swab to minimize bleeding, and release the animal back into its cage.
Finally, monitor the rat for at least 15 minutes. Observe for signs of distress, abnormal respiration, or injection site reactions. Record the administered dose, needle size, injection route, and any adverse observations in the laboratory log.
Adhering to these steps ensures precise drug delivery while maintaining ethical standards and experimental integrity.