How do you give a subcutaneous injection to a rat? - briefly
Using a sterile 25–30 G needle, lift a loose dorsal‑neck skin fold, insert the needle at a shallow angle, and slowly deliver the prepared volume subcutaneously. Ensure proper restraint, aseptic technique, and observe the rat for any adverse reaction after injection.
How do you give a subcutaneous injection to a rat? - in detail
Administering a subcutaneous injection in a laboratory rat requires precise preparation, aseptic technique, and careful handling of the animal. Follow each step to ensure reliable delivery of the material and minimize distress.
Materials
- Sterile needle (25‑27 G, 5‑7 mm length) attached to a syringe appropriate for the volume (typically 0.1‑0.5 ml)
- Injection solution, filtered and at room temperature
- Alcohol swabs (70 % isopropyl)
- Disposable gloves
- Sharps container
- Restraint device (e.g., a small Plexiglas tube or a manual cradle)
- Towels or absorbent pads
Preparation
- Verify the dose and concentration; calculate the exact volume for the animal’s weight.
- Warm the injection solution to 20‑25 °C to reduce viscosity and prevent shock.
- Attach the needle securely, expel any air bubbles, and confirm the correct volume in the syringe.
- Disinfect the injection site—generally the dorsal cervical area—by wiping with an alcohol swab and allowing it to air‑dry.
Technique
- Place the rat in the restraint device, ensuring the head is slightly elevated and the back is exposed.
- Hold the skin between the thumb and forefinger, creating a gentle “tent” to separate the subcutaneous layer from underlying muscle.
- Insert the needle at a 45‑degree angle into the tented skin, advancing until the bevel is fully under the skin but not penetrating muscle.
- Depress the plunger smoothly to deliver the solution; avoid rapid injection that could cause tissue rupture.
- Withdraw the needle at the same angle, release the skin, and apply gentle pressure with a sterile pad to prevent leakage.
Post‑injection care
- Observe the rat for at least five minutes; watch for signs of bleeding, swelling, or abnormal behavior.
- Return the animal to its home cage, providing easy access to food and water.
- Dispose of the needle in a labeled sharps container; clean any reusable equipment with appropriate disinfectant.
Safety considerations
- Wear gloves throughout the procedure to protect against accidental exposure.
- Maintain a clean work surface to prevent contamination of the injectate.
- Record the animal’s identifier, dose, injection site, and any observations in the laboratory log.