How should a subcutaneous injection be given to a rat? - briefly
Insert a 25‑gauge needle at a shallow angle into the loose skin over the dorsal thoracic region and deliver the volume slowly to prevent tissue trauma. Verify placement by the formation of a small bleb and observe the rat for any immediate adverse response.
How should a subcutaneous injection be given to a rat? - in detail
Administering a subcutaneous injection to a laboratory rat requires strict adherence to aseptic technique, appropriate equipment, and precise handling. The following protocol outlines each critical step.
Materials
- Sterile 1‑ml syringe
- 25‑27‑gauge needle, 5‑7 mm length
- Injection solution, pre‑warmed to room temperature
- Alcohol swabs (70 % isopropyl)
- Disposable gloves
- Restraint device (e.g., plexiglass tube or manual hold)
- Sharps container
Preparation
- Verify animal identification and health status.
- Confirm dose and volume; typical subcutaneous volumes for rats range from 0.1 ml to 0.5 ml, depending on body weight.
- Draw the exact amount into the syringe, expel air bubbles, and lock the needle.
- Label the syringe with drug name, concentration, and time of preparation.
Site selection
- Choose the loose skin over the dorsal neck or the lateral flank.
- Avoid areas with fur clumps, scar tissue, or visible vessels.
Injection technique
- Place the rat on a flat surface, secure the head and forelimbs using a gentle restraint.
- Clean the chosen site with an alcohol swab; allow to air‑dry.
- Pinch a fold of skin to create a tent, ensuring the subcutaneous space is isolated from underlying muscle.
- Insert the needle at a 45‑degree angle, bevel up, into the tented skin. The entire needle length should be within the tissue; resistance indicates proper placement.
- Depress the plunger steadily to deliver the solution.
- Withdraw the needle swiftly, maintaining the skin fold for a few seconds to prevent back‑flow.
- Release the skin fold, observe the injection site for leakage or swelling, and apply gentle pressure if needed.
Post‑procedure care
- Monitor the animal for at least 10 minutes for signs of distress, abnormal respiration, or excessive movement.
- Record injection details in the animal log, including site, volume, and any observations.
- Dispose of the needle and syringe in a labeled sharps container.
Adhering to this sequence minimizes tissue trauma, ensures accurate dosing, and promotes animal welfare during subcutaneous administration.