How to give a subcutaneous injection to a rat? - briefly
To administer a subcutaneous injection to a rat, gently restrain the animal, lift the dorsal skin to form a skin tent, insert a 25‑27 G needle at a shallow angle into the pocket, deliver the prescribed volume, and then release the rat while monitoring for any immediate reaction.
How to give a subcutaneous injection to a rat? - in detail
Perform the procedure in a clean, well‑ventilated area using aseptic technique.
Select a suitable needle (25–27 G, ½‑inch) and a syringe calibrated for the required volume (typically 0.1–0.3 mL for adult rodents). Attach the needle securely, ensuring no air bubbles remain in the barrel.
Prepare the animal: place the rat in a restraining device or gently hold it with one hand, supporting the torso and keeping the head elevated. Scruff the skin briefly to induce a mild stress response that facilitates handling.
Identify the injection site: the loose skin over the dorsal mid‑lumbar area, just posterior to the forelimbs, provides ample subcutaneous space. Pinch a fold of skin between thumb and forefinger to create a tent.
Insert the needle: angle the needle at 45–60° relative to the skin surface, advancing through the tented skin into the subcutaneous tissue. Avoid penetrating the underlying muscle or peritoneum. Confirm correct placement by the lack of resistance and the ability to gently lift the skin fold without tension.
Deliver the dose: depress the plunger steadily, injecting the solution over 1–2 seconds. Observe for any leakage or swelling; if resistance occurs, withdraw slightly and retry.
Withdraw the needle smoothly at the same angle, release the skin fold, and apply gentle pressure with a sterile gauze pad to minimize bleeding. Dispose of the needle and syringe in a puncture‑proof container.
Monitor the rat for at least 15 minutes, checking for signs of distress, abnormal behavior, or injection site reactions. Record the administered volume, drug, lot number, and any observations in the laboratory log.