How should I correctly inject a rat? - briefly
Restrain the animal securely, disinfect the injection site, and use a sterile 25‑27 G needle to deliver the prescribed volume into the appropriate compartment (commonly subcutaneously or intraperitoneally) at a controlled rate. Follow the dosage guidelines, monitor the rat for adverse reactions, and dispose of sharps according to biosafety protocols.
How should I correctly inject a rat? - in detail
Administering an injection to a laboratory rat requires strict adherence to aseptic technique, proper restraint, and accurate dosing.
First, gather all necessary materials: sterile syringes (1 mL or appropriate volume), suitable needles (e.g., 25–27 G for intraperitoneal or subcutaneous routes), the prepared solution, alcohol swabs, disinfectant, gloves, and a sharps container. Verify the dosage calculation based on the animal’s weight (mg/kg) and confirm the concentration of the solution.
Second, ensure the rat is healthy and correctly identified. Weigh the animal to the nearest gram; record the weight for dose verification. If the study protocol permits, provide a brief acclimation period in a clean, quiet environment before handling.
Third, apply appropriate restraint. For intraperitoneal or subcutaneous injections, use a gentle scruff technique: grasp the skin at the nape of the neck with thumb and forefinger, lifting the head slightly to expose the injection site. For intravenous administration, employ a specialized restrainer or tail vein access, ensuring the rat remains immobile without excessive stress.
Fourth, prepare the injection site. Clean the chosen area (lower right quadrant of the abdomen for intraperitoneal, dorsal neck region for subcutaneous) with an alcohol swab, allowing it to dry. Avoid excessive rubbing that could cause irritation.
Fifth, perform the injection:
- Attach the needle securely to the syringe, expel any air bubbles, and draw the calculated volume.
- Insert the needle at a 45‑degree angle for intraperitoneal delivery, advancing until a slight “pop” indicates entry into the peritoneal cavity. For subcutaneous injection, use a shallow 10‑15‑degree angle, creating a tent of skin before needle insertion.
- Depress the plunger smoothly to deliver the entire volume. Observe for resistance; if encountered, withdraw and reassess needle placement.
- Withdraw the needle swiftly, applying gentle pressure with a sterile gauze to minimize bleeding.
Sixth, dispose of the needle and syringe in a puncture‑proof container immediately. Disinfect any surfaces contacted during the procedure.
Seventh, monitor the rat post‑injection. Place the animal in a clean cage with easy access to food and water. Observe for at least 15 minutes for signs of distress, abnormal behavior, or injection site reactions. Record observations in the study log.
Finally, document all steps, including equipment lot numbers, solution preparation details, exact dose administered, and any deviations from the protocol. This record supports reproducibility and compliance with institutional animal care guidelines.