How to perform euthanasia on a rat? - briefly
Administer an approved inhalant anesthetic (e.g., isoflurane) to achieve deep, unresponsive sedation, then verify loss of reflexes and complete the procedure with a secondary physical method such as cervical dislocation or decapitation to ensure death.
How to perform euthanasia on a rat? - in detail
Humane termination of a laboratory rat requires a method that induces rapid loss of consciousness followed by irreversible cessation of vital functions. The most widely accepted techniques are inhalant anesthetic overdose, injectable barbiturate overdose, and carbon dioxide (CO₂) exposure. Each method must be performed by trained personnel in a controlled environment, with appropriate personal protective equipment and disposal procedures.
The inhalant anesthetic method uses isoflurane or sevoflurane. Place the rat in a sealed chamber sized for the animal. Introduce the anesthetic at a concentration of 5–7 % in oxygen, ensuring a flow rate of 1 L/min. Observe the animal until the loss of righting reflex and cessation of breathing are evident (approximately 2–3 minutes). Transfer the animal to a secondary container to confirm death by checking for absence of heartbeat and reflexes. Dispose of the carcass according to institutional biohazard guidelines.
The injectable method employs a sodium pentobarbital solution (e.g., 200 mg/kg body weight). Draw the calculated dose into a sterile syringe, remove air bubbles, and inject intraperitoneally using a 25‑gauge needle. The animal should become unconscious within 30–60 seconds, followed by respiratory arrest. Confirm death by absence of corneal reflex, lack of respiration, and no palpable pulse. Record the dose and time of administration, then follow disposal protocols.
For CO₂ exposure, use a calibrated euthanasia chamber equipped with a flow meter. Set the gas flow to achieve a gradual increase to 70 % CO₂ over 2 minutes, then maintain that concentration for an additional 5 minutes. Monitor the animal for loss of posture and breathing. After the exposure period, verify death as described above. Ensure adequate ventilation of the chamber after use to prevent residual gas accumulation.
General safety and compliance considerations:
- Verify that the chosen method complies with institutional animal care and use committee (IACUC) or equivalent ethical review board approvals.
- Wear gloves, lab coat, and eye protection to prevent accidental exposure to anesthetic agents or chemicals.
- Keep a detailed log of each procedure, including animal identification, method, dosage, and confirmation of death.
- Follow local regulations for the disposal of carcasses, hazardous waste, and anesthetic gases.
By adhering to these steps, personnel can ensure a humane, reproducible, and ethically compliant termination of a rat used in research or veterinary contexts.