Online First

2021 : Volume 1, Issue 1

Modified Cervical Dislocation, A Better Way in Laboratory Rat Euthanasia

Author(s) : Zeyi Cheng 1

1 Department of Cardiovascular Surgery , Sichuan University , China

Mod J Med Biol

Article Type : Editor Note


Killing experiment animals is an unpleasant task in scientific research, and it is must be done as humanely as possible. Although there are many known methods to kill rats, researchers who study animal welfare and euthanasia are increasingly worried that the widely used technology is not the most painful and stressful the smallest. We aimed to introduce a more safe, efficient, and environmentally friendly method named modified cervical dislocation to kill the rats abandoned after the experiment.

Key words: Euthanasia; Rat; Modified Cervical Dislocation


Rats are the most important and commonly usedexperimental animals in biomedical research; they havemade great contributions and sacrifices to our scientificresearch activities. Therefore, during the experiment, weshould abide by animal ethics and treat them well. After theexperiment, we should properly put them to death.

As bioscience and medical research workers, we mustkill rats after the experiment, but which method should wechoose? There are currently several ways to kill rats [1].

Cervical Dislocation

Grasp the tail of the rat with your right hand and pull it backward, while holding down the head of the rat with the thumb and index finger of your left hand, pull off the spinal cord and the brain, and the rat will die immediately, which causes rapid death, but skill must be learned and well grasped, otherwise, you can be bitten by them, I observed that many my colleagues/classmates are afraid to grab the rat with their hands, and then send the cervical dislocation to kill the rat.


The experimenters put on cotton gloves, hold the head of the rat with your right hand, and hold the back with your left hand, exposing the neck, the assistant uses scissors to cut off the head of the rat with scissors. It is a useful method when tissues must be free of euthanasia chemicals.


Grab the tail of the rat with the right hand and lifted it and slammed it on the head, the rat died immediately after the spasm. Or hitting the rat's head with a small wooden hammer can be fatal. This method seems ruthless.

Acute Massive Blood Loss

The acute massive blood loss of the orbital arteries and/or veins of the mouse can be used to make the mouse die immediately.

Chemical lethality

Inhalation of carbon monoxide, rats and mice can be fatal in an environment with a carbon monoxide concentration of 0.2% to 0.5%. Subcutaneous inhalation of ether and chloroform can be fatal.

We tend to recommend cervical dislocation to kill rats, because it no risk of blood contamination, there is no need to consume anesthetics, and it also avoids the possibility that experimenters may inhale anesthesia and save money. It feels rough to kill with a wooden stick, and the body may be incomplete. The rule of cervical dislocation can avoid the above shortcomings, but many colleagues around me, especially female colleagues, dare not use their hands to catch rat directly for fear of being bitten, some of them have been bitten by rats. So in order to overcome those problems, we have already created a very simple method named Modified cervical dislocation to kill a rat without any other tools or drugs (Table 1).




Cervical Dislocation

No need for anesthetics, economic, guaranteed results

Mass killing of rats, risk of being bitten


Fast and simple

Risk of blood contamination; additional blood further processing


Do not touch the rat directly, avoid being bitten

Cruel and inefficient

Acute Massive Blood Loss

Fast and easy

Risk of blood contamination; additional blood further processing

Chemical Lethality

Euthanasia, avoid being bitten

Cost of anesthetics, environmental pollution

Modified Cervical Dislocation

Safe and effective, economic, simple and easy

Mass killing of rats

Table 1: Comparison of rat killing methods.

Critical Technical Notes

Here we introduce the modified cervical dislocation. First, take a box with a smooth bottom, similarly, ensure that the ground is smooth and clean, put the rat in a box, you can also directly use the cage, (Figure 1), and then rotate the box/cage for about 1 minute, at this time, the rat will also follow the box (Movie, S1), you can see that rat is tense during this process, and the skin on the legs and lips is purple (Figure 2). After stopping the rotation, immediately grab the tail of the rat with your right hand (the proximal 1/3 of the tail, do not grab the tip of the tail), wear a thick glove with the left hand to hold the neck, press it on the ground, and then dislocate to death, during this process, generally, the rat will not resist, even if your left hand is not grasped (especially when you feel tired), the rat will not bite you, and then you can easily hold the neck again.

Figure 1: Put the rat in a box, the skin on the legs and lips is normal.