pixabay.com
You might have noticed that there was no post from me yesterday. That’s partly due to the fact that I’m having a guest over for the weekend, partly because I had an exam in the morning and mostly because I attended a so-called “mouse course”.
In this course, I learned most things (there is a second one I still have to attend) about how to treat mice that are being used as lab animals.
I’m a Biologist. I will hopefully be a researcher in the future and there is always the possibility that I’ll have to work with animals. Do I like it? Hell no! But I think it’s necessary. And if I don’t work with them, there might be someone who doesn’t care about their welfare working with them.
Not everyone is allowed to just handle and kill animals. In the EU it’s technically even illegal to kill mice you find at home. Only a properly certified person has the right to do that.
With all that being said, I wanted to share my experience with that course to maybe give you some insight on how animals for experiments are handled and how I feel about the whole thing.
If you are very sensitive and can’t stand the descriptions of animals being harmed and/or killed, I advise against reading this. There won’t be any graphic pictures but the descriptions might be upsetting.
The course, officially 2 courses with the names “handling, fixating, marking and sex determination of mice” and “application methods and killing mice according to the animal protection laws”, started out with each of us being placed in front of a plastic cage with our own mouse in it.
Mine was a white one, curious and relaxed as this breed often is.
By Rama 1
My neighbor didn’t have such luck, her significantly smaller mouse had fur like a wild one and behaved a lot like it. Afraid, skittish and not at all happy about being in this room. I couldn’t blame her.
Having handled mice before, I switched with my neighbor, knowing that she might be better off with a calmer mouse. The first task was to get familiar with the animal, get it to sit on your hand and then determine its sex.
By Rama 2
I had a female and after I put some effort into it, she let me touch and weigh her without jumping out of the scale bowl. 23g.
Next, we had to fixate them. You grab the mouse, who is sitting on something she can hold on to, by the tail and then pinch the neck fur/skin to keep it from moving. It’s hard to describe, I couldn’t take a picture and I can’t find one free for use. But I guess it should be fine if I link you to one. In the picture, the person holding the mouse is already injecting something, I will explain that later.
The fixating is a lot easier with rats as they are a lot more relaxed. If they’re used to it you can just grab them below their arms, inject something and put them back. They don’t really care that much.
By Janet Stephens 3
Having mastered the fixation technique, I was supposed to mark the mouse. That is either done by punching a hole into the ear (the piece of skin can then be used to determine which genes the mouse carries) or attaching a metal tag to the ear. My mouse accepted both with minimal resistance, but I still felt bad.
Then I heard terrified squeaks from across the room. Someone obviously failed to keep it as painless as possible. I looked at my mouse and promised to progress as careful as possible.
I had to start practicing injecting stuff. There are several methods:
- Below the skin
Either in the “neck skin” that’s scrunched together when you hold the mouse or at the side, somewhere above the hind legs. - Into the abdomen (shown in the picture I linked)
The best way is to hold the animal with the head down so that the inner organs don’t put pressure on the injection site. Then you just need to take care to not hit the bladder. - In a vain in the tail
The last one was a bit more complicated. The mouse has to be restrained in a plastic tube with only the tail hanging out which then has to be put into warm water so that the blood vessels widen. And then you need to hit the vain.
I tried. I really tried. I failed four times before I finally injected the NaCl solution (harmless for the animal, you’re given that stuff at the hospital to prevent dehydration) in the vain instead of the surrounding tissue.
I gave my mouse a break after that. Looking at her in that cage broke my heart. I didn’t want to hurt her. I wished that animal experiments were obsolete. I still wish that. But especially for genetic research, we can’t go without them. Not yet anyway, I hope in the near future it’s possible.
The last application method was an oral application. There are several things mice won’t eat because they taste horrible. While voles love alcohol, mice often rather die than drink it. So if you want to test a drug that needs to go through the digestion tract, you need to give it to them through some kind of feeding tube.
I’ll spare you the details, it wasn’t pleasant for either of us but in the end, I succeeded. Which left me with two tasks.
Killing my mouse (with a legal method of my choice) and killing a narcotized mouse (by breaking the neck).
The method I chose for my mouse was the fastest and least painful I was able to perform. An overdose of an anesthetic and she finally got rid of me.
Breaking the neck of the other mouse was … a lot less pleasant.
You see, you have to do it right or you just break its spine. That’s why we were supposed to practice on narcotized mice. The law states that the killing process has to be as painless as possible. But sometimes you might need to kill a mouse quickly because you might have fucked up in a way. Maybe you tried to give it a drug through a feeding tube but managed to squirt it into the lung instead.
You don’t want that poor thing to suffocate, do you? So you need to break its neck. And the feeling is horrible.
The crunching noise.
How it feels when you check if you really broke the neck. That soft, wobbly, wrong feeling.
The course ended with that. After three hours, I was deemed qualified enough to do most things associated with laboratory mice. But I think there is one thing they’re teaching that might not be so obvious: compassion for the animal.
”Keep pain to an absolute minimum.”
”Reduce animal experiments whenever possible.”
”Watch the mice. If they are in pain, see if you can stop.”
”Keep pain to an absolute minimum.”
Sources: My own experience.
Picture credit:
- By Rama (Own work) [CeCILL (http://www.cecill.info/licences/Licence_CeCILL_V2-en.html) or CC BY-SA 2.0 fr (https://creativecommons.org/licenses/by-sa/2.0/fr/deed.en)], via Wikimedia Commons
- By Rama (Own work) [CeCILL (http://www.cecill.info/licences/Licence_CeCILL_V2-en.html) or CC BY-SA 2.0 fr (https://creativecommons.org/licenses/by-sa/2.0/fr/deed.en)], via Wikimedia Commons
- By Janet Stephens (photographer) [Public domain], via Wikimedia Commons
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