Monday, December 3, 2007

So, where do animal protocols come from?

My dad asked, in a comment to "My Experience with Lab Mice", why the accepted protocol is to gas them with CO2 instead of nitrogen. He writes:
Anoxia through O2 starvation is demonstrably painless. Many research pilots go through it, to the point of unconsciousness, and the general comment on recovery is "Did something happen?"
CO2 overdose triggers the breath reflex, which O2 starvation does not, at least in humans.

I did a fair bit of searching, but all I could find was protocols describing various euthanasia methods. I couldn't find anything that motivated them. Sure, I found some discussion of why toe clipping is discouraged, but that's because toe clipping isn't The Method for identifying mice (anymore). CO2 gassing appears to be one of The Methods, if not The Method, for euthanizing a bunch of mice -- hence, not much debate or discussion.
I don't know how many readers I've got, but I'm throwing the question open: who decides what the `official' animal protocols are? (Does it differ if you're a university vs. a company?) How do new methods get invented, approved, and adopted? What happens when an alternative method gets officially discouraged/banned? Where can one go to find out all this information about a specific protocol? And if it's the case that O2 starvation by N2 surfeit is painless, why isn't it The Method?


  1. I of course don't know where these protocols come from, but I just wanted to mention in brief that a lot of the objection I personally have to the use of animals in research doesn't stem from their suffering--after all, certain kinds of euthenasia are painless--but from the fact that their deaths are used at all.

  2. I'm not sure I understand -- you would object less to experimentation that left the animal alive, all else being equal?

    (For the record, I strongly dislike animal experimentation too, but I'm in favor of continuing it until alternative methods are developed (and I'm also in favor of developing those methods ASAP).)

  3. On a similar note, why is lethal injection the standard for the death penalty given the potential of anoxia? Not to say that I support the death penalty, but if you're going to do it you might as well do it as painlessly as possible, and there are known problems with lethal injection (like doctors not doing their jobs and figuring out proper dosages, so that a big man might be left alive but with his organs half-gone...eeurgh).

  4. I honestly don't know. I mean, sure, lethal injection beats electric chair, hanging, guillotine, firing squad, etc. And from what I read about hypoxia, it sounds like it's quite a painless method overall. I can't find any literature on why it isn't used.

    This page lists the following criteria for evaluating euthanasia methods:

    * Rapid loss of consciousness and death without causing pain and distress
    * Reliable (i.e. same effect on animals every time)
    * Safety for personnel
    * Irreversible
    * Compatible with subsequent evaluation, examination or use of tissues
    * Emotional effect on personnel (and perceived public response)
    * Drug availability and human abuse potential
    * Compatibility with species, age, sex and health status of the animal(s)
    * Ability to maintain equipment in proper working order

    So now the question is, which of these does hypoxia-by-N2 fail? This page lists several commonly used methods of inducing hypoxia, including some fairly exotic-sounding chemicals as well as good ol' CO2, but not a word on N2.

  5. I am willing to bet that anoxia via nitrogen may simply be not well known, since it happens to test pilots, and they are a pretty small and tight community. Every community evolves its own methods and standards, and sometimes there just may not be appropriate incentives for people to go research alternative methodology.