This is actually an extension of an earlier post I had on animal welfare where I’ll be explaining why we have to use animals in biological research.
For some reason a large number of people believe that with today’s technology we are beyond using animals in even the most basic of tests. I’ve heard things like “well can’t we just model it on a computer” and “can’t you just test it on cell cultures?” more times than I’d like to mention. Unfortunately, even with as much as we know about biology there is far more that we do not know. This makes it impossible to use anything but live animals in experiments and conclude anything of value from them.
Every biologist I know would work with non-living systems if they could derive meaningful data from it, but the fact is that for most researchers that is not possible. In fact, every institution doing animal research has an animal use and care committee (IACUC, Drugmonkey has a good post partially about them) whose sole job is to look over protocols to see if there is any way to reduce or eliminate animal experimentation from the submitted protocol. If there is a more humane way to accomplish what the researcher wants to do then the protocol is not approved and the research cannot be done. Best of all, the committee isn’t even completely comprised of researchers! All contain at least one vet and, at least the ones I’m aware of, have one person unaffiliated with a university (a lay person).
Now that I’ve given an overview of the bureaucratic side of things it’s time to move on to what I know best: the science. Many people are genuinely interested about why we can’t use things like computers and cell cultures instead of whole animals in our research. Funny thing is that we do; where we can…
If you’ve ever seen a poster showing a signal transduction pathway you’d begin to understand why we can’t use a computer to model such a system. First, it’s far too complex. Second, we have to assume at all times that it’s incomplete (this is science). Lastly, a computer model would be nothing more than a generality, and generalities typically don’t work too well in biology.
Essentially the same things can be said of cell cultures, but they are much more useful than computer programs since they accurately model (go figure) living tissue. The problem with cell cultures arises when you take into account emergent properties. For those of you who don’t want to look up emergent properties (even though I linked it) of living beings it basically comes down to this: you can’t predict what will happen in a whole organism by studying a single tissue due to the complex ways different tissues interact to create that organism.
I should be a bit more specific, you can’t ALWAYS, ACCURATELY predict what the effect will be on the whole organism. You’ll notice the qualifiers I added in the last sentence; they are there for a reason. Some times, in context, cell culture studies are taken with a grain of salt due to the very emergent properties explained above. For example, cell culture research from your lab turned up two very good candidates for leukemia drugs. The next step is to do a simple cell toxicity screen before an animal screen. Drug 1 seems to be tolerated well by the cells while drug 2 seems to have an overall much higher toxicity, but since both showed so much promise in the initial testing they are both used for the animal tox screen. The results come in and, go figure, drug 2 can be used at a much more effective concentration than drug 1 even though drug 1 showed a lower tox level in cell culture. Without further testing no one will be sure why exactly this is, but the results stand and drug 2 moves on to clinical trials. Were we to stop tox screening with cell cultures we would have disregarded drug 2 in favor of drug 1, tested drug 1 on humans, and found out then that it was toxic (with possible deaths involved). Shit like this happens. That’s why we need to do every level of testing that is currently done and there is no other way of doing accomplishing that.
Are animals perfect? Hell no. In fact, rats and mice can show the exact opposite effects that humans do, but the chances of that are slim and they will picked up on with later testing. However, those animals are damn good filters and they’re the best we got outside of doing those studies on humans. Knowing that allows me to sleep soundly at night, and it should for you as well since you are the ones ultimately benefitting from what I do.
Okay, I’ve ranted enough about this. Ask any questions you have, I’d be happy to answer them or at least point you in the right direction.