We’ve used mice for drug studies for decades. It makes sense; we share 97.5% of DNA with them, making them almost ideal for studying everything from drug testing to determining what environmental factors can give us cancer.
But a new paper points out what may be a serious flaw in our process:
The problem with our lab mice is the following: our aim in studying these animals has been to test out as many chemicals and drugs on them before they die. Some of them die very soon, whereas others live to have more drugs tested on them. Over the decades, we have been playing the role of natural selection on these mice, continuing to test those who can withstand it, and discarding those who can’t. … What we now have in labs are a species of highly cancer-prone, bruise-resistant mice.
What this means for us that the list of things we’ve labelled “carcinogenic” may not need to be as long as it is. It is possible that it is only that long because we are doing animal testing on mice that are highly prone to cancer. On the other hand, we have reason to be more cautious of the chemicals that have passed animal testing. Our cells simply do not replicate as often as lab mouse cells, and as such they cannot repair tissue damage as effectively. This means that chemicals which cause these mice no harm may in fact be toxic to our own organs over time. We may be susceptible to damage from chemicals which these super-mice can handle without a problem.
A fascinating concept which may have serious consequences.
Source: University Observer Rats Out: Animal Testing may have Fatal Flaw