OF MICE AND MEN: Drugs that work for mice rarely work for humans. So why bother testing drugs on rodents?
May 20, 2019 • 1 min read
Most potential new drugs fail when they’re tested on people despite showing great promise when earlier tested on rats and mice.
Rodents are used as models in medical testing because they are made from many of the same genetic building blocks found in humans. When it comes to protein-encoding genes, mice are 85 per cent like humans – a similarity the National Human Genome Research Institute attributes to a shared ancestor about 80 million years ago.
While 85 per cent sounds like a close match, it could be miles apart, considering humans and mice have followed their own evolutionary paths for tens of millions of years. Mice ain’t furry little people.
So why persist with testing?
Rats and mice are popular with scientists and researchers for several reasons. Rodents are cheap to breed and house, reproduce quickly, don’t complain, and have a short lifespan, allowing several generations to be observed in a relatively short period of time.
Scientists are also engineering genetically altered mice, called transgenic mice, that carry genes similar to those that cause human diseases. They’re also turning genes on and off, creating ‘knockout mice’, which can be used to evaluate the effects of cancer-causing chemicals.
The good news for humans is that testing drugs on rats and mice will continue to improve. I guess that’s bad news for rodents.
Failing that, scientists might consider testing drugs on bananas which, surprisingly, still share about 60 per cent of the same DNA as humans.