Rats Taking Over from Mice in Labs

I recently fostered the sweetest little rat and I currently have two mice. Therefore, this Boston Globe article saddens me on both levels. And, of course, our old friend, Charles River Laboratories, will be a major supplier of lab rats.

Scientific advances over the last three years have now made it feasible to easily tinker with rat genes, creating the possibility of far better models of certain human diseases, and potentially shortening the time it takes to develop medications...

While both rats and mice have similarities to humans, rats win out in key areas.

Their blood system is much more similar, with a heart that beats four times faster than a person’s, instead of the mouse’s six times faster. Rat brains are far more complex than mouse brains, making them more likely to exhibit the behaviors of Parkinson’s, Alzheimer’s, schizophrenia, and autism, among other disorders. Their liver enzymes are more similar so they metabolize drugs more like people do.

Rats are also simply larger, as are their cancerous tumors, making them easier to study and to operate on.

But these innovations won’t mean the end of the lab mouse.

“To what degree the rat will replace the mouse remains to be seen,’’ said Iva S. Morse, corporate vice president for research model services at Charles River Laboratories, a Wilmington company that started by breeding lab rats in 1947 and has become a major supplier of rodents for research.