Considering the Mice (and Other Sundry Rodents)
So very much of the research we watch is conducted in mice, rats, and - increasingly - in naked mole rats and other more esoteric members of the rodent order of mammals. Some of this work is fairly directly applicable to we humans, and some of it is not. For example, the types and proportions of advanced glycation end-product (AGE) that accumulate to damage our cells in later life are very different between rodents and humans, and so early promising work in rats aimed at developing AGE-breaker drugs to wash out these unwanted compounds translated poorly to humans.
So how much attention should we give to promising results in mice? That can only be answered for any specific case by knowing more about the use of mice in the laboratory; it is very helpful for the layperson to have a better grasp as to the benefits, limitations, and expectations held by scientists when it comes to research in rodent species that is expected to be applicable to humans. On this note, let me draw your attention to a trio of long articles from Slate that examine the humble laboratory mouse:
Just how ubiquitous is the experimental rodent? In the hierarchy of lab animal species, the rat and mouse rule as queen and king. A recent report from the European Union counted up the vertebrates used for experiments in 2008 - that's every fish, bird, reptile, amphibian, and mammal that perished in a research setting, pretty much any animal more elaborate than a worm or fly - and found that fish and birds made up 15 percent; guinea pigs, rabbits, and hamsters contributed 5 percent; and horses, monkeys, pigs, and dogs added less than 1 percent. Taken together, lab rats and lab mice accounted for nearly all the rest - four-fifths of the 12 million animals used in total,
According to one estimate, distributors like Charles River and the scientists who buy from them have created at least 400 standard, inbred strains of mouse, and 200 inbred strains of rat. Yet one stands out from the rest as the model among models in biomedicine. If you want to set up a trading post for biology, a place where researchers from around the world can exchange and compare their data, then it helps to have a common coin - a stable currency that undergirds the system. In the global marketplace of discovery, the Black-6 mouse (more formally known as the "C57BL/6") serves as the U.S. dollar.
As a matter of taxonomy, the naked mole rat is closer to a guinea pig or porcupine than a mouse or a rat, but really it's neither one nor the other. Buffenstein knows that she's working with an oddball; she did a lot of the work that proves it. "[The naked mole rat] does have very unique mechanisms that are not seen in other animals," she says, referring both to its superficial quirks and to whatever private biochemistry helps it to shrug off cancer, deflect toxic chemicals, ignore painful stimuli, and otherwise live five times longer than one might expect....
Ten years ago, Buffenstein was one of just a handful of biologists studying naked mole rats in captivity; now her field comprises some three dozen labs around the world. Her colleagues have looked at why naked mole rats are immune to the pain caused by spicy foods, or how they avoid getting itchy when doused with histamine, or what allows their brains to get by without much oxygen and a shriveled pineal gland. In Rochester, N.Y., a pair of Russian-born biologists, Andrei Seluanov and Vera Gorbunova, are devoted to finding out exactly how naked mole rats keep from getting cancer.
If you read around the warnings of doom by laboratory rodent monoculture - good news sells no papers, and the story of mice as research tools is one of great success when considered at the high level - you'll find a great deal of fascinating information. It pays to understand more about how the sausage is made when it comes to longevity research, and mice are an important part of the process. Knowing more about the limitations helps to better place the steady flow of newly announced results into context.