Photograph by Janet Stephens. Public domain photo
Most well being journalists have heard they need to by no means, or at the least very not often, cowl animal research when reporting on circumstances associated to human well being. While some opposition to reporting on animal research consists of arguments relating to the ethics of utilizing animal fashions in scientific analysis in any respect, the extra salient argument for many journalists is how intently or precisely the animal mannequin can signify illness or hostile or therapeutic results in people.
Again in 2006, U.S. Health and Human Services Secretary Mike Leavitt famous that “9 out of 10 experimental medication fail in scientific research as a result of we can’t precisely predict how they may behave in folks primarily based on laboratory and animal research.” A study in JAMA that year equally discovered that solely a 3rd of “extremely cited animal analysis” translated to human randomized trials.
In any case, people aren’t mice, or rats, or pigs, and even monkeys. There’ll all the time be distinctive physiological variations between species that forestall full translation of animal research findings to people. And it’s essential to notice that even when inter-species traits had been extra related, people don’t stay within the synthetic laboratory circumstances of animal fashions.
Key takeaway: In the event you’re overlaying an animal research, take note of the circumstances of the lab animals’ atmosphere and the way these circumstances would possibly have an effect on the research outcomes.
Nonetheless, some circumstances justify reporting on animal research, particularly if there’s not one other efficient solution to examine a selected scientific query. One such space is environmental well being analysis involving exposures to numerous chemical substances. Since we will’t lock a bunch of people away for 10 years and expose them to chemical substances, animal research can provide insights into doable physiological results of various compounds.
Contemplating these research at the side of observational analysis in people then permits cautious conclusions in regards to the seemingly results of sure environmental exposures. This strategy comprises most research about endocrine-disrupting chemicals, for instance. Animal research may also assist elucidate how these results happen, resembling utilizing research on rats to grasp how diethylstilbestrol causes most cancers and infertility in ladies prenatally uncovered to it.
What to search for
However right here’s the rub: It’s these very research the place an typically neglected variable can throw a monkey wrench within the works. That variable is the lab animal’s atmosphere — its enclosure, food regimen, water supply, the containers used to feed and water it, the room its enclosure is in, temperature and lighting, and so forth.
So if you want to cowl an animal research, particularly if it’s associated to the results of an environmental publicity, pay shut consideration within the strategies part to how the animals are housed, fed, watered, and cared for and whether or not any of these components might affect the outcomes. If these components aren’t described within the research, ask the authors about it.
For instance, I’ll provide a couple of examples. An article (paywalled) by Jyoti Madhusoodanan in Nature last year examined how paying nearer consideration to lab animals’ diets might enhance research’ reproducibility — the dearth of which is already a major hindrance in scientific analysis. In her opening anecdote, she describes how two completely different analysis groups produced completely different findings from what appeared to be the identical research design — besides the completely different groups fed the monkeys completely different diets.
Or, contemplate a research investigating the results of a selected publicity on rats the place the water bottles within the rats’ enclosures should not all an identical. If some are glass and a few are plastic, chemical substances leached from the plastic — one thing that’s really been studied in rats — might confound the outcomes. Would any results noticed be from the chemical being studied or inadvertently from the plastic bottles?
The story of Rat Park
Writer Tara Haelle’s pet rats. Photograph by Tara Haelle
My favourite instance comes from a well-known collection of research from the late Nineteen Seventies and early 80s referred to as Rat Park. (Though I linked the Wikipedia article there for a quick abstract, this excellent comic narrating the story of Rat Park is rather more entertaining.)
Earlier than Rat Park, most analysis taking a look at animals’ self-administration of morphine concerned protecting lab animals in small steel cages by themselves. However rats, like canine, are social creatures who want enrichment, and Canadian psychologist Bruce Alexander questioned if the rationale rats often selected a water laced with morphine over plain water had extra to do with their austere atmosphere.
So he constructed an enclosure 200 occasions the scale of a typical cage and crammed it with each rat’s dream: meals, wheels, balls and different toys, greater than a dozen rat buddies, and loads of area to run, discover, and mate. It turned out, lab rats saved on this paradise had no want for morphine — regardless that the morphine water was sweetened — and fortunately sipped from the plain water bottle.
Though the experiment’s fame arose largely from the way it changed the narrative of addiction — lo and behold, atmosphere could affect the selection to self-medicate — the precise intent of the analysis was to grasp the significance of testing conditions for lab animals. Whereas Rat Park is an excessive instance, loads of far subtler aspects of testing circumstances can have an effect on outcomes. For instance, mice and rats are nocturnal, and light during nighttime, in addition to continuous light exposure and even simply ambient noise, can all contribute to weight acquire in rats (which, in flip, can improve the danger of a number of illnesses).
The underside line is that each little element in a research could make a distinction within the end result. And when animal research have already got so many different obstacles to beat in translating to people, it’s notably essential to concentrate to these particulars.
Assets:
