经济学人14:善待小鼠 它们可能会知恩图报

 　　Science and technology.

　　科技。
　　Animal testing.
　　动物实验。
　　Be nice to mice.
　　善待小鼠。
　　and they may return the favour.
　　它们可能会知恩图报。
　　Home, sweet home.
　　家，舒适的家。
　　ONLY one drug of every ten successfully tested in laboratory animals ends up working in people. One reason, of course, is that mice are not men. Another, though, might have to do with the fact that whereas human patients are afforded all manner of creature comforts, their animal proxies 1 are not.
　　用实验动物试验成功的药物最终只有十分之一对人体起效。原因之一当然是：老鼠毕竟不是人。但另一个原因可能是，患病的实验动物无法像人类患者一样能够得到方方面面的呵护。
　　Although medical science's favourite critters relish 2 temperatures of a little over 30°C, laboratories routinely keep them at five or ten degrees below that. This is not in order to torture the beasts but, rather, because when kept warm they are unmanageably aggressive. The downside is that they have to eat more than they otherwise would, in order to keep their bodies warm. That changes their physiology 3. And that in turn alters the way they metabolise drugs, with possibly confusing results.
　　虽然老鼠这种医学实验最喜欢使用的啮齿动物偏爱呆在稍高于30摄氏度的环境里，但实验室却常被控制在比这低5到10摄氏度的温度上。这并不是要存心虐待这些动物，而是因为当环境暖和了，它们会变得十分好斗，很难应付。而这样做的弊端是动物们为了保持体温，要比平常吃得更多。这样动物的生理机能就会有所改变，因此会影响到药物在动物体内的代谢，出来的实验结果也可能会很费解。
　　Joseph Garner 4, of Stanford University, thinks the answer is to keep the labs cool, but let mice cope with the low temperatures as they do in their natural habitat: not by eating more but by building nests. So far, though, no one has a clear idea of how much nesting material is needed to keep mice happy. Dr Garner and his colleagues therefore decided 5 to find out. They have just reported their results in the Public Library of Science.
　　斯坦福大学的约瑟?加纳（Joseph Garner）认为，解决办法就是令实验室保持低温，但让老鼠们像在自然环境中一样通过筑巢（而非吃得更多）来自行应对低温。不过至今都没有人清楚到底需要多少材料才能让老鼠们筑一个舒适的窝。于是约瑟?加纳博士及其同事决定要弄清这点，他们的实验结果刚刚发表在《公共科学图书馆》上。
　　Dr Garner and his team let each of their mice, 36 males and as many females from three strains commonly used in trials, roam free in two cages connected by a narrow tube. One cage was kept constant at one of six temperatures between 20°C and 35°C. The other was maintained at 20°C but was stocked with up to ten grams of finely shredded 6 paper, which the mice could use to weave a nest. The idea was to check whether the animals would rather build a nest in the cooler cage or move to the warmer one, possibly tugging 7 nesting material along with them strand 8 by strand.
　　约瑟?加纳博士及其实验小组让所有老鼠（公鼠、母鼠各36只，属于三个常用于实验的品系）在两个由一条窄通道相连的笼子里自由活动。其中一个笼子的温度保持在20-35摄氏度之间（总共有六档温度）。另一个温度保持在20摄氏度，但里面储有多达十克撕得很碎的纸条，以供老鼠们用来筑窝。实验目的是看看老鼠们是会在更冷的笼子里筑巢还是会移居到更暖的笼子里（可能还会将筑巢用的纸条一条条拖过去）。
　　The researchers found that the rodents 9' preferences varied 10 slightly between strains, as well as between sexes (with females partial to higher temperatures, possibly because of their thinner protective layer of fat), confirming that there is no single set of conditions in which all mice feel cosy 11. In general, though, with little nesting material around, the animals laboriously 12 carried strands 13 of paper over to the warmer spot, one or two at a time. But leave at least six grams of paper in the chilly 14 cage, and many mice will prefer instead to brave the cold and build a nest there. That seems a small price to pay for better drug trials.
　　研究者发现，老鼠们的偏好稍有差别，与性别和品系都有关（母鼠偏爱较暖和的环境，可能是由于其脂肪保护层比较薄），这就证明没有一个温度能让所有老鼠都感觉舒适。但通常在周围没什么筑窝的材料时，老鼠们会费力地将纸条拖至更暖的地方，每次一到两条。不过如果在温度较低的笼子里放至少六克纸条，那么会有很多老鼠宁愿忍受寒冷，在那里筑窝。用六克纸条就能让药物试验有更好的效果，这个代价看来微不足道。