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[交流] 【转帖】对待啮齿类动物更温和实验结果变异性会越小? 已有2人参与

对待啮齿类动物更温和实验结果变异性会越小?
标题：对待啮齿类动物更温和实验结果变异性会越小?
贾内尔•韦弗

1 在动物试验室研究中，常规捉放小鼠方法是抓住小鼠尾基部，但是，这是否是最佳的方法仍不清楚。现在，研究人员建议用杯状物舀小鼠或用似隧道的小鼠笼来运送小鼠能够降低小鼠的应激水平和激励双方合作双嬴。

2 今天发表于《自然方法1》杂志网络版上，英国利物浦大学行为生物学家简•赫斯特主持开展的一项试验研究，由于许多动物均具有防止被捕捉预警应急能力，当有人抓住她们的尾巴时，小鼠自然非常紧张。然而，科学家们却常常这样做，部分原因是避免被小鼠咬伤。采用这种方式捉小鼠增加他们的焦虑和降低它们与试验人员自愿互动合作的可能性。

3 研究人员将3个品系雌雄性小鼠分别分配到3个试验组。第一组采用戴手套或实验室大衣袖子套住手抓小鼠尾基部捉拿小鼠；第二组用充满了小鼠熟悉气味腈纶隧道笼来运送小鼠；第三组戴手套的手在小鼠周围慢慢地关闭带柄的小铲将小鼠舀起来，直到小鼠完全适应。每次1分钟每天9~16次。

4 使用腈纶隧道笼或用杯状物舀小鼠可能有助于使小鼠保持安静。简•赫斯特，
与抓住小鼠尾基部直接提起小鼠相比较，用隧道笼或用杯状物舀小鼠能够增加它们与处理装置之间的互动行为。与抓住小鼠尾基部直接提起小鼠相比较，试验人员拿住隧道笼或手持笼前半部1分钟，小鼠逐渐习惯这些花更多时间嗅，撕咬和爬上隧道笼的顶部或手步骤。而且这些小鼠进入到开放的，无保护的装置迷宫更频繁—焦虑降低的一个标志。

5 与之形成鲜明对比的是，抓住小鼠尾基部直接提起小鼠，引起小鼠排尿和排便增加—遇险信号的常见行为。抓其颈背，较少焦虑的小鼠不避处理器约束他们，同时抓住小鼠尾基部直接提起小鼠会急忙跑开。

6 麻烦的尾巴

7 加州大学伯克利分校行为神经科学家达林•弗朗西斯说，这项研究发现证实了研究人员已经知道的很多应激状态。她试验室的研究人员因为他们想避免改变应激措施的无关变量影响，已经总是采用用杯状物舀小鼠。她接着说，全面评估小鼠不同处理方法对行为影响情况具有十分重要的意义。“用杯状物舀小鼠或用似隧道的小鼠笼来运送，小鼠适应相当快速，”她说，“作者提供了令人信服地证据，技术方法却非常简单明白。”

8 “这篇论文又让我重新思考我们做过的一些事情，”纽约西奈山医学中心行为神经科学家斯科特•罗素说。他的试验室成员常规采用抓住小鼠尾巴捉小鼠，即使他们调查应激状态对焦虑、抑郁和成瘾性的影响研究时，也是这样。“处理尾巴方法绝对影响我们观察到的效应，”他说。众所周知，小鼠的焦虑行为是不一致的—品种之间波动频繁，甚至日间差异也明显，他说。“如果这是降低试验之间变异性的方法，那么这将是一项非常重要的发现。”

9 此外，通过一系列的研究课题以改善试验研究结果的可靠性—从癌症到免疫系统—变化的步骤可能代表动物处理的关键改进，赫斯特说。以后，她将与她研究所的各研究领域科学家合作研究以检测捉拿动物方法对试验动物的生理反应和试验结果可靠性的影响。

10 加州大学洛杉矶分校行为遗传学家德•史密斯说，但是，在中途改变试验方法将带来新旧试验研究方法的复杂比较。“假如有人在每次行为测试的每个阶段的所有可能步骤的所有变量都进行分析，我们最后将处于黑洞，而且实际上没有促进科学的发展。”但是，他补充道，“这项试验研究提出了一个令人感兴趣和有挑衅性的问题，将会激发进一步热烈讨论。”

参考文献

1 赫斯特J. L韦斯特R. S 《自然方法研究进展》2010年10.1038/nmeth.1500

Gentler ways of handling the rodents could keep them calm and reduce experimental variability.

Janelle Weaver

Picking up mice at the base of the tail is standard practice in laboratory research, but whether this is the best method is unclear. Researchers now suggest that cupping a mouse in the hand or carrying it in a small tunnel reduces stress and encourages cooperation.

As prospective prey for many animals, mice are understandably nervous when someone seizes their tail. Yet scientists do this regularly, in part to avoid being bitten. Gripping mice in this way increases their anxiety and decreases the likelihood that they will voluntarily interact with experimenters, according to a study led by Jane Hurst, a behavioural biologist at the University of Liverpool, UK, published online in Nature Methods1 today.

The researchers placed male and female mice from three strains into one of three experimental groups. Some mice were lifted by the base of the tail and held on a gloved hand or lab-coat sleeve. A second group of mice crawled into an acrylic tunnel filled with a familiar scent. In the third group, the handlers scooped mice up with gloved hands that loosely closed around the animals until the mice had adapted to the routine. Each of the 9-16 daily sessions lasted 1 minute.

Carrying mice in tunnels or cupping them in the hand may help to keep them calm.
Jane HurstCupping or carrying the mice in tunnels increased their interactive behaviour with the handlers compared with hoisting them by the tail. When the experimenters held a tunnel or hand in the front half of the cage for 1 minute, mice that were accustomed to these procedures spent more time sniffing, chewing and climbing on top of the tunnel or hand compared with those that had been grabbed by the tail. And the mice entered an open, unprotected arm of a maze more frequently — a sign of reduced anxiety.

By contrast, tail-grasping caused the mice to urinate and defecate more — behaviours that often signal distress. Less-anxious mice did not avoid handlers that restrained them by the scruff of the neck, whereas tail-snatched mice scurried away.

Troubling tail
The findings confirm what many stress researchers already know, says Darlene Francis, a behavioural neuroscientist at the University of California, Berkeley. Researchers in her lab always cup mice because they want to avoid extraneous variables that could alter measures of stress. Still, she says, it is important to systematically assess the effects of different handling practices on behaviour. "The animals habituated to the tunnel and cupping methods pretty quickly," she says. "The authors have convincingly demonstrated that the techniques are fairly straightforward and simple."

"The paper has made me rethink some of the things we do," says Scott Russo, a behavioural neuroscientist at Mount Sinai Medical Center in New York. His lab members routinely clutch mice by the tail, even though they investigate the effect of stress on anxiety, depression and addiction. "Tail handling could absolutely influence the effects we observe," he says. Anxiety behaviour in mice is notoriously inconsistent — it fluctuates across strains, and even across days, he says. "If this is a way to reduce inter-experimental variability, this would be a very important finding."

In addition to improving the robustness of results across a range of research topics — from cancer to the immune system — the alternative procedures may represent a key refinement in the treatment of animals, says Hurst. In the future, she will work with various scientists at her institution to measure the influence of handling practices on physiological responses and the reliability of experimental results.

But switching methods mid-stream could complicate comparisons between old and new studies, says Des Smith, a behavioral geneticist at the University of California, Los Angeles. "If one tried to analyse all possible variants of all possible practices at every stage of every behavioural test, we could end up in a black hole and not actually move forward with the science." But, he adds, "This study has raised an interesting and provocative issue that might fuel the fires of discussion for some time to come."

References
1.Hurst, J. L. & West, R. S. Nature Methods advance online publication doi:10.1038/nmeth.1500 (2010).

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