A run a day keeps the tumour at bayExercise protects against cancer. Researchers now understand whyFeb 27th 2016 | From the print edition AMPLE evidence shows that exercising regularly reduces the risk of cancer. Similarly, those who have survived the disease are less likely to see it return if they engage in lots of physical activity after treatment. All this suggests that such activity triggers a reaction in the body which somehow thwarts cancer cells, but the details of the process have remained murky. Now, a team led by Pernille Hojman at Copenhagen University Hospital, in Denmark, has reported in Cell Metabolism that the key to the mystery is adrenalin.
有充分证据显示有规律的运动可以降低患癌风险。同样，癌症患者在接受治疗后，进行适量的身体活动可以降低复发率。所有的这些证据表明身体锻炼能够触发机体内的一种反应，这种反应可以抑制癌细胞，但这种反应的细节还不十分清楚。如今，丹麦哥本哈根大学的Pernille Hojman团队在细胞代谢杂志上发表的文章，指出的这个反应的关键——肾上腺素。
Dr Hojman began her work by verifying that exercise truly does have beneficial anti-tumour effects. She and her colleagues gave some of the mice in their laboratory activity wheels, which the animals could run around inside as much as they liked. Other mice, meanwhile, were given no opportunity to exercise beyond moving about inside their cages. The researchers then induced mice of both sorts to develop one of three types of cancer. Some, they injected with a substance called diethylnitrosamine, which causes liver cancer. Others, they injected below the skin with melanoma cells, which then set up shop where they had been injected. Others still had their tails inoculated with melanoma cells. In mice, previous experience has shown, this leads to melanomas forming in the lungs.Hojman博士通过验证关于体育锻炼确实能够有效抗肿瘤的作用而开始这个项目的研究。她以及她的同事让实验室中的部分老鼠在滑轮笼子里活动，这种滑轮笼子可以使它们想活动多久都可以。同时，另一部分老鼠除了可以在笼子里移动以外，没有机会做其他活动。研究人员通过诱导这些小鼠，使它们分别患上三种类型的癌症之一。一部分老鼠注射二乙基亚硝胺，可以使老鼠发展为肝癌。一部分皮下注射黑色素瘤细胞，从而在注射部分发展为黑色素瘤。其他的老鼠从尾部灌输黑色素瘤细胞，先前实验证明，这种方式可在肺部形成黑色素瘤。The results were instructive. While all mice injected under the skin with melanoma cellsdeveloped that cancer, the tumours in animals which had had access to a running wheel were 61% smaller after six weeks than were those in mice that had been unable to exercise.A similar reduction in size (58%) pertained to lung tumours. And, of the mice injected with diethylnitrosamine, only 31% of those with wheels in their enclosures developed tumours at all—in contrast to a 75% tumour-development rate in mice lacking access to a wheel.结果是有教育意义的。期待您的翻译，您可将中文翻译留言在文章底部，第二天会有答案解析哦。在肺部肿瘤对照组中，肿瘤尺寸要小58%。并且，注射二乙基亚硝胺的老鼠，经过滑轮运动的只有31%的发展为肿瘤—相对于缺少运动的，75%的发展为肿瘤。To try to understand why exercise does this, Dr Hojman and her team put under a microscope some of the tumours they had induced. They found that those from well-exercised mice contained more immune cells than equivalent tumours from inactive animals. Specifically, the former had double the number of cytotoxic T-cells, which kill off body cells that are damaged, malfunctioning or infected with viruses. They also had five times more natural killer cells, a type that sounds the alarm and attracts other immune cells.为了了解锻炼作用的原因，Hojman博士及他的团队将他们制作的某种肿瘤置于显微镜下。他们发现比起不活动的老鼠，那些经过很好锻炼的老鼠在等量肿瘤细胞当中拥有更多的免疫细胞。尤其是前者拥有成倍的细胞毒性T细胞，这种T细胞能够杀死机体中受损伤的细胞以及失能或者被病毒感染的细胞。它们也拥有五倍的自然杀伤细胞，这种细胞具有警示功能并且能够吸引其他的免疫细胞。In light of these discoveries Dr Hojman repeated the experiment, this time on mice that had been engineered to lack cytotoxic T-cells. Again, she found that mice with access to wheels had smaller tumours. This suggested that the natural killer cells, not the T-cells, were the responsible agents. A third experiment confirmed this. She sabotaged natural killer cells by giving mice an antibody that eliminated these cells while leaving the rest of the immune system intact. With the natural killer cells gone, the tumours of all the mice, regardless of whether or not they could run in a wheel, grew to the same size.根据这些发现，Hojman博士重复做了这个实验，这次老鼠被制作成为一种缺乏细胞毒性T细胞的样本。她再次发现经过滑轮运动的老鼠所携带的肿瘤很小，这样就说明这种应答机制是由自然杀伤细胞引起的，而不是T细胞。第三次实验也证实了这个观点。通过给老鼠注射一种可以清除自然杀伤细胞的抗体，从而破坏老鼠机体的自然杀伤细胞，同时保留其他的免疫系统完好。随着自然杀伤细胞的消失，无论是否在滑轮上运动，这些老鼠体内的肿瘤尺寸都一样。Dr Hojman knew from past work that epinephrine, a hormone also commonly known as adrenalin, has the potential to mobilise natural killer cells. She knew, too, that this hormone’s levels in the blood rise during periods of physical exertion. That led her to wonder if it is epinephrine which is behind the cancer-thwarting effects of exercise.Hojman博士从以往的研究中得知肾上腺素（epinephrine，也叫做adrenalin）具有能够动员自然杀伤细胞的作用。她同样了解在机体进行强体力运动期间，血液中的这种激素水平会升高。这些结果使她猜想，运动的这种抗癌作用的背后是否是去甲肾上腺素在起作用。To find out, she ran a fourth experiment, in which mice induced to have cancer were injected either with epinephrine or with saline. The hormone performed well, reducing the growth of tumours by 61% in mice that had no access to a wheel. However, this was not as impressive as the reduction of 74% which the team saw in control mice that got regular exercise. There was, they concluded, something else involved. And they found it in the form of interleukin-6.为了探明真因，她又做了第四种实验，是患癌老鼠一部分注射肾上腺素，一部分注射生理盐水。激素发挥了很好的作用，那些没经过滑轮运动的老鼠的肿瘤增长率减少了61%。然而，经过规律的滑轮运动的老鼠这组效果更加令人振奋，肿瘤生长率减少了74%。因此，他们总结出一定还有其他因素起作用。它就是白介素-6.Levels of this molecule also spike during exercise—and it, too, helps immune cells home in on tumours. When Dr Hojman and her colleagues exposed sedentary mice both to epinephrine and to interleukin-6, the rodents’ immune systems attacked the tumours in their bodies as effectively as if those animals had engaged in regular wheel-runs.在锻炼期间，这种分子水平会升高，同样它也会帮助免疫细胞追踪肿瘤，当Hojman博士和她的同事们将不做运动的小鼠注射肾上腺素和白介素-6时，这些老鼠的机体免疫系统就会攻击肿瘤，效果相当于那些做着规律的滑轮运动的老鼠。Dr Hojman’s findings, then, suggest that epinephrine and interleukin-6 could be used as anti-tumour drugs. She is not proposing that they should be a substitute for exercise in those who are merely lazy—not least because exercise brings benefits beyond curbing oncogenesis. But people who are too old or too ill to be active might thus gain exercise’s anticancer benefits without the need to get sweaty.Hojman博士的发现成果显示肾上腺素和白介素—6都能够应用在抗肿瘤的药物中。但是她并没有表明这可以允许那些懒人取代运动，至少运动可以在控制肿瘤形成方面给机体带来益处。但是那些年龄太大或者身体较弱以至于不能够进行运动的人们，这个研究成果或许能够使他们不必出汗就能带来犹如运动的益处。
