(单词翻译:单击)
听力文本
From VOA Learning English, this is the Health Report.
Could young blood be the answer to cheating death? It may sound like the story in a vampire movie but now there is scientific research that supports the theory.
U.S. scientists have discovered a protein in the blood in young mice that can undo some effects of aging in old mice. The same protein is present in human blood and might one day help us lead healthier lives.
Two papers published in the journal Science discuss this protein, called GDF11.
Researchers at Harvard University in Cambridge, Massachusetts explain how GDF11 improved the brain and muscle ability of older mice. This protein is found in high levels in the blood of young mice. And it appears to help develop new blood vessels.
In one experiment, the scientists increased the levels of GDF11 in aging mice by surgically connecting (or infusing) the blood flow systems of young mice to the old mice. Blood containing higher levels of GDF11 flowed among both groups. In another experiment, they injected the protein into old mice.
Scientists saw the greatest change in the old mice that shared blood flow with the young.
The old mice formed new blood vessels. The animals' blood flow improved. And the aging process changed directions, or reversed, in every tissue the researchers observed.
Researcher Lee Rubin is a professor of stem cell research at Harvard's Stem Cell Institute. His team looked at the effect of GDF11 on brain tissue.
"So, this simple surgery, infusing an old mouse with young blood, actually produced some structural changes in the old brain, making the old brain, in essence, more like (a) young brain. And some people have used the phrase 'rejuvenating the old brain.' And similar things were observed in other tissues."
Rubin's teammate Amy Wagers said that GDF11 repaired DNA damage linked to aging. Wagers said earlier GDF11 research showed a change in the weakened hearts of older mice. The hearts returned to a more youthful size and beat more efficiently.
So, this is great news for old mice. But what does it mean for us? There is growing hope GDF11 might someday repair and renew unhealthy human hearts. Also, Mr. Rubin says the protein might improve memory power for Alzheimer's patients or physical movement for people with Parkinson's disease.
But the researcher says the protein is not a "fountain of youth." He says the aim of the research is not to lengthen life as much as to improve it.
"In other words, even if you did not live more years, at least you could remain healthier for the number of years you do live. And I think again, what we've shown is functional improvement in ... various different tissues in mice."
Researchers at Stanford University in California are doing similar research. They report that blood from young mice improved brain operations in older mice.
Researchers in Massachusetts and California are working with technology companies that specialize in human medicine to see how these findings can help humans.
Harvard University's Lee Rubin predicts human testing could begin in as little as three years.
And that's the Health Report. I'm Anna Matteo.
文本来自51voa，译文属可可原创，仅供学习交流使用，未经许可请勿转载
词汇解释
1.undo vt. 取消；解开；破坏；扰乱 vi. 撤消
A heavy-handed approach from the police could undo that good impression.
警察的专制手段能使那个好印象化为乌有。
2.reverse n. 背面；相反；倒退；失败 vt. 颠倒；倒转 adj. 反面的；颠倒的；反身的 vi. 倒退；逆叫
They have made it clear they will not reverse the decision to increase prices.
他们已经明确表示不会为了提高价格而转变这一决定。
3.rejuvenate vt. 使年轻；使更新；使恢复精神；使复原 vi. 复原；变年轻
Shelley was advised that the Italian climate would rejuvenate him.
有人建议雪莱说意大利的气候会使他年轻。
4.lengthen vt. 使延长；加长 vi. 延长；变长
The evening shadows were lengthening.
傍晚的影子正在变长。
内容解析
1.He says the aim of the research is not to lengthen life as much as to improve it.
as much as 差不多；尽…那样多
The output is twice as much as that of ten years ago.
产量是10年前的两倍。
The doctor will see you again next week. Meanwhile, you must rest as much as possible.
医生下周还会给你看病。在此期间，你一定要尽可能多休息。
参考译文
这里是美国之音慢速英语健康报道。
年轻的血液可以欺骗死神？这听起来像是吸血鬼电影里的故事，但现在有科学研究支持了这一理论。
美国科学家在年轻小白鼠血液内发现能抵消老年小白鼠老化的蛋白质，人体血液中也存在这种蛋白质，可能有一天能让人类过上更健康的生活。
《科学》杂志上发表的两篇论文都探讨了这种名为GDF11的蛋白质。
马萨诸塞州剑桥市哈佛大学的研究者解释了GDF11如何改善老年小白鼠大脑和肌肉的能力，这种蛋白质在年轻小白鼠血液内含量很高，似乎能帮助新的血管生长。
在一个实验中，科学家用外科手术将年轻小白鼠和老年小白鼠的血管系统连接起来，增加了老年小白鼠血管的GDF11含量。含有较高水平GDF11的血液在两个组的小白鼠体内流动。在另一个实验中，科学家将这种蛋白质注入老年小白鼠体内。
科学家说出现最大改变的是那些和年轻小白鼠共享血液循环的老年小白鼠。
老年小白鼠形成新的血管，其血液循环得到改善。老化过程也改变了方向，也就是逆转，研究者在每个组织都发现了逆转过程。
研究者李·鲁本是哈佛干细胞研究所从事干细胞研究的教授，他的团队研究了GDF11对大脑组织的影响。
“将年轻血液注入老年小白鼠体内这样的简单实验，事实上让老年大脑产生了结构性变化，让老年大脑更像年轻大脑了。有的人用了‘让大脑新生’这个说法了，其他组织也发生了类似的变化。”
鲁本的研究伙伴艾米·韦戈斯说，GDF11修复了与衰老有关的DNA损伤。韦戈斯说早先的GDF11研究表明老年小白鼠衰弱的心脏出现了改变，心脏恢复到更年轻的规格，其跳动也更有效。
所以这对老年小白鼠来说是个好消息，但这对人类来说意味着什么呢？人们越来越希望GDF11将来能修复不健康的人类心脏，使之焕发新生。鲁本说这种蛋白质可能改善老年痴呆症患者的记忆力，或是帕金森患者的身体活动能力。
但鲁本称这种蛋白质并不是“不老泉”，他说研究的目的是改善生命，而不是延长生命。
“也就是说，即使没有活很久，至少可以在活着的时候能更健康，我想我们已经证实了小白鼠各种组织功能的改善。”
加州斯坦福大学的研究者也在做类似的研究，他们报告出年轻小白鼠的血液能改善老年小白鼠的大脑运作。
马萨诸塞州和加利福尼亚州的研究者在和专门进行人类医学研究的科技公司合作，希望找到这些发现帮助人类的办法。
哈佛大学的李·鲁本预料人体试验将在不到三年内开始。
这就是健康报道，我是安娜·马特奥。
