VOA慢速英语 ：科学家发现能让老鼠返老还童的蛋白质2014-06-04

Could This Be the Fountain of Youth for Mice and Men?

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.

词汇解析

research

难度：5星基本词汇，属常用1000词

英汉解释

n.研究;调查

v.研究;调查

参考例句

用作名词 (n.)

Research indicates that men find it easier to give up smoking than women.

研究表明，男人比女人更容易戒烟。

用作动词 (v.)

They have been researching the effects of the drug on mice.

他们一直在研究老鼠对这种药物的反应。

protein

难度：4星核心词汇，属常用3000词

英汉解释

n.蛋白质

参考例句

用作名词 (n.)

You need more protein to build you up.

你需要增加蛋白质以增强体质。

journal

难度：4星核心词汇，属常用3000词

英汉解释

n.日志;日记;期刊

参考例句

用作名词 (n.)

He kept a journal during his visit to Japan.

他在访问日本期间坚持记日记。

ability

难度：4星核心词汇，属常用3000词

英汉解释

n.能力;才能

参考例句

用作名词 (n.)

This is a task well within your ability.

这完全是你力所能及的工作。

He shows exceptional ability in solving problems.

他处理问题才干过人。

tissue

难度：4星核心词汇，属常用3000词

英汉解释

n.纸巾;薄绢;(生物的)组织;织物

参考例句

用作名词 (n.)

She wiped off the sweat from her face with a piece of facial tissue.

她用一张面巾纸擦掉脸上的汗水。

Her dress was of silk tissue.

她的连衫裙是用薄绸做成的。

structural

难度：3星常用词汇，属常用6000词

英汉解释

adj.结构的;构造的;建筑的;建筑用的

参考例句

用作形容词 (adj.)

Note that in areas of monoclinal dip the closure of a trap may not be the same as its structural relief.

值得注意的是，在只有单斜地层的构造内，圈闭的幅度可能与构造的起伏不一样。

The structural type and design scheme for a building project should be based on its serviceable function and force conditions.

摘要建筑工程设计时，需要根据建筑的使用功能和建筑结构的受力特征，确定结构形式及设计方案。

youthful

难度：2星扩展词汇，属常用10000词

英汉解释

adj.年轻的;有青春活力的;年轻人的;(地质学)幼年期的

参考例句

用作形容词 (adj.)

No one can remain youthful forever.

没有人能永保青春。

If you want to retain youthful vigor,you have to take regular exercise.

如果你想保持青春活力，你就得经常锻炼。

researcher

英汉解释

n.研究人员

参考例句

用作名词 (n.)

Researcher redefines the physics of photons.

研究人员重新定义光子物理学。

Vendors would give public credit to the researcher.

销售商则将给予研究人员公开好评。