VOA慢速英语2016--黎巴嫩新一届内阁组建完成心脏肌肉再生也许成为可能（在线收听）

From VOA Learning English, this is the Health & Lifestyle report.

It may seem like a moment in a science fiction movie. In a fierce battle, a creature loses an arm but, then, grows another one to take its place.

However, this is not science fiction. It is scientific fact. Some fish and amphibians, such as salamanders, can regrow lost limbs and organs.

As mammals evolved they lost the ability to regrow, or regenerate, parts of their body. However, experiments show that it may be possible to regain that ability.

Tropical freshwater zebrafish are popular pets. They are also popular as lab animals. Their embryos are clear, or translucent. They can regrow damaged fins, skin and hearts. Zebrafish are also genetically similar to humans.

In 2013, the website Sci-News reported that researchers had found that 70 per cent of “protein-coding human genes” are related to genes found in the zebrafish. The report also said that researchers at the Wellcome Trust Sanger Institute in Britain also found that 84 per cent of genes known to be connected to human disease have a zebrafish counterpart.

These researchers published their findings in the scientific journal Nature. Sanger is a non-profit British genomics and genetics research institute.

So, it is no surprise that scientists at the University of Pittsburgh in Pennsylvania are using tiny zebrafish to regenerate severely damaged mouse hearts.

Scientist Wang Yadong is one of the Pittsburg researchers. He and his team are studying the ability of zebrafish to regenerate limbs and organs. Wang says you can cut away about 20 per cent of the zebrafish heart and it will regenerate. He add that same process may be able to help humans.

"So that amazing ability make(s) us think it's possible to borrow some of that repair regeneration mechanism and use that to help us to regenerate our heart."

Scientists injected an “extracellular matrix,” or ECM, from the heart of a zebrafish into a severely damaged mouse heart.

In biology, an extracellular matrix is a substance produced and released by cells that gives structural and biochemical support to surrounding cells. Think of ECM as cellular stuff that gives room and board to surrounding cells.

So, what did the researchers find?

They found that the heart muscle regenerated in days. They found something else. The healing was even faster when the ECM was taken from zebrafish that was itself in the process of re-growing damaged tissue.

Wang adds that if you had to choose between the two matrices, the “healing matrix” is more powerful of the two.

"Between the two, the healing matrix from the zebrafish heart is even more potent than the normal one."

A molecule called neuregulin 1 seems to play a major role in causing the regeneration to happen.

"We did see the zebrafish heart has more neuregulin 1 than the mouse heart. The healing zebrafish heart has even more than the normal. So, it does indicate that neuregulin probably plays a role but we have to do more study on that."

The next step will be to test the regenerative abilities of zebrafish ECM on larger mammals.

Words in This Story

limbs –n. referring to arms and or legs

regenerate –v. to regrow after being lost or damaged

translucent –adj. permitting light to pass through

counterpart –n. something that does the same job as something else

mechanism a process or system that is used to produce a particular result

extracellular matrix substance produced by cells and released into the environment in which the cells are embedded; In biology, the extracellular matrix (ECM) is a collection of extracellular molecules released by cells that provides structural and biochemical support to the surrounding cells.

room and board –idiom a place to stay and food to eat

potent –adj. active, strong

matrix –n. something from which something else develops

indicate –v. to show

role –n. the part something plays in a system