Fish Found to Regenerate Heart Tissue

Zebrafish have a very valuable ability — they can repair up to 20 percent of their heart muscle within weeks of sustaining damage. One researcher believes the heart-mending ability is due to the presence of a protein called thymosine beta-4, which stimulates the growth of new blood vessels and heart tissue. When zebrafish heart tissue is damaged, a blood clot is generated to stop bleeding around it. Then the clot is engulfed by the covering to the heart, which stimulates the regeneration of the area with the damaged tissue. Eventually, the new tissue is integrated back into the entire heart. They don’t only regrow heart tissue, however. It has been observed they also can regenerate fins, skin and eye cells.

Many, if not most, Care2 members are adamantly opposed to using animals in medical research, so some may not be happy to learn that a medical research foundation is studying zebrafish in hopes of finding a way of repairing human hearts as well. They are investing millions in the study of regenerative medicine, including investigating the heart function of zebrafish. The small translucent fish have two-chambered hearts, instead of four like humans, but they also have a backbone like we do, which means they are more closely related than some other research subjects like worms, so studying them may yield knowledge relevant to our own health.

The British Heart Foundation envisions a time when new medications might be able to regrow damaged heart tissue, instead of having to resort to transplants or implants. “The zebrafish does not use stem cells, what it uses are its own adult heart cells, which are able to divide and then re-accumulate together to form a new beating heart. And there is some interest in British Heart Foundation funded researchers that looking at cells that human hearts have that sit outside of the heart, that they might have the ability to become adult heart cells, said Peter Weissberg, medical director, British Heart Foundation. (Source:

Zebrafish are found natively in the freshwater bodies of India, Pakistan, Bangladesh, Nepal, and Myanmar.

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Nimue Pendragon

Yet another excuse to murder animals. Like humans need an excuse. STOP TORTURING AND KILLING ANIMALS, IT'S WRONG!

LMj Sunshine

Interesting, thank you.

LMj Sunshine

Interesting, thank you.

jane richmond
jane richmond5 years ago


Adelina Z.
Adelina L.5 years ago

really fascinating!

Savannah P.
Savannah P.5 years ago

*bottom muscle of his heart
Sorry about the typo.

Savannah P.
Savannah P.5 years ago

Well spoken Alisa C.

Chinmayee Jog, my grandfather has a genetic condition which causes the bottom muscle to weaken until it stops functioning. He's gotten copious amounts of exercise and eaten healthily all his life and his heart functioning is still dangerously low. Yes animal testing is a terrible thing, but sometimes it is necessary to save lives. He is a good man and truly loves not only his family but animals and nature in general. He would not like the fact animals must suffer for this treatment but he would sleep better knowing his grandchildren will have better medicine than he did.

Barbara Erdman
Barbara Erdman5 years ago


Julia A.
Julia A.5 years ago

Enough is enough, please! We have no moral right to torture other creatures like this - even though it will - as it has in the past - provide treatment for human disease in the first world. Use the money to apply the solutions we already have to the ills of the third world, where people are dying from dirty water - so easy to remedy!

Gabriela B.
Gabriela B.5 years ago

They are going to experiment on it now, right? That's the part of science I really don't like.