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It’s been an important week for the future of organ transplants. Like, game-changingly important.
这周是器官移植未来的重要一周，是对器官移植领域有着重大影响的一周。
In one paper, published on Wednesday in the journal Nature, a group of biologists announced that they’d genetically engineered a rat to grow a mouse’s pancreas,
在周三发表于《自然》杂志中的一篇论文中，一组生物学家团队宣布通过基因工程改造他们研制出了一只长有小鼠胰腺的大鼠，
then successfully used cells from that pancreas to suppress diabetes in mice.
他们成功地利用了胰腺中的细胞抑制大鼠中糖尿病。
And in another paper, published on Thursday in the journal Cell,
在另一篇发表于《细胞》期刊的论文中，
a different group announced that they’d genetically engineered a pig embryo to grow with some human cells.
另一组学家宣布他们也通过转基因研制出了一只长有人体细胞的猪胚胎。
There’s a long way to go before we’re able to grow functional human organs inside other animals.
要在其他动物体内生长功能性人体器官，还有很长的路要走。
But both of these studies mean that we’re a lot closer.
但这两项研究都意味着我们距离它更进了一步。
Right now, the organs used in transplants have to come from human donors.
目前用于移植的器官必须来自于人类捐赠者。
But the donor pool isn’t very big, especially for essential organs like hearts and lungs that can only be donated when someone dies.
但捐赠者并不多，尤其是像心脏和肺这样的必要器官仅能由死者捐赠。
It’s hard to find a match within that pool, and even if you can, the waiting list can be very long.
在捐赠者中找到匹配的器官很困难，即使有匹配习惯，等待的这个器官的人也非常多。
That’s why lots of researchers are looking into ways to grow human organs inside other animals,
这就是为什么众多研究者都在寻求在其他动物体内生成人类器官方式的原因，
so doctors could grow whatever healthy, functional organs they need.
这样医生们就能获取任何所需的健康功能器官。
The same team that published the Nature paper this week actually created the first combined rat-mice, back in 2010.
事实上本周在《自然》期刊上发表论文的团队早在2010年就研制出了第一批大鼠-小鼠合成物。
Any animal with a mix of cells with different genes is known as a chimera,
任何拥有不同基因混合的动物都被成为嵌合体，
and these were the first rat-mouse chimeras to be grown from embryos and survive.
而这些则是由胚胎发育而成且成功存活的第一批大鼠-小鼠嵌合体。
They injected rat stem cells into mouse embryos that had been genetically engineered so none of the mouse stem cells could develop into pancreatic tissue.
他们将大鼠干细胞注入转基因的小鼠胚胎中，这样小鼠干细胞就无法发展成为胰腺组织。
Those embryos grew into rat-mouse chimeras, with mixtures of rat and mouse cells throughout their bodies except for their pancreases,
那些胚胎长成大鼠-小鼠嵌合体，除了胰腺外，它们的体内遍布大鼠和小鼠的细胞混合，
because only the rat stem cells could grow into pancreatic tissue.
因为只有大鼠的干细胞才成长成胰腺组织。
That was a big deal on its own, but originally, the researchers also wanted to try transplanting clusters of the pancreas cells, called islets, into rats to suppress type I diabetes.
这本身就是一件了不起的大事，研究员们也希望尝试将胰腺细胞簇，即胰岛，移植入大鼠体内以抑制1型糖尿病。
Islets produce the insulin that helps regulate blood sugar. But in type I diabetes, the immune system destroys the islets.
胰岛能产生胰岛素帮助调节血糖。但1型糖尿病中，免疫系统会破坏胰岛。
The researchers were hoping to transplant new islets into rats with type I diabetes to get them to start producing insulin again.
研究员希望能将新的胰岛移植到患有1型糖尿病的大鼠体内，让它们重新开始产生胰岛素。
Problem was, the pancreases were mouse-sized, so they weren’t big enough for the researchers to get all the islets they needed for a successful transplant.
问题是胰腺是小鼠的尺寸，所以研究员们觉得这些胰腺太小而无法获取所需的全部胰岛素进行成功移植。
For the study published this week, the team tried the opposite of their 2010 experiment: they injected mouse stem cells into rat embryos.
对于本周出版的研究，团队做了与2010年相反的试验：他们将小数干细胞注入大鼠胚胎中。
And these embryos grew into mouse-rat chimeras with pancreases that were fully mouse.
这些胚胎发育成带有小鼠胰腺的小鼠-大鼠嵌合体。
This time, the pancreases were rat-sized, so the researchers were able to get enough islets to perform transplants.
这一次胰腺是大鼠的尺寸，所以研究员们能够获取用于移植的足够胰岛素。
They took islets from the mouse pancreases grown in the chimeras and transplanted them into mice with type I diabetes,
他们从生长于嵌合体的小鼠胰腺中获取胰岛素，并将其移植到患有1型糖尿病的小鼠中，
so the mice started producing insulin again and the disease was suppressed.
这样一来，小鼠就开始再次产生胰岛素，而疾病也得到抑制。
When it comes to organs, the pancreas is relatively simple.
说起器官，胰腺还是相对简单的了。
So this isn’t quite the same as growing and transplanting, say, an entire heart or lung. That would be much more complicated.
所以，这和生长以及移植并不相同，比如，完整的心脏或肺，要复杂得多。
But thanks to this research, we now know that organ transplants from chimeras can actually work. That’s just mice and rats, though.
但多亏了这项研究，我们了解到从嵌合体中进行器官移植可行的。虽然，只是这些小鼠和大鼠。
The goal of this line of research is to eventually grow human organs inside a species with similar-sized organs, like a pig or cow.
研究路线的最终目标是在一种有相似大小器官的物种体内种植人体器官，比如猪或牛。
And that’s where the paper published in Cell comes in.
正如发表于《细胞》期刊的论文所述。
This group of researchers wanted to create human-pig chimeras by injecting human stem cells into pig embryos.
该研究团队希望能通过将人体干细胞注入猪胚胎中以研制人-猪嵌合体。
But that’s a lot harder than creating a rat-mouse chimera.
但这比研制大鼠-小鼠嵌合体要困难得多。
For one thing, humans and pigs have much less DNA in common than rats and mice.
首先，人类和猪的类似DNA要更少，而两鼠之间则更多。
For another, pig fetuses only take about 16 weeks to develop, while human fetuses take 40 weeks.
另一方面，猪仔仅需16周就开始生长，而人类胎儿则需要40周。
So human stem cells and pig stem cells develop at different rates.
所以人体干细胞和猪的干细胞发展速率不同。
All this makes it harder for human cells to survive and become a healthy, integrated part of a pig embryo.
这些都让人类细胞作为猪胚胎健康整合部分而存活变得更加困难。
For this study, the researchers injected human stem cells into pig embryos, then implanted those embryos into female pigs.
对于该项研究，研究员将人体干细胞注入猪胚胎中，然后将那些胚胎植入母猪体内。
They let the fetuses develop for just 3 to 4 weeks, then euthanized them so they could analyze their cells in the lab.
他们让这些胎儿仅生长3到4周，然后将它们安乐死，这样他们才能在实验室中对细胞进行分解。
They found that the chimeras had developed with some human cells but not very many of them, and even fewer of them grew to a typical, healthy size.
他们发现嵌合体和一些人体细胞一同生长，但只是其中小部分，甚至只有少数长成了典型的健康尺寸。
The fetuses were mostly pig, with some human cells sprinkled in among the developing muscles and organs.
这些胎儿大部分是小猪仔，在生长肌肉和器官中散落了一些人类细胞。
But still, they did it: the researchers made the first human-pig chimeras.
即使这样他们还是做到了：研究员们研制出了第一只人-猪嵌合体。
And they’re hoping that the process can be improved to the point where pigs can be grown with specific human tissues or entire organs.
并且他们希望能够对研制过程进行完善，使其适于生长特定的人类组织或完整的器官。
There are lots of extra challenges involved in this kind of research though, and it is controversial.
在这场研究中还存在众多其他挑战，且备受争议。
For instance, nobody wants people growing pigs with, like, human brains.
例如，没人希望人类养的猪长着人一样的脑袋。
And we’re a long way away from being able to do anything like that, but scientists researching chimeras are still being really careful about the kinds of experiments they try.
而且距离完成实现这种想法还有很长的路要走，但研究嵌合体的科学家们仍然对其进行的试验非常仔细。
And it’s possible that someday this research will lead us to being able to grow functional, vital organs that people need.
或许某天这项研究将让我们能够研制出人类所需的功能性主要器官。
Thanks for watching this episode of SciShow, which was brought to you by all of our patrons on Patreon.
感谢收看本期科学秀，谢谢Patreon的所有赞助人。
Which is a place where people give money so that we can make a show for everyone.
使你们的支持才有了本期节目。
So there’s a small number of people who make SciShow available for a huge number of people. And they are so great.
少数人的支持为大部分人创造可能。他们真的非常棒。
Thank you to those patrons. If you want to learn more about that you can go to patreon.com/scishow.
如果你想了解更多，请登录patreon.com/scishow
And if you just want to keep watching and learning with us here at SciShow you can go to youtube.com/scishow and subscribe!
如果你想观看更多内容，请登录 youtube.com/scishow 进行订阅！
