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孕育婴儿的最初两周 – 译学馆
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孕育婴儿的最初两周

Building a baby: The first two weeks

This is how a human gets made.
人类是这样形成的
Every one of us started out this way.
每个人都是以胚胎的形式来到这个世界上
We have a pretty good idea what happens
我们清楚地知道
over the 9 months it takes to produce a newborn,
孕育新生儿的九个月里会发生什么
but there’s this one bit that’s been missing.
但有一段孕期我们了解的并不多
Right at the beginning,
那就是孕期刚开始的时候
before this animation even starts the very first few weeks.
也就是胚胎开始发育的前几周
Now armed with new ways of growing human embryos in the lab,
如今有了实验室培育人类胚胎这一新技术
scientists are learning what the very beginning of human development looks like.
科学家也借此在研究人类发育的最初阶段

[孕育婴儿]
For decades,
数十年来
studying this crucial, early time in a human embryo’s development
研究的关键 即人类胚胎发育的早期阶段
was a technical headache,
始终是个技术难题
embryos are hard to get and keep alive outside the body.
胚胎很难在体外存活
And it’s an ethical challenge.
同时这也是个道德难题
Guidelines put together in the late 70s and 80s
上世纪七八十年代的各种规定
prevent scientists from growing embryos for longer than 14 days.
都不允许科学家培育胚胎超过14天
Despite the hurdles,
尽管有着重重困难
scientists do know a bit about what happens in those critical weeks
科学家还是从动物和少数几例人体组织
often from animal studies or rare human tissue samples.
样本的研究中获悉了关键几周的发育情况
They know that sperm fertilises egg,
他们认识到精子使卵子受精
and one cell grows to two, four, eight, and so on.
一个细胞会分裂成两个 四个 八个乃至更多
Around day 5 or 6,
大约在第5天或第6天的时候
the blob starts to feature different types of cell.
这一团就开始转变成不同类型的细胞
Scientists call this blob a blastocyst.
科学家将这一团细胞命名为囊胚
All being well,
一切顺利的话
the cells in the blastocyst begin to differentiate.
囊胚中的细胞就会开始分化了
One week in, it implants into the wall of the uterus.
受精后一周内 囊胚会在子宫壁内着床
What happens next has been a bit of a mystery
接下来会发生什么一直是个谜
by implanting itself into the womb’s wall,
囊胚着床后
the embryo basically hides,
胚胎基本上就隐藏了起来
and that makes studying it in humans impossible.
在人体内对它进行研究就不太可能了
One way of exploring this crucial time is to study embryos
探索这个关键期的方法之一是研究那些
donated by people who no longer need them for fertility treatment.
无需继续进行生育治疗的夫妻所捐赠的胚胎
In the last few years, several labs
在过去的几年里 有些实验室
have developed new ways to nurture these embryos.
研发出了培育这些胚胎的新方法
Their techniques have allowed them to start building a picture
这些技术使得他们能够勾勒出一幅
of human development that’s more detailed than ever before.
比以往都更加详细的人类发展图景
Here’s a day 6 embryo growing in a lab.
这是个在实验室培育了六天的胚胎
Cells destined to become the actual fetus are tagged in green,
注定会发育成真正婴儿的细胞标为了绿色
those that go on to form the placenta in blue.
会继续形成胎盘的细胞标为了蓝色
By day 8 the cells are sorting and arranging themselves
第八天 胚胎内的细胞开始分类 排列
– the green fetal cells have condensed together,
图片显示 绿色的胎儿细胞凝聚在了一起
and in red here are the cells that
红色的细胞
will form the interface between the baby and the placenta.
会形成胎儿和胎盘之间的胎膜
It seems these ‘extra-embryonic’ structures develop a little later in humans
人类“胚胎外”组织的发育好像比
than expected from studies in other animals.
其他动物的要晚一些
Day 10. The whole thing increases in size,
第十天 整个胚胎开始变大
and bundles of cells start developing into support structures.
这团细胞开始发育成支撑结构
Surprisingly at this stage,
在此阶段 令人惊讶的是
the embryo can direct its own development, with no input from the mother’s tissues.
胚胎可以在没有母体供给的情况下自我发育
By day 12,
到了第12天
the outskirts of the embryo are preparing
胚胎外围正准备着
to bind more strongly to the wall of the uterus.
与子宫壁更牢固地结合在一起
After all, if this were a natural pregnancy,
毕竟自然受孕的情况下
the embryo would be there for the next 9 months.
胚胎会在子宫内度过接下来的九个月
You can even see little holes appearing
你甚至可以看到胚胎上出现了些小孔
ready for the mother’s blood vessels to start supplying the embryo
以便让母亲的血管开始向胚胎
with essential oxygen and nutrients.
输送必要的氧气和营养
By now the embryo is signalling its presence to the mother
胚胎现正在向母亲发送信号以宣告他的存在
via a hormone – the one that pregnancy tests pick up – HCG –
这个信号是孕检时会检测的HCG激素
labelled here in yellow.
此处被标记为黄色
After two weeks, the teams ended their experiments
两周后 研究小组结束了实验
in line with the ethical 14-day limit.
这符合14天的道德限制
To study what happens after 14 days,
为了研究14天后胚胎的生长情况
researchers had to turn to different techniques.
研究人员不得不采用不一样的方法
Recently scientists have built artificial, embryo-like structures from stem cells.
科学家最近利用干细胞研制出了一种人工胚胎状组织
Using these partial models,
通过这些局部模型
they can study things like cell signalling,
科学家可以研究细胞的信号传递
or even the formation of the primitive streak
甚至可以研究原条的形成
-the crucial thread of cells which guides the process called gastrulation.
原条的形成是细胞的关键过程 引导原肠胚的形成
That’s the moment the embryo decides which end will become the head.
原肠胚形成时胚胎会决定哪端是胎儿头部
Here they use human stem cells
科学家利用生长于动物胚胎内的
growing in an animal embryo to explore that process.
人类干细胞来探索这一过程
But even after this early phase is over,
但直到这一早期阶段结束
there is still a lot of work involved in building a body.
孕育婴儿还是有很多工作要做
To study later phases,
为了研究后期的成长情况
scientists have made and analysed
科学家制作并分析了
high-resolution 3D atlases of human embryos and fetuses.
人类胚胎和婴儿的高分辨率3D图谱
One team found that
其中一个小组发现
the left and right hands don’t simply mirror each other when growing their nerves.
左右手神经的生长并非简单的镜像过程
Instead, some branches take random paths in each limb.
相反 每只手的一些神经分支是随意生长的
Another group saw muscles that grew in early embryos,
另一小组观察到 早期胚胎内形成的肌肉
only to disappear as the fetus developed like these.
竟随着胎儿的发育而消失了 比如这些
As yet, they’re not sure why.
原因至今未明
It’s becoming ever clearer just how important to human embryos first few weeks are.
人类胚胎发展最初几周的重要性愈发明显
Many scientists hope that more research
许多的科学家希望更多的研究
will lead to a better grasp of why some pregnancies fail,
能利于更好地理解一些人无法怀孕的原因
and how birth defects arise.
以及先天缺陷是如何产生的
Maybe even make in vitro fertilisation work better.
甚至希望这些研究能改进体外授精技术
But some just want to understand
但有人只想了解
exactly what happens to this tiny ball of cells in this short spark of time
小小的细胞在短短的时间内
at the beginning of all of us.
即我们生命最初的那段时间究竟发生了什么

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视频概述

本视频介绍了婴儿胚胎在最初两周时间内的生长变化与研究发现

听录译者

收集自网络

翻译译者

Amanda

审核员

审核员 V

视频来源

https://www.youtube.com/watch?v=9AX1XwKCYQE

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