在线英语听力室_免费在线英语听力学习网站

科学家利用猪膀胱令损伤肌肉组织重生

The promise that stem cells may someday help regenerate¹ damaged tissue seems to be close to fulfillment. Scientists at the University of Pittsburgh School of Medicine report that some of their severely² injured patients grew new muscle tissue with the help of pigs’ bladders.

利用干细胞再造已损坏的人体组织，这一愿望似乎即将圆满达成。匹兹堡大学医学院的科学家们称，借助猪的膀胱，一些重伤患者已经长出了新的肌肉组织。

After a skiing accident in which he lost much of the muscle in his left calf³, Nicholas Clark could no longer do many of his regular activities.

尼古拉斯·克拉克在一次滑雪事故中损伤了左小腿的大部分肌肉组织。对于很多日常活动，如今他已经无力正常进行。

“In addition to the muscle loss, I had a lot of nerve loss and blood vessel⁴ loss and other tissue loss in that leg. So, it really limited any activity," said Clark.

患者尼古拉斯·克拉克说： “除了肌肉损伤，我的这条腿还有神经损伤、血管损伤等很多问题。这真是限制了我活动的能力。”

Skeletal muscles can regenerate after minor⁵ injuries with help from physical therapy, but if the loss is greater than 20 percent, the damage becomes permanent, says Doctor Stephen Badylak of the University of Pittsburgh School of Medicine.

匹兹堡大学医学院的斯蒂芬·巴迪拉克说，物理疗法可以帮助骨骼肌在受到轻伤之后重新生长。但如果损伤率超过百分之二十，就造成了永久性的伤害。

“You're left with this huge gap that just fills in with scar tissue," said Badylak.

匹兹堡大学斯蒂芬·巴迪拉克说： “组织损伤留下的巨大空隙，只有一些疤痕组织来进行填补。”

Scientists have long known that stem cells, applied⁶ at the point of injury, can actually turn into new muscle cells. But they need some sort of structure - a matrix - to grow on.

对于将干细胞应用于伤处，并帮助生成新的肌肉组织，科学家早有共识。但为此他们需要构建一种矩阵结构，以支持组织的再生。

Badylak's team created an “extracellular matrix” from a pig’s bladder. They removed all traces of cells from the tissue, so that the recipient’s immune system would not reject it.

巴迪拉克的团队借助猪的膀胱构建了一种细胞外基质。基质能够从人体组织中移出的所有的细胞，因此病患者自身的免疫系统便不会产生排异反应。

“The extracellular matrix is the glue, if you will, that holds all of the cells in our body together," said Badylak.

细胞外基质就像胶水，如果你愿意，它可以把你身上所有的细胞黏着在一起。

The matrix is implanted at the injury site, and as it slowly degrades in recipient’s body it releases chemicals that attract stem cells. Physical therapy helps the stem cells understand that they need to form muscle tissue.

基质被植入在损伤部位，它会在患者的体内逐渐变化，释放能够吸引干细胞的物质。物理疗法会促使干细胞形成新的肌肉组织。

All five patients in Badylak's study had lost 60 to 90 percent of the affected⁷ muscle. Six months after the start of therapy, all have grown some new muscle, and three patients had dramatic improvement. Clark says he can ride his bike again and even jump rope.

巴迪拉克的全部五名病人都有百分之六十至百分之九十的肌肉损伤。自疗程开始六个月后，他们全部长出了新的肌肉组织，其中三名病人更是恢复迅速。克拉克说，如今他又能骑自行车了，甚至跳绳也没问题。

“There are other things, just day to day things, that really make a huge difference," he said.

患者尼古拉斯·克拉克 说：“还有一些其他的事情，都是日常生活中的小事，确大大改善了我的生活。”

Scientists say they experimented mostly with old injuries, but that the new method probably works better for patients with more recent injuries.

科学家说实验大部分还围绕着旧伤而展开，但这种新方法很可能对于新伤有更好的效果。