The human cells, engineered to respond to blue light, influenced rat behavior when stimulated.
在遭到刺激時，經工程改造，來對藍光作出反應的人類細胞，影響了老鼠的行為。
圖1. 一個在老鼠部分大腦內，發出亮綠色光的人類類器官。 (圖援用自原文)
A human organoid glows bright green inside a section of a rat brain.
For the first time, researchers have successfully transplanted human neurons into the brains of baby rats, they report today (October 12) in Nature. The human cells formed connections with rat neurons and could be used to control the rats’ behavior.
研究人員們已首度成功，將人類神經元移植到幼老鼠大腦中。他們今日(2022年10月12日)發表於《自然》期刊。此些人類細胞與老鼠神經元形成連接，且能被用來控制老鼠的行為。
“It’s a very important . . . very cool study,” Yun Li, a molecular geneticist at the University of Toronto who was not involved in the research, tells MIT Technology Review. “The fact that they succeeded in many of these experiments is quite extraordinary.”
加拿大多倫多大學，未參與該項研究的分子遺傳學家，Yun Li告訴麻省理工學院《科技評論》期刊：「這是一項非常重要…非常酷的研究。他們於其中諸多實驗裡，獲得成功的事實，是相當令人訝異的。」
To perform human cell experiments, especially when studying the effects of certain drugs, scientists have developed models called organoids: tiny structures grown from stem cells that mimic the human brain or other organs. However, they can’t replicate the complexity of real human neuron development on their own, Science News reports.
為了進行人體的細胞實驗，特別是研究某些藥物的功效時，科學家們已經開發了，被稱為類器官的模型：也就是，從模仿人腦或其他器官之幹細胞，生長出的微小結構物。不過，美國雙周刊《科學新聞》期刊報導，它們無法自行複製，真實人類神經元發育的複雜狀態。
In a bid to further organoid development, scientists transplanted human cerebral organoids into the brains of days-old rat pups whose immune systems were tamped down so as not to reject the human cells.
在嘗試進一步的類器官開發上，科學家們將人類的大腦類器官移植到，幾天大之免疫系統遭抑制，以致於不會排斥人類細胞的幼老鼠大腦中。
By using young rats rather than adults, the researchers hoped the cells would be integrated more smoothly and form more connections in the rats’ brains. Indeed, they report, the human neurons matured successfully, growing six times larger than neurons grown in a dish and forming connections with rat neurons via synapses.
藉由使用年幼老鼠，而不是成年老鼠。此些研究人員期盼，這些細胞能更順利地被整合，而在此些老鼠的大腦中，形成更多連接。事實上，他們報告說，人類神經元成功地成熟，比在培養皿中生長的神經元大六倍，且經由突觸與老鼠神經元形成連接。
“They’re just absolutely immense,” Stanford University neuroscientist and lead author Sergiu Pașca tells Technology Review. “The cells have just moved to another level of maturation.”
首要撰文人，美國史丹佛大學神經科學家，Sergiu Pașca告訴《科技評論》期刊：「它們確實是絕對無限的。此些細胞已經剛進入另一成熟階段。」
To test whether the transplanted human neurons could affect the young rats’ behavior, Pașca and the other researchers genetically altered the human cells using a technique called optogenetics, which allows cells to respond to light.
為了測試被移植之人類神經元，是否能影響幼老鼠的行為。Pașca及其他研究人員利用一種，使細胞得以對光作出反應，被稱為光遺傳學的技術，來遺傳性改變了此些人類細胞。
They then used a fiber optic cable to shine a blue light on the rat-integrated human neurons whenever they provided the rats with water. The rats rapidly began to associate the shining of the light with water: After just two weeks, they began to lick in anticipation of drinking when the light was shone.
之後，每當給老鼠提供水時，他們使用了光纖電纜，來將藍光照射在被老鼠整合的人類神經元上。此些老鼠迅速開始，將光的照射與水聯繫起來：僅兩週後，當光照射時，他們開始舔舐，期待喝水。
The study has brought up ethical questions regarding the treatment of animals.
該項研究已經引發了，諸多有關對待動物的倫理問題。
“I do not think that it is ever—ever—ethically justified to treat animals as resources humans can exploit for human advantage,” Taimie Bryant, a professor of animal law at the University of California, Los Angeles, tells New Scientist.
美國加州大學洛杉磯分校的動物法規教授，Taimie Bryant告訴《新科學家》期刊：「我不認為，為了人類的利益，將動物視為人類可利用的資源，在倫理上，一直是合理的。
“It seems to me that rats’ consciousness as it is, without human manipulation, is rather remarkable and that damaging a rat’s brain is emblematic of an attitude towards nature that imperils human and non-human animals’ prospects for continued life on Earth.”
在我看來，老鼠的意識，在沒有人類操縱的情況下，是相當了不起的。破壞老鼠的大腦是一種，朝向危及人類及非人類動物，在地球上繼續生存前景之自然態度的象徵。」
Other experts voiced concern that the changes to the rat brain could open the door to advanced cognition in the lab animals. “It raises the possibility that you’re creating an enhanced rat that might have cognitive capacities greater than an ordinary rat,” Julian Savulescu, a bioethicist at the National University of Singapore, tells Technology Review.
其他專家們發出了，對老鼠大腦的改變，於實驗室動物中，可能打開高認知之大門的顧慮。新加坡國立大學的生物倫理學家，Julian Savulescu告訴《科技評論》期刊：「它提升了，人們正在創造一種，可能具有比普通老鼠更強認知能力之被增強了的老鼠可能性。」
The rats in this study didn’t show any evidence of advanced cognition or human behavior, Pașca tells Technology Review. Regardless of ethical concerns, he believes work like this could significantly advance drug development and help tackle complicated human disorders, he tells Science News.
Pașca告訴《科技評論》期刊，此些於該項研究中的老鼠，沒有顯示出任何，增強之認知或人類行為的證據。他告訴《科學新聞》期刊，不管倫理問題，他認為像這樣的研究，可能顯著地促進藥物開發，且有助於解決複雜的人類疾病。
“Challenging disorders will require bold approaches,” he says. “We will need to build human models that recapitulate more aspects of the human brain to study these uniquely human conditions.”
他宣稱：「具有挑戰性的疾病，需要大膽的方法。我們將需要建立，概括更多人類大腦層面的人類模型，來研究此些獨特的人類疾病。」
網址：https://www.the-scientist.com/news-opinion/researchers-transplant-human-neurons-into-rat-brains-70615
翻譯：許東榮
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