BEIJING, Dec. 15 (Xinhuanet) -- Stem cells that were injected into the brains of fetal mice have grwon and are functioning normally.
The results from American and Japanese scientists are significant in terms of brain development and the examination of human illnesses such as Parkinson.
(Photo source: zaman.com)
Geneticist Fred Gage injected embryonic human cells into two-week-old fetal mice as they developed in the womb. When the mice matured, some human stem cells survived and became functional components of the mice's brains and nervous systems.
Less than one-tenth of one percent of the test mice's brain cells are human.
"When we characterized these cells two months later, we found that [they] had the [form and structure] and characteristics of mouse cells," said Gage, co-director of the genetics laboratory at the Salk Institute for Biological Studies in San Diego.
"It is truly amazing that these human stem cells, although they are very immature, can still ¡ respond to different cues in their environment and can fit right in with their mouse neighbors."
"This illustrates that injecting human stem cells into mouse brains doesn't restructure the brain," Gage added.
The study was published in Tuesday's issue of the journal Proceedings of the National Academy of Sciences.
Some scientists hope that stem cells, which may develop into many different kinds of human cells, could someday be used to replace missing or damaged neurons in people with degenerative nerve diseases.
"This research is significant because it suggests that it will be possible to create mouse 'models' of human brain tissue, enabling scientists to try out both stem cell interventions and other potential cures on living human brain cells without having to use humans in the process," said Glenn McGee, director of the Alden March Bioethics Institute at Albany Medical College in New York State.
But such cross-species research raises red flags among some ethicists, who fear a slippery slope leading to the abuse of human-animal hybrids.
Of particular concern are experiments that include human sperm, eggs, or reproductive cells in animal hosts.
"Critics of this research would have you believe that to grow our cells in other creatures is repugnant and inhumane. Mice already grow human ears and are used in many experiments to grow colonies of other human cells," McGee said.
"The key to preventing some kind of new ethical problem is to watch in careful ways to ensure that the mice are¡ªbehaviorally¡ªmice." Enditem
(Agencies)
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