American scientists have recently created mice containing a small number of human brain cells. The goal is to develop realistic models for studying neurological disorders, such as Parkinson’s disease.
The research team led by Dr. Fred Gage from the Salk Institute produced these mice by injecting approximately 100,000 human embryonic stem cells into the brains of 14-day-old mouse embryos. As a result, the mice were born with about 0.1% human cells in their brains. However, injecting human stem cells does not restructure the mouse brain nor does it “humanize” this rodent species.
Researchers believe that mixing human cells with animal models is crucial for ensuring that experimental drugs and new tissue replacement therapies are safe for humans. This is the only way to advance tissue replacement therapy using stem cells, as it is too risky to conduct such trials on humans, and scientists still know too little about stem cells.
Some experts have conducted similar experiments with rabbits and chicken eggs. Meanwhile, scientists from the University of California, Irvine, reported that they were able to restore movement in mice after injecting them with human neurons. Over the years, doctors have successfully implanted pig heart valves into human hearts. The injection of human cells into laboratory animals has been happening for a much longer time.
Nevertheless, injecting human cells into animal brains has drawn particular attention due to concerns about a frightening prospect: a human brain could reside within an animal’s head. After all, 97.5% of mouse genes are identical to human genes. David Magnus, director of the Stanford Center for Biomedical Ethics, stated: “I don’t think research is getting close to that scenario.”
Minh Sơn
