Thawed brain organoids shown by an imaging technique called immunofluorescence staining
Weiwei Xue et al.
A new technique allows scientists to freeze human brain tissue and restore normal function after thawing, potentially opening the door to improved ways to study neurological conditions.
Brain tissue typically cannot withstand freezing and thawing, and this problem is a major impediment to medical research. To overcome this, Xiao Jichen Professors at Fudan University in Shanghai, China used human embryonic stem cells to grow self-organizing brain samples, known as organoids, for three weeks. This is a period long enough for the development of neurons and neural stem cells, which become various types of functional cells. brain cells.
The researchers then placed these organoids in various compounds, such as sugar or antifreeze, which they thought might help keep brain cells alive during freezing and allow them to grow after thawing.
After storing these organoids in liquid nitrogen for at least 24 hours, the researchers thawed them and examined cell death and neurite (neurite “branches”) growth over the next two weeks.
The researchers tried different combinations during freeze and thaw tests on a new set of organoids and selected the top compound candidates based on the rates of cell death and cell proliferation associated with each compound.
The combination that caused the least cell death and the most proliferation was a blend of methylcellulose, ethylene glycol, DMSO, and a compound called Y27632, which the scientists named “MEDY.” They suspect that MEDY may be interfering with a pathway that programs cell death.
Shao and colleagues tested MEDY through a series of experiments on brain organoids from 28 days old to more than 100 days old. The research team placed the organoids in MEDY, then froze and thawed them. The researchers observed its growth in the laboratory for up to 150 days after thawing.
They found that the appearance, growth, and function of thawed organoids were very similar to organoids of the same age that had never been frozen, even among organoids frozen for 18 months in MEDY. The research team observed similar results with organoids representing different regions of the brain.
Finally, the researchers took a 3-millimeter cube of brain tissue from a 9-month-old girl with epilepsy, placed it in MEDY, then frozen and thawed it. The tissue maintained its pre-frozen structure and remained active in laboratory culture for at least 2 weeks after thawing.
Being able to freeze human brain tissue could lead to better studies of brain development in health research labs, researchers say.Roman Bauer at the University of Surrey, UK.
Joao Pedro Magalhães The professor at the University of Birmingham in the UK said he was impressed by the success of his team’s method in preventing cell death and preserving function. “We know that brain cells are very fragile and sensitive to stress,” he says.
If more research is done and larger tissues are used, Magalhães says the research could one day lead to whole brain freezing. “If we think decades or even centuries down the road, we can imagine patients being frozen for terminal conditions, or astronauts being frozen for travel to other star systems.” he says. MEDY may be a “small step” toward that goal, Magalhães said.
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Source: www.newscientist.com
