February 14, 2014
Cambridge Scientists Crack Open The ‘Black Box’ Of Embryo Development
[ Watch the Video: Cells Organize Into Rosette-Like Arrangement ]
April Flowers for redOrbit.com - Your Universe Online
Scientists have uncovered much about how embryos develop, but implantation — a key step in the process — has remained a mystery. A new study from Cambridge University, published in the journal Cell, has discovered a way to study this "black box" of development.
Mammalian embryos develop in two phases: pre-implantation — where the embryo is a small, free floating ball of cells called a blastocyst — and post-implantation — the blastocyst embeds itself in the mother's uterus.
Blastocysts can be grown and studied outside of the body, but not implantation. Studying implantation in the womb is also problematic because of how closely connected the embryos are to their mothers.
According to Professor Magdalena Zernicka-Goetz of the University of Cambridge, "We know a lot about pre-implantation, but what happens after implantation – and particularly the moment of implantation – is an enigma."
Implantation is of interest to scientists because of the enormous changes that the embryo undergoes in such a short time.
"During these two days, it goes from a relatively simple ball to a much larger, more complex cup-like structure, but exactly how that happens was a mystery – a black box of development. That is why we needed to develop a method that would allow us to culture and study embryos during implantation," she explained.
Zernicka-Goetz collaborated with Dr. Ivan Bedzhov, working with mouse cells to create the right conditions outside the womb to examine the implantation process.
They created a system comprised of a gel and medium that had the right biological and chemical properties, as well as being of similar elasticity to uterine tissue, in order to support development. The gel was transparent to optical light, which allowed the researchers to film the embryo during implantation.
The new method allowed the researchers to observe that the blastocyst becomes a "rosette" of wedge-shaped cells on its way from ball to cup. The scientists have never seen this shape before.
"It's a beautiful structure. This rosette is what a mouse looks like on the 4th day of its life, and most likely what we look like on the 7th day of ours, and it's fascinating how beautiful we are then, and how these small cells organize so perfectly to allow us to develop."
The new method answers fundamental questions in biology, as well as allowing the researchers to study embryo growth and development at implantation, for the first time. This could help improve the success rates of IVF, as well as forward our knowledge of stem cells, advancing their use in regenerative medicine.
Developmental textbooks, however, might need to be rewritten. "The text books make an educated guess of what happened during this part of development, but we now know that what I learned and what I teach my students about this was totally wrong," said Professor Zernicka-Goetz.