For the first time, scientists have successfully fertilized mouse eggs that were grown in the laboratory. The eggs, derived from stem cells, developed into fertile mice. The findings may eventually lead to better infertility treatments for humans. The details are in a paper that was just published in the journal Nature.
Pluripotent stem cells are capable of growing into any kind of cell, making them invaluable for medical research. Scientists are able to induce stem cells to grow into specific cell types. While researchers have been able to derive eggs from stem cells, the eggs couldn’t develop properly in a laboratory setting.
A team of scientists from Japan obtained mouse stem cells from two sources. The first source was embryonic stem cells, which are already capable of developing into any type of cell. The team also extracted cells from mouse tail tips. These mature cells reverted back into pluripotent stem cells after being exposed to specific chemical signals and a custom growth medium. Both sets of stem cells were used to derive eggs, which were then allowed to grow and mature in the laboratory. Egg cells had never been raised to maturity this way and the team had to use a special culture system to accomplish the feat.
The mouse eggs were then fertilized and the embryos were transplanted to surrogate mice. While many of the offspring had chromosomal abnormalities and other deformities, some of the embryos grew into healthy mice. The mice were fertile and gave birth to normal offspring.
The research team is conducting further research to find out why so many of the embryos ended up with deformities. The fact that some of the offspring were healthy and fertile, however, is a major scientific advancement. There are some problems with the team’s method, including the need to use embryonic cells during certain stages of egg development. While many years away, the findings may eventually lead to infertility treatments.
Hikabe et al. Reconstitution in vitro of the entire cycle of the mouse female germ line. Nature (2016).