Researchers from the National Institute of Physiological Sciences in Japan have succeeded in growing mouse stem cells and converting them into sperm in the body of mice
A. Diagrams for generating mice with rat gametes. Mouse sperm isolated from rat testis is injected into unfertilized rat eggs to produce viable mice.
Okazaki, Japan – The making of gametes such as sperm and eggs from pluripotent stem cells, primitive cells that can manufacture all tissues, contributes significantly to effective livestock reproduction and reproductive medicine in the future. Researchers are paving the way to achieve this goal using an exotic animal body.
Researchers previously developed a method for growing stem cells into a complete organ in the body, known as blastocyst integration. A blastocyst is a structure of early embryos. If stem cells are implanted into a blastocyst taken from animals that cannot form a specific organ, the stem cells make up for the missing organ in the developing body, and make the entire organ. “We expected this method to also be applicable to the active production of gametes,” explains the author leading the study, Dr. Toshihiro Kobayashi.
A year ago, researchers created a transgenic mouse that completely lacked sperm and eggs. They hypothesized that the rat could be used as an excellent host for developing external stem cells into gametes.
The researchers first transplanted mouse allogeneic stem cells into blastocysts obtained from mice unable to form gametes, and they confirmed that all gametes are derived from stem cells. The gametes generated transmit genetic information from the stem cells to the next generation, enabling the efficient production of transgenic mice.
Next, the researchers tested whether mouse stem cells of abnormal origin could make mouse gametes in the body of mice. Significantly, mouse germ cells, including sperm and sperm, were observed in the testis of mice, and sperm can fertilize mouse eggs to produce healthy pups (see figures).
Another author who led the study, Dr. Masumi Hirabayashi, says, “The synthesis of gametes from stem cells, even in the embryogenic environment, is very important to implement this strategy.” “In the future, we may be able to use the method to conserve the endangered species, as their stem cells are available thanks to the pluripotent stem cell technology.”