At the brink of extinction, two northern white rhinos, who are both females, are being studied by scientists who want to create advanced assisted reproduction techniques. These scientists are extracting skin cells from rhinos to create induced pluripotent stem (iPS) cells that can eventually develop into immature egg cells, or oocytes.

A Japanese stem cell researcher at Kyushu university, Hayashi, has succeeded in generating egg cells from the skin in mice, then artificially fertilizing these cells and implanting them in females. The mice that were born were healthy and fertile.

Professor Michael Drukker, a stem cell researcher, and his teams at Hemzolt Zentrum München and at Leiden Academic Centre for Drug Research at Leiden University, have used a process known as episomal reprogramming to produce northern white rhino iPS cells. The researchers had to introduce foreign DNA molecules, also known as “plasmids,” into the skin cells that they obtained. According to Drukker, the rhino cells were, “barely distinguishable from human iPS cells,” when viewed under a microscope.

Unfortunately, there are some hardships in the making of these artificial eggs. For one thing, the germ cells used to make an egg need to be surrounded by ovarian tissue to mature into an oocyte. This tissue is nearly impossible to obtain for a living or a dead rhino, so they “have to create not only primordial germ cells but also ovarian tissue,” explains Berlin-based scientist Zywitza. Last year, Hayashi, who works very closely with Zywitza, successfully cultivated ovarian tissue from mouse stem cells. Scientists hope to use the method that Hayashi used to cultivate ovarian tissue from nearly extinct northern white rhinos.

Meanwhile, progress was also being made with assisted reproduction. 14 embryos were made when scientists at Avantea’s Laboratories in Italy inseminated immature egg cells, or oocytes, with the thawed spermicide of a dead rhinoceros male. The 14 northern white rhino embryos are stored in liquid nitrogen at a negative 196 degrees Celsius. In the near future, the embryos will be implanted into southern white rhinos to create a healthy northern white rhino calf.

Generating these rhinoceros eggs was a great achievement. Especially because it would save a species from extinction. If reproduction from stem cells works, this approach could serve as a model for other endangered species. We could use this technique to revive many more threatened or extinct species. However, a  scientist by the name of Diecke says that he does not want to use this technique again, and that we did more to preserve species before it was too late (One Step Closer to Artificial Rhino Eggs).