Scientists say rhinos on the verge of extinction could be saved thanks to sperm made in the lab from a now-dead male.
A piece of flesh taken from the shoulder of Malaysia’s last male Sumatran rhino, Tam, who died in 2019, has been used to make a world-first “mini rhino brain”.
And researchers believe that if they can produce a mini-brain in a box from frozen tissue samples from a dead rhino, they may be able to make sperm to help save the species.
Rhino populations are declining globally, with all five species battling poaching and habitat loss. Sumatran rhinos like Tam are only 80 in the world and are critically endangered.
By taking a tissue sample from Tam, scientists were able to transform the flesh into stem cells, transforming them into a genetic blank canvas that can be transformed into any tissue in the body.
In the study, published in iScience, the researchers made brain cells from the samples and cultured them in the lab for three months to create a brain organoid.
It’s the first time a mini-brain has been made for a rhino, with previous studies involving humans, mice and monkeys.
This breakthrough, according to the team, could shed light on the growth and evolution of mammalian brain development, which has not been studied in detail in rhinos since 1878.
“We were thrilled to observe the formation of mini Sumatran rhinoceros brains. [stem cells] in a manner apparently comparable to that described for human organoids,” said Sebastian Diecke, lead author of the Max-Delbrück-Center (MDC) study.
But the researchers’ ultimate goal is to use the same method to produce viable sperm from the samples to boost conservation programs and save the rhinos from extinction.
The tissue samples were taken before Tam died during a routine checkup. Vets biopsied his front leg and then stored it in liquid nitrogen before academics thawed it for this research.
The fibroblast cells were processed in a laboratory by scientists from the Helmholtz Association’s MDC for Molecular Medicine and transformed into stem cells.
The team then processed the new stem cells and transformed them into brain cells. Three months of growth saw the mini rhino brain reach a size of a few millimeters.
The conserved genetic code to pave the way for making sperm
In the experiment, the scientists kept Tam’s genetic code perfectly intact, which opens the door, they say, to using the method to make sperm.
The experimental method “created an opportunity to produce viable sperm for future reproduction,” the researchers write in their paper.
“As the quality of semen collected from Sumatran rhinos is poor directly after recovery and even worse after cryopreservation and thawing, in vitro generated sperm offer an excellent alternative to assisted reproduction.”
Stem cells made from ancient tissue samples were of “high quality”, according to the team, and therefore have “great potential to support the rescue of this critically endangered species”.
The potential is wider than Sumatran rhinos, the team says, saying the techniques used could help other endangered species.