Mouse sperm created in lab; hope for infertility

Feb 25, 2016, 4:22 PM EST
Source: Zappys Technology Solutions/flickr
Source: Zappys Technology Solutions/flickr
Scientists have created mouse sperm in a laboratory that is capable of fertilizing eggs. The sperm, created from stem cells, gives hope to future work that might be able to help infertile men pass on DNA to their offspring. The Washington Post reports:
The mouse work is reported by Chinese scientists in an article released Thursday by the journal Cell Stem Cell. The technique is now being tested in monkeys, a senior author said.
Qi Zhou of the Chinese Academy of Sciences in Beijing added in an email that the research has “a long way to go” before it could be used for infertile men.
The scientists began with mouse embryonic stem cells, which are found in embryos and can develop into any kind of cell in the body. In the lab these cells were exposed to chemicals to nudge them toward becoming sperm. While previous research has also generated sperm precursors in this way, these precursors then had to be transplanted into the testicles of mice to develop further.
Making sperm in the testes is one of the longest and most complicated processes in the body - taking more than a month from start to finish in most mammals.
Now scientists have been able to reproduce the feat in the lab.
An embryonic stem cell, which can morph into any other type of tissue, was guided towards becoming sperm with a cocktail of chemicals, hormones and testicular tissue.
In order to develop properly the cell must go through a crucial and delicate rearrangement of its DNA - its code of life - called meiosis.
Just like a female's egg, sperm must lose half of their chromosomes (bundles of DNA) so that a fertilised egg has a normal amount.
Compared to standard sperm that’s collected from male mice and injected into eggs, this new process fares pretty well. Among controls, about 92% of the injected eggs developed into two-celled embryos and the sperm created from stem cells yielded similar percentages. But the stem cell process is still not as efficient as using healthy normal sperm — overall the scientists transferred 317 embryos and produced nine newborns, a nearly 3% success rate. Using normally collected sperm, they transferred 148 embryos and 14 pups were born, about a 9% success rate.