To Boldly Grow Where No Sperm Has Grown Before: in a Petri Dish
What’s the News: For the first time in medical history, scientists have successfully grown mouse sperm in a laboratory. As Northwestern University cell biologist Erwin Goldberg told New Scientist, “People have been trying to do this for years.” It’s hoped that being able to grow sperm outside the testes will lead to improved fertility treatments for men.
How the Heck:
- The concept is simple: Combine the right dosage of chemicals that will provide nourishment to testes in a petri dish. Actually finding the magic amount is a tedious process of trial and error.
- First, the team genetically engineered mice “so that a protein only present in fully grown sperm would fluoresce green.”
- Next, the scientists extracted germ cells (which produce sperm) from the newborn mice testes, and put them in a bath of agarose gel, fetal bovine serum, testosterone, and other chemicals.
- After about a month, they discovered that virtually half of the lab-grown sperm were glowing, indicating that they were fully grown.
- They then used in vitro fertilization to impregnate female mice, who eventually gave birth to fertile mice themselves.
- Past attempts at lab-grown sperm weren’t very successful. Many of the sperm cells from aÂ 2006 study, for example, died before developing fully.
- Ed Yong has written about sperm, including the barbed sperm of the flatworm and the sperm wars between ants and bees.
- 80beats has covered how plastics decrease sperm counts, the secret of the sperm’s wild dash, and the shared 600-million-year-old sperm gene between humans, fish, and flies.
Not So Fast:
- The researchers developed offspring using only 100 sperm cells; doctors would like to see “millions if possible” to make successful fertility treatments in humans.
- Scientists may have observed “healthy and reproductively competent offspring,” but they don’t delve into the possible long-term side effects of creating people from sperm developed off the traditional route. In vitro sperm creation could be compared to IVF, a technique that leads to greater risk of diabetes and some other conditions. Researchers still aren’t sure why this is, though they have made some headway, discovering that the DNA of IVF-babies actually differs from other children.
Next Up: This technique still needs to be proved in humans, and if it is, it could have wide-ranging effects. For example, in the future, doctors might be able to extract testicular tissue from young boys—who haven’t yet developed mature sperm—and then grow sperm in the lab. Or for infertile men, doctors could extract germ cells, produce sperm, and then find out what’s wrong with them.
Reference: “In vitro production of functional sperm in cultured neonatal mouse testes” Takuya Sato et al. doi:10.1038/nature09850
Image: Wikimedia Commons / Bobjgalindo