SCIENTISTS IN Japan have developed a way to produce fully viable sperm from cultured testes cells.
The experiments were conducted using mouse cells but the researchers believe the approach could readily be used in humans.
Successful development of the method could become important in the area of male infertility.
Sperm from patients being treated for testicular and related cancers can readily be frozen. In this case, however, the researchers have frozen cell cultures from mouse testes. Once thawed the cultures could be induced to produce viable sperm cells. Details of the work were published yesterday in the journal Nature.
Spermatogenesis, the cellular process through which sperm is produced, is highly complex and one of the longest processes of its kind in the body, the authors from Yokohama City University and the Riken Bioresource Centre in Ibaraki wrote.
It takes more than a month for the cellular transformations to occur and deliver sperm cells, they said. “The whole process therefore has never been reproduced in vitro in mammals nor in any other species, with a very few exceptions in some particular types of fish.”
This makes it particularly noteworthy that they succeeded in taking neonatal mouse testes and using the immature sperm cells they contained to deliver mature sperm cells.
The researchers used these to “microinseminate” females, resulting in “healthy and reproductively competent offspring”.
They used testes tissue fragments of between one and three millimetres in diameter and grew them in culture. These could be frozen and induced to produce sperm cells after thawing.
“Our organ culture method could be applicable through further refinements to a variety of mammalian species,” they wrote. It could provide a clinical alternative for men undergoing anti-cancer treatments, but should also help researchers to better understand what cellular changes take place during sperm production.