Sperm stem cells allow infertile mice to father offspring

Infertile mice produced sperm and fathered offspring after transplantation of sperm progenitor cells grown in laboratory culture, according to research published in the online edition of Proceedings of the National Academy of Sciences.

Researchers successfully developed a culture medium with the precise combination of cellular growth factors needed for spermatogonial stem cells to reproduce themselves outside the body. These stem cells were implanted into infertile mice. The mice produced sperm and fathered offspring genetically related to the donor mice.

If the culture media is manipulated, the researchers may be able to induce spermatogonial cells to develop into sperm cells for the fertilization of eggs, said senior author Ralph L. Brinster, VMD, PhD, of the University of Pennsylvania School of Veterinary Medicine in Philadelphia.

"This finding is likely to be applicable to humans," Dr. Brinster said.

Spermatogonial stem cells could be cultured to increase numbers, frozen, and reimplanted at a later date in those males who lose their fertility from chemotherapy, spinal cord injury, Parkinson's disease, or heart disease.

The research was funded in part by the National Institute of Child Health and Human Development.