Mice become first animals to produce other spec...( than 100-fold. Similar cross-sp...)

Similar cross-species grafts of testicular tissue have been tried previously, but no sperm cells resulted. Dobrinski speculates that the mice's backs may have provided both an ideal temperature and suitable blood vessels to allow for the growth of functional testes.

"Dr. Dobrinski is one of the few investigators attempting to remove testicular stem cells and transplant them into recipients," said Michael D. Griswold, interim dean of science at Washington State University's School of Molecular Biosciences, who was not involved in the work. "The fact that she can graft portions of testes from other mammalian species into mice and get sperm produced is an important step forward."

The work also demonstrates that testosterone and other mammalian hormones can work across species, said David de Kretser, director of the Institute of Reproduction and Development at Monash University in Australia. "These data indicate that the hormones produced by the mouse are adequate to stimulate sperm production in a range of species."

Spermatogenesis is a highly organized process that generates virtually unlimited sperm cells during adulthood. Continuous proliferation and differentiation of germ cells occurs in a delicate balance with various testicular compartments.

"It seems that the testis grafts transferred this entire environment to the recipient mice," Dobrinski said.

She was joined in the work by Ali Honaramooz, Amy Snedaker, Michele Boiani and Hans Schler of Penn's Center for Animal Transgenesis and Germ Cell Research and Stefan Schlatt of the University Mnster in Germany. Schlatt conducted the group's research with mice, Honaramooz and Snedaker conducted the work involving pigs and goats, and Boiani completed the in vitro fertilization.

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Contact: Steve Bradt
bradt@pobox.upenn.edu
215-573-6604
University of Pennsylvania
14-Aug-2002