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Philadelphia, Pennsylvania - In a cross-species experiment that could have implications for human fertility, local researchers have developed mice that produce the sperm of pigs and horses and other large animals.
Scientists at the University of Pennsylvania Veterinary School in Chester County transplanted pieces of the testicles of pigs, goats, horses and sheep into mice. The testicles, attached to the backs of the mice, eventually matured and produced the sperm of the donor animal.
The results of just the goat and pig transfers were published today in the journal Nature, where they are bringing the Penn researchers international attention for the audacity of these experiments and their surprising conclusion - that testicles don't have to be attached to their original owners in order to produce working sperm.
The main point is to better understand how life works, but the scientists say that such tinkering with animal reproduction could lead to techniques for saving endangered species and will have applications in fertility and contraceptive research.
"Oh, my God... it's startling and surprising and remarkable," said Penn bioethicist Art Caplan, who, though he deals with cloning and other oddities of science all the time, said he was still surprised by the testicle transplants. "Maybe it's a guy thing."
Like cloning, this type of work will prompt some serious ethical considerations, said ethicist Caplan.
"People are going to become interested and very nervous about cross-species transplants in animals," he said. Some people, he said, will find this disturbing, though he believes that if it could lead to the preservation of species or help for the infertile, then the work is worth pursuing.
And, he said, since the mice have to be immune-compromised, it won't be easy to transfer this particular technology to humans. "You can't just take an animal or a person and make them a farm for your testicles."
