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["Steven M. Callahan" <smcallah AT monkeyland.com>]

February 4, 2004
Mice produce sperm from monkeys

http://news.bbc.co.uk/2/hi/science/nature/3458533.stm

By Dr David Whitehouse  
BBC News Online science editor  


Mice have been used to produce viable monkey sperm using tissue
transplanted from the testes of macaques.

The US scientists involved say their work might one day help to conserve
animals that are facing extinction.

It might also be possible to grow human sperm in mice, although the team
agree this would be a controversial move.

The researchers, from the universities of Pennsylvania and California,
report their studies in the latest issue of the journal Biology of
Reproduction.

In 2002, the same team produced goat and pig sperm from mice. It was the
first time that sperm had been produced outside the original animal.


Testis transplant

The latest procedure involves transplanting a tiny amount of testicular
tissue from an immature rhesus macaque monkey under the skin of a lab
mouse.

Ina Dobrinski, of the University of Pennsylvania, and colleagues
transplanted the tissue into mice that had deficient immune systems, so
that it would not be rejected. 

"We started this work with primate testis after we had success with
domestic animals," Professor Dobrinski told BBC News Online.

After seven months, the testes grafts on the backs of the mice were seen
to produce viable sperm.

Grafting immature testis tissue appears to work because the host mouse
had been castrated, Dobrinski says. 

This boosts levels of the brain hormones that switch on sperm
production, so the young tissue grows rapidly. The technique is expected
to work on adult testis grafts, too.

The Pennsylvania group will now try the procedure on testis tissue from
domestic cats, as a trial for endangered big cats that rarely survive to
reproductive age in captivity.

The technique could also produce offspring from other endangered species
or valuable livestock, even if only immature males exist. 

The latest work with primates will help reduce the number of such
animals used in laboratories.


Of mice and men

"The main benefits we see are that this approach provides a system to
study and manipulate primate spermatogenesis, thereby minimising the
need for experimentation in primates," Professor Dobrinski says.

In theory, human testis tissue grafted on to mice could produce sperm.

The technique may also provide a way of testing toxins or male
contraceptive drugs on sperm development.

Prepubescent boys undergoing treatment for cancer that will render them
sterile could benefit, Professor Dobrinski suggest.

Their immature testis tissue could be removed prior to treatment and
transplanted on to mice for sperm production.

Theoretically, it could enable a boy to become a father before he
reached puberty.