Research into using ultrasound as a male contraceptive was given a financial boost last week after researchers secured a $100,000 grant from the Bill and Melinda Gates Foundation.
The grant proposal followed research showing rats that had two ultrasound treatments within 48 hours stopped producing sperm and were infertile up to six weeks afterwards.
Dr James Tsuruta and Paul Dayton will use the grant money to investigate the mechanisms behind this ultrasound-induced infertility. They hope to trial the contraceptive on human participants by next year.
Elaine Lissner, from the Male Contraception Information Project (MCIP) in San Francisco, said the question of whether fertility would return after multiple uses over years still remained.
However, she added: 'The exciting thing is that we're getting started finding out. The smaller foundations don't have the money to get beyond proof of concept - so Gates has really saved the day'.
A male contraceptive has been a goal of many research groups, but has proven elusive so far. If successful, ultrasound could offer a short-term and cost-effective alternative to a hormone-regulating male 'pill'.
Ultrasound produces a mild heating that appears to disable sperm cells and deplete the supply of stem cells required to replenish sperm reserves in the testes. Post-treatment images of the rat testes showed the tubules inside the testes completely lacking in sperm with almost no immature stem cells.
The researchers are from the University of Carolina.
