A male contraceptive could be on the horizon as scientists believe they can stop sperm getting out of the testicles with an injection.
The therapy, proven to work in mice, was inspired by alcoholic cocktails which form separate layers in a glass.
Scientists inserted a concoction of layered chemicals into a tube coming out of the testicle of the rodents to plug it. It stopped them impregnating female mice.
By shining the testicles under a special light, the chemicals were then mixed and the contraceptive was stopped, proving it to be reversible.
If it works in humans, the technique could be a ray of hope for millions of men who want their own form of birth control.
Researchers from Nanchang University in China developed the method using gold particles and two types of chemicals to create a four-layered cocktail.
It includes a hydrogel, which acts as a physical barrier to the sperm trying to leave the vas deferens – the tube which carries them from the testicle to the penis.
This is separated with a layer of gold particles from a chemical called EDTA (short for ethylenediaminetetraacetic acid), which kills sperm and later breaks down the hydrogel when the contraceptive is finished with.
Sperm which do not get ejaculated out of the testicles are stored for a while then broken down and reabsorbed by the body.
To make the man fertile again, a near-infrared light is used to heat the gold particles which makes them move and the chemical mixes up and washes away to ‘unplug’ the sperm tubes.
When tested in mice the mixture successfully stopped them impregnating female mice for two months until the heat was used to break it down.
Professor Xiaolei Wang and colleagues hope they can create the world’s first medium-term male contraceptive.
Currently the only options are short-term – condoms – or permanent – vasectomies.
A survey published in the US earlier this month suggested nearly 40 percent of men want a long-term but reversible form of contraception.
The survey, done by pharmacy website Singlecare, found a hormonal daily pill would be the preferred method.
Past attempts to develop contraception for men have been cut short.
A trial of an injection found to be 100 percent effective was ended in 2016 because of side effects – men reported depression and pain and in one case a man developed an irregular heart rate, the New Scientist reported at the time.
The National Institutes of Health in the US announced in November it was funding a clinical trial of a hormonal skin gel which reduces sperm production to almost zero.
And the Bill and Melinda Gates Foundation has given Dundee University, in Scotland, more than £700,000 to screen existing medications and chemicals to see if any could work as a contraceptive.
The Chinese researchers who have developed the cocktail method say more tests are needed to confirm the ingredients are safe to use in humans.
Their research was published in ACS Nano, a journal run by the American Chemical Society.
-Daily Mail
