Treating the testicles with a large dose of ultrasound can stop sperm production, reports Reproductive Biology and Endocrinology.
Experiments in rats with equipment normally used for physiotherapy have shown that 3MHz ultrasound can reduce the sperm count in semen to a level of 10 million per milliliter. In humans, this would cause infertility (the limit value in humans is less than 15 million sperm per milliliter).
Exposure to ultrasound twice – 15 minutes each time – reduced both the number of cells that produce the sperm and the sperm cells themselves. The most effective was the use of two exposures, two days apart, using salty, warm water (37 degrees Celsius) as a medium facilitating the penetration of ultrasound into the testicles.
Scientists consider the effect of ultrasound as a promising method of reversible contraception, but before it is put into use, more research is needed – for example, to assess the safety of the repeated procedure (whether it will not be sterilized) and the durability of the obtained effect. You also need to investigate whether sperm production would be damaged after resuming sperm production.
A similar concept was first proposed in the 70s, but only now has it been continued by Dr. James Tsuruta’s team from the University of North Carolina, which received a grant from the Bill and Melinda Gates Foundation.