Sperm swimming toward an egg
An illustration of sperm swimming toward an egg Photo by Archive
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Visible light rays boost sperm activity and could improve the results of in-vitro fertilization treatments, Israeli researchers from Meir Hospital in Kfar Sava and Bar-Ilan University have discovered.

In recent years, 40 per cent of infertility cases among couples seeking treatment have been attributed to low-quality sperm. The researchers thus focused their efforts on examining sperm motility, or independent motion, in laboratory conditions using a CASA (computer-assisted semen analysis) device.

The scientists took sperm samples and applied light-wave radiation for three minutes. They found that the radiation, whose wavelength ranged from 400 to 700 nanometers, improved sperm motility.

The light waves emit particles of oxygen known as reactive oxygen species (ROS ), which are small molecules that include oxygen ions and peroxides. These apparently boosted sperm motility.

The radiation also led to an immediate increase in the activity of the protein kinase A (PKA ), an enzyme responsible for a number of key cell functions, within the sperm. The researchers also noticed an improvement in the movement of calcium ions within the sperm cells.

The study's findings were presented last week at an annual conference held by the Israel Fertility Association.

"In the process of preparing the sperm for in-vitro fertilization, the sperm undergoes a series of changes from the moment it is ejaculated or removed from the patient's body until it succeeds in penetrating the egg," said Prof. Adrian Shulman, director of the In Vitro Fertilization Unit of Meir's Obstetric and Gynecology Department. "Many studies have been done with the goal of improving the sperm's ability to fertilize."

Previous experiments on animal sperm found that radiation by nonvisible, ultraviolet rays, with a maximum wavelength of 400 nanometers, improved sperm motility. This latest trial confirms that human sperm motility can also be enhanced when subjected to visible light rays. Further tests by the researchers showed that the DNA make-up of the sperm was not harmed by the radiation.

If the results of the experiment are confirmed by additional testing, Shulman said, it could lead to improved treatments for couples struggling with fertility problems.

Current fertility treatments for low-quality sperm have a 90 percent success rate. For case in which the sperm is substandard in both quality and quantity, doctors use the micromanipulation method of fertilization, which entails the insertion of a single spermatozoon into the egg. This method also boasts a success rate of 90 percent.

"Our hope is that the new method which was tested, much like the additional methods that are currently being researched, could improve the success rate and provide hope to couples who are not helped by fertility treatments stemming from low-quality sperm," Shulman said.

In total, 26,679 rounds of in-vitro fertilization treatment were administered to couples in 2007. Of these, 4,585 resulted in the birth of a baby, a success rate of 17 percent.

Infertility stemming from poor sperm quality is diagnosed via tests performed at hospitals and health maintenance organizations. In most cases, doctors are unable to determine why the sperm is of substandard quality.

"Only in one third of cases is it possible to determine that the sperm is deficient due to hormonal or infective contamination," Shulman said. "The lifespan of a sperm, from the moment it is created until it is ejaculated from the body, is 72 days, so there are situations in which the tests reveal poor sperm that resulted from illness or medical treatments undergone by the patient two months earlier. Thus it is advisable to undergo a second sperm test between two and three months after the first one, just to confirm the validity of the findings."

In recent years, medical journals have published various articles pointing to a decrease in the quality of male sperm. The studies indicate that male sperm counts have declined due to environmental factors. One such study, conducted in the 1990s, found that since the middle of the 20th century, the average sperm count has decreased at an annual rate of one percent in all healthy men.

Follow-up studies also cited lower sperm counts for men in Britain, France, Denmark, Greece, Italy and Canada. However, elevated sperm counts were recorded in two American states, New York and Washington, as well as in Sweden.