An investigation that has been carried out by an international group of scientists, and that has been published in Science Translational Medicine, has revealed that the lack of a protein - the DEFB126- in sperm could be associated with male infertility.

As the lead author of the study, Gary Cherr, professor of Marine Laboratory Warehouse at the University of California-Davis (center that has led the research), this protein works as a camouflage thanks to which the sperm are not rejected by the woman's immune system, and can thus reach the egg.

Seven out of ten cases of male infertility lack a known cause, so this type of studies can help solve the problem, especially considering that it has been proven that male fertility does not depend on quality and quantity. of the sperm.

Lower fertility

The researchers were working on the development of new contraceptives when they began to observe DEFB126, a protein produced in the epididymis and that covers the sperm that accumulate in this organ.

When looking under the microscope, the sperm that have abnormal DEFB126 genes seems normal, and even the sperm move normally. But when the mobility of said sperm is checked in a synthetic gel similar to cervical mucus of the woman, it is seen that it is more reduced. However, by adding healthy protein to the sperm, they regain their normal capacity.

About half of the world's male population has an abnormal copy of the DEFB126 gene, and a quarter of two abnormal copies, and because of this their sperm are not able to move well through the mucus

The authors of the study worked with DNA samples from males from Africa, China, the United States, Japan and the United Kingdom, which allowed them to verify that around half of the world's male population had an abnormal copy of the protein, while the fourth part has two abnormal copies, and because of this, its sperm is not able to move correctly through the mucus.

And is that, if compared to the sperm of other mammals, such as monkeys, the sperm of humans have a high percentage of cells with defects, which lowers its quality. In addition, scientists have found that male fertility has declined worldwide, although the causes of this fact are unknown. Perhaps the deficiencies observed in the DEFB126 gene can explain, at least in part, this increase in infertility.


Overcoming male infertility (November 2019).