Adding a missing protein to in fertile human sperm can 'kick-start' its ability to fertilise an egg and dramatically increase the chances of a successful pregnancy, a new study has claimed.
Researchers from Cardiff University have found that sperm transfers a vital protein, known as PLC-zeta (PLCz), to the egg upon fertilisation.
This sperm protein initiates a process called 'egg activation' which sets off all the biological processes necessary for development of an embryo.
The research team has found that eggs that don't fertilise because of a defective PLCz, as in some forms of male infertility, can be treated with the active protein to produce egg activation.
The added PLCz kick-starts the fertilisation process and significantly improves the chance of a successful pregnancy.
"We know that some men are infertile because their sperm fail to activate eggs," said professor Tony Lai, who led the research.
"Even though their sperm fuses with the egg, nothing happens. These sperm may lack a proper functioning version of PLCz, which is essential to trigger the next stage in becoming pregnant," Lai said in a statement.
"What's important from our research is that we have used human sperm PLCz to obtain the positive results that we had previously observed only in experiments with mice.
"If this protein is inactive or missing from sperm, it fails to trigger the process necessary for egg activation - the next crucial stage of embryo development," said Lai.
"However, when an unfertilised egg is injected with human PLCz, it responds exactly as it should do at fertilisation, resulting in successful embryo development to the blastocyst stage, vital to pregnancy success.
"We've established that this one sperm protein, PLCz, is absolutely critical at the point where life begins," Lai added.
The research was published in the journal Fertility and Sterility.