Although spermicides do already exist, they're still not 100-percent effective. Scientists are developing what could be a more reliable alternative, in the form of a vaginally applied solution that keeps sperm trapped within the semen.
Ordinarily, semen is ejaculated as a gel, but it quickly liquifies upon entering the vagina. The sperm carried within it are then freed up to swim through the female reproductive system, potentially resulting in a pregnancy.
The liquefaction process is triggered shortly after ejaculation, mainly by an enzyme within the semen known as prostate-specific antigen (PSA). Secreted by the prostate gland, it breaks down gel-forming proteins in the semen, which are called semenogelins. These are what keep the sperm trapped and protected, until they (the proteins) are broken down.
In an effort to keep the liquefaction from occurring, a team at Washington State University looked to an antibody that inhibits PSA activity. Tests performed on fresh human semen samples showed that the antibody did indeed stop the semen from liquifying, keeping most of the sperm trapped inside. Additionally, the sperm that did make their way out showed a subtle reduction in motility.
More research still needs to be conducted, both on unwanted side effects and on other inhibitors which could be included along with the antibody. Ultimately, though, it is hoped that the end result could be a non-toxic, hormone-free commercial product.
"Our goal is to develop this into an easily accessible female contraceptive that would be available on-demand, meaning women could go buy it off the shelf," said Assoc. Prof. Joy Winuthayanon, senior author of a paper on the research. "It could be used in combination with a condom to lower the failure rate significantly."
The paper was published in the journal Biology of Reproduction.
Source: Washington State University