NEW YORK, Jan 14 (Reuters Health) -- Female mice that lack a cell protein
called CD9 are much less likely to become pregnant than mice that have the
protein, according to the results of two new studies. While researchers have not
looked at the effects of the protein in humans, they suspect that a defect in
CD9 may be responsible for some cases of infertility in people.
In one of two studies published in the January 14th issue of the journal
Science, a team of researchers in France bred a group of mice that lacked the
CD9 protein. The mice appeared to develop normally, but females were much less
fertile than ordinary mice.
Only about half of the mice without the cell protein became pregnant, and
those that did had smaller and less healthy litters than the normal mice,
according to the researchers from Institut National de la Sante et da la
Recherche Medicale in Villejuif, France.
Another team of researchers, led by Dr. Eisuke Mekada, of Kurume
University in Fukuoka, Japan, achieved similar results with mice that were also
genetically engineered to lack CD9.
But when the researchers injected sperm directly into the eggs of the
mice, the animals became pregnant at normal rates and gave birth to healthy
mice. Not having the protein did not seem to affect male mice, however, since
they were able to successfully mate with female mice who had CD9.
This suggests that CD9 plays a role in helping sperm and egg join together
but that the protein does not have an effect on later development, the
researchers report.
While there is no direct evidence that CD9 plays a similar role in people,
it is possible that a defect in the cell protein may be involved in some cases
of infertility in people, Mekada told Reuters Health.
