The finding, by investigators at Wayne State University School of Medicine in Detroit, was published in the Aug. 30 issue of the American Chemical Society's journal Biochemistry.
In their laboratory study, Anuradha Goud and colleagues gathered more than 1,500 eggs from mouse ovarian ducts one to two hours or four to six hours after ovulation. Mouse eggs that arent fertilized within hours of ovulation begin to age rapidly. After about six hours, these eggs are less likely to be fertilized properly, leading to chromosomal abnormalities in the embryos.
To prevent this, the researchers exposed the eggs to varying concentrations of nitric oxide, a multipurpose signaling molecule that, among other things, helps keep arteries supple and helps men achieve erections. In the "older" eggs, the compound appeared to slow the hardening of the eggs outer shells, diminish the activity of ooplasmic microtubules (the structures that attach to chromosomes and guide them to different parts of a cell during division), increase the release of cortical granules (the molecules responsible for preventing egg fertilization by more than one sperm) and delay other signs of aging.
In addition to possibly extending fertility in women, the results suggest that nitric oxide could help prevent chromosome errors during early embryonic development. These errors can lead to Down syndrome, spontaneous miscarriages and other problems associated with pregnancies later in life.
"Eggs from older women may be particularly sensitive to aging after they are released from the ovaries," said Husam Abu-Soud, Ph.D., a Wayne State University researcher an
Contact: Michael Bernstein
American Chemical Society