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Sept. 9, 2005 -- Nitric oxide, the same chemical that helps men achieve an erection, may also help women preserve their fertility and improve their chances of having a healthy baby by fighting the effects of aging on their ovaries.
A new study shows that exposure to nitric oxide delayed the signs of aging in mouse eggs, which, like eggs from older women, deteriorate rapidly and are more difficult to fertilize properly.
"Eggs from older women may be particularly sensitive to aging after they are released from the ovaries," states researcher Husam Abu-Soud, PhD, of Wayne State University, in a news release. "As a result, the time available for optimal fertilization of these women's eggs may be quite a bit shorter than the time frame in younger women."
But exposing the eggs to appropriate levels of nitric oxide "could extend this fertilizable time window in both old and young women," says Abu-Soud.
Researchers say the findings also suggest that nitric oxide may be used to enhance the fertility of eggs harvested for in vitro fertilization.
Nitric Oxide May Keep Eggs Young
In the study, published in the journal Biochemistry, researchers collected more than 1,500 eggs from the ovaries of mice within hours after ovulation.
Mouse eggs that aren't fertilized with sperm from a male begin to age quickly. After six hours, the eggs are less likely to be fertilized properly, and fertilization after this point can lead to genetic abnormalities in the embryos.
Researchers exposed the mouse eggs to varying concentrations of nitric oxide, a chemical that among other things keeps the arteries supple.
The results showed that nitric oxide appeared to slow the hardening of the eggs' outer shells, increase the release of molecules that prevent improper fertilization by more than one sperm, and fight other signs of aging that could interfere with fertilization.
Researchers say that in addition to possibly prolonging fertility in women, the results suggest that nitric oxide may help prevent genetic abnormalities during early embryo development, which may have applications in preventing Down syndrome, spontaneous miscarriages, and other problems often associated with pregnancies among older women.
SOURCES: Goud, A. Biochemistry, Aug. 30, 2005; vol 44: pp 11361-11368. News release, American Chemical Society.