Aging and female fertility

A key factor in influencing incidence of female fertility is the aging of oocytes. Our lab has identified several avenues through which oocyte aging is affected, including through nitric oxide (NO) dynamics and presence of various oxidants such as hydrogen peroxide (H2O2) and hypochlorous acid (HOCl). NO is a ubiquitous signaling molecule with a vast variety of effects in various biological systems, but our lab has found that exposure to NO can ameliorate effects of oocyte aging. For instance, we have observed decreases in oocyte aging-associated phenomena such as aberrations in microtubule and chromosomal arrangement, cortical granule exocytosis, and zona pellucida hardening when aging oocytes were treated with NO. These findings led us to further investigate mechanisms of regulating NO in the oocyte and ovary. Arginase II is an enzyme that catalyzes conversion of L-arginine to ornithine and urea; as L-arginine is also required by nitric oxide synthase (NOS) in the synthesis of NO, the interaction between these two enzymes is a promising area of current study in our lab. Current findings indicate that inhibiting the activity of arginase II could increase NO production and decrease effects of oocyte aging, improving overall fertility. This and study of other influences on NO production, such as NOS modulation, could uncover a possible avenue for ameliorating the effects of aging has on female fertility.