Chronological age enhances aging phenomena and protein nitration in oocyte.

Background: The average age of childbearing has increased over the years contributing to infertility, miscarriages, and chromosomal abnormalities largely invoked by an age-related decline in oocyte quality. In this study, we investigate the role of nitric oxide (NO) insufficiency and protein nitration in oocyte chronological aging.

Methods: Mouse oocytes were retrieved from young breeders (YB, 8-14 weeks [w]), retired breeders (RB, 48-52w) and old animals (OA, 80-84w) at 13.

Diminishing oocyte quality with advancing age is associated with deficiency of nitric oxide synthase cofactors, tetrahydrobiopterin, and zinc, in mouse oocytes.

Objective: To study the implications of decreased zinc and tetrahydrobiopterin (HB) associated with chronological aging on oocyte quality using a mouse model. HB and zinc are essential cofactors for nitric oxide synthase (NOS), because they aid in electron transfer and dimeric stability, and their bioavailability is crucial in regulating NOS coupling. We have previously shown that sufficient levels of nitric oxide (NO) are essential for maintaining oocyte quality and activation, and NO levels decrease in the oocyte as a function of age.

Direct real-time measurement of intra-oocyte nitric oxide concentration in vivo.

Nitric oxide (NO) is reported to play significant a role in oocyte activation and maturation, implantation, and early embryonic development. Previously we have shown that NO forms an important component of the oocyte microenvironment, and functions effectively to delay oocyte aging. Thus, precise information about intra-oocyte NO concentrations [NO] will result in designing more accurate treatment plans in assisted reproduction.

Dynamics of nitric oxide, altered follicular microenvironment, and oocyte quality in women with endometriosis.

Objective: To study follicular microenvironment in terms of free radical dynamics, oocyte quality, and assisted reproductive technology (ART) outcomes among women with (group A) and without (group B) endometriosis.

Design: Prospective cohort study.

Setting: University ART center.

Nitric oxide extends the oocyte temporal window for optimal fertilization.

Deteriorating oocyte quality is a critical hurdle in the management of infertility, especially one associated with advancing age. In this study, we explore the role of nitric oxide (NO) on the sustenance of oocyte quality postovulation. Sibling oocytes from superovulated mice were subjected to intracytoplasmic sperm injection (ICSI) with cauda-epididymal spermatozoa following exposure to either the NO donor, S-nitroso-N-acetylpenicillamine (SNAP, 0.

Reactive oxygen species and oocyte aging: role of superoxide, hydrogen peroxide, and hypochlorous acid.

Aging of the unfertilized oocyte inevitably occurs following ovulation, limiting its fertilizable life span. However, the mechanisms that regulate oocyte aging are still unclear. We hypothesize that reactive oxygen species such as superoxide (O2-), hydrogen peroxide (H2O2), and hypochlorous acid (HOCl) are likely candidates that may initiate these changes in the oocyte.

Reconstruction of ooplasm recipient oocytes with frozen-thawed donor microcytoplasts and influence on the microtubular spindle.

Objective(s): To cryopreserve micromanipulated ooplast segments (microcytoplasts) from mouse oocytes, compare microcytoplast and parent or recipient oocyte fusion performed within or without the zona pellucida, compare electrofusion of fresh or frozen oocyte with frozen-thawed microcytoplasts, and assess spindle integrity after reconstruction of oocytes.

Design: Prospective experimental study.

Setting: University-based experimental laboratory.

Activation of the cGMP signaling pathway is essential in delaying oocyte aging in diabetes mellitus.

Uncontrolled diabetes mellitus (DM) adversely affects oocyte maturation and embryo development via mechanisms that are yet unclear. Nonetheless, DM may cause uncoupling of nitric oxide synthases (NOSs) with reduction in the bioavailability of nitric oxide (NO), which is critical to maintain oocyte viability and prevent aging. The current study investigates the role of NO-mediated signaling related to oocyte aging in diabetic and nondiabetic mice.

Nitric oxide delays oocyte aging.

Nitric oxide (NO) is a ubiquitous signaling molecule that plays a crucial role in oocyte maturation and embryo development. However, its role in oocyte aging is unclear. To examine how NO affects oocyte aging, we retrieved young and relatively old mouse oocytes and exposed them to increasing concentrations of NO donor S-nitroso acetyl penicillamine (SNAP).

Dynamic changes in microtubular cytoskeleton of human postmature oocytes revert after ooplasm transfer.

Objective: Study of the influence of ooplasm transfer on the microtubule dynamics in human postmature oocytes.

Design: Prospective experimental study.

Setting: Academic hospital-based fertility center.