Mitochondrial membrane potential in 2-cell stage embryos correlates with the success of preimplantation development

Abstract

Hormonal stimulation in superovulation induces female mice to ovulate more oocytes than spontaneous ovulation. Because the superovulated oocytes contain a number of oocytes that normally regress before spontaneous ovulation or immature oocytes, the development of some embryos that derive from these oocytes by IVF is prevented. Therefore, the quality of superovulated oocytes should differ from that of spontaneously ovulated oocytes. In this study, we evaluated the quality of superovulated oocytes, by examining 1-and 2-cell stage embryos, in which the development mainly depends on the maternal mRNA, proteins, and mitochondria that are contained in the oocytes, and we then measured the mitochondrial membrane potential (DJ m ) of the 1-and 2-cell stage, in vivo-fertilized, and IVF embryos. The DJ m of 1-cell stage IVF embryos was lower than that of in vivo-fertilized embryos; however, there was no difference between IVF embryos. During the developmental process from 1-to 2-cell stage, the DJ m of in vivo-fertilized embryos was highly upregulated, whereas a number of IVF embryos remained unchanged. As a result, 2-cell stage embryos were divided into two groups: high-and low-DJ m 2-cell stage IVF embryos. The development of low-DJ m 2-cell stage IVF embryos tended to be arrested after the 2-cell stage. These results indicated that the upregulation of DJ m during the 1-to 2-cell stage was important in the development of early preimplantation embryos; there were some defects in the mitochondria of superovulated oocytes, which prevented their development.

DMBA acts on cumulus cells to desynchronize nuclear and cytoplasmic maturation of pig oocytes

“…Therefore, we examined mitochondrial Δ Ψm level and found DMBA exposure lowered mitochondrial Δ Ψm levels in both COC and CDO systems, indicating mitochondrial function was disturbed in oocytes exposed to DMBA. Both oxidative stress and mitochondrial dysfunction have been reported to link with developmental block of embryos cultured in vitro 9, 41 . Thus, DMBA induced oxidative stress and mitochondrial dysfunction were important reasons for the failure of embryo development.…”

Difference in Developmental Kinetics of Y-Specific Monoclonal Antibody Sorted Male and Female In Vitro Produced Bovine Embryos

“…Mitochondrial membrane potential (∆Ψ m ) is attributed to mitochondrial metabolic activity for the generation of ATP. ATP is critical for oocyte maturation, fertilization, and subsequent embryonic development [18]. To examine the effect of gender sex during development, we analyzed the mitochondrial distribution pattern, mitochondrial ∆Ψ m , and generation of reactive oxygen species (ROS) in X-and Y-sorted BLs.…”

“…In X-BLs, the ratio of J-aggregate versus J-monomer was lower compared to Y-sorted BLs ( Figure 2B). Low mitochondrial activity cannot actively eliminate the ROS from the cells [13,18]. The accumulation of ROS level also arrests the development at early stages [19].…”

Oocyte mitochondrial function and reproduction

“…Mitochondrial copy number, membrane potential and ATP content are decreased in murine oocytes following controlled ovarian hyperstimulation (COH) [66]. It is possible that mitochondria of superovulated mouse oocytes have some defects, which impairs their embryonic development [67]. COH causes mitochondrial abnormalities in granulosa cells of Rhesus monkeys [68].…”