Oocyte quality is decreased in women with minimal or mild endometriosis

Abstract

Endometriosis, a pathological condition in which the endometrium grows outside the uterus, is one of the most common causes of female infertility; it is diagnosed in 25–40% of infertile women. The mechanism by which endometriosis affects the fertility of females remains largely unknown. We examined the ultrastructure of oocytes from patients with minimal or mild endometriosis and control females undergoing in vitro fertilization (IVF) treatment by transmission electron microscopy (TEM) to investigate the physiological significance of oocyte quality for patients with minimal or mild endometriosis. The TEM results revealed that the oocytes from women with minimal or mild endometriosis exhibited abnormal mitochondrial structure and decreased mitochondria mass. Quantitative real time PCR analysis revealed that the mitochondrial DNA copy number was significantly reduced in the oocytes from women with minimal or mild endometriosis compared with those of the control subjects. Our results suggest that decreased oocyte quality because of impaired mitochondrial structure and functions probably an important factor affecting the fertility of endometriosis patients.

The mitochondrial DNA copy number, cytochrome c oxidase activity and reactive oxygen species level in metaphase II oocytes obtained from in vitro culture of cryopreserved ovarian tissue in comparison with in vivo‐obtained oocyte

“…showed that oocytes with normal development into blastocysts had mtDNA copy numbers similar to ones that lacked cleavage . These controversies may be due to the difference in species and the technique used to determine the mtDNA copy number of oocytes …”

Quantitative and qualitative changes of mitochondria in human preimplantation embryos

“…The numbers of mtDNA copy in oocytes or embryos have been shown to be involved in causes of infertility (ovarian insufficiency [12] and endometriosis [13]), mutations of mtDNA [14], female age [15], and aneuploidy of embryos [15,16]. On the other hand, it has been shown that overall levels of mtDNA are largely equal between blastocysts stratified by ploidy, age, or implantation potential [17].…”

Advanced oxidation protein products from the follicular microenvironment and their role in infertile women with endometriosis

“…The evaluation for oocytes was performed according in the following parameters: Expanded cumulus, appropriate cytoplasmic maturation, extruded first polar body and arrest in metaphase II. The embryo quality was scored at day 3 following fertilization and prior to placement in the uterus, as follows: Grade I, very good quality; grade II, good quality; grade III, medium quality; and grade IV, poor embryo quality (13). A good embryo (grades I and II) was defined as having seven or eight blastomeres, which were equally sized, with <20% fragmentation and no multinucleation.…”

“…The development of in vitro fertilization (IVF) is promising for infertile patients with EM; however, the success rate of this procedure remains at a low level (12). One of the main causes of failure may be the poor quality of oocytes (13). Thus, research has been focusing on determining the causes of poor oocyte quality in infertile women with EM and improving their quality.…”