The Influence Of Central Located Granular Cytoplasm And Cytoplasmic Vacuoles In Oocytes On Fertilization And Embryo Development

Background: Oocyte dysmorphisms mainly contained extracytoplasmic anomalies andcytoplasmic anomalies. The effect of these dysmorphisms in oocytes on its quality anddevelopment potential was still controversial. Most of them were researched, classified byabnormal cytoplasmic inside or outside in oocytes, but the comparability of data andpertinence is not obvious. Central located granular cytoplasmic and vacuole are one of themost common dysmorphisms in oocytes. Why and how did they happen? Whether they haveeffect on the fertilization, embryo development and clinical outcome? And for the forecastingvalue to assisted reproductive technology remains to be seen. However, before the effectiveand practical technology analysis in biochemical molecular to determine the quality ofoocytes, non-invasive study (morphological assessment) is still an important evaluationmethod.For these reasons, we investigated the patients with IVF-ET/ICSI cycles in thereproductive center of Tongji Hospital in Wuhan retrospectively. The aim was to confirm thereason and the predictive validity of the central located granular cytoplasm and vacuoles inoocytes on ART outcome.Objective:1. To investigate the influence of central located granular cytoplasm in oocytes onfertilization, embryo development and clinical pregnancy.2. To investigate the influence of cytoplasmic vacuoles in oocytes and cleavage stage onembryonic development in assisted reproductive technology.Methods:1. A retrospective study was conducted on patients undergoing IVF or ICSI from April 2010to December2011, at Reproductive Medical Center of Tongji Hospital.173womenwith all oocytes containing central located granular cytoplasm were enrolled,645womenwho had normal oocyte morphology as control participated in the study. The fertilization,cleavage, blastocyst and pregnancy outcome between the two groups were compared.2. A retrospective study was conducted on patients undergoing IVF or ICSI from May2010to May2011in our center.469women with at least one oocyte containing cytoplasmicvacuoles were enrolled.5392oocytes with normal morphology as the normal group.510oocytes which have vacuoles in cytoplasm were as the group of cytoplasmic vacuoles inoocytes. In this study, we also selected559oocytes with no vacuoles in oocyte stage butoccurred spontaneously in cleavage stage as the group of in cleavage stage. Relatively goodembryo rate and blastocyst formation rate in each group were compared.Result:；1. To compared with the normal morphology group, the mean of BMI (body mass index)was lower (20.68±2.492vs21.44±2.714; P<0.05); and the mean of Gn duration was higher(11.39±2.125vs10.47±2.356; P<0.05) in the central located granular cytoplasm group.Through the binary classification Logistic regression analysis, we confirmed that BMI was aprotective factor and the Gn usage time was a risk factor, and there is statistical difference (P<0.05). Between the control group and central located granular cytoplasm group in IVF-ETcycles, there were significant differences in the rates of fertilization, good quality embryos,and available blastocysts（58.7%vs51.9%;43.1%vs34.6%;36.9%vs23.4%; all P<0.001）.Likewise, between the control group and central located granular cytoplasm group in ICSIcycles, there were significant differences in the rates of fertilization（61.4%vs49.1%,P<0.001）, good quality embryos (42.6%vs26.1%，P<0.001) and available blastocysts（31.3%vs20.4%,P<0.001）. In IVF-ET cycles, the rates of implantation（28.3%vs20.5%）,clinical pregnancy （41.7%vs32.4%）, delivery rate （35.4%vs26.5%） and abortion（12.9%vs19.0%）in fresh cycles between the two groups were not significant different(allP>0.05). However, between the control group and central located granular cytoplasmgroups in ICSI cycles, there were significant differences in the rates of implantation （28.1%vs15.7%,P=0.006）, but not in clinical pregnancy rate（43.0%vs28.3%, P>0.05）,delivery rate（37.2%vs26.4%, P>0.05） and abortion rate（9.6%vs6.7%,P>0.05）in freshcycles.2. Between the group of cytoplasmic vacuoles in oocytes and the normal group, the rates ofgood quality embryo (40.8%vs42.9%) and available blastocysts (29.1%vs33.0%) were notsignificant different(P>0.05), but when the group of cytoplasmic vacuoles in oocytescompared with the group of vacuoles in cleavage stage, there was significant differences inthe good quality embryo rate (66.0%vs40.8%,P<0.001), but not in the available blastocystrate(36.7%vs29.1%,P=0.066).10patients were transplanted the embryos with cytoplasmicvacuoles, and three cases had single and live births at term. One of the newborns sufferedfrom neonatal hypoxic-ischemic encephalopathy, but the remaining two cases had no obviousabnormalities.Conclusion:1. The morphology of central located granular cytoplasm in oocytes may affect fertilization,embryo development and blastocyst formation; the Gn usage time and BMI may becorrelated with the central located granular cytoplasm in ART.2. The cytoplasmic vacuoles in oocytes and the spontaneous vacuoles in cleavage stage maynot affect embryo development, and could make a normal pregnancy and a viableoffspring.