Oocyte polarized light microscopy, assay of specific follicular fluid metabolites, and gene expression in cumulus cells as different approaches to predict fertilization efficiency after ICSI

Abstract

BackgroundThe complex relationship between oocyte morphology, specific follicular fluid metabolites, gene expression in cumulus granulosa cells, and oocyte competence toward fertilization and embryo development still needs further clarification.MethodsForty-six oocytes retrieved from the largest pre-ovulatory follicle of patients undergoing intra-cytoplasmic sperm injection (ICSI) were considered assessing: (a) oocyte morphological characteristics at polarized light microscopy (PLM), (b) specific follicular fluid (FF) metabolites previously suggested to influence oocyte competence (AMH, markers of redox status and of cytotoxicity), (c) transcription of AMH and AMH type II receptor genes in cumulus cells. Data were analyzed using mono-parametric tests and multivariable logistic analysis in order to correlate morphological and biochemical data with fertilization.ResultsComparing normally fertilized oocytes (n = 29, F group) with unfertilized (n = 17, nF group) we observed that: (a) the meiotic spindle area and major axis were significantly higher in nF group and in fertilized oocytes undergoing an early embryo development arrest; (b) AMH level in FF was comparable in F and nF groups; (c) the FF of nF group contained significantly higher levels of cytotoxicity (lactate dehydrogenase) and oxidative stress (Cu,Zn-superoxide dismutase, catalase, 4-hydroxynonenal-protein conjugates) markers; (d) cumulus cells of nF group showed significantly higher AMH receptor type II gene expression.ConclusionsTaken together, these observations suggest that an excessive cytotoxicity level can alter AMH signal transduction within cumulus cells, in turn leading to partial inhibition of aromatase activity, altered cytoplasmic maturation and increased oxidative stress, factors able to impair oocyte fertilization competence and embryo growth.Electronic supplementary materialThe online version of this article (doi:10.1186/s12958-017-0265-2) contains supplementary material, which is available to authorized users.

Effect of a Combination of Myo-Inositol, Alpha-Lipoic Acid, and Folic Acid on Oocyte Morphology and Embryo Morphokinetics in non-PCOS Overweight/Obese Patients Undergoing IVF: A Pilot, Prospective, Randomized Study

“…Our previous observations suggest that a MS of larger size is more frequently observed among women of advanced reproductive age and lower ovarian sensitivity to exogenous FSH, suggesting that the increased MS size could represent a marker of oocyte ageing, associated to maturation defects, causing fertilization failure or meiotic errors. Interestingly enough, we also reported that an increased MS size was associated with early embryo development arrest, before reaching the blastocyst stage [ 3 ]. Furthermore, the impact of female age on oocyte birefringent structures has been previously described and, in general, considered to be quite limited [ 3 , 51 , 54 , 55 ].…”

“…Interestingly enough, we also reported that an increased MS size was associated with early embryo development arrest, before reaching the blastocyst stage [ 3 ]. Furthermore, the impact of female age on oocyte birefringent structures has been previously described and, in general, considered to be quite limited [ 3 , 51 , 54 , 55 ]. In the present study, comparable maturation, fertilization, and cleavage rates were observed in the two groups, suggesting that in the analysed population the woman’s age may have exerted only a limited effect (if any) on oocyte quality and that the significant differences observed in the birefringent structures were likely to be related mainly to factors other than age.…”

“…Oocyte quality is a pivotal factor in determining IVF outcome, and the interest in the follicular microenvironment in which oocytes develop is witnessed by a series of recent studies [ 1 , 2 , 3 ]. Supplementation with antioxidants, vitamins, or hormones before and during controlled ovarian stimulation (COS) has been proposed as an attempt to improve the follicular microenvironment and, in turn, oocyte quality [ 4 , 5 , 6 ].…”

Oocyte Selection for <em>in vitro</em> embryo Production in Bovine Species: Non-Invasive Approaches for the New Challenges of Oocyte Competence

“…However, studies linking the FF features with the respective oocyte fate in bovines have not been performed yet. Reports in humans have positively associated the presence of anti-Müllerian Hormone (AMH) in FF with competence of the respective oocyte [163,164], although with some contradictory results [165,166]. Conversely, a recent study that used a large population of transferred embryos matching FF samples indicated that AMH level in FF following withdrawal from the ovarian follicle is closely linked to the oocyte's competence and it is a suitable predictor of a live birth after single embryo transfer [167].…”

Vesículas secretadas por células, proteínas e miRNAs associados à competência oocitária em bovinos: um modelo retrospectivo no microambiente folicular

“…Os outros dez miRNAs (miR-196a, miR-1225-3p, miR-1343-3p, miR-218, miR-23b-5p, miR-24, miR-760-5p, miR-455-3p, miR-483 (JOZWIK et al, 1999), os quais possuem maior competência a se desenvolver até o estágio de blastocistos (RIZOS et al, 2002) e, consequentemente de melhor qualidade. Esta enzima apresentou aumento significativo em fluido folicular associado a oócitos de menor competência, sugerindo uma maior necessidade de proteção antioxidante devido a um maior nível de dano oxidativo no FF de oócitos com baixo potencial de fertilização (REVELLI et al, 2017). O transcrito NOS2 é relacionado à resposta ao estresse oxidativo e senescência, quando comparadas células do cumulus entre mulheres jovens e mais velhas (MOLINARI et al, 2016), contudo, menos expresso em células do cumulus de melhor qualidade assim como neste estudo.…”