Effects of intracellular Ca2+ on developmental potential and ultrastructure of cryopreserved-warmed oocyte in mouse.

Maintaining appropriate intracellular calcium of oocytes is necessary to prevent ultrastructure and organelle damage caused by freezing and cryoprotectants. The present study aimed to investigate whether cryoprotectant-induced changes in the calcium concentrations of oocytes can be regulated to reduce damage to developmental potential and ultrastructure. A total of 33 mice and 1381 oocytes were used to explore the effects of intracellular calcium on the development and ultrastructures of oocytes subjected to 2-aminoethoxydiphenyl borate (2-APB) inhibition or thapsigargin (TG) stimulation. Results suggested that high levels intracellular calcium interfered with TG compromised oocyte survival (84.4 % vs. 93.4 %, p < 0.01) and blastocyst formation in fresh and cryopreservation oocytes (78.1 % vs. 86.4 %, and 60.5 % vs. 72.5 %, p < 0.05) compared with that of 2-APB pretreated oocytes in which Ca2+ was stabilized even though no differences in fertilization and cleavage was detected (p > 0.05). Examination by transmission electron microscopy indicated that the microvilli decreased and shortened, cortical granules considerably decreased in the cortex area, mitochondrial vesicles and vacuoles increased, and the proportion of vacuole mitochondria increased after oocytes were exposed to cryoprotectants. The cryopreservation-warming process deteriorated the negative effects on organelles of survival oocytes. By contrast, a low level of intracellular calcium mediated with 2-APB was supposed to contribute to the protection of organelles. These findings suggested oocyte injuries induced by cryoprotectants and low temperatures can be alleviated. More studies are necessary to confirm the relationship among Ca2+ concentration of the cytoplasm, ultrastructural injuries, and disrupted developmental potential in oocytes subjected to cryopreservation and warming.

Short-interval second ejaculation improves sperm quality, blastocyst formation in oligoasthenozoospermic males in ICSI cycles: a time-lapse sibling oocytes study.

Background: Does short-interval second ejaculation improve sperm quality, embryo development and clinical outcomes for oligoasthenozoospermia males received intracytoplasmic sperm injection (ICSI) treatment? Methods: All enrolled male patients underwent short-interval secondary ejaculation on the day of oocyte retrieval, and 786 sibling MII oocytes from 67 cycles were equally divided into two groups based on whether the injected spermatozoons originated from the first or second ejaculation. Semen parameters, embryo development efficiency, morphokinetic parameters and clinical outcomes were compared between the two groups to assess the efficiency and clinical value of short-interval second ejaculation in ICSI cycles. Results: Short-interval second ejaculation significantly improved sperm motility, normal morphological rate, and sperm DNA integrity both before and after sperm swim-up. The high-quality blastocyst rate (24.79% versus 14.67%), available blastocyst rate (57.56% versus 48.44%), and oocyte utilization rate (52.93% versus 45.29%) were significantly higher in the second ejaculation group (P<0.05). The clinical pregnancy rate (59.09% versus 47.37%), implantation rate (42.11% versus 32.35%) and live birth rate (40.91% versus 31.58%) were higher in the second ejaculation group, but the differences were not significant (P>0.05). Time-lapse analysis showed that morphokinetic time points after the 7-cell stage were earlier in the second ejaculation group but without a significant difference (P>0.05), and abnormal embryo cleavage patterns between the two groups were not significantly different (P>0.05). Conclusions: Short-interval second ejaculation significantly improves sperm quality in oligoasthenozoospermic males, and is beneficial for blastocyst formation efficiency in ICSI cycles. This study suggested a non-invasive and simple but effective strategy for improving ICSI treatment outcomes.

Perfluoroalkyl Acids in Follicular Fluid and Embryo Quality during IVF: A Prospective IVF Cohort in China.

BACKGROUND: Perfluoroalkyl acids (PFAA) have been measured in ovarian follicular fluid from women using in vitro fertilization (IVF), although associations between follicular fluid PFAA and IVF outcomes have been inconsistent. OBJECTIVES: We investigated the association between follicular fluid PFAA and embryo quality in women undergoing IVF. METHODS: We prospectively enrolled 729 women undergoing IVF treatment in Guangxi province, China, from July 2018 to December 2018. We measured 32 PFAA, including branched isomers, in follicular fluid using ultra-performance liquid chromatography coupled to tandem mass spectrometry. We applied restricted cubic splines, linear regression, and log-binominal regression models to investigate associations between follicular fluid PFAA and embryo quality, adjusting for confounding variables and investigated oocyte maturity as an intervening variable using causal mediation analysis. We further estimated the overall effect of the PFAA mixture on outcomes using Bayesian kernel machine regression (BKMR). RESULTS: We detected 8 of 32 measured PFAA in >85% of follicular fluid samples. Higher PFAA concentrations were associated with fewer high-quality embryos from IVF. The high-quality embryo rates at the 50th percentile of linear perfluoro-1-octanesulfonate acid (n-PFOS), all branched PFOS isomers (Br-PFOS) and linear perfluoro-n-octanoic acid (n-PFOA) were -6.34% [95% confidence interval (CI): -9.45, -3.32%], -16.78% (95% CI: -21.98, -11.58%) and -8.66% (95% CI: -11.88, -5.43%) lower, respectively, than the high quality embryo rates at the reference 10th percentile of PFAA. Oocyte maturity mediated 11.76% (95% CI: 3.18, 31.80%) and 14.28% (95% CI: 2.95, 31.27%) of the n-PFOS and n-PFOA associations, respectively. The results of the BKMR models showed a negative association between the PFAA mixture and the probability of high-quality embryos, with branched PFOS isomers having posterior inclusion probabilities of 1 and accounting for the majority of the association. DISCUSSION: Exposure to higher PFAA concentrations in follicular fluid was associated with poorer embryo quality during IVF. Branched PFOS isomers may have a stronger effect than linear PFOS isomers. More studies are needed to confirm these findings and to directly estimate the effects on pregnancy and live-birth outcomes. https://doi.org/10.1289/EHP10857.

Early rescue oocyte activation at 5 h post-ICSI is a useful strategy for avoiding unexpected fertilization failure and low fertilization in ICSI cycles.

Introduction: Attempts to artificially activate unfertilized oocytes at 24 h post intracytoplasmic sperm injection (ICSI) have generally resulted in poor outcomes. This study aims to explore a new strategy for early judgement and rescue activation of unfertilized oocytes at 5 h post ICSI to avoid unexpected fertilization failure (UFF) or unexpected low fertilization (ULF) in ICSI cycles. Methods: Firstly, time-lapse data from 278 ICSI cycles were retrospectively analyzed to establish an indicator for fertilization failure prediction. Secondly, 14 UFF and 20 ULF cycles were enrolled for an observational study, early rescue oocyte activation (EROA) was performed on oocytes without post-ICSI Pb2 extrusion to investigate fertilization efficiency, embryo development and clinical outcomes. Results: The average time to Pb2 extrusion post-ICSI was 3.03±1.21 h, 95.54% of oocytes had extruded Pb2 before 5 h, and the sensitivity and specificity for monitoring Pb2 extrusion at 5 h by time-lapse imaging to predict fertilization were 99.59% and 99.78%, respectively. Early rescue activation of oocytes with no Pb2 extrusion resulted in acceptable fertilization and embryo developmental outcomes, in terms of the fertilization rate (75.00, 72.99%), 2PN fertilization rate (61.36, 56.93%), good-quality embryo rate (42.59, 50.00%), blastocyst formation rate (48.28, 46.03%), good-quality blastocyst rate (34.48, 33.33%), and oocyte utilization rate (36.36, 27.74%), for both UFF and ULF cycles. The clinical pregnancy, embryo implantation, and early miscarriage rates in the rescue oocyte activation group did not significantly differ from those in the Pb2 extrusion group. Fourteen unexpected fertilization failures and 20 low fertilization ICSI cycles were rescued and resulted in clinical pregnancy rates of 40.00% (4/10) and 57.14% (8/14), respectively. Conclusions: This study demonstrates that monitoring Pb2 extrusion by time-lapse imaging can accurately predict fertilization outcomes, suggesting that early rescue oocyte activation at 5 h post ICSI is an effective strategy for avoiding unexpected fertilization failure and low fertilization in ICSI cycles.

Sperm DNA fragmentation measured by sperm chromatin dispersion impacts morphokinetic parameters, fertilization rate and blastocyst quality in ICSI treatments.

To determine the effects of sperm DNA fragmentation (SDF) on embryo morphokinetic parameters, cleavage patterns and embryo quality, this retrospective study analyzed 151 intracytoplasmic sperm injection (ICSI) cycles (1152 embryos collected) between November 2016 and June 2019. SDF was assessed using sperm chromatin dispersion. The cycles were divided into two groups based on the SDF rate: SDF < 15% (n = 114) and SDF ≥ 15% (n = 37). The embryo morphokinetic parameters, cleavage patterns, and embryo quality were compared between the two groups. The morphokinetic parameters tPNf, t2, t3, t4, t5, t6, and t8 were achieved significantly earlier in the SDF < 15% group compared with in the SDF ≥ 15% group. The fertilization and 2PN rates seemed to be significantly higher in the SDF < 15% group compared with in the SDF ≥ 15% group, while the abnormal cleavage rates were similar. However, a significantly higher rate of chaotic cleavage (CC) was observed in the SDF ≥ 15% group. The D3 high-quality embryo and available embryo rates were similar between the two groups. The blastocyst formation, high-quality blastocyst, and available blastocyst rates in the SDF < 15% group were significantly higher than those in the SDF ≥ 15% group. With an increase in SDF level, the chemical pregnancy, clinical pregnancy and implantation rates tended to decrease, while the miscarriage rate increased. This study demonstrated that SDF ≥ 15% reduces the fertilization rate of ICSI cycles and affects certain morphokinetic parameters. A higher SDF level can also induce a higher rate of CC, with subsequent decreases in the blastocyst formation rate and blastocyst quality.

[Chromosome polymorphisms and their influence on semen quality and sperm DNA integrity in males undergoing IVF/ICSI].

OBJECTIVE: To investigate the incidence of chromosome polymorphisms and their influence on semen quality and sperm DNA integrity in male patients receiving in vitro fertilization/intracytoplasmic sperm injection (IVF/ICSI). METHODS: We retrospectively analyzed the chromosomal karyotypes and the types and incidence rate of chromosome polymorphisms in 2 370 male patients undergoing IVF/ICSI between June 2016 and June 2018. We classified the patients into groups A (with variation in the secondary constriction region in the autosomal long arm), B (with variation in the short arm of the D/G group chromosomes), C (with interbrachial inversion of chromosome 9) and D (with Y chromosome polymorphisms), and compared the semen parameters and sperm DNA fragmentation indexes (DFI) between the patients with chromosome polymorphisms and those with normal chromosomes. RESULTS: Totally, 154 (6.50%) of the patients undergoing IVF/ICSI were found with chromosome polymorphisms, including 34 cases of secondary constriction variation in the long arm of the autosome (1.43% ï¼»34/2 370ï¼½, 22.08% ï¼»34/154ï¼½), 82 cases of short arm polymorphisms of the D/G group chromosomes (3.46% ï¼»82/2 370ï¼½, 53.25% ï¼»82/154ï¼½), 26 cases of interbrachial inversion of chromosome 9 (1.10% ï¼»26/2 370ï¼½, 16.88% ï¼»26/154ï¼½), 10 cases of Y chromosome polymorphisms (0.42% ï¼»10/2 370ï¼½, 6.50% ï¼»10/154ï¼½), and 2 cases of mixed chromosome polymorphisms (0.08% ï¼»2/2 370ï¼½, 1.42% ï¼»2/154ï¼½). The total sperm count was lower in group D than in the other polymorphism groups and the normal chromosome group, but with no statistically significant difference among the five groups (P > 0.05). The sperm progressive motility was also lower in group D than in the other five groups, with statistically significant difference from group B (27.5 ± 13.5 vs. 41.5 ± 21.1, P = 0.027), but not from the other groups (P > 0.05). No statistically significant difference was observed in the sperm DFI between the polymorphism groups and the normal chromosome group (P > 0.05), or among the polymorphism groups (P > 0.05). The proportion of normal semen was lower in group D than in the other four groups, but with no statistically significant difference among the five groups (P > 0.05). The incidence rate of asthenospermia was higher in group D than in the other four groups, but with no statistically significant difference among the five groups (P > 0.05), and so was that of oligoasthenospermia, with statistically significant difference from the normal chromosome group (30.0% vs 8.0%, P = 0.041), but not from the other polymorphism groups (P > 0.05). CONCLUSIONS: Short arm polymorphisms of the D/G group chromosomes are the most common type of chromosome polymorphisms in male patients undergoing IVF/ICSI. Polymorphisms of the Y chromosome have a negative effect on semen quality, while those of the other chromosomes do not significantly affect semen quality and sperm DNA integrity.

[Normal sperm morphology and the outcomes of routine in vitro fertilization].

OBJECTIVE: To explore the application value of morphology assessment of sperm from fresh semen in routine in vitro fertilization (IVF). METHODS: We analyzed the morphology of the sperm from fresh or optimized semen samples and, based on the sperm morphology of the raw semen, allocated 908 IVF cycles due to the pure tubal factor to different groups: morphologically normal sperm (MNS) ≤ 4%, > 4% - ≤ 15%, and > 15% in Trial 1 and MNS ≤ 1%, > 1% - ≤ 2%, > 2% - ≤ 3%, and > 3%-- ≤ 4% in Trial 2. We compared the rates of fertilization, cleavage, high-quality embryo, -blastocyst formation, and pregnancy among different groups. RESULTS: The total fertilization rate was significantly lower in the MNS ≤ 4% than in the MNS > 4% - ≤ 15% and >15% groups (74.40% vs 78.61% and 80.03%, P < 0.01). Compared with the MNS ≤ 1%, > 1% - ≤ 2%, and > 2% - ≤ 3% groups, the MNS > 3% - ≤ 4% group showed remarkably increased rates of 2PN normal fertilization (77.23%, 78.97% and 78.99% vs 85.47%, P < 0.01), cleavage (95.71%, 96.01% and 97.27% vs 98.73%, P < 0.05), and blastocyst formation (53.85%, 49.01% and 49.55% vs 63.41%, P < 0.01). No statistically significant differences were observed in the rates of clinical pregnancy, implantation, early abortion, live birth, or malformation at birth among different groups (P > 0.05). CONCLUSION: MNS ≤ 4% affected the total rate of fertilization while MNS ≤ 3% reduced the rate of normal fertilization in IVF. However, even MNS ≤ 1% did not result in fertilization disorder or failure. Therefore, teratozoospermia alone was not an indicator of ICSI and sperm mor- phology assessment had no obvious value for predicting the rates of embryo quality, clinical pregnancy, and live birth in IVF.

Effect of sperm DNA fragmentation on clinical outcomes for Chinese couples undergoing in vitro fertilization or intracytoplasmic sperm injection.

Objective To investigate the effect of sperm DNA fragmentation on the fertilization rate, embryo development and pregnancy outcome of in vitro fertilization (IVF) and intracytoplasmic sperm injection (ICSI) in a cohort of Chinese couples. Methods Infertile couples that had undergone assisted reproductive technology at our centre between January 2011 and December 2013 were included in this retrospective study. Fractions of prepared sperm samples were evaluated for sperm DNA fragmentation on the day of oocyte recovery. Results Of the 550 couples selected, 415 had undergone IVF and 135 ICSI. Sperm DNA fragmentation rate was significantly negatively correlated with the fertilization rate in the ICSI cycles but not the IVF cycles. No association was found between sperm DNA fragmentation and cleavage rate or good quality embryo formation rates in IVF or ICSI cycles. Receiver operating characteristic (ROC) curve analysis showed that the sperm DNA fragmentation rate was a statistically significant prognostic indicator of the clinical fertilization rate in ICSI cycles; a rate > 22.3% was associated with a lower fertilization rate following ICSI compared with a rate ≤ 22.3%. Conclusions High values of sperm DNA fragmentation were associated with a low fertilization rate following ICSI but were not associated with alterations in pregnancy or live birth rates in either ICSI or IVF in this cohort of Chinese couples.