Quality Of Cumulus-oocyte Complexes Research Articles

Qualitative and quantitative parameters analyses of buffalo ovaries

Buffalo ovaries were collected from abattoirs in Dhaka city. During collection, left and right ovaries were identified and recorded. After processing, the ovaries were categorized as (i) ovaries without corpus luteum (CL) and (ii) ovaries with corpus luteum (CL). Ovaries were then evaluated based on length (cm), width (cm), weight (g), total number of follicles on the surface of each category of ovaries, number of follicles aspirated, and total number of cumulus-oocyte-complexes (COCs). The experiment's findings indicated variations in the parameters related to the left and right ovarian categories. The CL% (27.12±0.11%) found highest in the right compared to the left (3.24±0.11%). The length (cm), width (cm), and weight (g) (2.75±0.06, 2.17±0.05, 4.74±0.13) were found significantly (p<0.01) higher in the right ovaries compared to left (2.27±0.06, 1.77±0.05, 3.90±0.13). The number of follicles in total and number of follicles aspirated were found significantly (p<0.01) higher (6.35±0.16 & 5.47±0.16) in the left ovaries compared to right (6.16±0.16 & 4.18±0.16). The number of normal COCs and total COCs was significantly (p<0.01) higher in the left ovaries (0.98±0.134 & 1.57±0.17) compared to right (0.84±0.16 & 1.54±0.17). The abnormal COCs were significantly (p<0.01) higher in the right ovaries (0.75±0.107) compared to left (0.57±0.107). Regarding ovarian categories; (76.47±0.01%) showed ovaries without CL, whereas (23.53±0.01%) showed ovaries with CL. The weight (g) was found significantly (p<0.01) higher in ovaries with CL (4.73±0.12) compared to ovaries without CL (4.36±0.12). The number of follicles in total and aspirated were found significantly (p<0.01) higher in ovaries without CL (7.60±0.14 & 5.28 ±0.14) compared to ovaries with CL (4.29±0.14 & 2.29±0.14). Regarding the number of total COCs, ovaries without CL showed a significantly (p<0.01) higher number of total COCs (1.41±0.11) compared to ovaries with CL (1.17±0.11), where the number of normal and abnormal COCs (0.55±0.01 & 0.86±0.03) were found significantly (p<0.01) higher in ovary without CL compared to the ovary with CL (0.5±0.01 & 0.54±0.03). Finally, it can be concluded that the left and ovaries without CL contain more follicles in total and aspirated and normal COCs. Thus, the left and ovaries without CL are best for collecting quality COCs in buffaloes. Res. Agric. Livest. Fish. Vol. 11, No. 2, August 2024: 125-135

In Vitro Embryos of Romosinuano and Tropical Milking Cattle during Three Seasons in Veracruz, Mexico.

One of the main factors that influences the fertility of cattle in grazing systems in hot tropical climates is heat stress. The objective of this study was to evaluate the effect of season, breed, hormonal and physiological condition on the quantity and quality of cumulus-oocyte complexes (COCs) and embryos produced in vitro, from Romosinuano (RM) and Tropical Milking (TM) donors. Three ovum pick-up and in vitro fertilization (OPU-IVF) were performed, one per season: hot dry (HD; 10, 10), hot humid (HH; 9, 9) and fresh dry (FD; 7, 10) in RM and LT donors. Serum levels of cortisol, insulin and glucose were measured, in addition to heart rate (HR), respiratory rate (RR) and rectal temperature (RT). Effect of season x genotype interaction (p ≤ 0.05) was observed in all COC variables and only in cleavage embryos (CLI) (p ≤ 0.05). Body weight (BW) affected all COC variables (p ≤ 0.01), except unviable (UNV) although affected degenerated embryos (DEG) (p ≤ 0.01) and total blastocysts (BLAST) (p ≤ 0.01). Cow age only affected viable COCs (VIAB) (p ≤ 0.05), code one blastocysts (BC1) and BLAST (p ≤ 0.01). Cortisol affected total COCs (COCsT), VIAB and total matured in vitro (TMIV) (p ≤ 0.01), as well as CLI, BC1 (p ≤ 0.01) and BLAST (p ≤ 0.05). Insulin affected COCsT (p ≤ 0.01), UNV (p ≤ 0.05), denuded oocytes (DE) (p ≤ 0.01), BC1 and code two blastocysts (BC2) (p ≤ 0.01). Glucose affected all COC variables (p ≤ 0.01), except UNV and all embryo variables except BC2. HR affected COCsT, DE, TMIV (p ≤ 0.01), CLI, BLAST and DEG (p ≤ 0.05). RR affected COCsT, UNV, VIAB, CLI (p ≤ 0.05), BC1, BLAST and DEG (p ≤ 0.01). RT only affected DE, VIAB (p ≤ 0.01) and BLAST (p ≤ 0.05). The seasonal climatic year variation of Veracruz and changes in physiological and hormonal variables have diverse effects on the cumulus-oocyte complexes and embryos produced by RM and TM donors.

Enhancing Oocyte Quality in Aging Mice: Insights from Mesenchymal Stem Cell Therapy and FOXO3a Signaling Pathway Activation.

Ovarian aging reduced the quality of oocytes, resulting in age-related female infertility. It is reported that mesenchymal stem cells (MSCs) therapy can improve age-related ovarian function decline and the success rate of in vitro maturation (IVM) in assisted reproductive therapy. In order to investigate the effectiveness and mechanisms of MSCs to enhance oocyte quality of cumulus oocyte complexes (COCs) in advanced age, this study focus on the respective functional improvement of oocytes and granulosa cells (GCs) from aging mice and further to explore and verify the possible mechanisms. Here, we studied a popular but significant protein of follicular development, Forkhead box O-3a (FOXO3a), which is a transcription factor that mediates a variety of cellular processes, but the functions of which in regulating oocyte quality in MSCs therapy still remain inconclusive. In this study, the RNA-seq data of metaphase II (MII) oocytes and GCs isolated from COCs confirmed that, GCs of immature follicles show the most potential to be the targeted cells of bone marrow mesenchymal stem cells (BMSCs) by FOXO3a signaling pathway. Furthermore, we demonstrated the effectiveness of BMSCs co-culture with aging COCs to enhance oocyte quality and found its mechanism to function via ameliorating the biological function of GCs by alleviating FOXO3a levels. These results provide significant fundamental research on MSCs therapy on ovarian aging, as well as offering guidance for raising the success rate of assisted reproductive technology such IVM in clinical and non-clinical settings.

Effects of ovarian phase on oocyte quality in cows

The effect of ovarian phase on oocyte quality in slaughterhouse material of cows was studied. Cumulus-oocyte complexes (COCs) were aspirated from all visible follicles. COCs were graded on the number and intensity of the cumulus cells and the homogeneity of the ooplasm as A (4 – 5 layers compact cumulus with a homogeneous ooplasm), B (1 - 2 layers compact cumulus with homogeneous ooplasm having a coarse appearance), C (slightly expanded cumulus with irregular cluster ooplasm), and D (denuded oocyte or expanded cumulus, irregular ooplasm). The overall aspiration rate of COCs was 37.2%. The aspiration rate was significantly higher (P<005) in follicular (41.2%) than in luteal phase (28.6%). The percentage of grade A and B oocytes was significantly (P<005) higher in the follicular phase (20.4 and 28.6%) than luteal phase (11.1 and 22.2%). The proportion of grade A COCs in the indigenous cows was significantly (P<005) higher (29.0%) than in crossbred cows (8.3%). Ovaries with diameter of 2.0 cm or more had higher proportion (P<005) of grade A and B COCs than others. It is suggested that follicular phase of the sexual cycle had significant effect on COCs quality.
 Bangl. vet. 2023. Vol. 40, No. 1-2, 1–7

Oocyte cumulus complex quality and oviduct transportation velocity in systemic autoimmune disease model mice.

Oocyte transportation by the oviduct involves the interaction between ciliated epithelial cells and cumulus cells. To determine whether the quality of cumulus-oocyte complexes (COCs) changes the transportation property of COCs, we compared the transportation velocity of COCs (TVC) by the infundibulum ex vivo with various combinations of infundibula and COCs collected from different mice. We used young and aged C57BL/6N and MRL/MpJ, and MRL/MpJ-Faslpr/lpr mice as the strains with intact female reproductive function and the systemic autoimmune disease model exhibiting oocyte pick-up dysfunction owing to the morphofunctional abnormality of ciliated epithelium, respectively. The TVC of aged MRL strains was less than that of aged C57BL/6N mice, suggesting that aging affects the transportation of COCs in MRL strains. The TVC of aged MRL/MpJ-Faslpr/lpr mice was the least among all examined combinations, whereas the TVC accelerated when the infundibulum or COCs were collected from other strains. These results indicate that the transportation property of COCs is determined not only by the ciliary function in the infundibulum but also by the properties of COCs.

Cryotolerance of in vitro matured and vitrified bovine oocytes supplemented with L-carnitine and niacin

The study was designed to compare the cryotolerance of in vitro matured bovine oocytes, supplemented with L- carnitine and niacin in maturation media, vitrified using cryoloop technique. Bovine ovaries were collected from the slaughterhouse and cumulus-oocyte complexes (COCs) were retrieved by follicular aspiration. Culture quality COCs were selected and randomly allocated to three different experimental groups. Group I oocytes (control), were subjected to in vitro maturation (IVM) in basic maturation media, while Group II and III oocytes (experimental groups) were matured in media supplemented with L- carnitine (0.6 mg/mL) and niacin (400 μM/mL), respectively. The mean per cent of cumulus cell expansion was 80.92 ±0.02, 79.18 ± 0.03 and 87.95 ±0.02 for Group I, II and III, respectively. A significantly high (p < 0.05) cumulus cell expansion could be observed in niacin treated group than L- carnitine, whereas a difference close to being statistically significant (p = 0.057) was noticed between niacin treated and control groups. The matured oocytes were subjected to cryoloopvitrification using dimethylsulfoxide (15%), ethylene glycol (15%) and sucrose (0.05M) as cryoprotectants. The mean survival rate observed in the study was 67.26 ± 0.05, 76.34 ± 0.05 and 79.68 ± 0.03 per cent for Group I, II and III, respectively. Shrinkage of cytoplasm was the most common type of cryodamage observed in all the three groups followed by cracked zona pellucida, abnormal shape and increased peri vitelline space. The survived oocytes were subjected to in vitro fertilisation with no significant difference between the groups in fertilisation rate. The present study revealed the beneficiary effect of supplementing niacin over L- carnitine in maturation media as it improved the maturation and survival rates of bovine oocytes.

203 Effect of aspiration pressure at the time of transvaginal ultrasound-guided follicle aspiration on cumulus-oocyte complex quality and embryo development in alpacas (

Reproduction, Fertility and Development is an international journal publishing original research , review and comment in the fields of reproduction and developmental biology in humans, domestic animals and wildlife

Optimization of gonadotropin stimulation protocols for in vitro embryo production in prepubertal Mediterranean water buffalo

Embryos can be produced from prepubertal donor animals using laparoscopic ovum pickup and in vitro embryo production technologies (LOPU-IVEP). Together, these tools can shorten the interval between generations, rapidly accelerating the rate of genetic gain. Here, we assessed the impact of different gonadotropin stimulation protocols in Mediterranean water buffalo heifer calves aged between 2 and 6 months old. Following gonadotropin stimulation, LOPU was performed at two-week intervals, with animals receiving different protocols on subsequent LOPUs. After collection, the cumulus-oocyte complexes (COCs) were matured and fertilized in vitro, and embryos were cultured to the blastocyst stage followed by transfer into synchronized adult recipients. The number and size of follicles aspirated during LOPU, the number and quality of COCs recovered, as well as cleavage, embryo development and pregnancy rates were assessed. First, we evaluated the impact of using FSH with and without eCG (administered 24-h prior to LOPU) and found that a combination of FSH and eCG was able to significantly improve embryo development rates (20.6 ± 2.0% vs. 9.0 ± 3.6%; P < 0.05). Second, we compared this protocol to a slow-release formulation of FSH reconstituted in hyaluronan. In addition to requiring less work to prepare the animals for LOPU, this slow-release formulation yielded numerically higher, but not statistically different, average number of recovered COCs (14.4 ± 2.1 vs. 10.3 ± 2.0; P > 0.05) and embryo development rates (22.9 ± 4.7% vs. 14.1 ± 5.2%; P > 0.05) compared to FSH given every 12 h. Next, we compared the length of gonadotropin treatment over 3-, 4- and 5-days prior to LOPU and found that as the length of gonadotropin treatment increased, although the number of COCs recovered steadily decreased (14.1 ± 2.4 vs. 8.7 ± 1.0 vs. 6.9 ± 0.7; P < 0.05), the embryo development rates steadily increased (14.4 ± 3.9 vs. 27.3 ± 4.4 vs. 35.9 ± 7.0; P < 0.05), presumably due to an increase in the proportion of large follicles at the time of LOPU. Numerically, the 4-day treatment yielded more transferrable embryos per donor per LOPU (2.70 ± 0.5) than 3-day (1.94 ± 0.6) and 5-day (2.25 ± 0.5) treatments. Finally, following embryo transfer, 26 of 90 recipient females became pregnant (28.9%). Pregnancies were established from all treatments, which suggests that post-implantation development was not affected among the gonadotropin treatments assessed.

The coasting time affects the quality of cumulus-oocyte complexes in superstimulated ewes

We hypothesized that the coasting time may be beneficial to the quality of cumulus-oocyte complexes recovered from live ewes, as reported in cattle. The present study assessed the effect of coasting times on the quantity and quality of cumulus-oocyte complexes (COCs) in sheep. All ewes were subjected to the “Day 0 protocol”, followed by an ovarian stimulation (80 mg of pFSH in three decreasing doses), varying only the coasting time [12 (G12), 36 (G36), or 60 h (G60]. In Experiment 1, data regarding follicular population was assessed. In Experiment 2, the COC quality was checked by their morphology, brilliant cresyl blue (BCB) test, evaluation of chromatin condensation pattern, and oocyte diameter. In Experiment 3, genes related to oocyte developmental competence were evaluated in BCB + COCs. The oocytes in the G60 group had more (P < 0.05) large follicles than the other groups and oocytes with a greater diameter than the G12. Oocyte morphology was similar (P > 0.05) among groups, as well as the BCB + COCs quantity. The G60-oocytes presented a better (P < 0.05) configuration of chromatin condensation compared with the other groups and a greater (P < 0.05) gene expression of BMP15, MATER, ZAR1, and PTGS2 compared with G12, and PTGS2 and HAS2 compared with G36 group. In conclusion, 60 h of coasting time positively affects the quality of COCs recovered after subjecting ewes to the “Day 0 protocol” and ovarian superstimulation. Implementing the appropriate coasting time to a given protocol can positively impact the in vitro embryo production outcomes in sheep.

Using Cumulus Cell Biopsy as a Non-Invasive Tool to Access the Quality of Bovine Oocytes: How Informative Are They?

The present study aimed to determine whether cumulus cells (CC) biopsy, acquired before or after in vitro maturation (IVM), presents similar gene expression pattern and if would compromises oocyte quality. First, immature cumulus oocyte complexes (COCs) were distributed: (1) maturated in groups (control); (2) individually maturated, but not biopsied; (3) subjected to CC biopsy before maturation and individually matured; (4) individually matured and submitted to CC biopsy after maturation; (5) individually matured and CC biopsied before and after maturation. Secondly, candidate genes, described as potential markers of COCs quality, were quantified by RT-qPCR in CCs before and after IVM. After in vitro fertilization (IVF), zygotes were tracked and sorted regarding their developmental potential: fully developed to embryo, cleaved and arrested, and not-cleaved. The COC's biopsy negatively affects embryo development (p &lt; 0.05), blastocyst cell number (p &lt; 0.05), and apoptotic cell ratio (p &lt; 0.05), both before and after IVM. The PTGS2, LUM, ALCAM, FSHR, PGR, SERPINE2, HAS2, and PDRX3 genes were differentially expressed (p &lt; 0.05) on matured CCs. Only PGR gene (p = 0.04) was under-expressed on matured CCs on Not-Cleaved group. The SERPINE2 gene was overexpressed (p = 0.01) in the Cleaved group on immature CCs. In summary, none of the selected gene studies can accurately predict COC's fate after fertilization.

Comparison of oocyte collection methods using caprine ovaries and in vitro embryo culture

The objectives of this study were to elucidate the efficiency of oocyte recovery through different techniques, grading of oocytes, and optimization of the caprine in vitro embryo production system. Ovaries were collected from the local slaughterhouse and classified based on the presence of a corpus luteum (CL). A total of 442 cumulus-oocyte complexes (COC) were retrieved from 178 ovaries aseptically through aspiration, slicing, and slashing techniques. Collected COC were categorized according to the compactness of cumulus cells around the oocyte and the homogeneous cytoplasm. In vitro maturation of graded COC was done for 27 h. In vitro fertilization (IVF) of the matured oocytes was performed using frozen semen. At 16 h of IVF, presumptive zygotes were in vitro cultured for 7 d. It was found that 31% of ovaries had a CL and 69% did not have a CL. The number of oocytes recovered per ovary (2.89 ± 0.22) and the percentage of excellent oocytes, grade A (29.84 ± 4.00%) and B (44.80 ± 2.32%), were significantly greater from the slashing technique than from the aspiration (2.16 ± 0.30 and 11.80 ± 0.61%, 30.80 ± 3.56%, respectively) and slicing technique (2.40 ± 0.15 and 22.62 ± 7.81%, 16.10 ± 1.29%, respectively). Results revealed a significantly greater ( P < 0.05) rate of grade A (61.14 ± 5.83%, 36.04 ± 0.32%, and 22.51 ± 3.07%) and grade B oocytes (23.31 ± 1.61%, 28.90 ± 7.47%, and 28.29 ± 5.04%) reached the metaphase II stage recovered from 3 methods (slashing, slicing and aspiration, respectively). The cleavage and blastocyst rates of presumptive zygotes were found to be 74.15 ± 6.80% and 37.50%, respectively. This study suggests that the slashing technique is more suitable for harvesting a greater number and superior quality of COC. The culture conditions used in this experiment were found to be optimal and efficiently supported in vitro maturation, IVF, and subsequent development of goat embryos to the blastocyst stage. Based on the results of this study, the culture conditions and slashing technique could be used in caprine in vitro embryo production and advanced biotechnology research.

Effect of the presence and location of corpus luteum on competence of bovine cumulus-oocyte complexes.

This study aimed to determine the effect of presence of the corpus luteum (CL) and its influence on cumulus–oocyte complexes (COCs) obtained from the ipsilateral or contralateral ovary in bovine on the recovery and capacity of the oocytes to sustain mono-spermic fertilization, undergo preimplantation development, and develop to the blastocyst stage. Ovaries were collected at a local slaughterhouse and kept in pairs corresponding to the same animal. In the first experiment the variables evaluated were compared between cows with (CCL+) and without (CCL-) CL, and for the second experiment, comparisons were made between ovaries with an ipsilateral (CL+), contralateral (CL−), and no (NCL). The recovery rate of COCs was higher in ovaries from CCL− cows, and a higher proportion of grade 1 COCs were recovered from this group. A higher proportion of metaphase I oocytes at 7 h of maturation, and a higher rate of cleavage were observed in the CCL+ group; however, a higher proportion of embryos were obtained from the CCL− group. Besides, COCs from the CL+ group had a lower proportion of grades 1 and 2 morphological qualities, lower rate of metaphase II oocytes at 22 h of maturation, and lower rate of formation of two pronuclei, whereas a higher proportion of unfertilized oocytes after in vitro fertilization. On the other hand, the COCs from the CL− group displayed a lower proportion of oocytes with more than two pronuclei, higher cleavage rate, and higher final blastocyst production were obtained when compared to CL+. Thus, the effects of CL on the competence of bovine COCs are different depending on the anatomical proximity of their location in the animal, negatively affecting the quality of COCs located in the same ovary, but not having negative effects on the competence of COCs in the ovaries contralateral to their location.

131&#x2003;The effects of dominant follicle removal on quality of cumulus-oocyte complexes in half-blood Bos indicus &#xd7; Bos taurus donor cattle.

Reproduction, Fertility and Development is an international journal publishing original research , review and comment in the fields of reproduction and developmental biology in humans, domestic animals and wildlife

Effect of zinc chloride and sodium selenite supplementation on in vitro maturation, oxidative biomarkers, and gene expression in buffalo (Bubalus bubalis) oocytes.

This study examined the effects of zinc chloride (ZnCl2) and sodium selenite (Na2SeO3) supplementation in maturation medium on in vitro maturation (IVM) rate, oxidative biomarkers and gene expression in buffalo oocytes. Ovaries from a slaughterhouse were aspirated and good quality cumulus-oocyte complexes (COCs) with at least four layers of compact cumulus cells and evenly granulated dark ooplasm were selected. COCs were randomly allocated during IVM (22 h) to one of four treatment groups: (1) control maturation medium (basic medium), or basic medium supplemented with (2) ZnCl2 (1.5 µg/ml), (3) Na2SeO3 (5 µg/l), or (4) ZnCl2 + Na2SeO3 (1.5 µg/ml + 5 µg/l, respectively). Oocytes were denuded after 22 h of IVM in the first four replicates. Specimens were fixed and stained to evaluate the stage of nuclear maturation. The spent medium was collected for biochemical assays of total antioxidant capacity (TAC), malondialdehyde (MDA) and hydrogen peroxide concentrations. A second four replicates were used for COCs for RNA extraction. The expression levels of antioxidant (SOD1, GPX4, CAT and PRDX1), antiapoptotic (BCL2 and BCL-XL) and proapoptotic (BAX and BID) genes were measured. Supplementation with ZnCl2 and Na2SeO3 during IVM increased the ratio of oocytes reaching metaphase II at 22 h, increased TAC and decreased MDA and H2O2 concentrations in the maturation medium (P < 0.05). Moreover, beneficial effects were associated with complementary changes in expression patterns of antioxidative, antiapoptotic and proapoptotic genes, suggesting lower oxidative stress and apoptosis. Supplementation medium with zinc chloride and sodium selenite improves the maturation rate, reduces oxidative stress and increases expression levels of antioxidative and antiapoptotic genes.

Cumulus-oocyte developmental competence: From morphological selection to molecular markers

The intrinsic quality of mammalian cumulus-oocyte complexes (COCs) is a determinant factor for pregnancy and fertility in general. The efficiency of assisted reproductive techniques required selection of good quality COCs.

Expression levels of FSHR, IGF1R, CYP11al and HSD3β in cumulus cells can predict in vitro developmental competence of bovine oocytes.

The efficiency of in vitro embryo production technologies would be improved by the development of suitable non-invasive biomarkers that allow the selection of good quality cumulus-oocyte complexes (COCs). The present study used whole, single oocyte culture to investigate whether the expression levels of follicle-stimulating hormone receptor (FSHR), insulin-like factor 1 receptor (IGF1R) and three steroidogenesis-related enzymes (CYP11al, CYP19al and HSD3β) in cumulus cells reflected the developmental competence of COCs. Cumulus cells were collected from single COCs before maturation culture and relative mRNA levels were assessed using real-time PCR. The analysis indicated that mRNAs for FSHR, IGF1R, CYP11al and HSD3β were present at higher levels in cumulus cells from COCs that failed to form blastocysts compared with cumulus cells from COCs that formed blastocysts. Moreover, FSHR and IGF1R mRNA levels were positively correlated with those of genes for steroidogenesis-related enzymes. In conclusion, poor developmental competence of COCs was related to higher expression of FSHR, IGF1R, CYP11al and HSD3β in cumulus cells, which may indicate the advanced differentiation of cumulus cells into granulosa cells.

The effects of follicle-stimulating hormone receptor (FSHR) -29 and Ser680Asn polymorphisms in IVF/ICSI.

Background The aim of this study was to analyze two different polymorphisms, Ser680Asn and -29 (G>A) promoter polymorphism, of the follicle-stimulating hormone receptor (FSHR) gene, individually but also in combination, in a sample of Greek women undergoing in vitro fertilization (IVF) or intracytoplasmic sperm injection (ICSI). Materials and methods One hundred and forty-one women undergoing IVF or ICSI and 94 controls were genotyped by real-time polymerase chain reaction (RT-PCR) for the two FSHR polymorphisms. The association of the alleles with the clinical, biochemical and other parameters concerning the controlled ovarian stimulation (COS) protocol and outcome was investigated, as well as the pregnancy rate. Results The study of each polymorphism individually revealed a positive correlation of the SerSer genotype (Ser680Asn polymorphism) with higher luteinizing hormone (LH) levels on the third day of the menstrual cycle. On the other hand, the A allele for the -29 (G>A) promoter polymorphism correlated with the increased number and quality of cumulus-oocyte complexes (COCs). No differences were detected when the different genotypes of the two polymorphisms were combined - the population study was grouped according to the number of polymorphic alleles they carried (0-4 alleles). Women who presented all polymorphic alleles, AsnAsn/AA, exhibited the lowest LH levels (2.62 ± 0.68 mIU/L), but were rarely detected (n = 2, 1.4% of the studied population). Conclusions The data from this study reflect that the investigation of the combination of polymorphisms, such as FSHR -29 and Ser680Asn, could offer a valuable tool in order to evaluate and anticipate the outcome of the ovulation induction protocols, especially in the group of patients with failed attempts.

Effect of autophagy induction and cathepsin B inhibition on developmental competence of poor quality bovine oocytes.

The present study investigated the effect of autophagy induction and cathepsin B (CTSB) inhibition on developmental competence of poor quality oocytes. Bovine cumulus oocyte complexes (COCs) were classified as good or poor according to their morphology. Autophagy activity was detected in good and poor germinal vesicle (GV) oocytes. Then E-64, a CTSB inhibitor, rapamycin (Rapa), an autophagy inducer, and combined administration was achieved during in vitro maturation (IVM) of poor quality COCs followed by detection of autophagy activity. In the next experiment, E-64, Rapa, and E64 + Rapa, were added during IVM to good and poor quality COCs followed by in vitro fertilization and culture for 8 days to investigate whether inhibition of CTSB and/or induction of autophagy improve embryonic development and quality. Autophagy activity was significantly lower in poor quality GV oocytes than in good quality ones. E-64, Rapa and E-64 + Rapa treatment during IVM significantly increased autophagy activity in poor quality oocytes. Addition of Rapa in good quality COCs did not increase the blastocyst rate, whereas E-64 increased the blastocyst rate and total cell number (TCN) with decreasing TUNEL-positive cells. In contrast, Rapa treatment in poor quality COCs significantly increased the blastocyst rate and TCN with decreasing TUNEL-positive cells. These results indicate oocyte quality has different responses to intracellular autophagy induction and CTSB activity control by potential autophagy and catabolic status, however, synergetic effect of autophagy induction and CTSB inhibition can increase developmental competence of both good and poor quality COCs, especially rescue effect in poor quality COCs.

Follicular fluid steroid profile in sows: relationship to follicle size and oocyte quality†.

Identification of reliable characteristics of follicle quality and developmental competence has been pursued in numerous studies, but with inconsistent outcomes. Here, we aimed to identify these characteristics by analysis of the follicular fluid (FF) steroid profile in relation to cumulus-oocyte complex (COC) morphology and follicle size, followed by molecular substantiation. Multiparous sows at weaning were used to facilitate analysis at the start of the follicular phase of the oestrus cycle. Sows with a higher average follicle size (≥5 mm vs. < 5 mm) had a higher follicular fluid β-estradiol concentration, but did not differ in other measured steroids. Sows with high compared to low percentage high-quality COCs (<70% vs. ≥70% high-quality) had follicular fluid with a higher concentration of β-estradiol, 19-norandrostenedione, progesterone, and α-testosterone, while the concentration of cortisol was lower. Transcriptome analysis of granulosa cells of healthy follicles of sows with a high percentage high-quality COCs showed higher abundance of transcripts involved in ovarian steroidogenesis (e.g., CYP19A2 and 3, POR, VEGFA) and growth (IGF1) and differential abundance of transcripts involved in granulosa cell apoptosis (e.g., GADD45A, INHBB). Differences in aromatase transcript abundance (CYP19A1, 2 and 3) were confirmed at the protein level. In addition, sows with a high percentage high-quality COCs lost less weight during lactation and had higher plasma IGF1 concentration at weaning, which may have affected COC quality. To the best of our knowledge, this study is also the first to report the relation between FF steroid profile and COC quality.

Supplementation of maturation medium with CoQ10 enhances developmental competence of ovine oocytes through improvement of mitochondrial function.

In vitro maturation (IVM) can impair the balance between antioxidant capacity and oxidative stress, and jeopardize embryo development by increasing oxidative stress, reducing energy metabolism, and causing improper meiotic segregation. Balancing the energy production and reduction of oxidative stress can be achieved by supplementation with coenzyme Q10 (CoQ10), an electron transporter in the mitochondrial inner membrane. To improve the in vitro production of ovine embryos, we studied the effect of CoQ10 supplementation during the maturation of sheep oocytes. A minimum of 100 cumulus-oocyte complexes (COCs) were matured in the presence of 15, 30, or 50 μM CoQ10 in three to five replicates; next, in vitro fertilization and culture in a subset of oocytes were done. Our data revealed that compared to control oocytes or other concentrations of CoQ10, supplementation with 30 µM CoQ10 resulted in a significant increase in blastocyst formation and hatching rates, improved the distribution, relative mass and potential membrane of mitochondria, decreased the levels of reactive oxygen species and glutathione and lessened the percentage of oocytes with misaligned chromosomes after spindle assembly. The relative expression levels of apoptosis markers CASPASE3 and BAX were significantly reduced in CoQ10-treated oocytes and cumulus cells whereas the relative expression level of GDF9, an oocyte-specific growth factor, significantly increased. In conclusion, supplementation with CoQ10 improves the quality of COCs and the subsequent developmental competence of the embryo.