Determinants of the follicular population and oocyte quality of Cameroonian native ewes

Cervical dislocation is a commonly used method of mouse euthanasia. Euthanasia by isoflurane inhalation is an alternative method which allows the sacrifice of several mice at the same time with an anaesthesia, in the aim to decrease pain and animal distress. The objective of our study was to assess the impact of these two methods of euthanasia on the quality of mouse oocytes. By administering gonadotropins, we induced a superovulation in CD1 female mice. Mice were randomly assigned to euthanasia with cervical dislocation and isoflurane inhalation. Oviducts were collected and excised to retrieve metaphase II oocytes. After microscopic examination, oocytes were classified into three groups: intact, fragmented/cleaved and atretic. Intact metaphase II oocytes were employed for biomedical research. A total of 1442 oocytes in the cervical dislocation group were compared with 1230 oocytes in the isoflurane group. In the cervical dislocation group, 93.1% of the oocytes were intact, versus 65.8% in the isoflurane group ( P ≤ 0.001). In light of these results, we conclude that cervical dislocation is the best method of mouse euthanasia for obtaining intact oocytes for biomedical research.

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Embryo transfer as an option to improve fertility in repeat breeder dairy cows

Journal of Veterinary Research ◽

10.2478/jvetres-2021-0018 ◽

2021 ◽

Vol 0 (0) ◽

Author(s):

Arkadiusz Nowicki

Keyword(s):

Dairy Cows ◽

Pregnancy Rate ◽

Embryo Transfer ◽

Oocyte Quality ◽

Poor Quality ◽

Early Embryo ◽

Reproductive Disorder ◽

Uterine Environment ◽

Repeat Breeder

Abstract Repeat breeding is a serious reproductive disorder in dairy cattle. The causes of repeat breeding are multifactorial and there are two main mechanisms: failure of fertilisation or early embryo death, mainly due to poor quality of oocytes and an inadequate uterine environment. Many methods have been used to increase the pregnancy rate for repeat breeder cows, such as intrauterine infusion of antibacterial agents or antibiotics, hormonal treatments for oestrus synchronisation and induction of ovulation, and progesterone supplementation or induction of accessory corpus luteum; however, the results were inconsistent between studies. Embryo transfer (ET) has the capability to minimalise the effects of poor oocyte quality and unfavourable uterine environments on early embryo development during the first seven days after ovulation in repeat breeder cows, and several studies showed that ET significantly improved the pregnancy rate in this group of animals. Thus, ET can be considered an option to increase the conception rate in repeat breeder dairy cows.

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Effect of the Stage of Sexual Cycle, Harvesting Technique and Season on Follicular Dynamics and Oocyte Quality of Zebu Cattle under Sudano-Sahelian Climate

10.31038/ijvb.2017111 ◽

2017 ◽

Vol 1 (1) ◽

Keyword(s):

Oocyte Quality ◽

Sexual Cycle ◽

Zebu Cattle ◽

Harvesting Technique ◽

Follicular Dynamics

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Improving the Quality of Oocytes of Old and Productive Ages White Rats (Rattus norvegicus) Using Pregnant Mare Serum Gonadotrophin

Jurnal Riset Veteriner Indonesia (Journal of The Indonesian Veterinary Research) ◽

10.20956/jrvi.v3i1.5627 ◽

2019 ◽

Vol 3 (1) ◽

Author(s):

Sultania A Suleman ◽

Andriyanto Andriyanto ◽

Aulia Andi Mustika ◽

Wasmen Manalu

Keyword(s):

Rattus Norvegicus ◽

Oocyte Quality ◽

The Other ◽

Female Rats ◽

Age Group ◽

White Rats ◽

Maze Test ◽

Swimming Test ◽

Pregnant Mare Serum Gonadotrophin

Abstract This study was conducted to improve the quality of oocytes in old-female rats by using pregnant mare serum gonadotrophin (PMSG). Female rats at productive age were used as a control. The experimental rats were injected with 4 doses of PMSG i.e., 0, 2.5, 5.0, and 10 IU PMSG. After 2 weeks of acclimation to the experimantal condition, the experimental rats were injected with PGF2α at a dose of 25µg/g BW two times with 2 days interval to synchronize estrous cycle. PMSG injections were conducted at the same time with the second PGF2α injection. After PMSG injection, the experimental rats were divided into two groups rats, i.e., rats without mating for masurement of oocyte qualities and rats mated for measurement of offspring qualities. Therefore, 16 experimental rats from each age group were sacrifized for maeasurement of oocyte qualities. The other 16 experimental rats for each age group were mated for measurement of offspring qualities. Parameters measured were hematological profile, uterine and ovarian weights, the qualities of oocytes, the qualities of the offsspring born by using swimming test and rat maze test. The collected data were analyzed by analysis of variance (ANOVA) and continued with Duncan test with a 95% confidence level. The data were analyzed using SSPS. The results showed that the improvement in the quality of oocytes in old female rats using the PMSG hormone in this study showed an increase in the quality of oocytes in old and productive age rats. The highest number of oocyte quality was found in rats of productive age (3.25) and significantly different (P< 0.05) from the other oocyte qualities. The quality of offspring born to old age and productive age rats injected with PMSG were improved. It was concluded that the improvement of oocyte quality by using PMSG also improves offspring qualities.

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How to Achieve High-Quality Oocytes? The Key Role of Myo-Inositol and Melatonin

International Journal of Endocrinology ◽

10.1155/2016/4987436 ◽

2016 ◽

Vol 2016 ◽

pp. 1-9 ◽

Cited By ~ 36

Author(s):

Salvatore Giovanni Vitale ◽

Paola Rossetti ◽

Francesco Corrado ◽

Agnese Maria Chiara Rapisarda ◽

Sandro La Vignera ◽

...

Keyword(s):

Assisted Reproductive Technologies ◽

Reproductive Technologies ◽

Oocyte Quality ◽

Fertilization Rate ◽

In Vitro Models ◽

The One ◽

High Level

Assisted reproductive technologies (ART) have experienced growing interest from infertile patients seeking to become pregnant. The quality of oocytes plays a pivotal role in determining ART outcomes. Although many authors have studied how supplementation therapy may affect this important parameter for both in vivo and in vitro models, data are not yet robust enough to support firm conclusions. Regarding this last point, in this review our objective has been to evaluate the state of the art regarding supplementation with melatonin and myo-inositol in order to improve oocyte quality during ART. On the one hand, the antioxidant effect of melatonin is well known as being useful during ovulation and oocyte incubation, two occasions with a high level of oxidative stress. On the other hand, myo-inositol is important in cellular structure and in cellular signaling pathways. Our analysis suggests that the use of these two molecules may significantly improve the quality of oocytes and the quality of embryos: melatonin seems to raise the fertilization rate, and myo-inositol improves the pregnancy rate, although all published studies do not fully agree with these conclusions. However, previous studies have demonstrated that cotreatment improves these results compared with melatonin alone or myo-inositol alone. We recommend that further studies be performed in order to confirm these positive outcomes in routine ART treatment.

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CHTF18 ensures the quantity and quality of the ovarian reserve†

Biology of Reproduction ◽

10.1093/biolre/ioaa036 ◽

2020 ◽

Vol 103 (1) ◽

pp. 24-35

Author(s):

Rebecca A Holton ◽

Abigail M Harris ◽

Barenya Mukerji ◽

Tanu Singh ◽

Ferdusy Dia ◽

...

Keyword(s):

Ovarian Follicle ◽

Reproductive Potential ◽

Oocyte Quality ◽

Double Strand Breaks ◽

Dna Double Strand Breaks ◽

Strand Breaks ◽

Chromosome Transmission ◽

Underlying Mechanisms ◽

Factor C

Abstract The number and quality of oocytes, as well as the decline in both of these parameters with age, determines reproductive potential in women. However, the underlying mechanisms of this diminution are incompletely understood. Previously, we identified novel roles for CHTF18 (Chromosome Transmission Fidelity Factor 18), a component of the conserved Replication Factor C-like complex, in male fertility and gametogenesis. Currently, we reveal crucial roles for CHTF18 in female meiosis and oocyte development. Chtf18−/− female mice are subfertile and have fewer offspring beginning at 6 months of age. Consistent with age-dependent subfertility, Chtf18−/− ovaries contain fewer follicles at all stages of folliculogenesis than wild type ovaries, but the decreases are more significant at 3 and 6 months of age. By 6 months of age, both primordial and growing ovarian follicle pools are markedly reduced to near depletion. Chromosomal synapsis in Chtf18−/− oocytes is complete, but meiotic recombination is impaired resulting in persistent DNA double-strand breaks, fewer crossovers, and early homolog disjunction during meiosis I. Consistent with poor oocyte quality, the majority of Chtf18−/− oocytes fail to progress to metaphase II following meiotic resumption and a significant percentage of those that do progress are aneuploid. Collectively, our findings indicate critical functions for CHTF18 in ensuring both the quantity and quality of the mammalian oocyte pool.

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Vitamin C protects carboplatin-exposed oocytes from meiotic failure

MHR Basic science of reproductive medicine ◽

10.1093/molehr/gaz046 ◽

2019 ◽

Vol 25 (10) ◽

pp. 601-613 ◽

Cited By ~ 1

Author(s):

Changyin Zhou ◽

Xue Zhang ◽

Yuwei Zhang ◽

Xiayan ShiYang ◽

Yu Li ◽

...

Keyword(s):

Vitamin C ◽

Oocyte Quality ◽

Platinum Compound ◽

Cortical Granules ◽

Sperm Binding ◽

Abnormal Distribution ◽

Vitamin C Supplementation ◽

Underlying Mechanisms

Abstract CBP (carboplatin) is a second-generation chemotherapeutic drug of platinum compound commonly applied in the treatment of sarcomas and germ cell tumours. Although it is developed to replace cisplatin, which has been proven to have a variety of side effects during cancer treatment, CBP still exhibits a certain degree of toxicity including neurotoxicity, nephrotoxicity, hematotoxicity and myelosuppression. However, the underlying mechanisms regarding how CBP influences the female reproductive system especially oocyte quality have not yet been fully determined. Here, we report that CBP exposure led to the oocyte meiotic defects by impairing the dynamics of the meiotic apparatus, leading to a remarkably aberrant spindle organisation, actin polymerisation and mitochondrial integrity. Additionally, CBP exposure caused compromised sperm binding and fertilisation potential of oocytes by due to an abnormal distribution of cortical granules and its component ovastacin. More importantly, we demonstrated that vitamin C supplementation prevented meiotic failure induced by CBP exposure and inhibited the increase in ROS levels, DNA damage accumulation and apoptotic incidence. Taken together, our findings demonstrate the toxic effects of CBP exposure on oocyte development and provide a potential effective way to improve the quality of CBP-exposed oocytes in vitro.

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Roles of Resveratrol in Improving the Quality of Postovulatory Aging Oocytes In Vitro

Cells ◽

10.3390/cells8101132 ◽

2019 ◽

Vol 8 (10) ◽

pp. 1132 ◽

Cited By ~ 4

Author(s):

Yan-Li Sun ◽

Shou-Bin Tang ◽

Wei Shen ◽

Shen Yin ◽

Qing-Yuan Sun

Keyword(s):

Binding Sites ◽

Aging Process ◽

Oocyte Quality ◽

Reproductive Technology ◽

Early Embryo ◽

Normal Morphology ◽

Sperm Binding ◽

Postovulatory Aging

After ovulation, mammalian oocytes will undergo a time-dependent process of aging if they are not fertilized. This postovulatory aging (POA) seriously affects the oocyte quality and then impairs the subsequent fertilization and early embryo development, which should be avoided especially in assisted reproductive technology (ART). Resveratrol is an antioxidant substance that can scavenge free radicals and is effective in improving ovary functions. Here, mouse oocytes were used to investigate the effects and mechanisms of resveratrol on POA oocytes in vitro. With 1.0 µM resveratrol treatment during aging process, the rates of fertilization and blastocyst in POA oocytes increased significantly compared with those in the POA group. Resveratrol can reduce the loss of sperm binding sites by stabilizing Juno. Resveratrol can maintain the normal morphology of spindle and mitochondrion distribution and alleviate the levels of ROS and early apoptosis. Additionally, resveratrol can reduce the changes of H3K9me2. Therefore, resveratrol can significantly improve the quality of POA oocytes in vitro to enhance the rates of fertilization and blastocyst, which may be very helpful during the ART process.

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Optimising vitrification of human oocytes using multiple cryoprotectants and morphological and functional assessment

Reproduction Fertility and Development ◽

10.1071/rd12136 ◽

2013 ◽

Vol 25 (6) ◽

pp. 918 ◽

Cited By ~ 12

Author(s):

V. Y. K. Seet ◽

S. Al-Samerria ◽

J. Wong ◽

J. Stanger ◽

J. L. Yovich ◽

...

Keyword(s):

Oocyte Quality ◽

Human Oocyte ◽

Significant Implication ◽

Oocyte Vitrification ◽

Morphological Appearance ◽

Functional Quality ◽

Important Approach ◽

High Concentrations ◽

Freezing Injuries

Oocyte vitrification is a clinical practice that allows preservation of fertility potential in women. Vitrification involves quick cooling using high concentrations of cryoprotectants to minimise freezing injuries. However, high concentrations of cryoprotectants have detrimental effects on oocyte quality and eventually the offspring. In addition, current assessment of oocyte quality after vitrification is commonly based only on the morphological appearance of the oocyte, raising concerns regarding its efficiency. Using both morphological and functional assessments, the present study investigated whether combinations of cryoprotectants at lower individual concentrations result in better cryosurvival rates than single cryoprotectants at higher concentrations. Surplus oocytes from IVF patients were vitrified within 24 h after retrieval using the Cryotop method with several cryoprotectants, either individually or in combination. The morphological and functional quality of the vitrified oocytes was investigated using light microscopy and computer-based quantification of mitochondrial integrity, respectively. Oocyte quality was significantly higher using a combination of cryoprotectants than vitrification with individual cryoprotectants. In addition, the quality of vitrified oocyte varied depending on the cryoprotectants and type of combination used. The results of the present study indicate that observations based purely on the morphological appearance of the oocyte to assess the cryosurvival rate are insufficient and sometimes misleading. The outcome will have a significant implication in the area of human oocyte cryopreservation as an important approach for fertility preservation.

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