Oocytes in horses are the female gametes involved in reproduction, playing a fundamental role in equine fertility and breeding. These cells are essential for the development of embryos following fertilization and are a focus of study in reproductive biology and veterinary medicine. Research on equine oocytes includes their maturation, quality, and the factors influencing their developmental competence. Studies often explore techniques for in vitro maturation and fertilization, as well as the impact of various physiological and environmental factors on oocyte viability. This page compiles peer-reviewed research studies and scholarly articles that examine the characteristics, developmental processes, and technological advancements related to oocytes in horses.
Willis P, Caudle AB, Fayrer-Hosken RA.Objectives of the present research were to determine the influences of types of media, sera, time and hormones on equine oocyte in vitro maturation (IVM). The following types of media and sera were evaluated: Menezo's B2 medium (B2), modified Tissue Culture Medium 199 (TCM), Defined Medium (DM), fetal calf serum (FCS), mare serum collected on the first day of estrus (MS), and mare serum collected on the day of ovulation (MSO). Resultant oocyte maturation was compared with the control: DM with bovine serum albumin (BSA). Effect of culture time (0, 15, and 32 hr) and the following hormones on oo...
Liu DY, Lopata A, Pantke P, Baker HW.The present study demonstrates that horse and marmoset monkey sperm can bind to the human zona of salt-stored oocytes that failed to fertilize in vitro. Marmoset monkey sperm are also able to penetrate the salt-stored human zona. In contrast, human sperm do not bind to the zona of either horse or marmoset monkey oocytes. These results suggest that human sperm binding to the zona pellucida is more strictly species-specific than it is for horse and marmoset monkey sperm. In contrast, horse and marmoset monkey sperm contain receptors recognized by the human zona.
Weber JA, Freeman DA, Vanderwall DK, Woods GL.The hypothesis that treatment of pregnant mares with prostaglandin E2 (PGE2) hastens the oviductal transport of equine embryos was tested by treating bred mares with PGE2 on Day 3 after ovulation and subsequently measuring the rate of hastened oviductal transport (estimated by the uterine embryo recovery rate on Day 4 after ovulation). In a preliminary, noncontrolled experiment, oviductal transport was apparently not hastened after intramuscular, intrauterine, or intraperitoneal PGE2 administration to bred mares (0/6, 0/3, and 0/3 mares, respectively). Oviductal transport appeared to be hasten...
Yu FH, Yun YW, Yuen BH, Moon YS.Immature female rats treated with superovulatory doses of pregnant mare serum gonadotropin (PMSG) were used to study the effects of the antiandrogen hydroxyflutamide on steroid production, particularly the biologically active androgens, in two experiments. In the first experiment, animals were given either 5 mg hydroxyflutamide or vehicle alone at 30 and 36 h following 40 IU PMSG. Compared with the vehicle group, hydroxyflutamide treatment significantly reduced the percentage of degenerate oocytes recovered from oviducts (p less than 0.05). Serum levels of testosterone and androstenedione, and...
Hinrichs K, DiGiorgio LM.A technique was developed in which immature horse oocytes, obtained from slaughterhouse specimens, were transferred to the pre-ovulatory follicle of a mare in vivo, with resulting oocyte maturation, ovulation, fertilization and embryo development. Oocytes were collected from all follicles greater than 3 mm, and were classified as immature, maturing, expanded or denuded. The transfers were performed in the standing, tranquilized mare. The ovary containing the pre-ovulatory follicle was grasped per rectum. A trochar and cannula were placed through the abdominal wall in the flank area, ipsilatera...
Padilla AW, Tobback C, Foote RH.A method for preparing stored unfrozen stallion spermatozoa for the zona-free hamster oocyte penetration test (HOPT) and a subsequent comparison of fresh and stored sperm by the HOPT were evaluated. In Experiment 1, sperm from 4 stallion ejaculates, cooled to 4 degrees C and stored for 24 h, were treated with 60, 90 and 120 microM of dilauroylphosphatidyl-choline (PC12) liposomes to initiate the acrosome reaction. The percentage of motile and acrosome-reacted (AR) sperm were recorded after 8, 15 and 30 min of incubation at 39 degrees C, by automated image analysis. Liposome concentration did n...
Okolski A, Bézard J, Magistrini M, Palmer E.The ovaries of 23 mares were collected at slaughter during April-June and follicles (4-40 mm in diameter) were dissected and punctured to obtain oocytes for culture. The follicles were grouped according to histology: (a) normal, (b) showing primary and (c) secondary atresia. Antral fluid was analyzed for steroid content; oestradiol and testosterone (but not progesterone or androstenediol) were closely correlated with follicle size and histological state. Oocytes were cultured early after slaughter in Medium 199 (Difco OSI, France) or Medium B2, the highest percentage of oocytes reaching Metaph...
Palmer E, Bézard J, Magistrini M, Duchamp G.Since the first successful collection of oocytes by non-surgical puncture, there have been numerous attempts to fertilize them but few segmented embryos have resulted. The latest attempts at follicular puncture (Palmer et al., 1987) provided 159 oocytes. Oocytes found broken (18%) were probably already broken, or at least fragile, before puncture. The 41 oocytes were fertilized only with semen treated with Ionophore A23187. Following ionophore treatment of semen, 16 ova segmented (of 113 inseminated oocytes) indicating fertilization, and another 7 showed signs of fertilization but not segmenta...
Zhang JJ, Muzs LZ, Boyle MS.In vitro fertilizing ability of stallion spermatozoa was assessed using horse follicular oocytes matured in vitro. After collection, stallion spermatozoa were either: 1) washed and incubated in TALP medium with 3 mg/ml bovine serum albumin (BSA) and 10 micrograms/ml heparin for 4h, 2) washed and incubated in TALP with 3 mg/ml BSA for 3 h and cultured for a further 1 h with 1 mM caffeine and 5 mM dbcAMP, 3) washed and incubated in TALP medium with 3 mg/ml BSA at pH 7.9-8.2 for 2-4 h, or 4) diluted and incubated in TALP medium with 10 mg/ml BSA and 7.14 microM calcium ionophore A 23187 for 5-10 ...
Vogelsang MM, Vogelsang SG, Lindsey BR, Massey JM.Mares were subjected to frequent examination by diagnostic ultrasound and data were compiled with respect to reproductive efficiency. The data were collected over a 3-yr period on 1032 light horse mares. The cummulative pregnancy rate at 35 d post-ovulation was 96.8% and the pregnancy rate per cycle was 76.0% as determined by ultrasound examination. The average number of cycles per conception was 1.43, with an average of 2.29 inseminations per cycle. The incidence of early embryonic death was 7.8%. Mares were subjected to an average of 5.04 scans during the follicular phase of the cycle. The a...
Pace-Owens S.Gamete intrafallopian transfer (GIFT), developed in 1984, was the result of further studies on in vitro fertilization (IVF). Since that time many nurses have worked in settings near in vitro fertilization centers and, therefore, have a basic understanding of the technology. An overview is given of the GIFT procedure to prepare nurses to advise and refer couples who may qualify for GIFT and to highlight the shift in the fertility program nurse coordinator's functions toward the positions of administrator and consultant.
Schuetz AW, Whittingham DG, Legg RF.Granulosa cells at different stages of differentiation were collected from ovarian follicles and oviducts during the periovulatory period, and their nuclear DNA content was monitored by flow cytometry to establish their cell cycle characteristics (G0 + G1, S, G2 + M). The proportion of cells in the three phases of the cell cycle varied in characteristics patterns depending upon the time they were collected, before or following ovulation. Granulosa (cumulus) cells recovered from ovulated oocytes were mitotically inactive as shown by the large proportion of cells with a 2C amount of DNA and the ...
Vogelsang MM, Kreider JL, Bowen MJ, Potter GD, Forrest DW, Kraemer DC.A series of experiments was conducted to develop a procedure for consistent, repeatable collection of oocytes from the preovulatory follicle of the mare. In one experiment, in situ follicular aspiration with a needle and syringe was performed on 19 mares. From 37 aspirations, four oocytes were recovered (10% recovery rate). In a second experiment, ovaries were visualized via standing flank laparotomy during which two different aspiration techniques were used. Use of a needle and syringe as in the first experiment resulted in successful oocyte recovery in one of seven (14%) attempts. Aspiration...
King WA, Bezard J, Bousquet D, Palmer E, Betteridge KJ.Confusion exists as to whether the oocytes of the domestic horse are ovulated at the first meiotic metaphase (MI) or the second (MII). In this study eight oocytes were collected from the preovulatory follicles of 16 mares 36 h after human chorionic gonadotropin CG treatment. Six of the eight oocytes were judged to be at MII by the presence of the first polar body and this judgement was confirmed by semithin sectioning in one. Of the two that had no polar body, one was found to be at MII after fixation for chromosomal analysis and the meiotic stage of the other remained undetermined. Since all ...
Okólski A, Babusik P, Tischner M, Lietz W.Comparisons were made between 2 methods of oocyte recovery from the ovarian follicles of slaughtered mares: 500 oocytes (3 per mare) were obtained by aspiration of follicular fluid from ovaries of 162 mares, and 120 oocytes (8 per mare) by isolation and rupture of follicles from ovaries of 14 mares. In the oocytes recovered after rupture of follicles, 89.2% were morphologically unchanged, in comparison to 29.3% obtained by aspiration of follicular fluid. Stallion spermatozoa capacitated in vitro were tested on zona-free hamster oocytes. The stallion spermatozoa were washed in TCM-199 and prein...
Vogelsang MM, Kraemer DC, Potter GD, Stott GG.Oocytes recovered by follicular aspiration were evaluated by light and transmission electron microscopy. Of the 22 oocytes, 4 exhibited characteristics of degeneration, and the remaining 18 were in various stages of meiotic development. Of the non-degenerate oocytes, 14 were in the germinal vesicle stage, 2 had undergone nuclear membrane disintegration, 1 displayed chromosomes in late metaphase I-early anaphase I, and 1 oocyte was in the process of extrusion of the first polar body. Although some oocytes retained complete cumulus cell investments, oocytes were predominantly enclosed only by th...
Ware VC.In an attempt to understand more fully processes that control the selection or recruitment of follicles for ovulation, the superovulation paradigm in combination with the androgen, 5 alpha-dihydrotestosterone, or the antiandrogens, cyproterone or cyproterone acetate, was used in the immature mouse to alter the developmental potential of follicles destined to ovulate or to become atretic. Quantitative analysis of the numbers of eggs ovulated after one or more rounds of stimulation by pregnant mare's serum gonadotrophin followed by human chorionic gonadotrophin (PMSG-hCG), revealed a dose-depend...
Liu IK, Shivers CA.Cross-reactivity tests indicated that the equine zona pellucida shares common antigen(s) with porcine zona. Porcine oocytes were therefore used to test for the presence of zona antibodies in the sera of horses. Serum samples were collected from 65 mares infertile for unexplained causes: 7 mares were strongly positive for antibodies reactive to porcine zona pellucida as determined by an indirect immunofluorescence method. Of these 7 mares, aged 8-23 years, 2 were nulliparous and 5 were multiparous. Zona-covered horse oocytes were treated with sera from 4 mares previously identified as zona posi...
Shivers CA, Liu IK.Sera and follicular fluid from mares previously determined as having antibodies to the zona pellucida were exposed to porcine ovarian oocytes before insemination with boar spermatozoa in vitro. There was a dramatic decline in the number of spermatozoa bound to zonae compared to treatments with sera and follicular fluid from mares negative for zona antibodies. These data suggest that antibodies reactive with the zona pellucida may be responsible for reduced or even complete infertility in some mares. In a group of 50 randomly selected mares tested for antizona antibodies, 2 pregnant mares were ...
Fulka J, Okolski A.Oocytes were removed from follicles 5-30 mm in diameter. The germinal vesicle was present in 69.6% (23/33) of the oocytes at the start of culture, but after 20-24 and 40 h 70.5% (12/17) and 68.2% (43/63) of the oocytes were in metaphase I and metaphase II with first polar body extruded, respectively.
Mattison DR, White NB, Nightingale MR.The polycyclic aromatic hydrocarbon (PAH) benzo(a)pyrene (BP) reduced the fertility of DBA/2N mice in a dose-dependent fashion. Control mice produced offspring at a rate of 0.91 pups/mouse per week. Treatment with BP at doses of 10, 100, 200, and 500 mg/kg decreased offspring production rates to 0.61, 0.20, zero and zero pups/mouse per week, respectively. BP also destroyed primordial oocytes in similarly treated mice. Treatment with BP at doses of 10, 50, 100, and 500 mg/kg destroyed 20%, 58%, 88%, and 100%, respectively, of the primordial oocytes in DBA/2N mouse ovaries. Dose-response curves ...
Deanesly R.During the 340 day pregnancy of the horse, the germ cells in the fetal ovary showed a meiotic prophase which began in days 60-70 and might be prolonged after day 200. Three or four successive oogonial mitotic proliferations passed into the meiotic prophase but the great majority of the oocytes first involved degenerated, and no appreciable numbers of primordial follicles were left behind. At 150 days of pregnancy and again at 197 days, oocytes in early meiotic stages filled the ovarian cortex. Primordial follicles were present, but rare. As the prophase gradually came to an end, groups of oocy...
Hillensjö T, Bauminger S, Ahrén K.Preovulatory follicles were explanted on the day before ovulation from immature rats given a single injection of Pregnant Mare's Serum gonadotropin (PMS) 2 days earlier. The follicles were incubated for 4 h in modified Krebs bicarbonate buffer containing glucose and albumin in absence or presence of ovine luteinizing hormone (NIH-LH-S18; 0.1-10 mug/ml). The accumulation of progresterone, androstenedione and 17beta-estradiol in the medium was determined by radioimmunoassay. As in indicator of LH exposure the meiotic stage of the follicle-enclosed oocyte was determined at recovery by interferenc...
Betteridge KJ, Mitchell D.An efficient surgical technique of collecting eggs from the oviducts of mares is described. Within 6 days after ovulation recovery was successful in 22/29 mares. The technique has been used to investigate the retention and ageing of eggs in the oviducts and to determine the origin and the nature of the accessory CL during pregnancy.
Deanesly R.A histological study of the developing germinal epithelium in the fetal horse ovary shows an enormous wastage of oocytes during the meiotic phase, between Days 73 and 150 of pregnancy. The first groups of oocytes to enter this phage undergo mass degeneration and eventually disappear; few, if any, oocytes develop to primordial follicles. Peripheral oogonia, dividing by mitosis, give rise to more oocytes which pass through the same changes and are also reduced by degeneration, but by Day 150 primordial follicles are fairly common.
Short RV.The infertility of the mule has proved a continuing challenge to scientific thought. Since the chromosomal differences between the two parental species are so great as to render normal meiosis impossible, it is postulated that all mules and hinnies are sterile. The problem now is to explain how mules and hinnies can occasionally produce spermatozoa or ova. The appearance of the mule was sufficient to persuade the ancients that both parents, not just the male, must contribute to the make-up of the offspring. The mule has also taught us that, when the number of oocytes in the ovary is reduced, t...
Lorenzo PL, Liu IK, Illera JC, Picazo RA, Carneiro GF, Illera MJ, Conley AJ, Enders AC, Illera M.Epidermal growth factor (EGF) has been reported to promote different functions in mammalian ovaries, including oocyte maturation. The aim of the present study was to establish: that EGF influences oocyte maturation in ovine and equine, that a tyrosine kinase-dependent intracellular mechanism mediates EGF effect and, that EGF-R receptor is detectable in ovarian follicles by immunohistochemistry methods. Selected ovine and equine oocytes were aspirated from 2-5 mm (ovine) or 25 mm (equine) follicles and cultured in TCM 199 for 22 (ovine) or 36 hours (equine). They are then subjected to culture w...
Song X, Jiang H, Lv P, Cui K, Liu Q, Yin S, Liu H, Li Z.Oocyte in vitro maturation is necessary for the study and application of animal-assisted reproduction technology in animal reproduction and breeding. The comprehensive transcriptional profile of equine oocyte maturated in vitro has not been fully mined yet, which makes many key transcriptional events still unidentified. Here, Smart-seq2 was performed to analyse the gene expression pattern and the underlying regulatory mechanism of horse germinal vesicle (GV) and in vitro metaphase II (MII) oocytes. The results showed that 6402 genes (2640 up-regulated and 3762 down-regulated in MII samples com...
Dell'aquila ME, Fusco S, Lacalandra GM, Maritato F.The aim of this study was to develope an efficient and reproducible procedure for in vitro maturation (IVM) and fertilization (IVF) in the horse. Cumulus-oocyte complexes (COCs) recovered from the ovaries of mares slaughtered during the breeding season were morphologically evaluated, and those showing a compact cumulus and homogeneously appearing cytoplasm were selected for culture. Effects on the maturation of estrous mare serum (EMS) versus estrous cow serum (ECS) as medium supplement were also evaluated (Experiment 1). In Experiment 2, the fertilization of in vitro matured oocytes with froz...
Brück I, Bézard J, Baltsen M, Synnestvedt B, Couty I, Greve T, Duchamp G.In mares, the shortage of oocytes and the variability in nuclear maturation at a certain time of the oestrous cycle hinders the optimization of methods for in vitro maturation and in vitro fertilization. Increasing the number of small-to-medium-sized follicles available for aspiration in vivo may increase the overall oocyte yield. The aims of the present study were to investigate whether administration of crude equine gonadotrophins affects follicular development, oocyte recovery rate, in vivo oocyte maturation and follicular concentrations of meiosis-activating sterols. During oestrus, all fo...
Graham JK.For many years, scientists have sought to develop laboratory assays that accurately predict the fertilizing capacity of a semen sample. This goal, however, has proven elusive and will most likely be very difficult to achieve, due to the complex nature of the problem. Part of the problem results from the many attributes that a spermatozoon must possess to fertilize an egg, and how laboratory assays can evaluate all of these attributes simultaneously. The percentage of motile sperm in a sample is most commonly used to evaluate semen quality. This assay, however, is not highly correlated with the...
Rossini JB, Rodriguez J, Bresnahan DR, Stokes JE, Carnevale EM.The clinical use of intracytoplasmic sperm injection (ICSI) in horses usually involves the transfer of embryos into recipient mares, resulting in substantial cost increases. This is essential when subfertile mares are oocyte donors; but some donors are fertile, with ICSI compensating for limited or poor-quality spermatozoa. Fertile oocyte donors could carry pregnancies, eliminating the need for a recipient. We assessed the potential of using oocyte donors as recipients for their own ICSI-produced embryos during the same cycle. Donors in oestrus and with large dominant follicles were administer...
Merlo B, Iacono E, Bucci D, Spinaci M, Galeati G, Mari G.In vitro embryo production in the horse is still not as efficient as in other species. Oxidative stress negatively affects oocyte and embryo culture. To attenuate/minimize the oxidative stress, antioxidants such as low-molecular thiol compounds can be added to culture media. Beta-mercaptoethanol (BME) has been shown to improve maturation and embryo development in different species. The aim of this study was to investigate whether the addition to maturation medium of BME at common (0.1 mM) and high (0.7 mM) concentration could improve oocyte maturation also in the horse. Equine oocytes recove...
Leal GR, Monteiro CAS, Carvalheira LR, Souza-Fabjan JMG.Simulated Physiological Oocyte Maturation (SPOM) mimics in vitro the physiological events of oocyte maturation. The system uses cAMP modulators in two steps (pre IVM and IVM) and has presented promising results that are arousing the curiosity of IVF programs in different animal species, generating several papers, adaptations, and controversies worldwide. This study systematically analyses the data in the literature on the use of SPOM and compares the outcomes to the original paper (Albuz et al. Hum. Rep., 25: 2999-3011 2010), classifying them into success or failure. The PubMed, Scopus, and ...
Carnevale EM.Assisted reproductive techniques that are based on oocyte manipulations have gained acceptance in the equine industry. Methods to collect and handle immature or maturing oocytes have been developed, and systems to ship oocytes now allow for collection in one location and intracytoplasmic sperm injection (ICSI) in another. Subsequently, ICSI-produced embryos can be transferred onsite, shipped to another location, or cryopreserved. Methods for the collection, identification, culture, maturation, and shipment of equine oocytes are reviewed, with an emphasis on procedures from laboratories providi...
Conforti VA, Vanderwall DK, Woods GL.The in vitro maturation (IVM) of equine oocytes is typically performed using various synthetic media; however, an optimal IVM system for equine oocytes has not been developed. The aim of the present study was to evaluate the effects of two types of follicular fluid (FF) obtained from cyclic mares and two incubation intervals for the IVM of equine cumulus-oocyte complexes (COCs). Follicular fluid was collected from medium-sized (20-29 mm diameter) and large (e30 mm; post-human chorionic gonadotrophin administration) follicles using transvaginal ultrasound-guided follicle aspiration. Compact (n ...
Shivers CA, Liu IK.Sera and follicular fluid from mares previously determined as having antibodies to the zona pellucida were exposed to porcine ovarian oocytes before insemination with boar spermatozoa in vitro. There was a dramatic decline in the number of spermatozoa bound to zonae compared to treatments with sera and follicular fluid from mares negative for zona antibodies. These data suggest that antibodies reactive with the zona pellucida may be responsible for reduced or even complete infertility in some mares. In a group of 50 randomly selected mares tested for antizona antibodies, 2 pregnant mares were ...
Schuetz AW, Whittingham DG, Legg RF.Granulosa cells at different stages of differentiation were collected from ovarian follicles and oviducts during the periovulatory period, and their nuclear DNA content was monitored by flow cytometry to establish their cell cycle characteristics (G0 + G1, S, G2 + M). The proportion of cells in the three phases of the cell cycle varied in characteristics patterns depending upon the time they were collected, before or following ovulation. Granulosa (cumulus) cells recovered from ovulated oocytes were mitotically inactive as shown by the large proportion of cells with a 2C amount of DNA and the ...
Martino NA, Marzano G, Mastrorocco A, Lacalandra GM, Vincenti L, Hinrichs K, Dell Aquila ME.Time-lapse imaging was used to establish the morphokinetics of equine embryo development to the blastocyst stage after invitro oocyte maturation (IVM), intracytoplasmic sperm injection (ICSI) and embryo culture, in oocytes held overnight at room temperature (22-27°C; standard conditions) before IVM. Embryos that developed to the blastocyst stage underwent precleavage cytoplasmic extrusion and cleavage to the 2-, 3- and 4-cell stages significantly earlier than did embryos that arrested in development. We then determined the rate of blastocyst formation after ICSI in oocytes held for 2 days at ...
Cremonesi F, Anderson K, Lange-Consiglio A.TWO METHODS HAVE BEEN DESCRIBED TO RECOVER OOCYTES FROM EQUINE FOLLICLES IN EXCISED OVARIES: aspiration and scraping. Aim of this work was to develop an effective method for collecting equine oocytes using Tuohy needle and comparing this technique to aspiration and scraping, with or without tunica albuginea removal. This hollow hypodermic needle, usually employed for inserting epidural catheters, is designed with a slightly curved tip, shaped similar to a small curette. In unpeeled ovaries, the recovery rates of Tuohy needle group was higher (P < .05) than in the 16 g needle aspiration and ...
Bresnahan DR, Lupole RE, Stilz CR, Carnevale EM.Zona pellucida (ZP) proteins are important for fertilization and sperm binding and are closely associated with cumulus cells. Communication between cumulus and oocytes is facilitated by intracellular membrane channels composed of connexins. The extent aging impacts potential differences in fertilization and reductions in fertility is not well understood. This study characterized age-related differences in transcript abundance of ZP proteins and connexins in cells from ovarian follicles. Additionally, differences in sperm binding to oocytes from old and young mares was evaluated. For experiment...
Seidel GE.Principles for selecting future research projects include interests of investigators, fundability, potential applications, ethical considerations, being able to formulate testable hypotheses and choosing the best models, including selection of the most appropriate species. The following 10 areas of assisted reproduction seem especially appropriate for further research: efficacious capacitation of bovine spermatozoa in vitro; improved in vitro bovine oocyte maturation; decreasing variability and increasing efficacy of bovine superovulation; improved fertility of sexed semen; improving equine IV...
Azuma T, Choi YH, Hochi S, Oguri N.The development of in-vitro matured and microfertilized horse oocytes was examined in vitro. Fertilized oocytes were produced by 20-h insemination of in-vitro matured and partially zona-removed oocytes with frozen spermatozoa that had been treated with caffeine/calcium ionophore A23187 (fertilization rate 34.2%, monospermy rate 76.9%). Embryonic development was assessed by the number of nuclei stained with Giemsa solution. In Experiment 1, a continuous 8-day culture of the microfertilized oocytes in TCM199 or modified synthetic oviduct fluid (m-SOF) supplemented with 10% fetal bovine serum or ...
Maclellan LJ, Albertini DF, Stokes JE, Carnevale EM.The impact of vitrification on oocyte developmental competence as a function of donor age remains an important issue in assisted reproductive technologies (ARTs). Methods: Equine germinal vesicle (GV) or metaphase II (M(II) oocytes were vitrified using the Cryotop® method. Spindle organization and chromosome alignment were evaluated from confocal imaging data sets of in vivo (IVO) or in vitro (IVM) matured oocytes subjected to vitrification or not. Intracytoplasmic sperm injection (ICSI) from the same groups was used to assess developmental potential. Results: An increase in chromosome misali...
Kunanusont N, Taesuji M, Kulthonggate U, Rattanamas K, Mamom T, Thongsri K, Phannithi T, Ruenphet S.African horse sickness (AHS) has become a newly emerging disease after an outbreak in northeastern Thailand in March 2020. Mass vaccination in horses with live-attenuated AHS virus (AHSV) vaccine is essential for AHS control and prevention. This study aimed to monitor the longitudinal humoral immune response before and after a single vaccination using a live-attenuated vaccine against AHS in stallions, mares, and pregnant mares, including maternal immunity in foals born from pregnant mares during the outbreak in Thailand. Unassigned: A total of 13 stallions and 23 non-pregnant and 21 pregnant ...
Hedia M, Angel-Velez D, Papas M, Peere S, Gerits I, De Coster T, Van den Branden E, Govaere J, Van Soom A, Leroy JLMR, Smits K.The in vitro production of equine embryos via ovum pick-up (OPU) and intracytoplasmic sperm injection (ICSI) has increased rapidly. There is a marked effect of the individual mare on the outcome of OPU-ICSI, but little is known about the influence of the mare's health condition. This study aimed to investigate the potential associations between the concentrations of interleukin-6 (IL-6), reactive oxygen metabolites (d-ROMs), and biological antioxidant potential (BAP) in serum of oocytes' donor mares and the subsequent embryonic development. Just before OPU, a blood sample was collected from 28...
Borges MA, Curcio BR, Gastal GDA, Gheno L, Junior ASV, Corcini CD, Nogueira CEW, Aguiar FLN, Gastal EL.The most adequate fixative solution for equine ovarian tissue is still to be determined as a tool to evaluate the improvement of methodological studies in assisted reproductive techniques and fertility preservation. This study aimed to evaluate a short-time ethanol 70% (ST-EtOH, 45 min) exposure as an alternative fixative compared with two classically fixatives [Carnoy's (CAR) solution and paraformaldehyde 4% (PFA)] at different fixation times (6 h, 12 h). The end points evaluated were morphology and classes of preantral follicles, follicular and stromal cell densities, and follicular and o...
Gonzalez-Castro RA, Carnevale EM.Phospholipase C Zeta 1 (PLCZ1) is considered a major sperm-borne oocyte activation factor. After gamete fusion, PLCZ1 triggers calcium oscillations in the oocyte, resulting in oocyte activation. In assisted fertilization, oocyte activation failure is a major cause of low fertility. Most cases of oocyte activation failures in humans related to male infertility are associated with gene mutations and/or altered PLCZ1. Consequently, PLCZ1 evaluation could be an effective diagnostic marker and predictor of sperm fertilizing potential for in vivo and in vitro embryo production. The characterization ...
Shen Y, Ulaangerel T, Ren H, Liu Q, Davshilt T, Yi M, Dugarjaviin M, Bou G.The reproductive cycle of equines tends to be seasonal and is influenced by factors such as light and temperature. The process and methods of regulating the mare oestrous cycle in the anestrus period are still immature. The effects of noncoding RNAs and mRNAs on the oestrous cycle have aroused much interest, but corresponding analyses of seasonal mare ovaries have not been reported. Here, we report a whole transcriptome analysis of the Mongolian horse ovarian cortex collected in anestrus and diestrus periods. In total, 1081 mRNAs, 205 lncRNAs, 54 circRNAs, and 13 miRNAs were upregulated in win...
Pollard CL.Years of sire and dam selection based on their pedigree and athletic performance has resulted in a reduction in the reproductive capability of horses. Mare age is considered a major barrier to equine reproduction largely due to an increase in the age at which mares are typically bred following the end of their racing career. Nicotinamide adenine dinucleotide (NAD) and its involvement in the activation of Sirtuins in fertility are an emerging field of study, with the role of NAD in oocyte maturation and embryo development becoming increasingly apparent. While assisted reproductive technologies ...
Leal Reis I, Lopes B, Sousa P, Sousa AC, Branquinho MV, Caseiro AR, Rêma A, Briote I, Mendonça CM, Santos JM, Atayde LM, Alvites RD, Maurício AC.Horses are high-performance athletes prone to sportive injuries such as tendonitis and desmitis. The formation of fibrous tissue in tendon repair remains a challenge to overcome. This impels regenerative medicine to develop innovative therapies that enhance regeneration, retrieving original tissue properties. Multipotent Mesenchymal Stem/Stromal Cells (MSCs) have been successfully used to develop therapeutic products, as they secrete a variety of bioactive molecules that play a pivotal role in tissue regeneration. These factors are released in culture media for producing a conditioned medium (...
Gabryś J, Gurgul A, Szmatoła T, Kij-Mitka B, Andronowska A, Karnas E, Kucharski M, Wojciechowska-Puchałka J, Kochan J, Bugno-Poniewierska M.Cumulus cell (CC) expansion is pivotal for oocyte maturation, during which CCs release factors that initiate paracrine signaling within the follicular fluid (FF). The FF is abundant in extracellular vesicles (EVs) that facilitate intercellular communication. Although bovine and murine EVs can control cumulus expansion, these effects have not been observed in equines. This study aimed to assess the impact of FF-derived EVs (ffEVs) on equine CC expansion, viability, and transcriptome. Cumulus-oocyte complexes (COCs) that underwent in vitro maturation (IVM) in the presence (200 µg protein/mL) or...
Catandi GD, Fresa KJ, Cheng MH, Whitcomb LA, Broeckling CD, Chen TW, Chicco AJ, Carnevale EM.Obesity is a growing concern in human and equine populations, predisposing to metabolic pathologies and reproductive disturbances. Cellular lipid accumulation and mitochondrial dysfunction play an important role in the pathologic consequences of obesity, which may be mitigated by dietary interventions targeting these processes. We hypothesized that obesity in the mare promotes follicular lipid accumulation and altered mitochondrial function of oocytes and granulosa cells, potentially contributing to impaired fertility in this population. We also predicted that these effects could be mitigated ...
Fonte JS, Alonso MA, Junior MPM, Gonçalves MA, Pontes JH, Bordignon V, Fleury PDC, Fernandes CB.This retrospective study aimed at identifying factors that contribute to the success of equine in vitro embryo production by intracytoplasmic sperm injection (ICSI). A total of 7993 ovum pick-up (OPU) sessions were performed, totaling 2540 donor mares and semen from 396 stallions. Oocytes were aspirated at multiple sites in Brazil and were sent to the laboratory, within 6 h from OPU, in pre-maturation medium where they were in vitro matured (IVM) followed by ICSI and in vitro embryo culture for 7-8 days. The number of recovered oocytes, matured oocytes, cleaved embryos and blastocysts were us...
Alkhadrawy JMH, Aboelmaaty AM, Abou-Ahmed MM, Ghallab AM.Mares are the only companion animals simulating women in the large diameter of their follicles. Horses start reproduction at the age of three years, and some of them live for >30 years, so aging influences their reproductive capacity. Mares are sensitive to summer heat stress as they can sweat like humans. Unassigned: The current work aimed to study the effects of age (young versus senile), season (cold versus hot), and the hormonal treatments during embryo collection on the dominant and subordinate follicular dynamics and hemodynamics and circulating ovarian hormones in embryo donor mares ...
