In vivo effect of interleukin-1beta and interleukin-1RA on oocyte cytoplasmic maturation, ovulation, and early embryonic development in the mare

A growing body of evidence suggests that the interleukin-1 system is involved in periovulatory events. Previous work from our lab demonstrated that in the mare, interleukin-1beta (IL-1beta) increases the ovulatory rate of metaphase II oocytes. The present study was conducted to analyze in vivo the effect of IL-1 on oocyte cytoplasmic maturation, ovulation and pregnancy rate. In the present work, IL-1beta (experiment 1, n = 13; experiment 2, n = 25) and interleukin-1RA (IL-1RA; experiment 1, n = 25) were injected intrafollicularly by using the transvaginal ultrasound-guided injection method. Injections were performed on cyclic mares when the diameter of the growing dominant follicle reached 30–34 mm. In experiment 1, mares were inseminated the day of the treatment and all the other day until ovulation. The time of ovulation was determined and a pregnancy diagnosis was performed 14 days after ovulation of the injected follicle. In experiment 2, the cumulus-oocyte complex from each injected follicle was collected by transvaginal ultrasound-guided aspiration 38 h after the intrafollicular injection. Oocyte nuclear stage and oocyte cytoplasmic maturation were assessed by analyzing chromatin configuration, cortical granules migration and mitochondria distribution under a confocal microscope. The results from experiment 1 confirm that an intrafollicular injection of 1 microgram IL-1beta induces ovulation in the mare whereas IL-1RA has no effect at the dose used in the present study. Furthemore, we demonstrated, that in our experimental conditions, IL-1beta and IL-1RA induced a decrease in embryo development. Experiment 2 leads us to observe that IL-1beta is unable to induce cortical granules migration and remodelling of mitochondria, that commonly occurs during oocyte maturation, whereas it acts on nuclear maturation. This result may explain the decrease in embryo development we observed after IL-1beta intrafollicular injection. In conclusion, the present study tends to demonstrate that IL-1beta plays a role in the ovulatory process and may acts on oocyte maturation in the mare, but additional factors are required to complete equine oocyte cytoplasmic maturation to allow embryo development

The secretions of oviduct epithelial cells increase the equine in vitro fertilization rate: are osteopontin, atrial natriuretic peptide A and oviductin involved?

ABSTRACT: BACKGROUND: Oviduct epithelial cells (OEC) co-culture promotes in vitro fertilization (IVF) in human, bovine and porcine species, but no data are available from equine species. Yet, despite numerous attempts, equine IVF rates remain low. Our first aim was to verify a beneficial effect of the OEC on equine IVF. In mammals, oviductal proteins have been shown to interact with gametes and play a role in fertilization. Thus, our second aim was to identify the proteins involved in fertilization in the horse. Methods & results In the first experiment, we co-incubated fresh equine spermatozoa treated with calcium ionophore and in vitro matured equine oocytes with or without porcine OEC. We showed that the presence of OEC increases the IVF rates. In the subsequent experiments, we co-incubated equine gametes with OEC and we showed that the IVF rates were not significantly different between 1) gametes co-incubated with equine vs porcine OEC, 2) intact cumulus-oocyte complexes vs denuded oocytes, 3) OEC previously stimulated with human Chorionic Gonadotropin, Luteinizing Hormone and/or oestradiol vs non stimulated OEC, 4) in vivo vs in vitro matured oocytes. In order to identify the proteins responsible for the positive effect of OEC, we first searched for the presence of the genes encoding oviductin, osteopontin and atrial natriuretic peptide A (ANP A) in the equine genome. We showed that the genes coding for osteopontin and ANP A are present. But the one for oviductin either has become a pseudogene during evolution of horse genome or has been not well annotated in horse genome sequence. We then showed that osteopontin and ANP A proteins are present in the equine oviduct using a surface plasmon resonance biosensor, and we analyzed their expression during oestrus cycle by Western blot. Finally, we co-incubated equine gametes with or without purified osteopontin or synthesized ANP A. No significant effect of osteopontin or ANP A was observed, though osteopontin slightly increased the IVF rates. CONCLUSION: Our study shows a beneficial effect of homologous and heterologous oviduct cells on equine IVF rates, though the rates remain low. Furthers studies are necessary to identify the proteins involved. We showed that the surface plasmon resonance technique is efficient and powerful to analyze molecular interactions during fertilization

Ultrabrza vitrifikacija u otvorenoj rastegnutoj slamci otvara nove mogućnosti za smrzavanje konjskih zametaka.

The aim of this research was to evaluate ultra rapid OPS vitrification on the embryo viability. The OPS vitrification technique is comprised of ultra rapid freezing of a small drop in which the embryo is placed. Before the thin straw was plunged into the liquid nitrogen, the embryos were treated with highly concentrated cryoprotectant (CPA) solutions as follows: 18% ethylene glycol (EG), 18% dimethyl-sulfoxide (DMSO) and 0.4 M sucrose. Surgical transfer into the recipient mares and morphologic examination of recollected embryos were used to measure the viability of transferred embryos. The research was performed on Welsh pony mares by collecting the embryos 6.75 days after ovulation. Twenty embryos were vitrified and transferred, four in each recipient mare. At day twelve, nine embryos were recollected after fl ushing of the recipient uterus (56%, 9/ 16). In one recipient mare, endometritis was detected when the uterus was fl ushed. Among the sixteen recollected embryos, seven (44%) had normal morphology and well developed embryonic vesicles. The vitrification procedure used proved to be encouraging.Svrha istraživanju bila je ustanoviti učinkovitost ultrabrze vitrifikacije u otvorenoj rastegnutoj slamci na vitalnost konjskih zametaka, prijenosom vitrificiranih pa otopljenih zametaka u sinkronizirane primateljice. Istraživanje je provedeno na stadu Welsh poni kobila. Davateljicama zametaka maternice su transcervikalno bile ispirane 6,75 dana nakon ovulacije, a zametci su nakon vitrifikacije bili pohranjeni u spremnik s tekućim dušikom. Nakon odmrzavanja, zametci su bili prenijeti u sinkronizirane primateljice. Maternice primateljica bile su ispirane petoga dana nakon prijenosa odmrznutih zametaka. Ukupno je bilo preneseno dvadeset zametaka, a ispiranjem maternica primateljica dobiveno je devet zametaka što iznosi 56% s obzirom da je u jedne primateljice ispiranjem ustanovljen endometritis. Od zametaka dobivenih ispiranjem primateljica, sedam (44%) je imalo morfološki normalno razvijene zametne mjehure. Na osnovi provedenih istraživanja zaključeno je da su rezultati ostvareni vitrifikacijom u otvorenoj rastegnutoj slamci ohrabrujući, ali bi ih s obzirom na mali broj prenijetih zametaka trebalo potvrditi na većem uzorku, posebice sa zametcima odabranoga promjera te brojem ždrebadi

Changes in histone H4 acetylation during in vivo versus in vitro maturation of equine oocytes

abstract: Epigenetic modifications are established during gametogenesis and preimplantation embryonic development. Any disturbance of the normal natural environment during these critical phases could cause alterations of the epigenetic signature. Histone acetylation is an important epigenetic modification involved in the regulation of chromatin organization and gene expression. The present study was aimed to determine whether the proper establishment of post-translational histone H4 acetylation at lysine 8 (AcH4K8), 12 (AcH4K12) and 16 (AcH4K16) of equine oocytes is adversely affected during in vitro maturation (IVM) when compared with in vivo matured oocytes collected from naturally cycling mares not undergoing ovarian hyperstimulation. The acetylation patterns were investigated by means of indirect immunofluorescence staining with specific antibodies directed against the acetylated lysine residues. Our results indicate that the acetylation state of H4 is dependent on the chromatin configuration in immature germinal vesicle (GV) stage oocytes and it changes in a residue-specific manner along with the increase of chromatin condensation. In particular, the levels of AcH4K8 and AcH4K12 increased significantly, while AcH4K16 decreased significantly from the fibrillar to the condensed state of chromatin configuration within the GV. Moreover, during meiosis, K8 and K12 were substantially deacetylated without any differences between in vivo and in vitro conditions, while K16 displayed a strong acetylation in oocytes matured in vivo, and in contrast, it was markedly deacetylated following IVM. Although the functional meaning of residue-specific acetylation during oocyte differentiation and meiotic resumption needs further investigation, our results support the hypothesis that IVM conditions can adversely affect oocyte ability to regulate the epigenetic reprogramming, critical for successful meiosis and subsequent embryonic development

Conceptual Art

Providing a re-examination of what Osborne identifies as a major turning point in contemporary art, this monograph takes a chronological and stylistic look at conceptual art from its “pre-history” (1950-1960) to contemporary practices that use conceptual strategies. Osborne surveys the development of the movement in relation to the social, cultural and political contexts within which it evolved. With extended captions, key works are compiled according to ten themes that also serve to present a collection of critical texts, artists’ statements, interviews and commentaries. Includes biographical notes on artists (6 p.) and authors (2 p.), a bibliography (2 p.) and an onomastic index (4 p.) Circa 150 bibl. ref

Combined effect of sulpiride and light treatment on the onset of cyclicity in anestrous mares

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A single subcutaneous administration of buserelin induces ovulation in the mare: field data

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Le transfert d'embryons chez les équidés

National audienceCet article fait partie du dossier : Actualités en reproduction équin

Procréation assistée chez les mammifères domestiques et l'Homme

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