C Wrenzycki

Justus-Liebig-Universität Gießen, Gieben, Hesse, Germany

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Publications (115)254.75 Total impact

  • [Show abstract] [Hide abstract]
    ABSTRACT: There are still major differences between IVP-derived and in vivo derived bovine blastocysts. Therefore, intra-follicular oocyte transfer (IFOT) was emerged in the present study to allow early embryonic development within the physiological oviductal environment subsequently to avoid harmful effects of the in vitro culture environment. Using modified Ovum-Pick-Up (OPU) equipment, in vitro matured oocytes were transferred into the pre-ovulatory follicle of synchronized heifers (follicular recipients) enabling subsequent ovulation, in vivo fertilization as well as in vivo development. When 1646 in vitro matured oocytes were transferred to 28 follicular recipients, a total of 583 embryos (35.2%) were recovered in excess after uterine flushing at Day 7. While numbers of generated extra embryos were highly variable, preovulatory follicles with a diameter of 13-14 mm delivered significantly (P < 0.05) higher amounts of extra embryos (34.3 vs. 7.3) as well as extra morula and blastocysts (8.3 vs. 0.8) compared to follicles with a diameter of 9-10 mm. Nevertheless, developmental rate to the blastocyst stage was lower in IFOT compared to in vitro-derived control (VITRO) embryos at Day 7 (8.0 vs. 36.5%). Likewise, cumulative developmental rates to the morula or blastocyst stage until Day 7 were lower in IFOT-derived embryos when related to the number of transferred (8.4 vs. 51.7%) or flushed embryos (22.8 vs. 51.7%). Of the latter, IFOT-derived embryos yielded significantly lower cleavage rates compared to the VITRO control (63.2 vs. 88.8%) and developmental rate to the morula or blastocyst stage where lower even when related to the proportion of cleaved embryos (36.8 vs. 58.2%). In contrast, lipid content and cryotolerance did not differ between IFOT and fully in vivo-produced embryos whereas IFOT-derived embryos showed significantly lower lipid content (P < 0.05) and significantly higher cryotolerance compared to IVP-derived embryos cultured in CR1aa medium supplemented with estrus cow serum (ECS) but not when cultured in SOFaa medium supplemented with fatty acid free BSA (BSA-FFA). Finally, transfer of 19 frozen-thawed IFOT-derived blastocysts to synchronized recipients (uterine recipients) resulted in pregnancy rates comparable to those obtained after transfer of fully in vivo-derived embryos or IVP derived embryos cultured in SOFaa+BSA-FFA whereas pregnancy rate following transfer of IVP-derived blastocysts was significantly lower when cultured in CR1aa+ECS (42.1 vs. 13.8%). All in all, 7 pregnancies presumed to be IFOT-derived went to term and microsatellite analysis confirmed that 5 calves were indeed derived from IFOT. To our knowledge, these are the first calves born after IFOT in cattle. Interestingly, the average birth weight of FOT derived calves was lower than that of IVP-derived calves even when embryos were cultured in SOFaa+BSA-FFA indicating that the environment during early embryo development might cause fetal overgrowth. Taken altogether, for the first time we were able to show that IFOT is a feasible technique to generate bovine blastocysts by transferring in vitro matured oocytes derived from slaughterhouse ovaries. These IFOT derived blastocysts closely resemble in vivo derived blastocysts in terms of lipid content and freeze-survival. Thus the present study prepared the floor for newly-created scientific experiments enabling novel analytical possibilities. Nevertheless, IFOT derived embryos still reached lower pregnancy rates by trend compared to in vivo derived embryos implicating also an important role of the maturational environment for further developmental characteristics. Copyright 2015 by The Society for the Study of Reproduction.
    Biology of Reproduction 04/2015; 92(6). DOI:10.1095/biolreprod.114.124883 · 3.45 Impact Factor
  • C Wrenzycki · H Stinshoff
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    ABSTRACT: Reproductive biotechnology has manifold applications and includes a great innovation potential in livestock. Due to the global changes the new findings and techniques can aid to meet the future challenges. The use of biotechnology in animal production can guarantee enough high quality food for the whole population. Genetic resources of animals can be preserved via sperm and embryo banking. Early diagnosis of hereditary defects, generation of offspring with predetermined sex and the avoidance of animal transports for breeding employing shipment of frozen embryos will improve animal welfare. A special application is the use of animal models for human assisted reproductive technologies. Therefore, not only in Germany research related to the methodologies in reproductive biotechnology and their improvement need to be supported.
    Tierärztliche Praxis. Ausgabe G, Grosstiere/Nutztiere 03/2015; 43(2). DOI:10.15653/TPG-140671 · 0.47 Impact Factor
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    ABSTRACT: The objective of this study was to investigate the effect of time of first postpartum ovulation on endometrial inflammation in dairy cows with and without uterine disease during the early puerperal period. Transvaginal follicular puncture (FP) was carried out to suppress postpartum ovulation and formation of a CL until Day 42. Fifty-three lactating Holstein Friesian cows were divided into four groups on the basis of presence (UD+) or absence (UD-) of uterine disease, which was defined as retained fetal membranes and/or metritis, and whether FP had (FP+) or had not been (FP-) carried out. This resulted in the following groups: UD-FP- (n = 15), UD-FP+ (n = 13), UD+FP- (n = 13), and UD+FP+ (n = 12). Cloprostenol was given on Days 55 to 60 postpartum, and GnRH was administered 2 days later for synchronization of ovulation. In the FP- groups, endometrial swab and biopsy samples were collected during the second estrus (approximately Day 40) and during the estrus after synchronization. In the FP+ groups, the same samples were collected during the first estrus (approximately Day 49) and during the estrus after synchronization. The prevalence of positive bacteriologic cultures of the endometrium was not affected by FP (P > 0.05). Histologic signs of endometritis were more severe in UD+FP- cows at second sampling than in UD+FP+ cows (P ≤ 0.05). Endometrial expression of IL1α (in UD- after first sampling and in UD+ after second sampling) and IL1β (in UD- and UD+ after first sampling) was higher (P ≤ 0.05) in FP- cows than in FP+ cows. Regardless of group, cows with histopathologic evidence of endometritis had higher expression (P ≤ 0.05) of IL1α, IL1β, IL6, and TNFα than cows without endometritis. In conclusion, suppression of early ovulation by transvaginal FP enhances clearance of uterine inflammation in postpartum cows. Copyright © 2015 Elsevier Inc. All rights reserved.
    Theriogenology 03/2015; 84(1). DOI:10.1016/j.theriogenology.2015.03.003 · 1.85 Impact Factor
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    ABSTRACT: Pituitary growth hormone (GH) release and hepatic insulin-like growth factor-I (IGF-I) production increase after an injection of 17β-estradiol (E2) in ovariectomized dairy cattle. However, whether endogenous sexual steroid hormones also influence the hepatic GH receptor (GHR) signaling pathway during a physiological estrus cycle remains unclear. The aim of this study was to analyze the hepatic GHR signaling pathway during the luteal phase and after a period of increased E2 concentrations (after ovulation) as well as in 7 heifers before ovulation. Ovarian ultrasounds were performed daily during repeated physiological cycles (n = 56) of 30 Holstein Friesian heifers to determine ovulation [before ovulation (n = 7, bOv) and after ovulation 24-60 h after the appearance of estrus signs (n = 49, aOv)] and luteal phase (CLP; d 12 ± 1 after ovulation). Blood samples and liver biopsies were obtained, and blood concentrations of E2, P4, insulin-like growth factor (IGF)-I, IGF-II, and GH were measured. In the liver biopsies, we determined mRNA expression of the estrogen receptor α (ERα), GHR, Janus kinase 2 (JAK2), signal transducer and activator of transcription 5B (STAT5B), suppressor of cytokine signaling (SOCS)2 and 3, IGF-I, and IGF-II by quantitative reverse transcription-PCR. The concentration of E2 was higher bOv than aOv and CLP, as expected. The concentrations of IGF-I and GH were higher bOv and aOv compared with CLP. In contrast, concentrations of IGF-II were lower aOv compared with bOv and CLP. The mRNA expression of GHR was higher in liver biopsies obtained bOv compared with aOv and CLP. Notably, the expression of SOCS2 was higher bOv than aOv and in the CLP. Increased hepatic expression of SOCS2 during estrus was detectable concurrently IGF-I concentrations were high; this result might indicate that SOCS2 expression attenuates the GHR signal transduction pathway during the phase of increased pituitary GH release. In conclusion, hepatic GHR and SOCS2 mRNA expression appeared to be promptly and sensitively regulated by increased E2 levels before ovulation of dairy heifers. Copyright © 2015 American Dairy Science Association. Published by Elsevier Inc. All rights reserved.
    Journal of Dairy Science 02/2015; 98(4). DOI:10.3168/jds.2014-8734 · 2.55 Impact Factor
  • 48th Annual Conference on Physiology and Pathology of Reproduction /; 02/2015
  • C. Blaschka · H. Stinshoff · F. Poppicht · C. Wrenzycki
    48th Annual Conference on Physiology and Pathology of Reproduction /; 02/2015
  • H. Stinshoff · C. Wrenzycki
    48th Annual Conference on Physiology and Pathology of Reproduction /; 02/2015
  • J. Stoehr · H. Stinshoff · C. Wrenzycki
    48th Annual Conference on Physiology and Pathology of Reproduction /; 02/2015
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    ABSTRACT: The ability of bovine embryos to develop to the blastocyst stage and to implant and generate healthy offspring depends greatly on the competence of the oocyte. Oocyte competence is attributed to its close communication with the follicular environment and to its capacity to synthesize and store substantial amounts of messenger RNA. Higher developmental competence of bovine oocytes has been associated with both the expression of a cohort of developmental genes and the concentration of sex steroids in the follicular fluid. The aim of this study was to identify differences in the expression of FST in cumulus cells and OCT-4 and MATER in oocytes and the influence of the follicular progesterone and follicular estrogen concentration on the competence of bovine oocytes retrieved 30 minutes or 4 hours after slaughter. Cumulus-oocyte complexes (COCs) were left in postmortem ovaries for 30 minutes (group I) or 4 hours (group II) at 30 °C. Aspirated oocytes were then subjected to IVM, IVF, and IVC or were evaluated for MATER and OCT-4 messenger RNA abundance by quantitative real-time polymerase chain reaction. Total RNA was isolated from pools of 100 oocytes for each experimental replicate. Progesterone and estradiol concentration in follicular fluid was evaluated by immunoassay using an IMMULITE 2000 analyzer. Three repeats of in vitro embryo production were performed with a total of 455 (group I) and 470 (group II) COCs. There were no significant differences between the cleavage rates (72 hours postinsemination [hpi]) between both groups (63.5% vs. 69.1%). However, blastocyst (168 hpi) and hatching (216 hpi) rates were higher (P < 0.05) in group II compared with those of group I (21.3% vs. 30.7% and 27.6% vs. 51.5%, respectively). Group II oocytes exhibited the highest MATER and OCT-4 abundance (P < 0.05). Follicular estradiol concentration was not different between both the groups, whereas the progesterone concentration was lower (P ≤ 0.05) in group II follicles. These results indicate that retrieving COCs 4 hours after slaughter could increase bovine in vitro developmental competence, which is linked to higher levels of oocyte MATER and OCT-4 transcripts and lower follicular progesterone concentration. Moreover, the results of the present study contribute to the identification of factors involved in the developmental competence of immature oocytes. Copyright © 2015 Elsevier Inc. All rights reserved.
    Theriogenology 12/2014; 83(7). DOI:10.1016/j.theriogenology.2014.12.024 · 1.85 Impact Factor
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    ABSTRACT: The in vitro production (IVP) of bovine embryos is a well-established technique that has been available for nearly 20 years. However, there remain major differences between IVP-derived blastocysts and their in vivo-derived counterparts. Many studies have pointed out that most of these differences are due to the in vitro developmental environment. To circumvent these negative effects due to in vitro culture conditions, a new method - intrafollicular oocyte transfer (IFOT) - was established in the present study. Using modified ovum pick-up (OPU) equipment, in vitro-matured oocytes derived from slaughterhouse ovaries were injected into the dominant preovulatory follicle of synchronised heifers (follicular recipients) enabling subsequent ovulation, in vivo fertilization, and in vivo development. A total of 810 in vitro-matured oocytes were transferred into 14 heifers. Subsequently, 222 embryos (27.3%) were recovered after uterine flushing at Day 7. Based on the number of cleaved embryonic stages, 64.2% developed to the blastocyst stage, which did not differ from the IVP-derived embryos (58.2%). Interestingly, lipid content of IFOT-derived blastocysts did not differ from the fully in vivo-produced embryos, whereas IVP-derived blastocysts showed significantly higher lipid droplet accumulation compared with fully in vivo-derived and IFOT-derived blastocysts (P<0.05). Accordingly, IFOT blastocysts showed significantly higher survival rates after cryopreservation than complete IVP-derived embryos (77% v. 10%), which might be attributed to a lower degree of lipid accumulation. In agreement, transfer of frozen-thawed IFOT blastocysts to synchronized recipients (uterine recipients) resulted in much higher pregnancy rates compared with transfer of IVP-derived blastocysts (42.1 v. 13.8%) but did not differ from frozen-thawed ex vivo blastocysts (52.4%). Of these presumed IFOT pregnancies, 7 went to term, and microsatellite analysis confirmed that 5 calves were indeed derived from IFOT, whereas 2 were caused by fertilization of the follicular recipient's own oocyte after AI. Taken together, IFOT-derived blastocysts closely resemble in vivo-derived blastocysts, confirming earlier suggestions that the ability to develop to the blastocyst stage is already determined in the matured oocyte, whereas the quality in terms of lipid content and survival rate after cryopreservation is affected by the environment thereafter. However, to the best of our knowledge, this is the first study reporting healthy calves after intrafollicular transfer of in vitro-matured oocytes.
    Reproduction Fertility and Development 12/2014; 27(1):136. DOI:10.1071/RDv27n1Ab86 · 2.58 Impact Factor
  • J M K Nielsen · C Wrenzycki · P Hyttel · F Poppicht · L Strøbech
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    ABSTRACT: The purpose was to examine effects of different media for bovine in vitro oocyte maturation (IVM) and in vitro embryo culture (IVC) on blastocyst rates, morpho-kinetics, and relative abundance of mRNA of 8 genes associated with critical processes and developmental competence in the embryo. Abattoir-derived cumulus-oocyte complexes (COC) were in vitro matured (IVM) in either TCM199 [+0.5% BSA and gonadotropins (Suigonan Vet 150 I.E.mL(-1))] or in a novel commercially available media (Bo-IVM), and a total of 1196 presumptive zygotes, from 4 replicates, were submitted to in vitro culture (IVC) and cultured in either SOF (+0.5% BSA) or in a novel commercially available media (Bo-IVC). Blastocyst rates and morpho-kinetics were assessed on Day 8 after fertilization. The high-quality blastocysts from each group were analysed by RT-qPCR, on single blastocysts using earlier verified primers, for BAX, BCL2L1, DNMT3A, FASN, G6PD, HSPA1A, SLC2A1, and SLC2A3. Data on blastocyst rates were analysed for statistical differences using a linear regression model, using a binary reproach and general estimating equations. One-way ANOVA was used to detect differences in the relative abundance of mRNA between groups, whereas differences between maturation and culture media were analysed by a 2-way ANOVA. Blastocyst rates in the Bo-IVM/Bo-IVC (37%), TCM199/Bo-IVC (33%), Bo-IVM/SOF (26%), and TCM199/SOF (28%) groups were significantly different from each other (P<0.0001). Specifically, the Bo-IVM/Bo-IVC group differed significantly from both SOF-cultured groups (P<0.01). Subjectively, this group also had embryos of the highest quality and most advanced development. Significantly increased levels of mRNA transcripts were found for embryos cultured in Bo-IVC for all genes (P<0.05) except BCL2L1. In conclusion, the developmental rates and gene expression of in vitro-produced bovine blastocysts were affected by the use of different culture media. Increased blastocyst rates, apparently superior embryo quality, and more abundant gene expression were achieved when blastocysts were cultured in Bo-IVC culture media compared with SOF.
    Reproduction Fertility and Development 12/2014; 27(1):206-7. DOI:10.1071/RDv27n1Ab234 · 2.58 Impact Factor
  • C Blaschka · H Stinshoff · F Poppicht · C Wrenzycki
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    ABSTRACT: Steroid hormone concentration and property can be modulated via different processes. Sulfoconjugation via sulfotransferases (SULT) changes steroids from hydrophobic to hydrophilic, necessitating a transport system such as the sodium-dependent organic anion transporter (SOAT; SLC10A6). Steroid sulfatase (STS) removes the sulfate moiety from conjugated steroids, transforming them to the free active ones. Moreover, present in vitro maturation systems do not completely mimic the in vivo situation resulting in oocytes of reduced quality. The present study investigates the local effects of sulfated steroids during follicular and oocyte development in vivo and in vitro. Follicles of bovine abattoir-derived ovaries were categorized according to their size (3 to 5, 6 to 8, 9 to 14, and >15mm) after dissection and measurement via a caliper. Only nonatretic follicles were used (Kruip and Dieleman, 1982). Follicular fluid was collected via aspiration and analysed for the presence of steroids and their sulfated counterparts via LC-MS/MS. Moreover, oocytes were in vitro maturated with a standard protocol. The medium was measured via radioimmunoassay after 0, 4, 8, 12, 16, 20, and 24h to detect 17β-oestradiol (E2) and progesterone (P4). Data were tested using analysis of variance (ANOVA) followed by multiple pairwise comparisons using Tukey's test. A P-value of ≤0.05 was considered significant. It was possible to detect 17β-oestradiol, progesterone, testosterone, 17β-oestradiol sulfate, estrone sulfate, pregnenolone sulfate, cholesterol sulfate (Table 1), and furthermore androstendione, estrone, androsterone, and 17OH-pregnenolone. During IVM, P4 significantly increased in the medium (4h: 3.3±1.0ngmL(-1); 24h: 9.8±1.7ngmL(-1)), whereas the E2 concentration did not change (4h: 52.8±12.1pgmL(-1); 12h: 68.4±3.7pgmL(-1); 24h: 66.9±19.7pgmL(-1)). In addition, preliminary data suggest that transcripts of the steroid metabolizing and transporting enzymes (SULT1E1, STS, SLC10A6) were present in cumulus cells from immature bovine COC. These results indicate for the first time that only small amounts of sulfated steroids are present in bovine follicular fluid. However, the related enzymes are present at the mRNA level. Further studies are underway to analyse the protein level.
    Reproduction Fertility and Development 12/2014; 27(1):226. DOI:10.1071/RDv27n1Ab275 · 2.58 Impact Factor
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    ABSTRACT: To investigate the usefulness of follicular fluid (FF) in relation to blood plasma and bile as indicators of exposure of dairy cows to ZEN, DON and their metabolites, a dose–response study was performed with 30 dairy cows. The cows, 10 in each group (named CON; FUS-50, FUS-100), received a diet with three different concentrations of Fusarium toxin-contaminated maize. Thereby, the following dietary concentration were reached: CON (0.02 mg ZEN and 0.07 mg DON, per kg dry matter, DM), FUS-50 (0.33 mg ZEN and 2.62 mg DON, per kg DM) and FUS-100 (0.66 mg ZEN and 5.24 mg DON, per kg DM). ZEN, DON and de-epoxy-DON (de-DON) were detected in FF. Based on the linear regression between toxin concentration in plasma and FF, it seems that about 50 % (m = 0.5) of ZEN present in plasma is present in FF while an increase of 1 ng/ml DON or de-DON in plasma is paralleled by an increase of 1.5 ng/ml DON or 1.1 ng/ml de-DON in FF. ZEN, DON and their metabolites, except zearalenone (ZAN), were also detected in bile. Contrary to DON and de-DON, ZEN and its metabolites were accumulated in bile so that the concentration of ZEN and metabolites was much higher than for DON and de-DON. The main compound was β-zearalenol (β-ZEL). The biliary ZEN, α-zearalenol (α-ZEL) and β-ZEL concentration correlated linearly with each other with an uncertainty of <15 % (r2 ≥ 0.86), whereas the ratio between ZEN: α-ZEL: β-ZEL was about 1.5:1:11. With the help of established linear relationship between toxin intake and toxin concentration, bile could be used as diagnostic indicator to assess the exposure of cows.
    J Anim Physiol a Anim Nutr 12/2014; DOI:10.1111/jpn.12285 · 1.32 Impact Factor
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    Sophia Mayer · Christine Wrenzycki · Wolfgang Tomek
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    ABSTRACT: The mammalian target of rapamycin (mTor), a Ser/Thr protein kinase, is implicated in the phosphorylation-triggered inactivation of translation repressors, the so called eukaryotic initiation factor 4E (eIF4E)-binding proteins (4E-BPs). Previous observations in porcine and bovine oocytes revealed an increasing phosphorylation of 4E-BP1 during meiotic maturation. The factor is hypophosphorylated in the germinal vesicle (GV) stage and highest phosphorylated in the metaphase II (M II). In the present approach we intended to block 4E-BP1 phosphorylation specifically to impair initiation of translation and elucidate effects on resumption of meiosis. Torin2, which acts as an active-site mTor inhibitor, reduces 4E-BP1 phosphorylation without any effect on eIF4E and arrests up to 60% of the oocytes in the M I stage. Effects of Torin2 treatment, analyzed by site-specific substrate phosphorylation, were also observed at protein kinase B (Akt, PKB) and cyclin dependent kinases (CDKs). However, if at all, only minor side effects were found at protein kinase A, C (PKA, PKC), ATM/ATR (Ataxia telangiectasia mutated/AT and Rad3-related protein) and the mitogen activated protein kinases (MAPK) ERK1, 2. The inhibition of 4E-BP1 phosphorylation by Torin2 is reversible when cultivating oocytes for additional 24 h in Torin2-free medium. However, even so, oocytes persist in the M I stage. This may indicate the necessity of spatiotemporally regulated translation during meiosis, which cannot be restored later. In conclusion, Torin2 enables an effective and specific inhibition of 4E-BP1 phosphorylation and such an approach may be valuable to investigate maturation specific protein synthesis in more detail. Mol. Reprod. Dev. © 2014 Wiley Periodicals, Inc.
    Molecular Reproduction and Development 04/2014; 81:363-375. DOI:10.1002/mrd.22305 · 2.68 Impact Factor
  • C Wrenzycki · C Blaschka · H Stinshoff
    Experimental and Clinical Endocrinology & Diabetes 03/2014; 122(03). DOI:10.1055/s-0034-1372092 · 1.76 Impact Factor
  • F Poppicht · H Stinshoff · C Wrenzycki
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    ABSTRACT: Insulin-like growth factor 1 (IGF1) is essential for regulating physiological processes such as growth and development of fetal and placental tissues (Bauer et al. 1998, Fowden 2003). During early embryonic development, IGF1 plays an important role, as it leads to a reduction of apoptosis and decreases early embryonic mortality (Block et al. 2007). The signal transduction of IGF1 is carried out by its specific binding to the membrane-embedded insulin-like growth factor 1 receptor (IGF1R). The expression of IGF1R is a potential quality marker of in vitro produced embryos (Liu et al. 1997, Yaseen et al. 2001). Thus far, analysis of the relative amount of specific transcripts is the method of choice to study bovine pre-implantation embryos, as information on protein expression is scarce. Therefore, it is of great interest to analyse protein expression and to determine if and to which extent these results differ from results obtained in previous mRNA expression analyses. In the present study, a total of 4800 cumulus-oocyte-complexes were deployed in 60 in vitro produced runs. The cleavage rates averaged 57.4±7.3% and blastocyst rates were 27.6±7.5% at Day 8 of culture. Embryos at the blastocyst stage were frozen and stored at -80°C for further experiments. The protein expression of the IGF1R during early embryonic development was investigated by Western blot analysis testing 8 different antibodies. Seven of these antibodies were commercially available and mainly not tested in the bovine species. Only 1 of these antibodies resulted in a weak signal for the IGF1R protein in bovine blastocysts. Therefore, a specific peptide antibody against 2 peptide sequences of the α unit of the bovine IGF1R was produced. The analysis of the IGF1R protein with this antibody resulted in the determination of a signal in a pool of 100 blastocysts, which was weaker than in the positive control (20μg of bovine liver protein extract). The detection of the IGF1R protein localization was possible in all different stages of embryonic development from the zygote to the expanded blastocyst using immunfluorescence staining with the specific peptide antibody. The IGF1R protein was mainly expressed in the plasma membrane of single blastomeres and also weakly in the cytoplasm. As the early bovine embryo expresses IGF1R throughout all stages, the main function of IGF1 in embryonic development needs to be further elucidated.
    Reproduction Fertility and Development 12/2013; 26(1):149. DOI:10.1071/RDv26n1Ab70 · 2.58 Impact Factor
  • H Stinshoff · S Kruse · F Poppicht · S Dänicke · C Wrenzycki
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    ABSTRACT: Whole plant corn silage is an important component of dairy cow nutrition. Growing conditions in a moderate climate, as are present in large parts of Europe and North America, are often beneficial for mould contaminations to occur. Very commonly, varieties of Fusarium spp. grow on the corn plant producing the non-steroidal estrogenic mycotoxin zearalenone (ZEN). Numerous studies have shown that ZEN massively interacts with the porcine reproductive system. Nevertheless, only a few studies have assessed the possible effects on dairy cows, most publications being field studies following accidental exposure. Therefore, it was aim of the present study to assess the effects of a controlled dietary exposition on selected reproductive parameters in dairy cows. The chosen exposure concentration was within the range of the 'Commision Recommendation on the presence of deoxynivalenol, zearalenone, ochratoxin A, T-2 and HT-2 and fumonisins in products intended for animal feeding' of the European Union. Corn plants were artificially inoculated with Fusarium spp. and the silage obtained from the whole plant was analysed to determine to which degree the silage contained ZEN. Thirty Holstein Friesian cows and heifers (aged between 2 years 3 months and 5 years at calving) were allocated to 3 groups with 10 animals each: control (CTL), uncontaminated silage; ZEN 50, silage with 0.25mg of ZEN/day; and ZEN 100, silage with 0.5mg of ZEN/day. The contaminated rations were distributed by automated feeding stations to ensure an equal uptake. Feeding began 7 days post-parturition. Blood samples were obtained twice weekly for 12 weeks and were analyzed regarding the progesterone level via radioimmunoassay. At the same time, the oestrous cycle was monitored by ultrasonography. Furthermore, the size of the corpus luteum (CL) was measured 7±2 days after the third ovulation. Simultaneously, the luteal blood flow was documented via Doppler ultrasonography. The peripheral blood progesterone level (xgeom.±CV; CTL: 9.3±1.7; ZEN 50: 8.5±1.6; ZEN100: 7.1±1.5) did not differ among groups. Furthermore, it was not possible to detect differences in luteal blood flow, size of the CL (mean±SD; CTL: 6.4±1.7cm(2); ZEN50: 5.9±1.3cm(2); ZEN 100: 5.0±1.0cm(2)) or the ratio of luteal size and size of the area supplied with blood (CTL: 0.1±0.1; ZEN 50: 0.1±0.0; ZEN 100: 0.1±0.1). Although the mean length of the oestrous cycles (n=60; distributed among groups) did not differ among groups (CTL: 24.0±1.7 days; ZEN 50: 27.2±1.6 days; ZEN 100: 27.7±1.4 days), it was possible to detect an interaction between the age of the animal and the treatment regarding the cycle length in tendency (P<0.07) by two-way ANOVA. The results of the present study indicate that, independent of the age of the animal, exposure to ZEN even within recommended dosages might result in an endocrine disruption in dairy cows. A larger sample size would contribute to the verification of these findings. Further analyses regarding the peripheral level of 17β-estradiol as well as molecular examinations are under progress.
    Reproduction Fertility and Development 12/2013; 26(1):149-50. DOI:10.1071/RDv26n1Ab71 · 2.58 Impact Factor
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    ABSTRACT: Progesterone (P4) is important for the developmental competence of cumulus-oocyte complexes (COC) used for in vitro maturation (IVM). In a recent study, we were able to show that circulating P4 concentrations had an effect on the molecular quality of COC recovered during repeated ovum pickup sessions, which might affect further development. (Schlüter et al. 2013 Reprod. Fertil. Dev. 25, 250). The aim of the present study was to determine the influence of different P4 concentrations during IVM on the molecular quality of bovine COC. The COC were collected from slaughterhouse ovaries and cultured as described recently (Stinshoff et al. 2011 Theriogenology 76, 1433-1441). The IVM medium was supplemented with 0, 50, 150, 300, and 450ngmL(-1) P4. Ethanol served as vehicle control. After IVF with a bull of proven fertility, the presumptive zygotes were cultured in SOF under 5% oxygen (Stinshoff et al. 2011). Cleavage and developmental rates were determined at Day 3 and Day 7/8 (Day 0: IVF). Additionally, maturation rates were assessed. For mRNA analysis, immature and matured denuded COC (n=5) were individually frozen at -80°C to analyse the relative transcript abundance using RT-qPCR. The transcripts studied play important roles during oocyte development [growth differentiation factor 9 (GDF9), bone morphogenetic protein 15 (BMP15), glucose transporter 1 (SCL2A1), hypoxia inducible factor 2α (HIF2α), nuclear progesterone receptor (PGR), progestin and adipoQ receptor 5 (PAQR5), progesterone receptor membrane component 1 and 2 (PGRMC1, PGRMC2)]. Data were tested using ANOVA followed by multiple pairwise comparisons using Tukey's test. A P-value of <0.05 was considered significant. The percentage of oocytes that reached the MII stage was similar in oocytes from all treatment groups (82.2-88.1%). Despite similar cleavage rates across all groups, the developmental rates did show significant differences. More embryos developed to the blastocyst stage stemming from oocytes cultured without any supplement or cultured only with alcohol compared to oocytes stemming from the group cultured with less than 50ngmL(-1) P4 (25.4±5.7 and 27.9±7.2 v. 15.8±2.6). The relative abundance of SCL2A1, BMP15, and PGRMC1transcripts in single oocytes did not show differences related to the supplementation of the IVM medium, whereas GDF9, HIF2α, and PAQR5 mRNA was reduced in oocytes of all groups compared with immature ones. The PGR and PGRMC2 transcripts were increased in matured oocytes of the control group and the vehicle control group (PGRMC2). In summary, supplementation of the IVM medium with different P4 concentrations had an effect on the molecular quality of oocytes after IVM, which might affect further development.
    Reproduction Fertility and Development 12/2013; 26(1):171. DOI:10.1071/RDv26n1Ab114 · 2.58 Impact Factor
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    C Wrenzycki · H Stinshoff
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    ABSTRACT: In vitro production (IVP) of bovine embryos has been improved immensely throughout the last decades. Nevertheless, embryos generated in vitro still differ from their in vivo-produced counterparts. It is possible to achieve blastocyst rates of up to 70% if in vivo-matured oocytes are used. In contrast, if oocytes are matured in vitro, blastocyst rates are only half that of those matured in vivo. This rather limited success may be attributed to the heterogeneous population of oocytes which are normally retrieved from follicles of 3-8 mm rather than from preovulatory follicles. In contrast to the in vivo-ovulated oocyte, these oocytes lack development up to the preovulatory stage and are matured in vitro. Therefore, much effort has been devoted to the establishment of non-invasive and non-perturbing means for selecting the most competent oocytes, for example the extensiveness and compactness of the cumulus-corona investment and the granulation of the ooplasm. In vitro culture (IVC) conditions have been enhanced in the last few years, mainly by adjustment of media formulations, whereas the in vitro maturation (IVM) protocols stay invariable. Consequently, maintaining or mimicking the in vivo situation in vitro will aid to improve the quality and developmental competence of the resulting matured oocyte. The scope of this review is to give an overview of the current situation of in vitro maturation of mammalian oocytes with emphasis on the bovine species. Special attention has been paid to the in vivo situation in the follicle and how a better understanding of these intrafollicular factors will aid to improve the in vitro maturation conditions.
    Reproduction in Domestic Animals 09/2013; 48 Suppl 1:38-43. DOI:10.1111/rda.12204 · 1.18 Impact Factor
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    ABSTRACT: The objective of this study was to investigate the effect of time of first postpartum ovulation after calving on uterine involution in dairy cows with and without uterine puerperal disease. Transvaginal follicular puncture (FP) of follicles >6 mm suppressed ovulation and development of a CL until Day 42 after calving. Fifty-three lactating Holstein Friesian cows (3.4 ± 1.2 years old, parity 2.5 ± 1.0 [median ± mean absolute deviation]) were divided into groups on the basis of the presence (UD+) or absence (UD-) of uterine disease and whether FP was carried out (FP+) or not (FP-). Uterine disease was defined as the occurrence of retained fetal membranes and/or metritis. This resulted in the following groups: UD-FP- (n = 15), UD-FP+ (n = 13), UD+FP- (n = 13), and UD+FP+ (n = 12). A general examination, vaginoscopy, transrectal palpation, and transrectal B-mode sonography of the reproductive organs were conducted on Days 8, 11, 18, and 25 and then every 10 days until Day 65 after calving. After hormonal synchronization of ovulation (cloprostenol between Days 55 and 60 postpartum and GnRH 2 days later), cows were inseminated in the next spontaneous estrus. On average, the cows ovulated on Day 21.0 ± 6.0 (UD-FP-), 50.0 ± 4.0 (UD-FP+), 16.0 ± 3.0 (UD+FP-), and 48.0 ± 2.0 (UD+FP+) postpartum. Calving-to-conception interval and first-service conception rates were not affected by FP (P > 0.05). Healthy cows with FP had smaller (P < 0.05) uterine horn and cervical diameters assessed sonographically than cows without FP. FP reduced the prevalence of purulent vaginal discharge and uterine size assessed transrectally in UD+ cows (P < 0.05). The results showed that suppression of an early ovulation by transvaginal FP improved uterine involution in cows with and without uterine disease.
    Theriogenology 06/2013; 80(5). DOI:10.1016/j.theriogenology.2013.05.017 · 1.85 Impact Factor

Publication Stats

3k Citations
254.75 Total Impact Points

Institutions

  • 2013–2015
    • Justus-Liebig-Universität Gießen
      • Faculty of Veterinary Medicine
      Gieben, Hesse, Germany
  • 2008–2013
    • University of Veterinary Medicine Hannover
      • Reproduktionsmedizinische Einheit der Kliniken
      Hanover, Lower Saxony, Germany
  • 2011
    • Friedrich Loeffler Institute
      • Institute of Farm Animal Genetics
      Griefswald, Mecklenburg-Vorpommern, Germany
  • 2007
    • University of Buenos Aires
      Buenos Aires, Buenos Aires F.D., Argentina
    • Selcuk University
      • Division of Reproduction and Artificial Insemination
      Conia, Konya, Turkey
  • 2006
    • Food Allergens Laboratory
      Retimo, Crete, Greece
  • 2004
    • Universidad Centro Occidental Lisandro Alvarado, UCLA
      • Departamento de Produción Industrial y Animal
      Barquisimito, Lara, Venezuela
  • 2000
    • Tufts University
      • Department of Anatomy and Cellular Biology
      Бостон, Georgia, United States
  • 1999
    • The University of Western Ontario
      • Department of Obstetrics and Gynaecology
      London, Ontario, Canada