102. THE EFFECT OF INSULIN ON EMBRYONIC STEM CELL PROGENITOR CELLS IN THE MOUSE BLASTOCYST

Human ESCs are produced from embryos donated at the mid-stage of pre-implantation development. This cryostorage reduced viability. However, it has been shown that this can be improved by the addition of growth factors to culture medium. The aim of the present study was to examine whether the addition of insulin to embryo culture medium from the 8-cell stage of development increases the number of ES cell progenitor cells in the epiblast in a mouse model. In vivo produced mouse zygotes (C57Bl6 strain) were cultured in G1 medium for 48h to the 8-cell stage, followed by culture in G2 supplemented with insulin (0, 0.17, 1.7 and 1700pM) for 68h, at 37 o C , in 5% O2, 6%CO2, 89% N2 . The number of cells in the inner cell mass (ICM) and epiblast was determined by immunohistochemical staining for Oct4 and Nanog. ICM cells express Oct4, epiblast cells express both Oct4 and Nanog. The addition of insulin at the concentrations examined did not increase the ICM. However, at 1.7pM insulin increased the number of epiblast cells (6.6±0.5 cells vs 4.1±0.5, P=0.001) in the ICM, which increased the proportion of the ICM that was epiblast (38.9±3.7% compared to 25.8±3.4% in the control P=0.01). This indicates that the increase in the epiblast is brought about by a shift in cell fate as opposed to an increase in cell division. The effect of insulin on the proportion of cells in the epiblast was investigated using inhibitors of phosphoinositide3-kinase (PI3K) (LY294002, 50µM); one of insulin's main second messengers, and p53 (pifithrin-α, 30µg/ml); a pro-apoptotic protein inactivated by PI3K. Inhibition of PI3K eliminated the increase caused by insulin (4.5±0.3 cells versus 2.2±0.3 cells, P<0.001), while inhibition of p53 increased the epiblast cell number compared to the control (7.1±0.8 and 4.1±0.7 respectively P=0.001). This study shows that insulin increases epiblast cell number through the activation of PI3K and the inhibition of p53, and may be a strategy for improving ESC isolation from human embryos.

126. IMPLICATIONS FOR FETAL AND PLACENTAL DEVELOPMENT FOLLOWING MITOCHONDRIAL PERTURBATION IN THE EMBRYO

The environment an embryo is exposed to can profoundly influence peri- and post-natal development despite having some capacity to adapt. Whilst the mechanisms responsible remain largely unknown, mitochondria are a likely target. In this study we deliberately perturbed mitochondrial function in the mouse embryo, using a model we have established that shows step-wise changes in embryo metabolism and development. The aim of this study was to provide direct evidence implicating mitochondrial dysfunction in the embryo with perturbed fetal and placental development. Zygote stage embryos were recovered from superovulated female mice and cultured in control conditions to the 2-cell stage. Embryos were then allocated to one of three treatments; control media (0μM-AOA), 5μM or 50μM of the known mitochondrial inhibitor, Amino-Oxyacetate, in the absence of pyruvate (5μM-AOA, 50μM-AOA). Embryos were cultured to the blastocyst stage, then transferred to pseudopregnant recipients, with fetal and placental parameters measured on day 18 of pregnancy. Implantation rates and fetal survival for both 5μM-AOA and 50μM-AOA was comparable to control embryos. For 5μM-AOA there was a significant reduction in placental weight (P=0.02) but normal fetal weight, and a significant increase in fetal: placental weight ratio (P=0.002) relative to the control, suggesting increased placental efficiency. When mitochondria were further perturbed (50μM-AOA), the fetuses and placentas were both considerably compromised: that is, decreased fetal and placental weights (P=0.002), reduced placental diameter (P=0.03) and decreased fetal crown rump length (P=0.07). This study demonstrates that mitochondrial function in the embryo impacts on peri-natal development, providing compelling evidence for mitochondrial function involvement in the mechanisms underpinning “embryo programming”. This data suggests a threshold effect, whereby embryos can only adapt up until a point after which development is compromised. Further elucidating these mechanisms is important for understanding how maternal environments and embryo culture systems determine development of future offspring.

147. PATERNAL OBESITY IMPAIRS SPERM FUNCTION AND SUBSEQUENT EMBRYO AND PREGNANCY OUTCOMES

Despite the increased prevalence of obesity in males of reproductive age, the effects of male obesity on conception and pregnancy have been largely ignored. Hence, the aim of this study was to elucidate the effects of paternal Diet Induced Obesity (DIO) on sperm function, embryo development and pregnancy. Six week old C57BL/6 male mice (n=36) were allocated to either standard chow or a high fat diet (HFD). After eight weeks, mice were either sacrificed and spermatozoa assessed, for motility, reactive oxygen species (ROS) and DNA damage or mated and zygotes collected and cultured to the blastocyst stage. Blastocyst development, cell number and apoptosis were assessed, and fetal outcomes analyzed following embryo transfer. Differences between treatments were assessed using GLM. The percentage of motile spermatozoa was decreased (36% vs. 44%, p<0.05) in the HFD group compared to controls. Intracellular ROS were elevated (692units vs. 409units, p<0.01) in the HFD group compared to controls. Overall levels of sperm DNA damage were also increased (1.64% vs. 0.17%, p<0.05) in the HFD group. Blastocyst development was reduced when males were fed a HFD (64% vs. 84%, p<0.05). Similarly, blastocyst cell number (37.9±2.8 vs. 46.6±2.5, p<0.05), inner cell mass number (11.4±0.9 vs. 15.3±0.9, p<0.05) were reduced and apoptosis (12.8±1.9 vs. 6.6±0.6, p<0.05) increased in embryos sired by a male fed a HFD. Implantation (86.7% vs. 72.5%, p<0.05) and fetal development (38.7% vs. 22.5% p<0.05) were also significantly reduced when blastocysts came from a male fed a HFD. This is the first report providing comprehensive evidence that paternal DIO significantly impairs embryo quality and pregnancy rates. These effects may be related to the observed increase in oxidative stress and sperm DNA damage. These data provide compelling evidence that male obesity impacts on male fertility, embryos as well as pregnancy and therefore studies in human are warranted.

125. REGULATION OF STRESS PROTEIN GENES DURING PRE-IMPLANTATION EMBRYO DEVELOPMENT IN MICE BY GRANULOCYTE-MACROPHAGE COLONY-STIMULATING FACTOR (GM-CSF)

In vitro culture has been shown to be detrimental for pre-implantation embryo development and this has been associated with culture stress and elevated expression of apoptotic genes. Granulocyte-macrophage colony-stimulating factor (GM-CSF) has been shown to promote development and survival of both human and mouse pre-implantation embryos. To investigate the mechanism of action of GM-CSF in mouse embryos, gene expression was examined in in vitro cultured blastocysts with and without recombinant mouse GM-CSF (rmGM-CSF) and in vivo blastocysts flushed from Csf2 null mutant and wild-type mice. Microarray analysis of the effect of GM-CSF on transcription profile implicated apoptosis and stress response gene pathways in blastocyst responses to rmGM-CSF in vitro. Groups of 30 blastocysts were collected from in vitro cultured and in vivo developed blastocyst were analysed using quantitative real-time polymerase chain reaction (qRT-PCR). qRT-PCR analysis of in vitro blastocysts revealed that addition of rmGM-CSF causes differential expression of several genes associated with apoptosis and cellular stress pathway, including Cbl, Hspa5, Hsp90aa1, Hsp90ab1 and Gas5. Immunocytochemical analysis of common proteins of the apoptosis and cellular stress response pathways BAX, BCL2, TRP53 (p53) and HSPA1A/1B (Hsp70) in in vitro blastocysts revealed that HSPA1A/1B and BCL2 proteins were less abundant in embryos cultured in rmGM-CSF, but BAX and TRP53 were unchanged. In in vivo developed blastocysts, Csf2 null mutation resulted in elevated levels of only the heat shock protein Hsph1, suggesting that in vivo, other cytokines can compensate for GM-CSF deficiency as the absence of GM-CSF has a lesser effect on the stress response pathway. We conclude that GM-CSF is a regulator of the apoptosis and cellular stress response pathways influencing mouse pre-implantation embryo development to facilitate embryo growth and survival, and the effects of GM-CSF are particularly evident in in vitro culture media in the absence of other cytokines.

152. INVOLVEMENT OF TRP53 IN SIRT1 FUNCTION DURING EMBRYO DEVELOPMENT

Sirtuin 1 (SIRT1) is an NAD+-dependant deacetylase with significant functions in cell survival and metabolism, including glucose homeostasis and mitochondrial physiology. TRP53 is a universal effector of cellular stress responses and is an important target of SIRT1. Transcriptional activity of TRP53 in the pre-implantation embryo is associated with retarded development, however examination of SIRT1 function and how it relates to TRP53 activity remains to be elucidated. We therefore assessed whether SIRT1 is involved in pre-implantation embryo development and determined whether TRP53 interacts with SIRT1 function. Zygotes were collected from superovulated female mice and cultured to the blastocyst stage in optimised conditions (F1 mouse strain, G1/G2 series sequential media, 5%CO2, 5%O2, 90%N2, group culture) or compromised conditions (C57Bl/6 strain, mHTF static media, 5%CO2 in air, individual culture). Embryo development and blastocyst cell number was assessed following exposure to a SIRT1 inhibitor (0, 1, 10, 100 or 1000µM sirtinol). In subsequent experiments, embryos were cultured in a 2x2 factorial design (±1µM sirtinol and ±30µM pifithrin-α (TRP53 inhibitor)) and embryo development and cell number determined. Sirtinol caused a dose-dependent reduction in total cell number in blastocysts during culture in both optimised and compromised conditions (p<0.05), while the rate of development of zygotes was reduced for embryos in compromised but not optimised conditions (p<0.05). When SIRT1 was inhibited, in the presence or absence of TRP53 inhibition, blastocyst development and cell number for embryos in optimal conditions was unchanged. However, blastocyst development (83% vs 55%, p<0.05), and cell number (39 vs 54 cells, p<0.05) was reduced when SIRT1 was inhibited in compromised embryos, and in the absence of TRP53, development was resolved to control levels. These results show that SIRT1 is important for embryo development, particularly under compromised conditions, and that TRP53 is a likely target for SIRT1 deacetylase activity in the mammalian embryo.

535. THE EFFECT OF ALTERING GLUCOSE LEVELS DURING COLLECTION AND MATURATION OF MOUSE OOCYTES ON SUBSEQUENT DEVELOPMENTAL COMPETENCE

The preconception environment is known to influence oocyte developmental competence. In particular, hyperglycaemic conditions during cumulus-oocyte complex (COC) maturation result in decreased oocyte quality. This is, in part, due to perturbations in O-linked glycosylation in the cumulus cells. In embryos, even a brief exposure to glucose during early cleavage can have significant impact on O-linked glycosylation and further development. The aim of this study was to determine the effect of altering glucose concentrations during the collection and maturation phases of COCs on oocyte developmental competence. COCs were collected and matured for 17h at 37°C in 6% CO2 with 0 or 10mM glucose in a 2 x 2 factorial design. A fifth group used standard concentrations of 0.5mM and 5.55mM glucose in the collection and maturation media respectively. Following maturation, oocytes were inseminated and cultured to the blastocyst stage. The average time for collection was 1 h. COCs exposed to 0mM glucose during collection and 10mM glucose during maturation had the greatest cumulus expansion despite no change in the proportion of COCs completing nuclear maturation. However, this same treatment group resulted in significantly lower blastocyst production than the control group (8.4% vs. 25.0%, P<0.05). These results show that glucose concentration in collection medium has a significant influence on maturation indices and oocyte developmental competence, as determined by blastocyst development rates. Our data further supports the concept that the conditions used for the collection of oocytes can have profound effects on subsequent development. We intend to investigate if these effects are related to perturbations in cumulus cell O-linked glycosylation.

131. INDUCED OOCYTE IN VITRO MATURATION (IVM) SUBSTANTIALLY IMPROVES EMBRYO YIELD AND PREGNANCY OUTCOMES

Oocyte maturation in vivo is a highly orchestrated, induced process, whereby 3'-5'-cyclic adenosine monophosphate (cAMP)-mediated meiotic arrest is overridden by the gonadotrophin surge prior to ovulation. However, in vitro matured (IVM) oocytes resume maturation spontaneously hence compromising developmental competence. Hence we hypothesized that establishing an induced system in vitro would synchronise oocyte-somatic cell communication leading to improved oocyte quality. Bovine or mouse oocytes were treated for the first 1-2 h in vitro with the adenylate cyclase activator forskolin and a non-specific phosphodiesterase (PDE) inhibitor, IBMX, which substantially increased cumulus-oocyte complex (COC) cAMP (180 vs. 2 fmol/ COC , treated vs. control, P<0.001) to in vivo physiological levels. To maintain oocyte cAMP levels and prevent precocious oocyte maturation, oocytes were then cultured with an oocyte-specific (type 3) PDE inhibitor, cilostamide. The net effect of this system (“Induced IVM”) was to increase oocyte-somatic cell gap-junctional communication (bovine: 1000±148 vs. 340±73 units; treated vs. control, p<0.05) and to slow meiotic progression through prophase I to metaphase II, extending the normal IVM interval (bovine: 30 vs. 24h, mouse: 22 vs. 18 h; treated vs. control). These effects on oocyte and somatic cell functions had profound consequences for oocyte developmental potential. In bovine, Induced IVM more than doubled embryo yield (69% vs. 27%; treated vs. control, p<0.05). In mouse, Induced IVM increased blastocyst rate (86% vs. 55%; treated vs. control, p<0.05), implantation rate (51 vs. 25%), fetal survival rate (29% vs. 5%) and fetal weight (0.9g vs. 0.5g, p<0.01). All these developmental outcomes in mice were restored, by using Induced IVM, to levels obtained from in vivo matured control oocytes (conventional IVF). In conclusion, Induced IVM mimics some of the characteristics of oocyte maturation in vivo and substantially improves oocyte developmental outcomes. This should lead to an increase in the use of this technique in reproductive biotechnologies.

118 THE PEAK OF OXYGEN CONSUMPTION AT THE TIME OF SPERM PENETRATION IS ASSOCIATED WITH AN INCREASE IN REACTIVE OXYGEN SPECIES PRODUCTION IN BOVINE ZYGOTES

Oxygen is essential for the generation of cellular energy (ATP) via oxidative phosphorylation, and thus oxygen consumption is a key indicator of metabolic activity within cells. Increased oxidative activity at the time of fertilization has been described for marine invertebrate oocytes. The objective of the present study was to determine if changes in oxygen consumption would occur at the time of fertilization and cell cleavage in bovine zygotes. The oxygen consumption of presumptive zygotes (n = 57) was measured individually and continuously from 6 until 30 h after IVF using the Embryoscope™ (Unisense Fertilitech A/S). A control group of in vitro matured oocytes (n = 9) that had not been fertilized was also measured continuously from 6 h after transfer to IVF medium. Time-lapse images were acquired during the measurements at intervals of approximately 36 min and used for evaluation of the developmental progress. Oocytes/zygotes were subsequently stained with Hoechst 33342 for more accurate classification by fluorescence microscopy. Cohorts of oocytes/zygotes (n = 55) were individually stained with REDOX-Sensor Red CC-1 and Hoechst 33342 at 0, 7, 12, 17 and 24 h after IVF and imaged by confocal microscopy to determine the REDOX potential and the distribution pattern as well as nuclear stage. Data was analyzed statistically using Proc Mixed, SAS. The mean oxygen consumption of the developing zygotes peaked markedly at 9 h after fertilization (0.552 nL h–1; value 14% over and above baseline oxygen consumption) and fell abruptly until 20 h after IVF (0.482 nL h–1). Following this, an oxygen peak of lower magnitude (0.487 nL h–1; value 1% over and above baseline oxygen consumption) was observed at the time of the first cleavage (detected between 21 to 32 h). The curve pattern for the control group was statistically different: the mean oxygen consumption was at its greatest from 8 to 12 h after IVF and then fell gradually until 30 h after IVF with no visible small increase in oxygen consumption at the supposed time of first cleavage. Mean respiration rates of the oocytes in the control group were significantly greater than those of the developing zygotes at all time points during the measurements. The mean pixel intensity of the REDOX-Sensor Red CC-1 staining was significantly greater at 7 h and at 24 h after IVF, when compared with the other group. The two distinct peaks of oxygen consumption were coincident with the REDOX pulses occurring at the time of sperm penetration and cell cleavage. However, due to the considerably higher magnitude of the oxygen peak occurring around the time of sperm penetration (signaling fertilization) we were led to speculate that only this peak was associated with an increased reactive oxygen species production. The REDOX pulse observed at the time of cleavage did not seem to be an oxygen-derived REDOX pulse because the oxygen consumption by the bovine zygotes was only changed marginally. ASL is supported by FCT, Portugal. The authors thank Unisense-Fertilitech for their collaboration.

130. MICROARRAY ANALYSIS OF FOETAL MOUSE BRAIN FOLLOWING INDUCTION OF MITOCHONDRIAL DYSFUNCTION DURING PRE-IMPLANTATION EMBRYO DEVELOPMENT

Environmental stress can disrupt mitochondrial function in the pre-implantation embryo, subsequently hindering embryo viability. Brain tissue is also sensitive to developmental perturbations, and we have previously discovered genes involved in neurological function and epigenetic modification are differentially expressed in blastocysts following mitochondrial dysfunction by amino-oxyacetate (AOA). In this study CBAxC57Bl6 2 cell stage mouse embryos were cultured in 5μM-AOA without pyruvate for 72h to induce mitochondrial dysfunction. Blastocyst stage embryos were then transferred to pseudopregnant recipients and the expression profile of day 18 foetal brains was interrogated using microarray. mRNA from mouse whole brain (4 per treatment) was extracted and analysed using an Affymetrix gene array. Ingenuity Pathway Analysis software identified persistent alterations in gene expression pathways in foetal brain after AOA treatment during embryo culture, that were subsequently confirmed by qPCR. Expression was significantly increased by both array and qPCR (>1.5 fold, p<0.05) for; 1) Eomes (1.9, 2.9 fold respectively), a T-box transcription factor involved in differentiation, cell death and development, 2) Nr4a3 (1.8, 2.2 fold respectively), a steroid hormone receptor and putative transcriptional activator and 3) Nola3 (1.7, 1.9 fold respectively), a small nucleolar ribonucleoprotein involved in rRNA processing. Neurological disease, behavioural disorders, carbohydrate metabolism, cellular growth and proliferation, cell death, DNA replication, recombination and repair pathways also showed altered gene expression (>1.25 fold). qPCR was performed on 28 genes exhibiting the greatest change in expression. 24/28 genes confirmed the array data, and of the 4 genes that did not; two had expression not detected by qPCR (Snhg1, Speer6-ps1), and two contradicted array results (Atp1b3 p=0.05, Stk38l p=0.06). This study links mitochondrial dysfunction during early embryo development and persistent molecular changes in the developing foetal brain. This indicates that insults incurred during early embryo development can cause permanent changes that we predict results from aberrant epigenetic modification.

114. HUMAN CUMULUS - OOCYTE COMPLEXES SECRETE CUMULUS EXPANSION ENABLING FACTOR(S)

Interactions between the oocyte and its companion somatic cells are crucial to establish and maintain a highly specialized microenvironment required for oocyte viability. Specifically, cumulus cell expansion in the mouse is reliant on oocyte-secreted factors (OSF). Little is know about factors secreted by the human oocyte and how they may interact with cumulus cells. Therefore, the aim of this study was to establish whether human cumulus oocyte complexes (COC) produce OSF that induces cumulus expansion. COC of patients undergoing routine clinical IVF were cultured individually for 6h following oocyte retrieval. The human oocyte conditioned medium (HOCM) was collected. The bioactivity of OSF in the HOCM was assessed using an established assay of cumulus expansion of mouse oocytectomized complexes (OOX). Cumulus expansion was assessed blinded using the scoring system; 1 (no expansion) to 4 (maximally expanded) and gene expression was assessed by real time RT-PCR. Culture of OOX in control media with or without FSH did not induce expansion. Similarly, OOX cultured in HOCM without FSH did not expand. However, culture of OOX in HOCM with FSH significantly induced expansion (2.4±0.1 compared with control 1.1±0.04, P<0.05). Furthermore, this expansion was not different to OOX co-cultured with human (2.9±0.1) or mouse (2.6±0.1) denuded oocytes. Cumulus/OOX gene expression of hyaluronan synthase-2 and cyclooxygenase-2 was significantly up-regulated 4-5 fold when OOX were cultured in HOCM compared to control (P<0.05). Interestingly, different patients produced HOCM which resulted in different levels of expansion (range from 1.5-3.7). This study has established that human COC secrete paracrine factor(s) that enable cumulus expansion. This expansion was dependent on the presence of FSH. The identity of these factor(s) are currently unknown however it appears that COC from different patients produce differing levels of these cumulus expansion enabling factor(s).

224. Disruption of bi-directional oocyte-cumulus paracrine signalling during oocyte in vitro maturation reduces subsequent mouse fetal survival

During folliculogenesis, oocyte to cumulus cell (CC) bi-directional communication is essential for normal development of the oocyte. We recently showed that addition of recombinant oocyte paracrine factor growth differentiation factor 9 (GDF9) during mouse oocyte in vitro maturation (IVM) increased fetal viability. GD.F. 9 signals through SMAD 2/3. Hence the effects of disrupting SMAD2/3 signalling and its interaction with FSH/EGF during IVM on oocyte development and subsequent fetal outcomes were investigated. Cumulus-oocyte complexes (COCs) from antral follicles (n = 400–500) of eCG treated pre-pubertal (C57BL/6xCBA F1 hybrid) mice were cultured for 18 h in Waymouth's medium+5% serum, with or without 50 mIU/mL FSH and 10ng/mL EGF, SMAD2/3 inhibitor SB-431542 (4µM), or its 0.04% DMSO control. Meiotic maturation was assessed by first polar body (PB1) extrusion immediately after culture. COCs were fertilised and cultured to the blastocyst stage in G1.2/G2.2 media at 37°C in 6%CO2:5%O2:89%N2. Blastocysts were either transferred to pseudo-pregnant Swiss females or differentially stained. Pregnancy outcome was assessed on Day 18 of pregnancy. Inhibition of SMAD 2/3 signalling did not alter meiotic maturation. No differences were observed in the percentage of blastocysts or hatching blastocysts from cleaved embryos with SMAD2/3 inhibition or the absence of FSH/EGF. However, IVM with SB-431542 or without FSH/EGF significantly decreased (P < 0.001) blastocyst inner cell mass percentages (26% v. 35% control;18% v. 28% control respectively). Fetal survival (fetuses per embryo transferred) of oocytes matured with SB-431542 was significantly decreased (30% v. 50% controls; P < 0.05) although implantation rates and subsequent fetal weights were unaffected. These findings demonstrate the importance of oocyte-CC communication throughout IVM. Inhibition of oocyte signalling through SMAD2/3 resulted in reduced blastocyst quality and fetal survival; outcomes similar to that of oocytes matured without FSH/EGF. Oocyte–cumulus cell bi-directional communication is thus an important feature of oocyte viability and has a substantial impact on subsequent fetal outcomes.

403. Differential effect of hexoses on sperm metabolism and function in culture

Currently there is lack information regarding how human spermatozoa regulate their energy metabolism. This is surprising considering that carbohydrate metabolism is a vital point for the understanding of sperm function. This coupled with the increased use of assisted reproductive technology and the importance of a well balanced culture media has led us to hypothesise that an imbalance of carbohydrate presence in the media may alter sperm function, particularly in relation to oxidative stress, DNA damage and lipid peroxidation. Sperm samples were obtained from three healthy normospermic donors for this study. Motile sperm were separated from semen samples using density gradient separation. Samples were incubated at different media conditions with varying glucose or fructose concentrations (0, 2.5, 25 mM) for 6–24hrs. Reactive oxygen species (ROS) were measured using 5-(and-6)-carboxy-2', 7'-dichlorofluorescein diacetate (DCFDA). Sperm DNA damage was determined using terminal deoxynucleotidyl transferase-mediated deoxyuridine triphosphate-nick end labelling (TUNEL). Lipid peroxidation was assessed using the probe BODIPY (581/591) C11. Carbohydrate uptake from the media was measured using a fluorometric procedure. Statistical differences between treatments were assessed by ANOVA and Bonferroni post-hoc test. No significant motility differences were found following treatments. Results showed an increased level of ROS production as glucose concentration increased (P < 0.05). This was accompanied by an increased number of TUNEL positive cells (P < 0.05). Furthermore, lipid peroxidation of spermatozoa was significantly increased when incubated under high glucose concentrations (P < 0.01). In contrast, increases in fructose concentrations did not alter ROS levels or the number of TUNEL positive cells. Sperm metabolised both glucose and fructose in vitro and the removal of one carbohydrate resulted in a compensatory increase in the metabolism of the other. To our knowledge, this is the first report providing evidence that altered carbohydrate metabolism may induce ROS production, lipid peroxidation and increase the number of sperm exhibiting DNA damage.

214. Altered placental gene expression following disruption of mitochondrial metabolism in mouse embryos

Metabolic changes in the preimplantation embryo are known to alter blastocyst viability. We used a mouse embryo model, inhibiting the malate-aspartate shuttle (MAS) which is required for energy metabolism in the early embryo, to examine the consequences on subsequent fetal and placental development, and placental gene expression. Mouse zygotes were obtained from C57BL6xCBA females after gonadotrophin stimulation. Following culture in G1.2 for 48h, 8-cell embryos were cultured to the blastocyst stage in either G2.2 control media (C), G2.2 media without pyruvate (-P), or -P with 0.5 mM aminooxyacetate, an inhibitor of MAS (-P+AOA). Blastocysts were transferred to day 4 pseudopregnant Swiss mice, and fetuses and placentas were harvested on day 18 of pregnancy. RNA was extracted from placentas for real time PCR expression analysis by ddCt relative to 18S. Expression of mitochondrial transcription factors (mTERF, mTFAM, Nrf-1, Nrf-2), glucose transporters (Glut1 and Glut3) and amino acid transporters (Slc38a2 and Slc38a4) were analysed. Following transfer, fetal development per implantation was significantly reduced when embryos were cultured in –P+AOA conditions (25.9%) relative to both C and –P conditions (57.5% and 68.8% respectively). Although placental weight did not differ between treatment groups, fetal weight was significantly reduced for –P and –P+AOA groups (P < 0.05), suggestive of altered placental function thus gene expression was examined. There were no differences in gene expression between placentas from C and –P conditions for any of the genes analysed. When compared with C placentas, -P+AOA conditions reduced the expression of Glut 1 (P = 0.055) and Glut 3 (P = 0.043). The –P+AOA placentas also tended to have significantly reduced expression of Glut 3 (P = 0.06) compared with placentas from –P conditions, but all other genes were expressed similarly. This data suggests that decreased glucose transport may be the cause of reduced fetal growth as a consequence of metabolic perturbations in the embryo.

404. Repercussions of a transient decrease in pH on embryo viability and subsequent fetal development

Changes in the environment to which the preimplantation embryo is exposed can significantly influence fetal outcomes, indicative of ‘embryo programming'. Although many previous in vitro stress models have demonstrated programming changes using high dose stress effects, it is possible to induce similar effects with a physiologically relevant stress model. This study investigates the effect of a subtle transient pH change, during the first cleavage division, on blastocyst viability and fetal outcomes after embryo transfer. Zygotes from F1 hybrid mice (C57BL6xCBA F1) were cultured to the 2-cell stage (19h) in either control G1 medium or in G1 containing a weak acid, 2 mM DMO (5,5-Dimethyl-2,4-oxazolidinedione), then cultured to the blastocyst stage in control media G1/G2 (72h). Exposure to DMO induced a decrease in intracellular pH from 7.25 (control) to 7.10 (DMO). At the blastocyst stage, inner cell mass (ICM) cell number and cellular apoptosis were assessed, or embryos were transferred to pseudopregnant recipients to assess implantation and fetal outcomes. Differences were assessed using Student's t-test or generalised linear modelling followed by post-hoc tests. Exposure to DMO during the first cleavage division significantly reduced total blastocyst cell number from 83.0 ± 6.4 to 63.6 ± 3.8 (P < 0.05), reduced ICM number from 30.6 ± 3.6 to 20.2 ± 1.8 (P < 0.05) and significantly increased the apoptotic cell index from 1.9% to 3.2% (for control verses DMO embryos respectively) (P < 0.05). Blastocyst development was unchanged. Exposure to DMO during the first cleavage division did not alter implantation rates however fetal weight was decreased from 1058.9 mg ± 25.2 (control) to 949.1 mg ± 26.7 (DMO) (P < 0.05) and crown–rump length decreased from 21.9 mm ± 0.4 (control) to 20.6 mm ± 0.5 (DMO) (P < 0.05). In conclusion, this study demonstrates that a transient reduction in pH of only 0.15 units during early preimplantation embryo development significantly reduces resultant blastocyst viability and perturbs fetal growth, indicative of altered embryo programming. The mechanism behind this permanent change however is currently unknown.

262. Human cumulus cell gene expression as a marker of clinical embryo grade

In Australia, Assisted Reproductive Technology (ART) accounts for ~3% of births. However, the success rate remains around 65% for women under 35 years of age, hence multiple embryo transfer is frequently preferred to improve the probabiity of achieving a term pregnancy. A biochemical marker for oocyte and embryo developmental potential would augment successful pregnancy outcomes following IVF/ICSI by optimising oocyte and embryo selection, therefore increasing the number of single embryo transfers (SET) performed in ART cycles. Changes in expression levels in human cumulus cells may reflect the quality of their enclosed oocyte. We investigated cumulus cell gene expression and subsequent embryo development to find a marker of embryo quality. Paired samples of cumulus cells were collected from oocytes that progressed to embryos of either high or low grade from eleven IVF/ICSI patients. Following cumulus oocyte complex retrieval cumulus cells were trimmed from the oocyte, and all oocytes and resulting embryos were cultured and tracked individually. Cumulus cell gene expression was assessed using a real-time RT–PCR assay, measuring expression of cyclooxygenase 2 (COX2; PTGS2), Pentraxin 3 (PTX3), Versican (VCAN), Tumour Necrosis Factor Alpha Induced protein 6 (TNAIFP6; TSG6), Lactate Dehydrogenase A (LDHA), Phosphofructokinase Platelet (PFKP), Gremlin (GREM1), Glyceraldehyde-3-Phosphate Dehydrogenase (GAPDH) and 18S rRNA. Standard curves using plasmid subclones for each target were run to assess copy numbers of genes. Embryo morphology was assessed by an embryologist and correlated with relative gene expression. Cumulus cell gene expression was altered in cumulus cells from oocytes which subsequently developed into higher quality (Grade 1 and 2) embryos compared with cumulus cells from oocytes which developed into lower quality (Grade 3 and 4) embryos. This may lead to establishment of markers prognostic for developmental outcome, facillitating more reliable selection of higher quality embryos, increasing single embryo transfers and improving health outcomes from ART.

261. Disruption of mitochondrial function in the blastocyst alters expression of the chromatin remodeler ATRX

Exposure of an embryo to suboptimal environments, including poor embryo culture media or inadequate maternal diet, can disrupt fetal and placental development and whilst the exact mechanisms responsible remain unknown, perturbed embryo metabolism has been implicated. We propose that stress applied to an early embryo causes mitochondrial dysfunction, resulting in a permanent epigenetic change. Thus the aim of this study was to determine the affect of directly perturbing mitochondria in the embryo, on development, metabolism and expression of the ATP-dependant chromatin remodelling protein, ATRX. Zygotes collected from gonadotrophin stimulated C57BL/6xCBA mice were cultured to the two-cell stage and then exposed to one of three treatments; control medium (C), medium lacking pyruvate (-P; embryos dependant on the mitochondrial Malate Aspartate Shuttle, MAS) or medium lacking pyruvate plus 5µM amino-oxyacetate (AOA), a specific MAS inhibitor (-P+AOA). Blastocyst development and metabolism were assessed by determining cell number and allocation, glycolysis, and ATP:ADP ratio. Relative gene expression of ATRX, was examined using RT PCR. Embryos dependant on the MAS alone (-P) had significantly decreased blastocyst development (87.1% v. 98.2%, P < 0.05), with a compensatory increase in glycolysis (0.20 v. 0.07 pmol/cell/hr, P < 0.001) despite a decrease in ATP:ADP (0.10 v. 0.13, P < 0.06), relative to the control. Inhibition of the MAS (-P+AOA) further reduced blastocyst development,(77.3%, P < 0.001) and decreased ATP:ADP (0.08, P < 0.004), but there was no change in glycolysis relative to control embryos (0.09 pmol/cell/hr, P = 0.3). Expression of ATRX was significantly increased for –P+AOA embryos relative to the control (1.63 v. 1.0, P < 0.007) but did not differ for –P embryos (1.1). This study demonstrates that direct perturbations of mitochondrial function in the embryo compromises its metabolic regulation and blastocyst development, and the expression of the epigenetic modulator ATRX. Further studies are underway to elucidate the implications of disrupted metabolic control and this epigenetic modulator on pregnancy outcomes.

Oxygen concentration during mouse oocyte in vitro maturation affects embryo and fetal development

BACKGROUND

Little is known of how the oxygen environment in the ovarian follicle affects oocyte and embryo development, but this has an important impact on the conditions used for in vitro maturation (IVM) of oocytes. We investigated the effect of varying oxygen concentrations during IVM on subsequent pre and post-implantation development.

METHODS

IVM of mouse cumulus-oocyte complexes (COCs) was performed under 2, 5, 10 or 20% O(2) (6% CO(2), balance N(2)). In vivo-matured COCs were collected post ovulation. Embryos were generated by IVF and culture. Blastocyst development, cell number and apoptosis were assessed, and fetal and placental outcomes analysed following embryo transfer at day 18 of pregnancy.

RESULTS

Oxygen concentration during IVM did not affect oocyte maturation or subsequent fertilization, cleavage and blastocyst development rates. Maturation of oocytes under 2% O(2) increased blastocyst trophectoderm cell number compared with all groups and numbers at 5% were higher than 20% (both P < 0.05). Percentage of apoptotic cells was increased in blastocysts developed from 2% O(2)-matured oocytes, compared with maturation at 5% O(2) or in vivo (P < 0.05). Rates of embryo implantation and development into a viable fetus were not altered by IVM oxygen. However, fetal weight was reduced following oocyte maturation at 5% O(2) compared wiht 20% O(2) and maturation at 5% O(2) also reduced placental weight, when compared with in vivo-matured oocytes (both P < 0.05).

CONCLUSIONS

Level of O(2) exposure during oocyte maturation can alter the cellular composition of blastocysts, but these changes in cell number do not correlate with the altered fetal and placental outcomes after transfer.

Metabolism of the bovine cumulus-oocyte complex and influence on subsequent developmental competence

The two types of cells that make up the cumulus-oocyte complex (i.e. the oocyte and cumulus cells) have very different metabolic demands, with glucose occupying a central role in metabolic activity. Cumulus cells have a significant requirement for and utilise high levels of glucose, yet appear to have little need for oxidative metabolism. In contrast, oocytes have a requirement for oxidative metabolism, although limited glucose metabolism may also be an important aspect of meiotic and developmental competence. Nevertheless, because of the metabolic and communication link between the cumulus and the oocyte, glucose availability and metabolism within the cumulus can have a significant impact on oocyte meiotic and developmental competence. In particular, the role of the hexosamine biosynthesis pathway within cumulus cells appears critical for the supply of substrate from glucose for extracellular matrix production, yet if overstimulated can significantly decrease developmental competence of the oocyte. Current static systems for in vitro maturation are clearly incompatible with meeting substrate demands, especially glucose. In the future, in vitro maturation will include a more dynamic approach, which will adjust nutrient components to meet the changing functional requirements of cumulus-oocyte complexes during the final process of maturation.

339 OXYGEN CONCENTRATION DURING IN VITRO MATURATION OF MURINE OOCYTES INFLUENCES SUBSEQUENT FETAL AND PLACENTAL OUTCOMES

Although the oxygen environment of the ovarian follicle is thought to influence oocyte developmental competence, little is known of the optimal oxygen environment for oocyte in vitro maturation (IVM). Previously, we found that oxygen concentration (either 2, 5, 10, or 20% O2; 6% CO2; and balance of N2) during IVM of murine oocytes had no effect on maturation rate or subsequent fertilization, cleavage, and blastocyst development rates. However, 2% O2 results in blastocysts with a higher (P &lt; 0.05) trophectoderm cell number (mean � SEM, 35.1 � 2.3) when compared to 20% (19.4 � 1.7), with 5 and 10% O2 yielding similar but intermediate cell numbers. When examined for cell apoptosis by TUNEL labelling, the 2% O2 IVM-derived embryos were also found to have a significantly higher percentage of cells undergoing apoptosis compared to the 5% O2 IVM-derived embryos and embryos derived from in vivo matured oocytes (unpublished data). Although the blastocyst development rate is not affected by varying oxygen environment during oocyte maturation, the resultant blastocysts exhibited signs of differing quality. The aim of this study was to investigate the effect of varying oxygen during IVM on post-transfer outcomes. Immature cumulus-oocyte complexes (COCs) were collected from the ovaries of eCG-stimulated CBAB6F1 females (21 days) and cultured for 17–18 h under 2, 5, or 20% O2, whereas in vivo-matured COCs were also collected post-hCG. After IVF/C (both under 5% O2), 6 blastocysts were transferred to each uterine horn of pseudopregnant Swiss recipients. Fetal and placental parameters were measured on Day 18 of pregnancy. The ability of the embryos to implant or develop was not altered by IVM oxygen concentration. However, the average weight of fetuses derived from 5% O2 matured oocytes was reduced (823.3 � 28.1 mg, P &lt; 0.05) compared to those in the 20% O2 group (928.5 � 26.1 mg). The average weight of the placenta in the 5% O2 group was also reduced (87.4 � 4.0 mg) compared to those derived from in vivo-matured oocytes (104.5 � 5.4 mg). In contrast, the fetal:placental weight ratio was unchanged in the 5% O2 treatment, suggesting these placentae, although small, are still efficient. This is the first evidence that programming of fetal/placental growth occurs from treatments applied during oocyte maturation.

A comparison of hypnotic and analgesic based sedation in a general intensive care unit †

BACKGROUND

Sedation of the critically ill patient has several components including hypnosis and analgesia. Hypnotic-based sedation (HBS), where midazolam and/or propofol are used, with morphine or another analgesic added as needed has been common. The advent of remifentanil has allowed greater use of analgesia-based sedation (ABS) where relief of discomfort from the tracheal tube or pain are the important objectives, and hypnosis is given as necessary. Method. We compared HBS and ABS (remifentanil-based sedation) within a general intensive care unit (ICU). During the first study period of 12 weeks, 111 patients received HBS. After the development of new guidelines for the use of remifentanil in the ICU, a second 12 week study period used an analgesia-based regimen, with hypnotics added only if needed.

RESULTS

Ninety-six patients received ABS, and 79 received remifentanil. It was possible to manage 29 (37%) of the patients receiving remifentanil without the use of supplementary hypnotic agents. In the remaining 63% the use of remifentanil was associated with a reduction in the amount and duration of propofol used. Significantly more patients receiving ABS had satisfactory levels of sedation during synchronized intermittent mandatory ventilation (19 [2,55] vs 50 [14,83], P<0.001).

CONCLUSIONS

The use of ABS allowed patients to be managed more comfortably, either without a hypnotic drug or with less hypnotic drug, than using conventional HBS.

Efficacy of particle-based DNA delivery for vaccination of sheep against FMDV

As an alternative strategy to classical inactivated viral vaccine against FMDV, naked DNA vaccine is attractive because of safety, flexibility and low cost. However DNA vaccination is usually poorly efficient in target species. Indeed we found that naked DNA plasmids encoding for P1-2A3C3D and GM-CSF proteins did not induce any detectable immunity against FMDV in sheep. Interestingly, we demonstrate herein that formulations of DNA on poly(D,L-lactide-co-glycolide) (PLG) or in lipofectin triggered divergent types of immune responses: PLG stimulated a T cell response and could elicit significant neutralising antibody titers, whereas lipofectin generated even higher antibody titers but no significant T cell response. The DNA/PLG regimen used in five sheep protected against clinical symptoms and viraemia and prevented the carrier state in four of them. Thus formulated DNA can be remarkably efficient against FMDV in a ruminant species that is usually refractory to DNA vaccination.