Biomarkers and prognostic stratification in psoriatic arthritis

In rheumatic diseases, biomarkers may serve as surrogate endpoints for diagnosis, prognosis, disease activity, therapeutic response and disease outcome. In recent years a great effort has been made to identify useful tools to establish early diagnosis, prognosis and therapeutic response especially in rheumatoid arthritis (RA). In psoriatic arthritis (PsA) serological biomarkers have been frequently borrowed from RA, but this approach have sometimes lead to inappropriate choices of biomarkers and incorrect conclusions. Furthermore, the heterogeneous spectrum of articular manifestation of PsA and the variable course of the disease can make diagnosis and prognosis difficult. Recently, the Group for Research and Assessment of Psoriasis and Psoriatic Arthritis (GRAPPA) identified two key areas for biomarkers development in psoriasis and PsA: the diagnosis of the articular disease in patients with psoriasis and the evaluation of joint damage in PsA. In this review we revised the currently available and the new potential markers for PsA, such as serum, genetic, cellular and histological biomarkers, clinical and imaging data, with particular attention on the prognostic aspect in order to identify progressive disease suitable for a more aggressive treatment.

Unveiling mRNA changes during meiotic progression and pre-implantation development: help from large animal models

Assisted reproductive technologies (ART) are successfully applied in several mammals, including humans, thanks to the ability of oocytes and embryos to face maturation, fertilization and first development in vitro. However, efficiency and safety of ART represent main issues. Mammalian oocytes and early embryos are transcriptionally inactive, and rely exclusively on maternal RNAs and proteins, deposited during oocyte growth, until embryonic genome activation (EGA). Such transcriptional quiescence needs complex post-transcriptional and post-translational mechanisms to coordinate meiotic maturation, fertilization, and reprogramming of the nascent genome. These events are the final outcome of complex, hormonally regulated biological processes that translate into specific molecular mechanisms, which are still far from being fully understood. A deep knowledge of these early phases of development is crucial to understand the core mechanisms of life onset, and to optimize the safety and efficiency of in vitro reproductive technologies. This work focuses on meiotic progression and pre-implantation development in mammals, underlining the importance of fundamental molecules stored during oocyte growth and selectively used during early embryogenic stages. Taking into account the species-specific behaviour of these pivotal molecules, this review describes the advantages of using large domestic animals for research in the reproductive field and proposes large domestic animals as models to improve human ART.

High hydrostatic pressure treatment improves the quality of in vitro-produced ovine blastocysts

Exposure to sub-lethal hydrostatic pressure (HP) treatment is emerging as an approach to improve the general resistance of gametes and embryos to in vitro conditions. The present study was aimed to evaluate the effect of HP treatment on in vitro-produced ovine blastocysts. Experiment 1 was aimed to define optimal treatment parameters: two different HP treatments were applied to blastocysts and embryo survival was evaluated. In Experiment 2, HP parameters (40 MPa, 70 min, 38 °C) selected in Experiment 1 were used to treat blastocysts. Embryo quality was assessed and compared with untreated controls by counting total cell number, the inner cell mass (ICM) and trophectoderm (TE) cells and by evaluating nuclear picnosis. HP-treated blastocysts were processed for gene expression analysis (AQP3, ATP1A1, BAX, CDH1, HSP90β, NANOG, OCT4 and TP53) 1, 5h after the end of HP exposure. Results showed that the hatching rate of embryos treated at 40 MPa was significantly higher than that of the 60 MPa-treated group (P<0.01) and similar to untreated embryos. Blastocysts exposed at 40 MPa showed higher ICM (P<0.05) and TE (P<0.01) cell number and a lower percentage of picnotic nuclei (P<0.05) compared with the control group. Significantly lower abundance for BAX (P<0.01) and OCT4 (P<0.05) transcripts were observed in HP embryos than in the control group. In conclusion, treatment with HP improved the quality of in vitro-produced ovine blastocysts by increasing their cell number and reducing the proportion of nuclear picnosis.

124 EXPRESSION OF PLURIPOTENCY MARKERS IN GENITAL RIDGES OF OVINE FOETUSES

Fundamental problems of primordial germ cell (PGC) allocation, characterization, lineage restriction, and differentiation have been extensively studied in the mouse. Historically, these cells can be identified using criteria as alkaline phosphatase, but also by the expression of other pluripotency markers suchas OCT4, Nanog, cKIT, SSEA1, SSEA4. Much less is known about PGC inother mammals. The objective ofthis study wasto describe, for the first time, the expression of multiple pluripotency markers in the genital ridges of ovine fetuses evaluating the binding of antibodies for stem cell surface markers (SSEA-1 and EMA-1) and the expression of Oct4, Nanog, and Sox2 genes. Ovine fetuses (24 and 27 days) were collected from slaughtered ewes and transported in a PBS solution at 4°C, to be processed as follows: Immunohistochemistry: 4 foetuses for each age were frozen in OCT TissueTek freezing compound and stored at -80°C. Tissue blocks were cut in 6-μm sections, placed on slides, and immediately prepared for indirect immunofluorescent staining. Section were fixed in 4% paraformaldehyde (10 min) and incubated overnight with SSEA-1 (1:100) and EMA-1 (1:50) antibodies (Hybridoma bank). Antibodies were detected with fluorescently-labelled goat anti-mouse secondary antibodies (1:100 dilution; Sigma) in 15% goat serum in DPBS for 1 h at room temperature. After washing, slides were mounted using ProLong antifade mounting medium (Molecular Probes). Gene expression: total RNA was extracted from fetal genital ridge samples with Trizol™ (Invitrogen). Any contaminating DNA was removed with RNase-free DNase I (Invitrogen). First strand cDNA synthesis was performed with SuperScript™ III RNase H-Reverse Transcriptase (Invitrogen) in the presence of RNase inhibitor (Promega). Real Time PCR amplification was performed in a BioRad iCycler™, with Platinum SYBR Green qPCR Super Mix UDG (Invitrogen). The relative quantification of the target genes was calculated with the 2-ddCt method (Livak and Schmittgen 2001 Methods 25, 402-408), after normalization against β-actin expression levels. Fragment identity was confirmed by sequencing. Our results indicate that the cortical region of the genital ridges is positive to stem cell surface markers. A larger number of positive cells was recorded in Day 24 fetuses with respect to Day 27 ones. The SSEA-1 and EMA-1 showed identical expression patterns. Similar levels of Oct4 and Nanog mRNA were detected in the genital ridges at both stages, whereas Sox2 displayed a lower abundance at Day 27. In conclusion, ovine PGC can be recognized by stem cell surface antigens and by the expression of Oct4, Nanog, and Sox2 pluripotency markers, as in mouse. The combined biomolecular and immunohistochemical approach provides a useful tool to follow the ovine PGC during in vitro culture to derive pluripotent stem cells in this species.

324 CELL LINES DERIVED FROM MAMMALIAN PARTHENOGENETIC EMBRYOS DISPLAY ABNORMAL CHROMOSOME COMPLEMENTS AND ABERRANT CENTRIOLE NUMBER

Mature oocytes can be activated in vitro, leading to the generation of parthenotes that will develop in culture forming blastocysts morphologically indistinguishable from those derived from fertilized eggs. Parthenotes have been used as a source of pluripotent cells that show the traditional features associated with their biparental counterpart: expression of totipotency markers, telomerase activity, embryoid body formation, in vitro differentiation and, in most cases, teratoma formation. However, many aspects still need to be elucidated and, in particular, little attention has been paid to the inci- dence of aneuploidy in these cells. Limited data available for parthenotes derived from different mammalian species indicate a high rate of aneuploidy, whichis consideredtobecaused by the lackofthe paternal contribution, because alterations of the centrosome are knowntolead to multipolar spindles that, in turn, cause aneuploid cells. In this study, we analyzed the rate of aneuploidy and centriole distribution (as a marker of centrosome anomalies) in pluripotent cell lines (pSC) previously derived in our laboratory from pig parthenogenetic embryos and in primary fibroblast cultures and sections obtained from sheep parthenogenetic fetuses (n = 3) that reached 24 days of development in vivo. This protocol was chosen to separate the effect related tooocyte activation from those of the procedures used to derive pSC lines. Centriole number and distribution were assessed both by immunocy- tochemical analysis using an anti-centrin-1 antibody (1 : 200, Abcam, Cambridge, UK) and an appropriate secondary antibody, and by ultrastructural evaluation of thin sections, using a Jeol 1010 EX electron microscope (Jeol, Tokyo, Japan). Karyotyping was performed on mitotically active cells. Metaphases were fully karyotyped under a Leica HC microscope (Wetzlar, Germany). Images were then captured with a Leica DC250 digital camera and cells karyotyped using the Leica CW4000 Karyo software. The results obtained indicate that cell lines of parthenogenetic origin have, in all examined cases, an incidence of aneuploidy significantly higher than that of their respective controls. In particular, although the diploid configuration represented the modal value, the majority of the cells displayed a consistently lower number of chromosomes, between <1N (hypohaploid) and >1N to <2N (hypodiploid).This resultis possibly related toa lossofchromosomes during the mitotic process.Ahigher incidence ofmultiple centrioles was also detected, suggesting that aneuploidy may be related to the lack of paternal contribution that results in abnormal centrosome formation, incorrect control of the process of spindle rearrangement, and consequent chromosomal malsegregation.Abnormal segregation and multicentriolar distribution were not limited to parthenogenetic cell lines but was observed in parthenotes as well, indicating that culture artifacts are unlikely to be the cause. PUR 2007, PUR 2008.

87 HIGH HYDROSTATIC PRESSURE TREATMENT IMPROVES THE QUALITY OF IN VITRO-PRODUCED OVINE BLASTOCYSTS

High hydrostatic pressure (HHP) has been introduced into the field of embryology recently. It has been reported that a sublethal HHP could induce the synthesis of molecular chaperons to protect the embryos from other environmental stresses. The possible beneficial effect of HHP was examined on embryo vitrification, and improved cryotolerance has been achieved in HHP-treated mouse and bovine embryos. In the present study we evaluated, first, the behavior of in vitro-produced ovine blastocysts after treatment with 2 different HHP conditions. In the second part of the study, optimized pressure treatment was combined with a cryopreservation protocol. Day 7 in vitro-produced ovine blastocysts were loaded in 0.5-mL straws and pressure treated in a custom-made hydrostatic pressure chamber (Cryo-Innovation Ltd., Budapest, Hungary) according to the following conditions: -60 MPa, 70 min, 38°C; and -40 MPa, 70 min, 38°C. After HHP treatment, embryos were cultured for 24 h and their survival evaluated upon morphological appearance, re-expansion of the blastocoel, and hatching from the zona pellucida. Blastocysts were fixed and stained, observed with confocal microscope to evaluate blastocyst cell number, and mitotic and picnotic index. Untreated blastocysts were used as controls. On the basis of results obtained in this experiment, groups of blastocysts were exposed to 40 MPa for 70 min at 38°C and, following 2 h incubation after HHp treatment, were vitrified using cryotops. After warming, embryos were checked for re-expansion and hatching and finally fixed and stained as described for fresh embryos. Vitrified untreated blastocysts were used as controls. Results showed that the hatching rate of embryos treated at 40 MPa was significantly higher than that of 60 MPa-treated group (87.5 v. 0%; P < 0.01, chi-squared test) and similar to that of control embryos (85.3%) after 24 h culture. Blastocysts exposed at 40 MPa showed higher cell number compared with control embryos (161.3 ± 8.7 v. 123.9 ± 9.4, P < 0.01, ANOVA ± SD) and a lower picnotic index (PI: 1.3 ± 0.4% v. 3.8 ± 0.6%, P < 0.05). Similar re-expansion rate has been recorded between HHP treated and untreated (86.6 v. 89.6%) vitrified blastocysts as well as hatching rates (53.3 v. 48.3) and embryo cell number (131 ± 4.6 v. 139 ± 5.8). Conversely, HHP treatment significantly decreased picnotic index of vitrified treated embryos compared with control (2.3 ± 0.9 v. 4.8 ± 0.5, P < 0.05). We concluded that HHP treatment significantly improved the quality of in vitro-produced ovine blastocysts by increasing their cell number and reducing the proportion of picnosis. The HHP treatment exerted a positive effect in vitrified blastocysts, decreasing the number of picnotic nuclei. Further studies are needed to evaluate the possible beneficial effect at the molecular level of HHP treatment after vitrification and also to test if different interval times between HHP treatment and embryo cryopreservation could affect embryo response.

In vitro production and cryotolerance of prepubertal and adult goat blastocysts obtained from oocytes collected by laparoscopic oocyte-pick-up (LOPU) after FSH treatment

This study compares the developmental capacity and cryotolerance of embryos produced from oocytes of stimulated prepubertal and adult Sarda goats. Twelve prepubertal and 13 adult goats were each given 110 and 175 IU FSH, respectively, and cumulus-oocyte complexes (COCs) were collected by laparoscopic oocyte-pick-up (LOPU). After in vitro maturation, fertilisation and culture (IVMFC), blastocysts were vitrified, warmed and blastocoel re-expansion and gene expression were evaluated. Prepubertal goats produced a higher COCs number than adults (mean +/- s.e.m., 89.67 +/- 5.74 and 26.69 +/- 3.66, respectively; P < 0.01). Lower developmental competence was demonstrated in the prepubertal oocytes as shown by a higher number of COCs discarded before IVM (21.1% and 14.7% for prepubertals and adults, respectively; P < 0.01) and IVF (23.4% v. 9.1%; P < 0.01) and by the lower cleavage (55.6% and 70.3%, respectively; P < 0.01) and blastocyst rates (24.2% and 33.9%, respectively; P < 0.05). Compared with the adult, prepubertal vitrified/warmed blastocysts showed significantly (P < 0.05) lower in vitro viability, as determined by the re-expansion rate (62.5% and 40.3%). No differences were observed in the time required for blastocoel re-expansion or in cyclin B1, E-cadherin, Na/K ATPase, HSP90beta and aquaporin 3 messenger RNA quantity. These results show that in vitro-produced embryos produced from prepubertal goat oocytes have a lower developmental rate and cryotolerance compared with their adult counterparts. However, we can assume that the quality of re-expanded embryos does not differ between the two groups.

177 EMBRYOS PRODUCED IN VITRO FROM PREPUBERTAL LAMB AND ADULT SHEEP OOCYTES DISPLAY DIFFERENT GENE EXPRESSION PATTERNS

Breeding from prepubertal females reduces the generation interval and increases the rate of genetic gain in animal breeding programs. Despite considerable interest in this technology, its efficiency remains too low. Reduced in vitro and in vivo developmental competence of oocytes derived from prepubertal animals have been reported in association with morphologic, metabolic, and biochemical differences. The objective of this study was to compare the relative transcript abundance of a panel of developmentally important genes in embryos produced in vitro from prepubertal lamb and adult sheep oocytes. Cumulus–oocyte complexes derived from ovaries of regularly slaughtered 1-month-old prepubertal and adult sheep were matured in vitro in TCM-199 with 10% heat-treated oestrus sheep serum (OSS), 10 μL mL–1 of FSH/LH and 100 μm cysteamine, in 5% CO2 in air at 38.5°C for 24 h. Matured oocytes were fertilized with frozen–thawed ram semen in SOF medium + 2% OSS for 22 h at 38.5°C and 5% CO2, 5% O2, and 90% N2 atmosphere. Zygotes were cultured in SOF + AA + 0.4% BSA in 5% CO2 and 5% O2 up to blastocyst stage. Three groups of 10 blastocysts for each class (4 replicates) were used to quantify the relative expression of 15 genes by reverse transcription followed by real-time PCR. The relative quantification of the transcripts was performed with the 2-ddCt method (Livak and Schmittgen 2001 Methods 25, 402–408), after normalization against the β-actin expression levels. The analysis of gene expression evidenced higher relative abundance for Aquaporin 3, P34Cdc2, cyclin B, Oct4, H2A.Z, and Nanog transcripts in sheep embryos than in prepubertal-derived ones (ANOVA; P < 0.05), while interferon τ and insulin-like growth factor (IGF) 2 mRNAs were significantly more abundant in lamb-derived embryos (ANOVA; P < 0.01). No differences were observed for the remaining analyzed transcripts (BAX, IGF2R, heat shock protein 90, NaKATPase, E-cadherin, PAP, and glyceraldehyde 3-phosphate dehydrogenase). Overall, results show that embryos produced in vitro from prepubertal and adult oocytes display different patterns of expression at the blastocyst stage. Such difference may be related to the generally observed reduced in vitro and in vivo developmental competence. Increased understanding of the gene expression status during pre-implantation development may provide valuable insights into the molecular basis underlying the very early stages of life and an opportunity for optimizing in vitro embryo production systems.

Expression pattern of zygote arrest 1 (ZAR1), maternal antigen that embryo requires (MATER), growth differentiation factor 9 (GDF9) and bone morphogenetic protein 15 (BMP15) genes in ovine oocytes and in vitro-produced preimplantation embryos

The expression patterns of four maternal effect genes (MEG), namely zygote arrest 1 (ZAR1), maternal antigen that embryo requires (MATER), growth differentiation factor 9 (GDF9) and bone morphogenetic protein 15 (BMP15), were determined in ovine oocytes and in vitro-produced preimplantation embryos. The existence of ZAR1 and MATER in ovine species has not been reported previously. Reverse transcription–polymerase chain reaction was performed on germinal vesicle and IVM MII oocytes, as well as in in vitro fertilised and cultured two-, four-, eight- and 12/16-cell embryos, morulae and blastocysts. Quantification of gene expression by real-time polymerase chain reaction showed the highest abundance of all transcripts analysed in the immature oocyte. During the following stages of preimplantation development, the mRNAs examined exhibited different patterns of expression, but often significant decreases were observed during maturation and maternal–embryonic transition. The transcription of the four genes did not resume with activation of the genome.

Morphological and biochemical analysis of immature ovine oocytes vitrified with or without cumulus cells

The cryopreservation of oocytes is an open problem as a result of their structural sensitivity to the freezing process. This study examined (i) the survival and meiotic competence of ovine oocytes vitrified at the GV stage with or without cumulus cells; (ii) the viability and functional status of cumulus cells after cryopreservation; (iii) the effect of cytochalasin B treatment before vitrification; (iv) chromatin and spindle organization; (v) the maturation promoting factor (MPF) and mitogen-activated protein kinase (MAPK) activity of vitrified oocytes after in vitro maturation. Sheep oocytes were vitrified at different times during in vitro maturation (0, 2, and 6 h) with (COCs) or without cumulus cells (DOs). After warming and in vitro maturation, oocytes denuded at 0 h culture showed a significantly higher survival and meiotic maturation rate compared to the other groups. Hoechst 33342/propidium iodide double staining of COCs and microinjection of Lucifer Yellow revealed extensive cumulus cell membrane damage and reduced oocyte-cumulus cell communications after vitrification. Cytochalasin B treatment of COCs before vitrification exerted a negative effect on oocyte survival. After in vitro maturation, the number of vitrified oocytes with abnormal spindle and chromatin configuration was significantly higher compared to control oocytes, independently of the presence or absence of cumulus cells. The removal of cumulus cells combined with vitrification significantly decreased the MPF and MAPK levels. This study provides evidence that the removal of cumulus cells before vitrification enhances oocyte survival and meiotic competence, while impairing the activity of important proteins that could affect the developmental competence of oocytes.

Effect of vitrification solutions and cooling upon in vitro matured prepubertal ovine oocytes

The vitrification procedure effects on molecular and cytoskeletal components and on developmental ability of in vitro matured prepubertal ovine oocytes were evaluated. MII oocytes were divided into three groups: (1) vitrified in cryoloops (VTR); (2) exposed to vitrification solutions and rehydrated without being plunged into liquid nitrogen (EXP); (3) without further treatment as a control (CTR). Two hours after treatment, membrane integrity, assessed by propidium iodide/Hoechst staining, was lower in VTR and EXP than in CTR (70.6%, 88.5% and 95.2%, respectively). Cleavage rate after fertilization was statistically different among all groups (21.4%, 45.4% and 82.8% for VTR, EXP and CTR groups respectively; P<0.01). Blastocyst rate in VTR (0.0%) and EXP (2.8%) groups was lower (P<0.01) than in CTR (22.8%). Maturation promoting factor activity was lower (P<0.01) in VTR and EXP groups compared with CTR at both 0 h (82.2%, 83.6% and 100%, respectively) and 2 h (60% and 53.9% and 100%, respectively) after warming. Immediately after warming VTR and EXP oocytes showed a lower rate of normal spindle and chromosome configuration compared to CTR (59.1%, 48.0% and 83.3%, respectively; P<0.01). After 2 h of culture in standard conditions the percentage of oocytes with normal spindle and chromosome organization decreased in both VTR and EXP groups compared to CTR (36.4%, 42.8% versus 87.5%, respectively). In conclusion the exposition to the tested cryoprotectant solution and the vitrification in cryoloops modified cytoskeletal components and alter biochemical pathways that compromise the developmental capacity of prepubertal in vitro matured ovine oocytes.

A Low Oxygen Atmosphere during IVF Accelerates the Kinetic of Formation of In Vitro Produced Ovine Blastocysts

Among the factors that affect in vitro embryo development, oxygen atmosphere is considered to be of great influence. In this study, we evaluated the influence of two different oxygen atmospheres during in vitro fertilization (IVF) of ovine oocytes on their developmental capacity and quality assessed by cryotolerance. Cumulus oocyte complexes derived from ovaries of slaughtered sheep were matured in vitro and subsequently fertilized under low (5%) or high (20%) oxygen atmospheres, and cultured in SOF + aa + 0.4% BSA in 5% CO2 and 5% O2 up to blastocyst stage. The cleavage rates obtained in the fertilization system at 20% O2 were significantly higher than those obtained in the 5% O2 fertilization system (61.2% vs 50.8%; p < 0.01). The distribution of cleaved oocytes at 22, 26 and 40 h of culture intervals was not different in the low or high O2 atmosphere (31.4%, 26.4% and 42.1% vs 28.0%, 29.3% and 42.7% respectively). Blastocysts output on the 6th day post-fertilization (dpf) was significantly higher when oocytes were fertilized under 5% O2 concentration (63.04% in 5% O2 vs 47.36% in 20% O2), while on the 7th dpf the higher number of blastocysts was obtained in the 20% O2 system (35.10%.in 20% O2 vs 26.09% in 5% O2). After vitrification no differences were observed between low or high oxygen atmosphere in the viability rates of blastocysts obtained on day 6 (93.6% vs 96.5%), on day 7 (46.3% vs 41.7%) and on day 8 (11.1% vs 6.6%). After differential staining, no significant differences were observed in the total cell number and inner cell mass and trophoblastic cells ratio of blastocysts produced on 6 dpf (189.6 +/- 51.3 and 0.260 +/- 0.07 vs 223.3 +/- 45.6 and 0.277 +/- 0.09), on 7 dpf (168.3 +/- 25.1 and 0.316 +/- 0.06 vs 172.1 +/- 33,6 and 0.320 +/- 0.06) and on 8 dpf (121.2 +/- 23,8 and 0.302 +/- 0.03 vs 117.0 +/- 35.1 and 0.313 +/- 0.04) under low or high oxygen atmosphere respectively). In conclusion, our data suggest that low oxygen atmosphere during IVF affects positively the production of high quality ovine blastocysts.

108 EFFECT OF CAFFEINE TREATMENT ON MPF AND MAPK ACTIVITY AND PARTHENOGENETIC ACTIVATION OF VITRIFIED MII OVINE OOCYTES

Cryopreservation of oocytes is still an open problem because of their structural sensitivity to the cooling and freezing process. Meiotic spindle disorganization and chromosomal aberrations are frequently observed, possibly due to the alteration of molecules involved in the meiotic cell cycle regulation and spindle formation such as maturation promoting factor (MPF) and mitogen-activated protein kinase (MAPK). In this study we treated MII ovine oocytes with caffeine before vitrification and we evaluated the effect on (1) MPF and MAPK activity and (2) oocyte spontaneous or induced parthenogenetic activation. Oocytes from slaughterhouse sheep ovaries were in vitro-matured for 21 h in TCM-199 + 10% FCS + FSH, LH + cysteamine, and then incubated for 2 h with (+) or without (-) caffeine (20 mM; Sigma-Aldrich, Milan, Italy). Thereafter, MII oocytes were vitrified by equilibration with 10% ethylene glycol (EG) + 10% DMSO (30 s), exposure to 20% EG + 20% DMSO + 0.5 M sucrose (20 s), loading onto the Cryotop, and plunging into liquid nitrogen. After warming, groups of (+) and (-) oocytes were used for MPF and MAPK assays or (A) cultured in TCM-199 + 10% FCS for 24 h to evaluate spontaneous parthenogenetic activation, or (B) activated with ionomycin (5 �M, 5 min; Sigma) and cultured as in A. Fresh (+) and (-) oocytes were processed as above as controls. All oocytes were stained with glycerol-Hoechst 33342 to evaluate chromatin configuration. After vitrification, similar rates of spontaneous parthenogenetic activation between (+) and (-) oocytes (12/38, 31.6% vs. 16/38, 42.1%, respectively) were observed. However, the number of oocytes with a regular chromatin configuration in the MII plate was significantly higher (P &lt; 0.01; chi-square test) in vitrified (+) compared to (-) oocytes (22/38, 57.9% vs. 4/38, 10.5%, respectively). After incubation with ionomycin, a significantly (P &lt; 0.05) lower proportion of activated oocytes was recorded in the (+) compared to the (-) group (19/49, 38.8% vs. 32/53, 60.4%, respectively). In the control oocytes, the treatment with caffeine significantly (P &lt; 0.01) decreased the activation rate after ionomycin stimulation compared to that of non-caffeine-treated control oocytes (6/51, 11.8% vs. 28/46, 60.9%, respectively), but no difference in spontaneous parthenogenetic activation was found between (+) and (-) groups (6/38, 15.8% vs. 6/46, 13.0%, respectively). Analysis of MPF and MAPK activities showed that caffeine treatment significantly increased (P &lt; 0.05; ANOVA) the levels of the 2 kinases of vitrified MII oocytes, and these values are comparable to those of MII fresh oocytes. These results show that caffeine can increase MPF and MAPK activity in vitrified ovine oocytes and thus may contribute toward maintaining a regular chromatin organization in the MII plate and toward the decrease in parthenogenetic iomomycin-induced activation. Experiments are in progress to test the efficiency of caffeine treatment to improve the development competence of vitrified MII ovine oocytes.

Vitrification devices affect structural and molecular status of in vitro matured ovine oocytes

We evaluated the effect of three different cryodevices on membrane integrity, tubulin polymerization, maturation promoting factor (MPF) activity and developmental competence of in vitro matured (IVM) ovine oocytes. IVM oocytes were exposed during 3 min to 7.5% DMSO and 7.5% ethylene glycol (EG) in TCM199 and 25 sec to 0.5 M sucrose, 16.5% DMSO and 16.5% EG, loaded in open pulled straws (OPS), cryoloops (CL) or cryotops (CT) and immersed into liquid nitrogen. Untreated (CTR) or exposed to vitrification solutions but not cryopreserved (EXP) oocytes were used as controls. After warming, double fluorescent staining evidenced a lower membrane integrity in vitrified groups compared to the controls (P < 0.01). After in vitro fertilization and culture OPS and CL groups evidenced a lower cleavage rate than CT and controls (P < 0.01) while blastocysts were obtained only in CL and EXP, at a lower rate than CTR (P < 0.01). All vitrified groups showed alterations in spindle conformation, which were partially recovered in OPS and CT groups. MPF activity was lower in treated compared to CTR and CT showed the lowest value (P < 0.01). After 2 hr culture MPF activity was restored in all groups except CT. Parthenogenetic activation was higher in treated compared to CTR and CT evidenced the highest value. Our results indicate that cryodevice influences not only the ability to survive cryopreservation but is also associated with molecular alterations which affect developmental competence.

A new selection criterion to assess good quality ovine blastocysts after vitrification and to predict their transfer into recipients

The feasibility to accurately select viable embryos would be valuable for improving pregnancy rates and avoiding futile transfer attempts. The aim of our study was to assess if in vitro-produced embryo quality could be determined by the timing of blastocoelic cavity re-expansion after vitrification, warming, and in vitro culture using sheep as a model. Blastocysts were produced in vitro, vitrified/warmed, and cultured in TCM-199 plus 10% FCS for 72 hr. Embryos were divided into two groups: re-expanded within 8 hr (A) and from 8 to 16 hr (B) of IVC after warming. Fast re-expanded blastocysts showed higher in vitro hatching rates and total cell number calculated on the hatched blastocysts compared with slow re-expanded ones (P < 0.01). Peroxide status evaluation (P < 0.01) and TUNEL test (P < 0.05) revealed a higher number of positive cells in group B compared with group A. The quantitative analysis of protein synthesis revealed a higher synthesis in fast compared with slow re-expanded embryos (P < 0.05). Quantitative RT-PCR showed that 90-kDa Heat Shock Protein beta was more expressed in group A than in group B (P < 0.05), while the quantity of P34(cdc2), Cyclin b, Aquaporin 3, Na/K ATPase, and Actin did not differ between the two groups. Pregnancy rates after transfer to synchronized recipients were higher in fast compared to slow re-expanded blastocysts (P < 0.05). Our results evidenced that timing of blastocoelic cavity re-expansion after vitrification/warming and in vitro culture can be considered as a reliable index of in vitro produced embryo quality and developmental potential.

258 EXPRESSION PATTERN OF THE MATERNAL FACTOR ZYGOTE ARREST 1 (ZAR1) GENE IN OVINE OOCYTES AND PRE-IMPLANTATION EMBRYOS

Zygote arrest 1 (ZAR1) is an ovary-specific maternal factor that plays essential roles during the oocyte-to-embryo transition. It is evolutionary conserved in vertebrates, and the protein is characterized by the presence of a homeobox zing finger domain, suggesting its role in transcription regulation. Discovered in mice (Wu et al. 2003 Nat. Genet. 33, 187-191), its expression pattern has been analyzed in oocytes and pre-implantation embryos in mice, cattle, and pig (Pennetier et al. 2004 Biol. Reprod. 71, 1359-1366; Brevini et al. 2004 Mol. Reprod. Dev. 69, 375-380; Reprod. Biol. Endocrinol. 21, 4-12). Because no information on Zar1 ortholog in the ovine species is available, the aim of this study was to assess its presence and to analyze its expression pattern in oocytes and pre-implantation embryos. Reverse transcription-polymerase chain reaction (RT-PCR) was performed in germinal vesicle (GV) and IVM metaphase II (MII) oocytes, and, following IVFC, in 2- (2C), 4- (4C), 8- (8C), and 12-16- (12C-16C) cell embryos, morulae, and blastocysts. Primers were designed on the basis of bovine and swine conserved sequences and contained an intron-spanning region. The PCR product was sequenced and the alignment, performed with BLAST (www.ncbi.nlm.nih.gov/BLAST/), confirmed its homology with the Zar1 orthologous genes present in public databases, sharing 98%, 92%, and 89% nucleotide identity with the bovine, porcine, and human sequences, respectively. Real-time PCR revealed that Zar1 is present at its highest level in the GV oocyte, has a major decrease at the MII stage (around 10-fold), remains constant in the embryo first cleavage steps (2C-4C), drops again at the 8C stage (around 30-fold), and disappears in morulae and blastocysts. Our data demonstrate that a Zar1 ortholog is present in the ovine species. Results are also in accordance with the expression patterns characterized in other mammalian species and suggest that Zar1 transcript in the ovine oocyte may be necessary for normal female reproduction in the transition from oocyte to embryonic life.

Oocyte cryopreservation: oocyte assessment and strategies for improving survival

Despite significant progress in cryopreservation of mammalian oocytes and embryos, many of the molecular and biochemical events that underlie this technology are poorly understood. In recent years, researchers have focused on obtaining viable oocytes that are developmentally competent. Even under the most favourable conditions, experimental approaches have achieved only limited success compared with fresh oocytes used in routine in vitro embryo production. Chilling injuries and toxic effects of the cryoprotectants are the major adverse consequences following cryoprocedures. To overcome these problems, different strategies have been developed for improving cryopreservation results. These strategies include reducing container volumes, increasing the thermal gradient, changing the cell surface/volume ratio, enhancing cryotolerance by supplementation with various additives or modifying the lipid composition of the oocyte membrane. In order to develop new strategies for reducing the various forms of stress associated with oocyte cryopreservation, it is fundamental to gain a better understanding of the major changes responsible for poor post-thaw survival. With this knowledge, we hope that oocyte cryostorage will become a fully reliable reproductive technique in the near future.

Vitrification of in vitro matured ovine oocytes affects in vitro pre-implantation development and mRNA abundance

The impact of vitrification procedures on in vitro matured (IVM) ovine oocytes mRNA content and ability to undergo successful fertilization, cleavage and embronic development was assessed. Vitrified-warmed (n = 113) and control (n = 140) IVM oocytes were in vitro fertilized and cultured up to blastocyst stage under standard conditions. Vitrified oocytes showed lower cleavage rate (47% vs. 75%, P < 0.001) and development to blastocyst stage (17% vs. 57%, P < 0.001) than controls. In addition, the timings of the first cleavage and blastocysts production were significantly delayed in the vitrified-warmed group (P < 0.001 in both cases). In parallel, we analyzed by reverse transcriptase real-time PCR the relative abundance of beta-actin, H2A.Z histone, Poli A Polimerase (PAP), Heat Shock Protein 90 beta (HSP90 beta), P34(cdc2), Cyclin b, Na/K-ATPase and Type I cadherin (E-Cad) transcripts in single IVM controls (n = 24) and vitrified-warmed oocytes (n = 40). Results were normalized against the exogenous rabbit alpha-globin mRNA standard and the beta-actin housekeeping gene and similarly described a lower abundance of most mRNAs in oocytes subjected to vitrification procedures. When normalized against the exogenous standard mRNA, all transcripts except for beta-actin and H2A.Z showed a significantly different abundance in the two classes of oocytes. The same results were obtained after normalization against the internal standard, except for HSP90 beta and E-Cad transcripts, whose lower abundance in vitrified-warmed oocytes resulted prominent, but not significant (P = 0.083 and P = 0.068, respectively). The oocyte lower transcripts abundance following vitrification might be an early indicator of poor quality in good correlation with the developmental data to blastocyst stage.

Relations between relative mRNA abundance and developmental competence of ovine oocytes

The present study was conducted to investigate the relation between in vitro developmental competence and the expression of a panel of developmentally important genes in germinal vesicle (GV) stage oocytes. One-month-old prepubertal and adult sheep oocytes were used as models of low and high quality gametes, respectively. Cumulus-oocyte complexes (COCs) derived from lambs and ewes were in vitro matured and fertilized, and their cleavage rate at 22, 26, and 32 hr post fertilization and the blastocyst yield were observed to assess their developmental potential. In parallel, the relative abundance (RA) of 11 genes was analyzed by semi-quantitative Reverse Transcription Polymerase Chain Reaction (RT-PCR) assay in the two groups of oocytes. We observed similar maturation and fertilization rates in the two groups, but a significant lower rate of cleaved prepubertal oocytes (P < 0.05), a general delay in the timing of their first division (P < 0.01), and a lower blastocysts production (P < 0.05). The analysis of gene expression evidenced no difference in the RA of four transcripts [superoxide dismutase (SOD), ubiquitin, beta-actin, cyclin B] in the two classes of oocytes, but a statistically lower RA of seven messenger RNAs (mRNA) [Na(+)K(+)ATPase, p34(cdc2), Glucose-transporter I (Glut-1), Activin, Zona Occludens Protein 2 (PanZO2), Poli(A)Polymerase (PAP), E-Cadherin (E-Cad)] in the prepubertal oocytes compared to the adult ones. The present data show for the first time in the ovine species that the lower developmental competence is associated with deficiencies in the mRNAs storage during the oocyte growth.

321 OOCYTE DIAMETER INFLUENCES THE MEIOTIC RESUMPTION AND PROGRESSION INDUCED BY OKADAIC ACID IN DOG

The acquisition of meiotic competence, in the bitch as in many other mammalian species, is related to the oocyte diameter. This study was designed to determine the effect of okadaic acid (OA), a potent inhibitor of seronine/threonine 1 and 2A phosphatases, on meiotic resumption and progression in canine oocytes with different diameters. In two experiments, healthy cumulus-oocytes complexes were collected from ovaries of bitches at various stages of the estrous cycle and divided, by diameters, into three treatment groups for in vitro maturation: <110 �m, 110-120 �m, and >120 �m. In Experiment 1, oocytes were pre-incubated for 1 h in TCM-199 + 20% estrous canine serum (SCE) + cysteamine + OA (0.5 �M). Then, oocytes were cultured for 48 h in the same medium without OA at 38.5�C, 5% CO2 in air. As a control group, oocytes were matured in vitro under the same conditions but without pre-incubation with OA. In Experiment 2, to determine if the effect of OA is mediated by cumulus cells, >120 �m oocytes were denuded from cumulus cells, incubated with or without OA, and cultured in vitro as previously described. At 48 h, all oocytes were stained and fixed with glycerol-Hoechst 33342 to assess the stage of meiotic maturation. In Experiment 1, OA induced a significantly higher incidence of meiotic resumption in oocytes <110 �m (16/108, 14.8%; P < 0.05) and 110-120 �m (70/130, 53.8%; P < 0.01) as compared to that of oocytes in the <110 �m and 110-120 �m control groups (2/58, 3.4%; 24/82, 29.3%). The percentage of oocytes in the 110-120 �m OA group that underwent in vitro maturation to metaphase II (MII) was significantly higher than in the 110-120 �m control group (18/130, 13.8% vs. 4/82, 4.9%, respectively; P < 0.05). In contrast, smaller oocytes (<110 �m) did not develop to MII with or whitout OA. Meiotic resumption rate of >120 �m OA group (64/78, 82.0%) was similar to the >120 �m control group (56/72, 77.8%), but a significantly higher proportion of the oocytes pre-incubated with OA progressed to MII than did the control oocytes (40/78, 51.3% vs. 12/72, 16.7%, respectively; P < 0.01). Low rates of meiotic resumption were observed in denuded >120-�m oocytes with (7/63, 11.1%) or without OA (7/55, 12.7%) and none of them progressed to MII. In conclusion, the results of the present study indicate that treatment of fully grown (>120 �m) oocytes with okadaic acid at the onset of in vitro maturation can result in a higher frequency of meiotic maturation than previously reported. Also, we determined that the beneficial effect of okadaic acid was mediated by cumulus cells.

83 VITRIFICATION OF IMMATURE AND IN VITRO-MATURED HORSE OOCYTES

Few attempts have been carried out to cryopreserve equine oocytes, and an effective cryopreservation protocol is not defined yet. Studies were conducted to compare the viability of immature and in vitro-matured horse oocytes vitrified by the minimal volume cooling (MVC) cryotop vitrification method (Kuwayama et al. 2005 Reprod. BioMed. Online 11, 300–308). Oocytes were recovered from slaughterhouse ovaries and divided, on the basis of the morphology of cumulus cells, into cumulus-expanded (CE) and cumulus-compacted (CC) oocytes. Groups of CC and CE oocytes were vitrified immediately after recovery [germinal vesicle (GV) stage] or matured in vitro (IVM) and cryopreserved at the MII stage as follows: oocytes were incubated 30 min in TCM-199 + 20% FCS + 10% ethylene glycol (EG) + 10% DMSO, followed by 20 min in TCM-199 + 20% FCS + 20% EG + 20% DMSO + 0.25 M sucrose, loaded in cryotops (2 µL), and plunged into liquid nitrogen. Warming was performed at 38.5°C by washing the oocytes in TCM-199 + 20% FCS with decreasing sucrose concentrations (1.25 M, 0.62 M, 0.31 M). After warming oocytes cryopreserved at the GV stage were matured in vitro for 24 h (CE) or 36 h (CC) in TCM-199 + 10% FCS + FSH, LH each at (0.1 UI/mL) + cysteamine, fixed, and stained with glycerol-Hoechst 33342 to assess nuclear maturation. Oocytes vitrified at the MII stage were in vitro cultured for 2 h to evaluate their morphological survival on the basis of the presence of an intact zona pellucida and membrane. Nonvitrified oocytes undergoing the same maturation protocol were used as controls. Results (Table 1) indicated that the survival rate of oocytes vitrified at the GV stage, after IVM, was similar between CE and CC oocytes (43.6% vs 42.6%). Significantly (P < 0.01) higher numbers of vitrified CE MII oocytes (52.9%) survived, compared to CC (34.8%), after 2-h culture. The percentages of viable MII oocytes from CE and CC GV vitrified oocytes were 43.6% and 40.9% respectively and were comparable to those from vitrified MII oocytes (CE, 52.9%; CC, 34.8%) and control oocytes (CE, 56.4%; CC, 53.3%). In conclusion, the results of this study showed that vitrification by the MCV Cryotop method of horse oocytes at either the GV or the MII stage allows a similar number of viable mature oocytes to be recovered. Table 1. Maturation and survival rates of immature and mature equine oocytes vitrified by the MCV Cryotop method

Delay on the in vitro kinetic development of prepubertal ovine embryos

In the present study we characterize the developmental potential of prepubertal and adult ovine oocytes, analyzing the developmental speed to two-cell and blastocyst stages and its relationship with hatching from the zona pellucida, development after vitrification and the number and allocation of inner mass and trophoblastic cells. Prepubertal and adult ovine oocytes were matured and fertilized in vitro and first cleavage rates at 22, 26 and 32 h were recorded. Cleaved oocytes were cultured and blastocyst production was assessed at 6-9 days post-fertilization (dpf). Blastocysts from the two sources obtained on different days were divided into two groups: the first was vitrified, warmed and cultured in vitro to evaluate re-expansion of the blastocoelic cavity; blastocysts of the second were cultured separately to allow for hatching and count of trophoblastic and inner mass cells of hatched blastocysts by differential staining. We observed a significantly lower rate (P < 0.01) of cleaved prepubertal oocytes at 22 and 26 h after fertilization while it was higher (P<0.01) at 32 h than in the adult ones. Adult blastocyst production was significantly lower (P < 0.01) in prepubertal than in adult groups and began on the seventh dpf, later (P < 0.01) than in the adult group, where they appeared on the sixth dpf. Prepubertal blastocysts hatched at a lower rate than the adult ones (P < 0.01) and in both experimental groups faster blastocysts showed a higher (P < 0.01) hatching rate. Similarly, prepubertal derived blastocysts showed lower viability after vitrification (P < 0.01) compared to the adult counterparts, and in particular slower embryos had reduced viability after vitrification compared to the fastest (P < 0.01). Cell number was not different between blastocysts of both groups obtained at 6 and 7 dpf, which were higher (P < 0.01) than those obtained at 8 and 9 dpf. The ICM/trophoblast cell ratio was similar in 6- and 7-day obtained blastocyst and increased (P < 0.01) in those obtained 1 or 2 days later. These findings show that differences in kinetic development between prepubertal and adult derived embryos reflect differences in developmental capacity of the oocytes from which they derive and could be indicative of embryo quality.

Superoxide dismutase affects the viability of thawed European mouflon (Ovis g. musimon) semen and the heterologous fertilization using both IVF and intracytoplasmatic sperm injection

This study evaluated the effects of superoxide dismutase (SOD) on viability and acrosome integrity of European mouflon spermatozoa after cryopreservation and on the fertilization rates of sheep oocytes after i.v.f. or intracytoplasmatic sperm injection (i.c.s.i.). Frozen semen was thawed and washed with synthetic oviduct fluid supplemented with 0.6% bovine serum albumin. After centrifugation, the spermatozoa pellet was split into two culture systems: (i) without SOD; and (ii) in the presence of 1500 IU mL(-1) SOD. Sperm viability and acrosome integrity were evaluated simultaneously, immediately after thawing and after 3, 6 and 9 h of culture (5% CO2, 39 degrees C, 90% humidity), by incubating sperm with propidium iodide and fluorescein isothiocyanate-labelled Pisum sativum agglutinin. At the same time, sperm were assessed for motility using a standard scoring system (independent operators' observation of sperm) that graded degree of motility (i.e. 1 = immotile to 10 = maximum motility, as observed at the moment of thawing). For i.v.f., frozen-thawed semen derived from the two culture systems was placed in culture together with in vitro-matured sheep oocytes. For i.c.s.i., semen derived from the same culture systems as that for i.v.f. was used, and incubated for 1 h under standard conditions. The results showed a marked difference (P < 0.01) between the percentages of live spermatozoa in medium with SOD and those obtained in medium alone, after 3, 6 and 9 h of culture. The percentages of intact acrosome spermatozoa were higher in medium with SOD after 6 h (P = 0.05) of culture. Spermatozoa motility decreased significantly in SOD containing medium at 3 and 6 h of culture compared with motility in control medium. Fertilization rates were significantly lower in medium with SOD than in medium alone, whereas in the i.c.s.i. system fertilization rates were significantly higher in the presence of SOD. The results indicate that the addition of SOD to the culture media enhances the viability rates and the acrosome integrity of cryopreserved mouflon spermatozoa.

In vivo and in vitro fertilizing capacity of cryopreserved European mouflon [Ovis gmelini musimon] spermatozoa used to restore genetically rare and isolated populations

European mouflon sheep are an endangered species of ovidae residing primarily in the mountenous habitat of the islands of Sardinia and Corsica. The purpose of this study was to assess the fertilizing capacity of cryopreserved European mouflon spermatozoa after AI in synchronized mouflon and domestic ewes and after IVF in in vitro matured mouflon and domestic ewe oocytes collected by OPU technique. Domestic ram (Ovis aries) spermatozoa served as control. Semen was collected by artificial vagina from three mouflons and three domestic rams during the breeding season and was cryopreserved. At thawing, no significant differences in sperm viability were found between the wild and the domestic species (53.1 +/- 4.6% versus 56.0 +/- 4.7%) whereas the percentage of acrosome-intact sperm was lower in mouflon (55.5 +/- 4.6%) than in ram semen (62.7 +/- 3.1%; P < 0.05). Lambing rate did not differ between synchronized mouflon and domestic ewes (5/11 versus 8/12) after 150 and 156 days of pregnancy, respectively. After two OPU sessions, 87 and 132 oocytes were collected from three hyperstimulated mouflon and three domestic ewes. Cryopreserved/thawed semen was inseminated with an endoscope into the uterus of corresponding species during the non-breeding season. The oocytes were matured and fertilized in vitro; 61/73 mouflon and 81/101 domestic ewe oocytes were found to be fertilized. From these, we obtained 6/61 and 17/81 blastocysts. After vitrification and thawing, the hatching rate showed no significant difference between mouflon and sheep blastocysts (4/6 versus 14/17). In conclusion, our data showed that cryopreserved mouflon spermatozoa can be successfully used to carry out a genuine and complete program of genetic restoration in small and isolated groups of European mouflons.

278 MEIOTIC RESUMPTION IN VITRO OF CANINE OOCYTES: COMPARATIVE METHODS

In the bitch, mechanisms responsible for the meiotic resumption and progression of the oocytes are not known. In order to better understand cellular signals involved in canine oocyte meiosis, the present study was performed to investigate the ability of bitch oocytes to resume meiosis in vitro (1) after culture with okadaic acid (OA), and (2) after cell fusion with bovine MII oocytes. For this purpose oocytes were collected from ovaries of bitches undergoing ovariectomy. Ovaries were sliced repeatedly to release oocytes; only cumulus-oocytes complexes with two or more dense layer of cumulus cells, darkly granulated cytoplasm, and >110 μm in diameter were selected for experiments. In the first experiment, oocytes were pre-incubated for different times (1, 3, 20 h) in TCM 199 + 20% FCS + 0.5 μM or 2 μM OA and thereafter cultured for 48 h in the same medium without OA. A group of oocytes was matured in TCM 199 + 20% FCS for 72 h as control. At the end of culture, oocytes were stained with glycerol-Hoechst 33342 to evaluate meiotic stage. Results indicated that incubation with 2 μM OA for 1, 3, and 20 h determined a significantly higher (P < 0.001) meiotic resumption (GVBD) of canine oocytes compared to that in the control group, but the percentage of oocytes reaching MI and MII did not increase. Similar results were obtained after culture with 0.5 μM OA for 3 and 20 h. However, meiotic progression to MI and MII was significantly improved (P < 0.05) after incubation with 0.5 μM OA for 1 h. In the second experiment canine oocytes at GV stage were fused with MII bovine oocytes matured in vitro. This experiment was designed to test whether the high activity of MPF of MII bovine oocytes was able to determine modification of GV of canine oocytes. The zonae pellucidae from both GV and MII oocytes were removed using 0.1% pronase. Pairs of oocytes (n = 37) were agglutinated in medium containing 250 mg/mL phytohemoagglutinin placed between two electrodes in 0.5% glucose fusion medium, fused with a single pulse of direct current (1.25 KV/cm for 80 ms) and cultured for 2–3 h in TCM 199 + 10% FCS. After culture fused partners (n = 36) were stained with glycerol-Hoechst 33342 and evaluated. Results indicated that the fusion of MII bovine oocytes to GV reporter canine oocytes failed to induce nuclear membrane disassembly, chromatin condensation, or modification of canine nuclei in all of the fused combinations. These data suggest that OA induces meiotic resumption of canine oocytes. However, the cell fusion results seem to indicate that increased levels of MPF are not able to determine cell cycle progression. Furthermore, incubation times and concentration of okadaic acid could be refined to optimize a system for meiotic maturation of bitch oocytes. Table 1. Meiotic progression of bitch oocytes after incubation with okadaic acid This work was supported by MIUR (ex 40%).

M-phase promoting factor (MPF) and mitogen activated protein kinases (MAPK) activities of domestic cat oocytes matured in vitro and in vivo

This work was undertaken in order to examine M-phase promoting factor (MPF) and mitogen-activated protein kinases (MAPK) activities during meiotic progression of cat oocytes cultured in two different media for two different incubation times and preovulatory cat oocytes that reached MII in vivo. Oocytes recovered from ovaries of ovariectomized cats were cultured either in TCM 199 or SOF for 24 h and 40 h. In vivo matured oocytes were recovered by follicular aspiration from ovaries of domestic cats ovariectomized 24 h to 26 h after hormonal treatment. Results showed that the kinetic of MPF and MAPK activity was similar during meiotic progression of cat oocytes matured in TCM 199 and SOF. After 24 h of incubation, MII oocytes had significantly (p < 0.001) higher MPF and MAPK levels than MII oocytes cultured for 40 h in both culture media. MPF and MAPK activity was significantly (p < 0.01) lower in the oocytes matured in vitro than in those matured in vivo. This study provides evidence that the two different maturation media did not determine differences in MPF and MAPK fluctuations and levels during meiotic progression of cat oocytes and that the time of maturation influenced the level of the two kinases. Moreover, it shows that MPF and MPK activity is higher in in vivo matured oocytes than in in vitro matured oocytes, suggesting a possible incomplete cytoplasmic maturation after culture.

FSH different regimes affect the developmental capacity and cryotolerance of embryos derived from oocytes collected by ovum pick-up in donor sheep

The objective of the present study was to compare the developmental capacity of sheep oocytes obtained by OPU after two different ovarian stimulations, and cryotolerance to vitrification procedures of in vitro derived embryos after in vitro maturation, fertilisation and culture of these oocytes. Sheep were divided into three groups: (A) no treatment (control); (B) constant doses of FSH (FSH-c); (C) decreasing doses of FSH (FSH-d). Ovine groups FSH-c and FSH-d were synchronised by the insertion of intravaginal sponges left in situ for 7 days; FSH (total dose: 96IU) was administered in four doses given every 12h starting on Day 5. Twelve hours after the last FSH administration oocytes were collected by OPU technique. The control group showed a significantly lower number ( P<0.05 ) of follicles (166) than FSH-c (294) and FSH-d (317) groups, while the number of follicles >5mm was significantly higher ( P<0.01 ) in FSH-d group, showing that this protocol stimulates the growth of a different follicle population compared to FSH-c group. The control group showed a higher number of <2mm follicles ( P<0.01 ). We did not find any difference in oocyte quality between the three groups and therefore the percentage of discarded oocytes was similar. No significant differences were found between control, FSH-c and FSH-d groups in terms of maturation (90.9, 85.7 and 87.7%, respectively) and fertilisation rates (75.2, 80.9 and 83.7%, respectively) while a significantly higher ( P<0.01 ) blastocyst rate was observed in the FSH-c group than in the FSH-d and control groups (20.4% versus 11.8 and 13.7%, respectively). After vitrification, warming and 72 h in vitro culture, the hatching rate was significantly higher ( P<0.01 ) in the control (87.5%) and FSH-c (90.5%) groups than in the FSH-d group (66.7%). Control and FSH-c groups showed a significantly higher ( P<0.001 ) number of total cells than FSH-d group ( 217.6+/-26.5 and 203.0+/-33.2 versus 147.5+/-20.2 ), while no differences were observed in ICM cell rates in the control ( 35.6+/-3.8 ), FSH-c ( 37.1+/-4.6 ) and FSH-d ( 36.6+/-6.7 ) groups. These results indicate that donor sheep stimulated with FSH-c produced better quality oocytes and blastocysts showing better cryotolerance than ewes given the decreasing doses treatment.

202FERTILIZING ABILITY OF EPIDIDYMAL CAT SPERMATOZOA AFTER CRYOPRESERVATION OR STORAGE AT 4°C

The possibility of harvesting cat epididymal spermatozoa from excised testis represents a potentially important tool for preserving valuable genetic material from males that die unexpectedly. The purpose of this study was to evaluate plasma membrane integrity, acrosomal status and in vitro fertilizing capability of epididymal cat sperm after short- and long-term storage at 4°C and after cryopreservation. Spermatozoa were collected by flushing the cauda epididymis and the vasa deferentia removed from adult cats undergoing orchiectomy. Spermatozoa were split into three aliquots: A-fresh, B-frozen, and C-cooled. The A portion was immediately tested on the day of collection (control), the B portion was frozen in pellets in Test Yolk Buffer (TYB) with 8% glycerol, while the C portion was extended in TYB and stored at 4°C for 1 day, 2 days or 7 days. Cat oocytes recovered from minced ovaries were matured for 24h in TCM 199+1UI/mL hCG+0.5UI/mL FSH+0.3% BSA at 38.5°C in 5% CO2. In vitro fertilization (IVF) of in vitro-matured (IVM) oocytes was performed using spermatozoa from portions A, B or C in modified Tyrode’s solution supplemented with 0.6% BSA at 38.5°C in 5% in air. Before IVF, aliquots of sperm samples from the three portions were stained simultaneously with fluorescein isothiocyanate-labelled Pisum Sativum agglutinin (FITC-PSA) and propidium iodide to evaluate the percentage of plasma membrane-intact spermatozoa with acrosomes present. At least 200 spermatozoa were counted in duplicate for each sample. After 24h of incubation, to evaluate fertilization rate, the oocytes were stained with aceto-lacmoid. Oocytes with two pronuclei, presumably male and female, were classified as fertilized. The percentages of spermatozoa maintaining plasma membrane integrity and intact acrosomes after 1 day or 2 days of storage at 4°C were 75% and 65%, respectively, and were similar to that of fresh epididymal spermatozoa (78%). However, the percentages of spermatozoa with intact plasma membranes that had intact acrosomes after 7 days of storage at 4°C (52%) or after cryopreservation (48%) were significantly lower (P&lt;0.01, ANOVA) than those of samples stored for 1 or 2 days at 4°C. As shown in the Table, fertilization rates of oocytes inseminated with fresh spermatozoa and spermatozoa stored for 1 or 2 days were similar. In contrast, the fertilization rates of oocytes inseminated with spermatozoa that had been cryopreserved or stored for 7 days were significantly lower than those obtained with spermatozoa used immediately after collection or storage for 1 day. From our results, we suggest that storage of epididymal spermatozoa at 4°C may be a potentially useful method for temporary storage of spermatozoa from endangered cats, and may allow more efficient use and long-distance transport of genetically important germplasm. This work was supported by MIUR (ex 40%). Table 1 In vitro fertilization of in vitro-matured cat oocytes with fresh, stored at 4°C and cryopreserved epididymal cat spermatozoa

240OVINE PREPUBERTAL OOCYTE SHOWS ALTERATE GENE EXPRESSION AND LOW DEVELOPMENTAL COMPETENCE

The aim of this work was to evaluate developmental competence and gene expression of prepubertal and adult ovine oocytes. GV prepubertal and adult oocytes were matured, fertilized and cultured in vitro until blastocyst stage;; the time (days) needed to reach this stage was recorded. Blastocysts developed on different days were cultured for hatching to evaluate their quality in relation to cleavage rate. Adult and prepubertal GV oocytes and blastocyst-stage embryos produced, respectively, at 6 and 7 days were compared for quantitative expression of poly(A) polymerase (polyA-P), glucose transporter I (Glut-I), desmocollin II (desmoII), plakofilin (plako) and heat shock protein 70.1 (HSP70) genes. Confirming previous results (Ledda et al., 1996 Zygote 4, 343–348), fertilized prepubertal ovine oocytes developed to blastocyst stage at lower rates than the adult ones (19.9 v. 51.3%, respectively, P&lt;0.001) and this stage was delayed 24h in prepubertal compared to adult embryos (P&lt;0.01), reflecting a lower quality (Fenwick et al., 2002 Hum. Reprod. 17, 407–412) of the former. In fact, 44.7, 25.0, 30.3 and 0% of adult blastocysts were obtained after 6, 7, 8 and 9 days, respectively, of postfertilization culture compared to 0, 48.4, 34.3 and 17.2% of prepubertal ones. Faster-developed blastocysts showed higher hatching rate in both prepubertal (54.8%, 7 days of culture) and adult (89.8%, 6 days). Hatching rate dropped to 18.2% when blastocysts were obtained at 8–9 days in prepubertal and to 54.5% and 32.5% at 7 and 8 days, respectively, in adult embryos. Analysis of gene expression showed that HSP70, plako and desmo genes were not expressed in GV oocytes, and Glut-I mRNA was lower in prepubertal GV oocytes than in the adult ones (P&lt;0.01). All genes were expressed in blastocysts;; we found that Glut-I was at lower levels (P&lt;0.01) in prepubertal-derived blastocysts whereas HSP70 was highly expressed (P&lt;0.05) in prepubertal blastocysts than in those derived from adult oocytes. In conclusion this work shows that prepubertal ovine oocytes have a lower developmental competence compared to the adult ones, correlated to an altered gene expression during the growth phase of the oocyte and early embryonic development. Supported by MIUR (cofin).

Resumption of metabolic activity of vitrified/warmed ovine embryos

To evaluate resumption of metabolic activity of vitrified ovine embryos during a short time immediately after warming, blastocysts collected from superovulated Sarda ewes were incubated with (35)S-methionine. In vitrified/warmed embryo groups the protein secretion significantly (P < 0.05) increased from 0 to 24 hr of culture, reaching significantly (P < 0.01) higher activity at 18-24 hr and dropping to values similar to the control nonvitrified embryo group at 29-35 hr. Within the control group at 29-35 hr there was a significantly (P < 0.01) higher level of protein secretion compared to the other interval times. The electrophoretic pattern showed a 48-50 kDa secreted protein identified as urokinase-type plasminogen activator (PA). The caseinolytic assay of PA activity showed a course similar to protein secretion in both vitrified and control groups. During 29-35 hr of culture, we did not observe any improvement in PA activity as seen for secreted proteins. At this time, we observed the secretion of a new 20 kDa protein that was not present in vitrified/warmed embryos. Analysis of BrDU incorporation in newly synthesised DNA showed a significant (P < 0.01) improvement in positive cell number from 3 to 9 hr after warming, reaching a value similar to that of the control group at 12 hr of culture. Our results suggest that vitrified/warmed embryos require 9-12 hr of culture to complete resumption of DNA synthesis and 29-35 hr to re-acquire the full capacity of protein secretion but not the qualitative secretion pattern.

Defined media for vitrification, warming, and rehydration: effects on post-thaw protein synthesis and viability of in vitro derived ovine embryos

The purpose of this study was to assess the viability (rates of re-expanding and hatching in vitro), of in vitro derived ovine blastocysts using vitrification and warming/rehydration media containing fetal calf serum (20% FCS) or polyvinyl alcohol (0.1% PVA), and the incorporation of labelled methionine in protein synthesised during the first 4h after cryopreservation. In experiment 1, after 60 h culture in TCM-199 supplemented with 10% FCS, the hatching rates of blastocysts that had been vitrified, warmed, and rehydrated in media containing only PVA (p/p) were significantly (P<0.05) lower than those vitrified in medium containing PVA with warming and rehydration in medium containing FCS (p/s). Blastocysts that were vitrified in medium containing FCS and warmed and rehydrated in medium with PVA (s/p) had hatching rates that were significantly lower (P<0.01) than those vitrified, warmed, and rehydrated in media with only FCS (s/s). After warming, the number of dead cells in the p/p group was significantly (P<0.05) lower than in all other groups. In experiment 2, the [35S]methionine uptake by embryonic cells of the s/p group was significantly (P<0.01) higher than in other groups. The incorporation of labelled methionine into newly synthesised proteins was significantly lower in the p/p group (P<0.01) than in all other groups. No differences in the newly synthesised proteins were observed between groups. In conclusion, these results suggest that it is possible to replace serum with defined macromolecules in vitrification and warming/rehydration media for in vitro derived ovine blastocysts but this leads to a decrease in viability and a reduction in protein synthesis after warming.

The effect of co-culture on the development of in vitro matured equine oocytes after intracytoplastic sperm injection

It is clear that, in the horse, there are many weak links in the process of in vitro embryo production; an optimal culture system for equine oocytes does not exist, and related data are conflicting. Therefore, the ability of 3 different culture systems to support embryonic development of ICSI horse oocytes was examined. Oocytes (n = 261) suitable for culture were collected from 55 ovaries and divided, according to cumulus morphology, into 2 categories: expanded cumulus and compacted cumulus. Oocytes with expanded and compacted cumulus were cultured for in vitro maturation in TCM 199 + 10% FCS + 0.1 iu/ml FSH/LH at 38.5 degrees C under 5% CO2 in air for 24 and 40 h, respectively. Oocytes (n = 149) reached metaphase II and were subjected to ICSI with frozen semen and then incubated in 3 different culture systems: A) TCM 199 + 10% FCS alone or B) on granulosa cell monolayer, C) SOF + MEM amino acids + 0.8% BSA. Cultural conditions were 39 degrees C and 5% CO2 in air for A and B, while a gas mixture (5% CO2, 5% O2, 90% N2) was used for C. The fertilisation rate was 32%. The cleavage rate in Group A was 74.4% (32/43); 18 embryos reached 2-6 cell stage, eight 8-16 cell, four 16-32 cell and two >32 cell. In Group B, the cleavage rate was 73.5% (36/49) with better results in embryonic development; 14 reached 2-6 cell stage, eighteen 8-16 cell, twelve 16-32 cell and five >32 cell. In Group C, the cleavage rate was significantly lower then in A and B; only 15 of 47 ICSI oocytes (39.1%) cleaved with maximum development to 2-6 cell stage. The remaining oocytes (68.1%) degenerated during culture. In conclusion, IVM horse oocytes can be fertilised in vitro with high efficiency with ICSI and co-culture systems showed to be superior in supporting in vitro embryo culture compared to simple ones. The identification of the factors beneficial to in vitro embryo development provided by the somatic cells could be important to optimise the embryo culture systems for equine embryos.

Influence of cadmium exposure on in vitro ovine gamete dysfunction

This study was conducted to determine the in vitro effects of three different cadmium concentrations (0, 2, and 20 microM CdCl(2)) on oocyte maturation, fertilisation, and acrosome integrity and sperm viability in sheep. Cumulus-oocyte complexes were recovered from ovaries of slaughtered sheep and sperm were collected by artificial vagina from adult rams. The oocyte maturation rate was significantly affected (P < 0.001) by Cd at both concentrations, with a metaphase II (MII) rate of 96.8, 63.8, and 32.0% for 0, 2, and 20 microM cadmium, respectively. In the second experiment, the presence of Cd significantly decreased (P < 0.01) the rate of oocytes resting in MII after 24-h postmaturation culture, compared with the control group (93.8 versus 29.0 and 19.8%, respectively, for 0, 2, and 20 microM Cd). Oocytes cultured with Cd 2 microM showed a higher activation rate (59.5%, P < 0.001) with one or two pronucleus than with 0 and 20 microM Cd (6.2 and 22.9%, respectively). During fertilisation the presence of fertilised oocytes was decreased in both culture systems with Cd compared with the control (76.1, 25.9, and 4.7% for 0, 2, and 20 microM Cd, respectively; P < 0.001) while polyspermy was increased in the 2 microM Cd group (23.5 for 2 microM versus 6.7 and 0%, respectively, for 0 and 20 microM groups). In both experiments Cd significantly increased (P < 0.001) the rates of oocyte degeneration. In the third experiment, Cd 20 microM significantly decreased (P < 0.01) the viability rate (35.6%) of spermatozoa compared with 2 microM (57.6%) and 0 microM (54.4%) while Cd 2 microM increased (P < 0.01) acrosome-reacted spermatozoa (45.2%) compared with 20 microM (32.5%) and control (31.9%). The results suggest that in vitro cadmium at the lowest dose tested affects the physiological function of both ovine gametes but at higher dose tested can compromise cell viability.

[Early electroretinografic changes in elderly RA patients treated with hydroxychloroquine]

OBJECTIVE

To evaluate the effectiveness of fundoscopy, electrooculography, electroretinogram and visually evoked potentials in early detection of hydroxychloroquine retinal toxicity in RA patients and to evaluate the influence of patients' age, drug dosage, concomitant therapy (prednisone and methotrexate) and serum creatinine levels in the development of this side effect.

METHODS

From september to december 1999, we have enrolled 32 RA patients (13 males, 19 females) starting hydroxychloroquine treatment. The patients underwent regular ophthalmological examination (fundoscopy, electro-oculography, electroretinogram and visually evoked potentials) every 4 months. Disease activity was evaluated every two months by clinical and routine serological examination.

RESULTS

No patients developed retinopathy during 1 year's follow-up; fundoscopy, electrooculography, and visually evoked potentials did not vary from the baseline. On the other hand, electroretinogram showed early alterations of scotopic and photopic response; moreover a significant statistical correlation between patients' age (more than 65 years) and b1 photopic wave increase (p < 0,05) was observed. No correlation was found between the development of electro-retinographic alterations and hydroxychloroquine dosage, concomitant therapy and serum creatinine levels

CONCLUSION

Our data show the inefficacy of fundoscopy, electrooculography and visually evoked potentials in early detection of hydroxychloroquine retinopathy. On the other hand electroretinogram allows early detection of retinal alterations during hydroxychloroquine treatment, in patients older than 65 years.

Influence of co-culture with oviductal epithelial cells on in vitro maturation of canine oocytes

The process of oocyte maturation in the canine species is unique among mammals: oocytes are immature at ovulation and the resumption and progression of meiotic maturation occur in the oviduct. This study was performed to investigate (i) the effect of co-culture with infundibulum and ampullar oviductal epithelial cells on the in vitro maturation of canine oocytes and (ii) the culture time necessary to reach full meiotic maturation. For this purpose the oocytes, collected from the ovaries of bitches undergoing ovariectomies, were divided into three groups and cultured for 48 and 72 h with the following systems: (A) TCM 199 + 10% oestrus bitch serum + FSH (0.1 IU.mL(-1)), LH (0.1 IU.mL(-1)) + progesterone (1 microg.mL(-1)) + oestradiol (1 microg.mL(-1)) + cysteamine (100 microM); (B) medium A plus infundibulum cells; (C) medium A plus ampullar cells. Infundibulum and ampullar cells were recovered from the oviducts of bitches at the oestrus stage of their cycle. The results showed that after 48 h of incubation, a significantly higher meiotic resumption (P < 0.01) was observed in the oocytes cultured with infundibulum (59%) and ampullar cells (60.0%), than in the control group (40.0%). There was also a significantly (P < 0.01) higher meiotic progression to the MII in systems B and C (15.6% and 16.7%) than in system A (4.0%). After 72 h of culture, the percentages of meiotic resumption and progression were unchanged. These results showed that both the infundibulum and the ampullar oviductal epithelial cells positively influence the meiotic resumption and progression of canine oocytes and that 48 h are sufficient for the completion of nuclear maturation.

Intracytoplasmic sperm injection of in vitro matured oocytes of domestic cats with frozen-thawed epididymal spermatozoa

The ability to mature and fertilize oocytes of endangered species may allow us to sustain genetic and global biodiversity. The first objective of this study was to compare the effect of two different culture media and two different incubation times on in vitro maturation (IVM) of domestic cat oocytes. The second objective was to determine the developmental competence of in vitro matured cat oocytes after intracytoplasmic sperm injection (ICSI) with cat spermatozoa. Oocytes recovered from ovaries of ovariectomized cats were cultured either in TCM 199 medium or in synthetic oviductal fluid (SOF), both of which were supplemented with cysteamine, BSA, FSH, LH. Nuclear maturation was assessed after 24 h and 40 h of incubation. Results of IVM showed that the percentage of oocytes reaching MII after 24 h and 40 h of incubation were significantly higher (P<0.001) after culture with SOF (88/110, 80% and 159/192, 82.8%) than TCM 199 (86/129, 66.7% and 58/90, 64.4%). Oocytes (n = 231) matured in vitro in SOF for 24 h were fertilized by ICSI with frozen-thawed epididymal cat spermatozoa. After ICSI, one group of oocytes (n = 129) was activated with ethanol, and a second group (n = 102) was not activated. The developmental competence of all ICSI oocytes was examined after 7 days of in vitro culture. After 28 h of culture, the cleavage frequency of ICSI-activated oocytes was significantly higher (P<0.001) than that of IC

Cell coupling and maturation-promoting factor activity in in vitro-matured prepubertal and adult sheep oocytes

We examined some differences between prepubertal and adult ovine oocytes; in particular we analyzed the functional status of the cumulus-oocyte complex, protein synthesis during in vitro maturation, and because no information is available on prepubertal and adult sheep, maturation-promoting factor (MPF) fluctuations throughout meiotic progression both in prepubertal and adult sheep oocytes. After 24 h of maturation, percentages of MII oocytes were similar between prepubertal and adult animals. Electron microscopy examinations showed that prepubertal oocytes had fewer transzonal projections than adult oocytes. Methionine uptake was significantly lower in prepubertal cumulus-enclosed oocytes examined through meiotic progression. On the contrary, denuded prepubertal oocytes showed a higher methionine incorporation in the first 4 h of incubation compared with adult oocytes. We also found some differences in MPF activity between prepubertal and adult oocytes at MII stage. In fact, prepubertal MII oocytes had a significantly lower level of MPF activity than adult oocytes did and, after fusion with germinal vesicle oocytes, they were unable to induce nuclear breakdown and chromosome condensation 1-2 h post-fusion, whereas adult MII oocytes could induce these processes. Our findings show that the lesser competence of prepubertal oocytes could be due to morphological anomalies and alterations in physiological activity and that oocytes do not reach full developmental competence until puberty.

Sheep embryos derived from FSH/eCG treatment have a lower in vitro viability after vitrification than those derived from FSH treatment

In the non breeding period, the effect of two superovulatory treatments (eCG/FSH in single dose or FSH alone in four decreasing doses) on the production of embryo quality following in vitro viability after vitrification procedures was investigated using forty-four adult Sarda breed ewes. In sheep treated with eCG/FSH, the mean number of corpora lutea was significantly (P < 0.05) higher (11.8+/-4.0 vs. 8.05+/-3.8), although the recovery rate was significantly (P < 0.01) lower (74.6 vs. 59.9) than with FSH alone. After vitrification (ethylene glycol and glycerol) was repeated three times, the rates of re-expansion at first and second warming were significantly (P < 0.01) higher in embryos derived from FSH alone than in those with both gonadotrophins (94.9 and 41.9 vs. 72.8 and 18.6) and after the last vitrification the hatched blastocyst rates were 22.5 and 7.6. After differential stain, blastocysts derived from FSH alone showed a mean number of cells significantly higher than blastocysts from eCG/FSH (184.2 vs. 157.7). It was concluded that superovulatory treatment with eCG/FSH may increase the ovarian responses compared with FSH alone, but these embryos showed a reduction in viability rates after repeated vitrification.

Oocyte cryopreservation and ovarian tissue banking

Oocyte cryopreservation, despite its impact on conservation of genetic resources, is not yet an established technology. Several problems need to be solved before this technology can be applied regularly. Chilling membrane susceptibility and formation of ice due to the large volume of the cell are the major problems observed. However, during the last years, several studies were done to obtain viable oocytes after cryopreservation. The addition of molecules known to stabilize membranes and the creation of freezing systems with rapid cooling throughout the transition phase have yielded a good percentage of viable immature and mature oocytes More recently, storage of female gametes was achieved by cryopreservation of cortical ovarian tissue. The possibility of restoring fertility by transplantation of frozen ovarian tissue or its long-term culture in vitro represents an important future means of preserving the fertility of patients and of storing the gametes of rare animals.

Vasoactive intestinal peptide influences hatching of ovine blastocysts

Expanded blastocysts collected from superovulated Sarda ewes were divided at random into four groups for culture in a simple medium that does not support blastocyst hatching (CZB) or a complex medium that is permissive to hatching (TCM 199), with or without vasoactive intestinal peptide (VIP), a known embryo mitogenic peptide. Plasminogen activator (PA) secretion after 24 h of culture, and the number of cells, diameter of blastocysts and hatching rate after 48 h of culture were compared. The results showed an increase in hatching rate (78.6 v. 6.7%; P<0.01), diameter and number of cells (220.89 v. 210.44 microm, P<0.01 and 246 v. 232, P<0.01 respectively) and caseinolytic areas (1.33 v. 0.92 cm, P<0.01) of blastocysts cultured in TCM 199 compared with those cultured in CZB. Supplementation of the culture media with VIP increased these parameters in CZB (P<0.01) and partially in TCM 199. In particular, cell number, diameter and PA activity were significantly higher (P<0.01) after culture with VIP in both media. Immunoneutralization of exogenous VIP in culture with anti-VIP antibody caused a decrease in the hatching rate (P<0.01) of embryos cultured in medium with VIP, similar to the rate in unsupplemented CZB (P<0.01). These results suggest a receptor-mediated response. In immunohistochemical studies, VIP was shown to bind receptors in hatched blastocysts demonstrating the VIP-receptor interaction, and VIP receptors of approximately 150 kDa were revealed by electrophoretic studies. In conclusion, ovine preimplantation embryos exhibit VIP receptors, providing a basis for a receptor-mediated influence of VIP in the hatching of ovine blastocysts.

Activity of Maturation Promoting Factor (MPF) and Mitogen-Activated Protein Kinase (MAPK) after Parthenogenetic Activation of Ovine Oocytes

The maturation promoting factor (MPF) and mitogen-activated protein kinase (MAPK) are the key regulators of both meiotic and mitotic cell cycles. Knowledge of the dynamics of these two kinases during the transition from meiosis to mitosis would be of great importance for cloning by nuclear transfer. In this study, experiments were designed to assay the changes of MPF and MAP kinase activity of in vitro matured ovine oocytes after chemical activation and culture in 0 mM or 2 mM 6-dimethylaminopurine (6-DMAP) for 12 h. Moreover, to determine the biological significance of the fluctuations of MPF, activated oocytes were fused with GV-staged partners. The biochemical results showed that the high MPF activity of MII oocytes fell to basal level precipitously within the first hour after activation, started to increase at 6-8 h, rising to 80 +/- 4% of MII after 12 h. MAPK activity decreased to a low level 4 h after activation, increased between 6-12 h, but remained below 30 +/- 3.6% of MII values. The incubation with 6-DMAP had no effect on the kinetics of MPF and MAP kinase activity. Fusion of MII oocytes to GV partners induced rapid breakdown of the GV, whereas no breakdown occurred when GV were fused with eggs in the first hours post activation. Interestingly, the high biochemical levels of MPF activity at 8-12 h after activation were not able to induce GVBD in fusion partners.

Novel approach to cell sampling from preimplantation ovine embryos and its potential use in embryonic genome analysis

The major obstacle in the extensive analysis of the embryonic genome is the small number of cells typically obtained after the embryo biopsy. The object of the present study was to develop a simple approach that would allow the collection of a sufficient number of cells from a single embryo for use in further analyses. A micromanipulator was used to make a hole in the zona pellucida of 28 compacted morulae, 27 early blastocysts and 31 expanded blastocysts. After further culture, the trophoblastic cells, which herniated through this hole, were cut and cultured in vitro for different periods and used for embryo sexing. The results showed that biopsies can be taken successfully from 96.3% of early blastocysts, compared with 67.7% of expanded blastocysts and 71.4% of compacted morulae. The trophoblastic vesicles contained 20.8 +/- 6.7 cells (mean +/- SEM) and, when cultured, formed a confluent monolayer. The sex of cells cultured was assayed by PCR and the 12 lambs born after transfer of biopsied embryos confirmed its 100% accuracy. Moreover, no significant differences were found in the viability rates in vitro among blastocysts vitrified immediately after biopsy (77.8%), blastocysts biopsied and vitrified after 24 h culture (76.9%) and blastocysts vitrified without manipulation (88.5%). In experiments in vivo, the lambing rate of biopsied and vitrified blastocysts was significantly (P < 0.05) lower (40.0%) compared with vitrified control embryos (68.7%). This new approach to the biopsy of preimplantation embryos is a useful good model in the assisted reproductive technologies of domestic, wild and human species.

Production and lambing rate of blastocysts derived from in vitro matured oocytes after gonadotropin treatment of prepubertal ewes

The aim of this study was to evaluate the effect of gonadotropin treatment on the in vitro maturation, blastocyst production, and developmental potential to term of oocytes collected from Sardinian neonatal and prepubertal ewes at 4 to 6 wk of age. Cumulus-oocyte complexes were recovered at 24 h after withdrawal of a 1/6th size progestagenated pessary from the donors, of which each received 120 IU FSH/LH and 400 IU PMSG in a single dose 36 h before sponge removal. Treated donors produced a greater (P<.01) number of oocytes per animal (86.2 +/-7.9) compared with slaughterhouse (untreated) prepubertal ewes (55.5+/-6.1) of the same age or with treated neonatal ewes (6.1+/-0.7) 10 d old. During oocyte maturation, there were no differences in the percentage of germinal vesicle break-down (78.08 vs. 74.24), metaphase I (89.13 vs. 87.18), and metaphase II (77.91 vs. 76.38) when evaluated after 8, 14, and 24 h of maturation, respectively, between oocytes from treated and slaughterhouse (untreated) prepubertal ewes. The embryo cleavage (71.1 vs. 73.7) and blastocyst rates (22.2 vs. 19.8) were similar in the treated and the untreated prepubertal ewes after transfer of in vitro matured oocytes into ligated oviducts of temporary recipients. The in vitro viability rates of vitrified blastocysts (81.2 vs. 76.9) and the in vivo survival rates (46.1 vs. 50.0) of embryos derived from in vitro matured and in vivo fertilized oocytes showed no difference. The data suggest that gonadotropin treatment increases oocyte production per animal but has no effect on oocyte quality because embryo production and lambing rates of blastocysts derived from in vitro matured oocytes were not markedly different from those derived from untreated prepubertal ewes of the same age.

Follicular size affects the meiotic competence of in vitro matured prepubertal and adult oocytes in sheep

Non-atretic follicles dissected from prepubertal and adult ovaries were allocated in three groups: a) < 1 mm; b) 1-2 mm; c) > 2 mm. After 24 h of maturation, a lower percentage of adult oocytes from group a (P < 0.01) reached metaphase II than those from groups b and c (70.4 versus 89.5 and 95.5). Prepubertal oocytes showed similar results (P < 0.01; 27.2 versus 79.8 and 81.8). There was a significant difference (P < 0.01) in meiotic progression between prepubertal and adult oocytes of < 1 mm follicles. The diameter of prepubertal oocytes derived from group a was significantly lower (P < 0.01) compared to groups b and c (138.1 versus 142.1 and 145.6); adult oocytes showed similar results (P < 0.01; 142.2 versus 157.2 and 158.1). Oocytes with the same diameter derived from different follicles of prepubertal and adult ovaries showed similar meiotic progression rates.

Membrane integrity and fertilizing potential of cryopreserved spermatozoa in European mouflon

There is a pressing need to develop and use assisted reproductive techniques in wildlife species living in small and captive groups. We evaluated the effect of freezing on membrane integrity and fertilizing capacity of European mouflon (Ovis gmelini musimon) spermatozoa collected during the breeding season. After thawing, the percentage of live spermatozoa, stained with fluorescein isothiocynate labeled Pisum Sativum agglutinin and propidium iodide, was 47% of which 19% showed intact acrosomal membrane. After culture in TCM 199 + 10% FCS, the number of live spermatozoa was significantly (P < 0.01) lower than in a medium with oviductal epithelial cells. The absence of oviductal cells decreased significantly the fertilization rates (P < 0.05), 24.0 vs. 63.1 with oviductal epithelial cells and 59.1 in vivo of in vitro matured ovine oocytes. Polyspermic fertilization rate of oocytes was lower (P < 0.05) with oviductal epithelial cells (1.6) than in absence of cells (12.8). However, the percentage of embryos that reached blastocyst stage was significantly higher in vivo than in vitro. These results provide interesting preliminary data for the development of genetic resource banks for European mouflon.

Polyvinyl alcohol as a defined substitute for serum in vitrification and warming solutions to cryopreserve ovine embryos at different stages of development

The purpose of this study was to assess the viability of ovine embryos after replacing fetal calf serum (FCS) with polyvinyl alcohol (PVA) in vitrification and warming solutions. Ovine embryos were obtained from superovulated Sardinian breed ewes at 4, 5, 6, and 7 days after insemination. All vitrification and warming solutions were prepared using buffered saline solution with 20% FCS (group a) or 0.1% PVA (group b). Embryos were vitrified in 20 microliters of glycerol 3.4 M + ethylene glycol 4.6 M and loaded into the centre of 0.25 ml straws between two columns of sucrose solution (0.5 M), and plunged immediately into liquid nitrogen. After being warmed in a water bath at 35 degrees C for 10 s, the vitrified embryos were moved to 0.25 M sucrose solution for 3 min. Embryos were cultured in TCM-199 after washing with 10% FCS and sheep oviductal epithelial cells up to hatching or re-expansion of the blastocoelic cavity. No significant difference in the viability rates was observed between embryos vitrified/warmed in PVA or FCS solutions. In both groups, the rate of in vitro viability was (P < 0.01) lower at the precompacted and compacted morula stages than at the expanded, hatching or hatched blastocyst stage. In both groups, early blastocysts were less viable than expanded (P < 0.01), hatching or hatched blastocyst (P < 0.05). There was no significant difference in survival rates at days 14 (79 and 76%) and 45 (63 and 59%) after transfer into sychronised recipients between vitrified expanded blastocysts of groups a and b, respectively. These results suggest that it is possible replace serum with PVA in vitrification and warming solutions without reducing in vivo and in vitro viability.