Effect of recombinant human FSH and LH on in vitro maturation of sheep oocytes; embryo development and viability

Clinical Outcomes of In Vitro Maturation After Oocyte Retrieval With Gynecological Surgery for Refractory Polycystic Ovary Syndrome: A Retrospective Cohort Study

OBJECTIVE

To explore the clinical outcomes of unstimulated in vitro maturation (IVM) after oocyte retrieval with gynecological surgery (IVM-surgery) for refractory polycystic ovary syndrome (PCOS) and analyze the influencing factors.

METHODS

Patients with refractory PCOS who underwent unstimulated IVM-surgery from June 2014 to September 2018 were included in this retrospective cohort study. Matured IVM oocytes were freshly fertilized and subsequently frozen at the blastocyst stage. Frozen-thawed embryo transfer was then conducted according to the desire of patients. Oocytes and embryological outcomes, reproductive outcomes were evaluated. Influencing factors of oocytes and embryological outcomes were analyzed by univariate analysis and multivariate analysis. Receiver operating characteristic curves were used to evaluate the predict value of serum hormone levels for oocytes and embryological outcomes.

RESULTS

A total of 93 patients with refractory PCOS who underwent unstimulated IVM-surgery were included in this study.13 patients (13/85, 15.3%) had spontaneous pregnancy and live birth after surgery. 34 patients (34/93, 36.6%) obtained blastocysts and received embryo transfer, of which 13 patients (13/34, 38.2%) eventually achieved live birth by IVM. Higher anti-Mullerian hormone, antral follicle count and basal serum luteinizing hormone (LH) levels were strongly correlated with higher number of oocytes retrieved (P = 0.004, 0.004, 0.040, respectively). Higher basal serum follicle-stimulating hormone (FSH) and LH were significantly associated with higher oocyte maturation rate (P = 0.001 and P = 0.004, respectively) and blastocyst formation (P = 0.036 and P = 0.003, respectively). There was a significant linear correlation between basal serum FSH and LH (r = 0.500, P <0.001). What is more, basal serum FSH and LH had predictive value for oocytes and embryological outcomes.

CONCLUSION

Unstimulated IVM-surgery provided the opportunity for both spontaneous pregnancy and assisted reproductive technology. Basal FSH and LH were significantly associated with oocyte maturation rate and blastocyst formation of unstimulated IVM-surgery.

Effects of Tannic Acid on Antioxidant Activity and Ovarian Development in Adolescent and Adult Female Brandt's Voles

It is well known that tannins can influence the reproduction of animals, but there is little research published to elucidate the mechanics of this phenomenon. The purpose of this study was to investigate the role of antioxidation in the influence of tannic acid on the ovarian development of Brandt's voles (Lasiopodomys brandtii), which is a species of prairie animal that feeds on plants containing tannins. Postnatal 4-week-old female Brandt's voles were treated with 0 (control), 0.3% (low dose), or 0.6% (high dose) tannic acid for 4 or 9 weeks (i.e., when they reached puberty [8 weeks] or sexual maturity [13 weeks], respectively). The results showed that in both adolescent and adult Brandt's voles, firstly, treatment with tannic acid produced a higher ovary coefficient (ratio of the weight of ovaries to body weight), a greater proportion of mature follicles, and an increased follicular diameter. Secondly, tannic acid increased the serum contents of luteinizing hormone, follicle-stimulating hormone, and serum estradiol. Thirdly, tannic acid elevated the levels of antioxidant enzymes (superoxide dismutase, glutathione peroxidase, and catalase) and reduced the level of malondialdehyde. Therefore, it is suggested that tannic acid may promote the ovarian development of female Brant's voles by enhancing their antioxidant capacity.

Follicle-stimulating hormone administration affects amino acid metabolism in mammalian oocytes†

Culture media used in assisted reproduction are commonly supplemented with gonadotropin hormones to support the nuclear and cytoplasmic maturation of in vitro matured oocytes. However, the effect of gonadotropins on protein synthesis in oocytes is yet to be fully understood. As published data have previously documented a positive in vitro effect of follicle-stimulating hormone (FSH) on cytoplasmic maturation, we exposed mouse denuded oocytes to FSH in order to evaluate the changes in global protein synthesis. We found that dose-dependent administration of FSH resulted in a decrease of methionine incorporation into de novo synthesized proteins in denuded mouse oocytes and oocytes cultured in cumulus-oocyte complexes. Similarly, FSH influenced methionine incorporation in additional mammalian species including human. Furthermore, we showed the expression of FSH-receptor protein in oocytes. We found that major translational regulators were not affected by FSH treatment; however, the amino acid uptake became impaired. We propose that the effect of FSH treatment on amino acid uptake is influenced by FSH receptor with the effect on oocyte metabolism and physiology.

In vitro survival, growth, and maturation of sheep oocytes from secondary follicles cultured in serum-free conditions: impact of a constant or a sequential medium containing recombinant human FSH

This study evaluated the in vitro development and maturation of ovine oocytes from secondary follicles cultured in serum-free medium containing fixed or sequential concentrations of recombinant human FSH (rhFSH). Follicles were cultured in α-MEM⁺ alone or with constant (500, 750, or 1,000 ng/mL) or sequential concentrations of rhFSH (seq. 1: day 6 = 500; day 12 = 750; day 18 = 1,000 ng/mL and seq. 2: day 6 = 100; day 12 = 500; day 18 = 1,000 ng/mL). At the end of the experiment, follicular survival was higher (P < 0.05) in 750 ng/mL rhFSH than the control and 1,000 ng/mL rhFSH. As early as day 6 of culture, antral cavity formation was observed in all treatments. Follicular diameter increased progressively and significantly in all treatments throughout 18 d of culture. Furthermore, addition of rhFSH to the medium promoted a significant increase in the percentage of fully grown oocytes in all treatments compared to α-MEM⁺. Mitochondrial activity was higher in rhFSH treatments than in the control, except in rhFSH seq. 2 (P < 0.05). Maturation rates increased in oocytes from intact follicles cultured in 750 ng/mL rhFSH compared to the control (P < 0.05). In conclusion, rhFSH at 750 ng/mL maintained the survival of secondary follicles cultured in serum-free medium, improved oocyte growth, mitochondrial activity, and oocyte maturation.

Effect of kisspeptin on in vitro maturation of sheep oocytes

Aim:

The aim of this study was to investigate the effect of kisspeptin (KP) on in vitro maturation (IVM) of sheep oocytes aspirated from the ovaries collected from slaughterhouse.

Materials and Methods:

Two different experiments were conducted to investigate the effect of KP (5, 10 and 15 µg/ml) alone (experiment 1) or in combination with follicle-stimulating hormone (FSH), luteinizing hormone (LH), and Estradiol (E₂) (experiment 2) on IVM of sheep oocytes. Tissue culture medium 199 supplemented with Gentamicin was used as control medium. Good quality oocytes were randomly allocated into different IVM media and cultured at 38.5°C in 5% CO₂ under humidified atmosphere for 24 h. The oocytes were evaluated for their cumulus cell expansion (CCE) and extrusion of the 1^st polar body (PB) at the end of maturation.

Results:

The proportion of oocytes showing CCE and extrusion of PB was highest when the oocytes were matured in the medium supplemented with 10 µg/ml of KP. In experiment 2, oocytes were matured in 12 different maturation media (G₁-G₁₂: G₁: Control, G₂: KP alone, G₃: FSH, G₄: FSH+KP, G₅: LH, G₆: LH+KP, G₇: E₂, G₈: E₂+KP, G₉: FSH+LH+E₂, G₁₀: FSH+LH+E₂+KP, G₁₁: FSH+LH+E2+fetal bovine serum (FBS), G₁₂: FSH+LH+E₂+FBS+KP). The proportion of oocytes showing cumulus expansion and PB extrusion was highest (98.33±1.05 and 89.17±2.38) when they were matured in FSH+LH+E₂+FBS+KP (G₁₂) and was significantly higher than other groups. The proportion of CCE and extrusion of PB was significantly increased when KP was supplemented to FSH and E₂, but no effect was observed with LH. The maturation rates were significantly increased when FSH, LH, and E₂ (G₉) containing media were additionally supplemented with KP (G₁₀).

Conclusion:

This study demonstrated that the addition of KP (10 µg/ml) to the FSH, LH, and E₂ supplemented media would enhance the sheep oocyte maturation in vitro.

Follicle-stimulating hormone-induced rescue of cumulus cell apoptosis and enhanced development ability of buffalo oocytes

The effect of follicle-stimulating hormone (FSH) on apoptotic status of cumulus cells, expression of proapoptotic and antiapoptotic genes, and development rate of in vitro fertilization-produced buffalo embryos were investigated. FSH supplementation in in vitro maturation-medium resulted in a dose-dependent reduction in the expression of proapoptotic genes namely, BCL2-associated X protein (BAX), cytochrome c, and caspase-3 and increase in the expression of antiapoptotic genes such as B-cell lymphoma 2 (BCL2) and X-linked inhibitor of apoptosis protein (XIAP) in cumulus cells of mature oocyte. Cumulus expansion, oocyte maturation, cleavage, and blastocyst development rates were significantly higher (P < 0.05) in 5 and 10-μg/mL FSH-supplemented groups as compared with control. Significant increase in the expression of FSH receptor messenger RNA was also found with 5 and 10-μg/mL FSH (P < 0.05). Terminal deoxynucleotidyl transferase dUTP nick end labeling assay confirmed that the population of apoptotic cumulus cells of matured oocytes was reduced in the FSH-treated groups as compared with control (P < 0.05). In conclusion, our data suggest that FSH may attenuate apoptosis in cumulus cells via mitochondria-dependent apoptotic pathway by increasing XIAP expression, resulting in a more favorable ratio of BCL2/BAX expression and decreasing the cytochrome c and caspase-3 expression, eventually contributing to developmental competence of oocytes. The information generated will help in improving the in vitro embryo production program in buffalo.

Effect of sericin supplementation in maturation medium on cumulus cell expansion, oocyte nuclear maturation, and subsequent embryo development in Sanjabi ewes during the breeding season

The purpose of this study was to evaluate the effect of sericin with different concentrations (0% [control], 0.1%, 0.5%, 1.0%, and 2.5%) added to the IVM medium on cumulus cell expansion, oocyte nuclear maturation, and subsequent embryo development in Sanjabi ewes during the breeding season. The resumption of meiosis was assessed by the frequency of germinal vesicle breakdown and the first polar body extrusion. After IVF with fresh ram semen, presumptive zygotes were cultured 8 days in potassium simplex optimization medium supplemented by amino acids, and the percentages developing to the two-cell and blastocyst stages were measured as the indicators of early embryonic developmental competence. More cumulus-oocyte complexes matured with 0.5% sericin underwent germinal vesicle breakdown and reached metaphase II stage compared with the control cumulus-oocyte complexes matured without sericin (P ≤ 0.05). The present findings indicated that supplementation with 0.5% sericin during the maturation culture may improve the nuclear maturation and the cumulus cell expansion. Furthermore, the percentage of blastocysts obtained from 0.5% and 0.1% sericin (37.8 ± 1.76% and 34.8 ± 1.09%, respectively) was higher (P ≤ 0.05) than that of the control medium (29.60 ± 1.67%). However, addition of 1% and 2.5% of sericin to the IVM medium oocytes had a negative effect on nuclear maturation and cumulus cell expansion. Furthermore, the percentage of cleavage and blastocyst rate was significantly lower in the 1% and 2.5% sericin groups than in the control group. These findings showed that supplementation of IVM medium with 0.5% sericin may improve the meiotic competence of oocytes and early embryonic development in Sanjabi ewes during the breeding season.

Time course of the meiotic arrest in sheep cumulus-oocyte complexes treated with roscovitine

Temporary meiosis arrest with cyclin-dependent kinases inhibitors has been proposed in order to improve the quality of in vitro matured oocytes. In sheep, however, this phenomenon has been rarely investigated. Therefore, the present study aimed to evaluate the effect of different incubation times with roscovitine on nuclear maturation and cumulus cell expansion of sheep cumulus-oocyte complexes (COCs). For this, COCs were cultured for 0, 6, 12 or 20 h in basic maturation medium (Control) containing 75 μM roscovitine (Rosco). After, they were in vitro matured (IVM) for 18 h in the presence of luteinizing hormone (LH) and follicle-stimulating hormone (FSH). At the end of each treatment, cumulus cell expansion and nuclear maturation were assessed under a stereomicroscope and by Hoechst 33342 staining, respectively. In the Control and Rosco groups, the absence of cumulus cell expansion prevailed at 0, 6, 12 and 20 h. After IVM for 18 h, total cumulus cell expansion in the Rosco treatments was dependent on the exposure time to roscovitine. A significantly high percentage of oocytes treated with roscovitine for 6 h (87%), 12 h or 20 h (65%) were arrested at the germinal vesicle (GV) stage. In contrast, 23% GVBD, 54% metaphase I (MI) and 61% MII oocytes were observed in the Control groups at 6, 12 and 20 h, respectively. In all treatments, a significant percentage of oocytes reached MII after IVM for 18 h. Therefore, roscovitine reversibly arrested the meiosis of sheep oocytes during different culture times with the maximal efficiency of meiotic inhibition reached at 6 h. In addition, reversibility of its inhibitory action on cumulus cells was exposure-time dependent.

FSH in vitro versus LH in vivo: similar genomic effects on the cumulus

The use of gonadotropins to trigger oocyte maturation both in vivo and in vitro has provided precious and powerful knowledge that has significantly increased our understanding of the ovarian function. Moreover, the efficacy of most assisted reproductive technologies (ART) used in both humans and livestock species relies on gonadotropin input, mainly FSH and LH. Despite the significant progress achieved and the huge impact of gonadotropins, the exact molecular pathways of the two pituitary hormones, FSH and LH, still remain poorly understood. Moreover, these pathways may not be the same when moving from the in vivo to the in vitro context. This misunderstanding of the intricate synergy between these two hormones leads to a lack of consensus about their use mainly in vitro or in ovulation induction schedules in vivo. In order to optimize their use, additional work is thus required with a special focus on comparing the in vitro versus the in vivo effects. In this context, this overview will briefly summarize the downstream gene expression pathways induced by both FSH in vitro and LH in vivo in the cumulus compartment. Based on recent microarray comparative analysis, we are reporting that in vitro FSH stimulation on cumulus cells appears to achieve at least part of the gene expression activity after in vivo LH stimulation. We are then proposing that the in vitro FSH-response of cumulus cells have similitudes with the in vivo LH-response.

Different in vitro culture systems affect the birth weight of lambs from vitrified ovine embryos

It has been reported that different in vitro culture systems affect the birth weight of lambs. The aim of this study was to test body weight and lambing rate of lambs born from five different in vitro culture systems after vitrification. Oocytes of Sarda sheep were matured in TCM-199 plus 0.4% bovine serum albumin (BSA) using systems: (i) 4 mg/ml fatty acid-free BSA (BSA4); (ii) 8 mg/ml fatty acid-free BSA (BSA8); (iii) BSA8–hyaluronan (BSA8–HA); (iv) BSA8–charcoal-stripped FBS (BSA8–CH); or (v) with 10% fetal bovine serum (FBS; serum) and fertilized with fresh semen. The presumptive zygotes were cultured up to the blastocyst stage with BSA8, BSA8-HA, BSA8-CH or serum or BSA4. In the third and fifth days of culture 5% charcoal-stripped FBS was added into BSA8-CH and serum, while 8 mg/ml or 4 mg/ml fatty acid-free BSA was added as BSA8, BSA8-HA and BSA4 respectively; 6 mg/ml HA was added to BSA8-HA. In total, 240 vitrified blastocysts were transferred into synchronized ewes. The lambing rate was not significant different between BSA groups or between serum groups (BSA8-CH and serum), while serum groups showed significant lower values when compared with BSA groups. Only BSA8 groups produced heavy lambs (≥4.5 kg) with a significant difference between BSA4 and BSA8 groups (P < 0.05).

Assisted reproductive technologies in the reproductive management of small ruminants

In modern agriculture, assisted reproductive technologies are being used for out of season oestrus induction, enhancement of reproductive performance and genetic improvement. In addition, they can have substantial contribution in preservation of endangered species or breeds, as well as in eradication programs of various diseases. While their applications are widespread in cattle, in small ruminants it is almost restricted to artificial insemination. The main limitations of a wider application in small ruminants are the naturally occurring anoestrus period, the variability of response to superovulatory treatments, the fertilisation failure and the need of surgery for collection and transfer of gametes and embryos. Nonetheless, during the last 30 years, considerable progress has been made in sheep and goat embryo technologies, especially in the fields of oestrus synchronisation, superovulation and in vitro embryo production. This paper reviews the status of assisted reproductive technologies in sheep, analysing the prospects offered by recent advances in in vivo and in vitro embryo production from mature and juvenile lambs.

Derivation and characterization of ovine embryonic stem-like cell lines in semi-defined medium without feeder cells

Domestic animal embryonic stem (ES) cells would provide an invaluable research tool for genetic breeding and the production of transgenic animals. Unfortunately, authentic domestic animals ES cells have not been established despite progress made over more than two decades. Here, we show that ovine ES-like cells can be efficiently derived and propagated in a semi-defined medium that contains N2, B27, GSK3 inhibitor (CHIR99021), and basic fibroblast growth factor (bFGF). These ovine ES-like cells had a characteristic three-dimensional appearance, showed a bFGF dose-dependence, expressed specific markers such as alkaline phosphatase (AP), Oct-4, Sox2, Nanog and can be maintained for 30 passages. Moreover, these cells differentiated in vitro into neuronal cells, and formed teratomas containing a variety of different tissues including cartilage and neural tissue when injected into kidney capsules of severe combined immunodeficiency (SCID) mice. But the cell lines fail to contribute to embryonic development upon blastocyst transplantation. To our knowledge, this is the first experiment to use semi-defined medium without feeder-cells to derive ES-like cells from ovine blastocysts, and opens the door to deriving authentic ES cells from domesticated ungulates.

Effect of lanosterol on the in vitro maturation in semi-defined culture system of prepubertal ewe oocytes

The choice of medium and supplements can affect meiotic regulation and may have an impact on the regulation of mammalian oocyte growth and embryonic cell function. The aim of the present study was to assess the effects of oxygen concentration and endogenous lanosterol on the in vitro maturation (IVM) media without serum and based on recombinant human chorionic gonadotrophin in prepubertal ewe oocytes. Firstly, the effect of varying oxygen concentrations (5% and 20%) during IVM in TCM-199 supplemented (4 mg/ml bovine serum albumin (BSA), 100 μM cysteamine, 0.3 mM sodium pyruvate, 0.1 UI/ml recombinant follicle-stimulating hormone (r-FSH; Gonal-F® 75 UI, Serono, Italy), 0.1 UI/ml recombinant leuteinizing hormone (r-LH; Lhadi® 75 UI, Serono, Italy) and 1 μg/ml estradiol-17β) on subsequent nuclear maturation of oocytes examined under ultraviolet light following staining with bisbenzimide (Hoechst 33342) was investigated. Secondly, two concentrations of lanosterol (0, 10 and 50 μM) were added to the IVM medium. Nuclear maturation of oocytes was examined as previously. Lipid content in oocytes, an important indicator of cytoplasmic maturity, was also measured using Nile red fluorescent stain. The results showed that low oxygen concentration affected the nuclear maturation. Similarly, a significantly higher rate of meiosis resumption was observed with 10 μM (72.3%) of lanosterol compared with the control (51.8%) or 50 μM of lanosterol (59.4%). A significantly higher content of lipids was also observed with 10 and 50 μM of lanosterol (7.3 ± 0.2 × 106 and 7.4 ± 0.2 × 106 arbitrary units of fluorescence) compared with the control (6.7 ± 0.2 × 106 arbitrary units of fluorescence). The results indicate that 10 μM lanosterol during IVM in medium without serum and based on recombinant human chorionic gonadotrophin has a positive effect on maturation of prepubertal ewe oocytes.

Progesterone and 17beta-estradiol, but not follicle stimulating hormone, alter the sex ratio of murine embryos fertilized in vitro

The objective was to determine the effects of adding progesterone, 17beta-estradiol (17beta-E2), and FSH during in vitro fertilization on development and sex ratio of murine embryos. Progesterone (33-330 pg/mL), 17beta-estradiol (17beta-E2); 10-70 pg/mL), and FSH (0.01-0.05 IU/mL), were added to human tubal fluid (HTF); this medium (with or without hormones) was used to pre-incubate sperm (2h) and to co-incubate sperm and oocytes (6h). Thereafter, the ova were washed and incubated in mM16 medium and embryo sex was determined (by PCR) on Day 4 (insemination=Day 0). There was no effect (P>0.05) of hormone treatments on rates of cleavage (6 h after cessation of co-incubation with sperm). The only significant effects of added hormones on development were a decrease in the rate of development to at least the morula stage in 165 pg/mL progesterone (0.46+/-0.03 vs. 0.54+/-0.05 in the control, mean+/-S.D.; P<0.05) and a decrease in the blastocyst rate in 0.03 IU/mL FSH (0.34+/-0.00 vs. 0.42+/-0.04 in the control, P<0.05). However, the ratio of male to female embryos was 1.61 and 2.90 following the addition of 99 pg/mL progesterone and 70 pg/mL 17beta-E2, respectively; both of these ratios were different (P<0.01) than in the control group (1.20). In contrast, the addition of FSH to the medium had no significant effect on this ratio (range, 0.78-1.02). We concluded that the addition of progesterone and estradiol to the media during in vitro fertilization did not enhance embryonic development, but significantly increased the proportion of male murine embryos.

Glutathione content and glutathione peroxidase expression in in vivo and in vitro matured equine oocytes

The in vitro developmental competence of equine oocytes is still low in comparison with other domestic mammals. A major factor affecting the viability of cells during in vitro culture is the increased oxidative stress. Oxidative modifications could be responsible for oocyte incompetence for in vitro maturation (IVM). Cysteamine, a glutathione (GSH) synthesis enhancer, has been shown to increase intracellular GSH content and to improve embryo development when added during IVM of bovine, porcine, and ovine oocytes. The aim of the present study was (1) to determine whether equine cumulus-oocyte complexes (COCs) benefit from the addition of cysteamine during IVM, (2) to compare the GSH content of oocytes after in vivo maturation and IVM, (3) to assess whether cysteamine administration during IVM of equine oocyte enhances early embryonic developmental capability following ICSI, (4) to study the glutathione peroxidase (GPX) mRNA level in COCs. In vivo matured COCs were collected by aspiration from preovulatory follicles, and analyzed at collection. Immature COCs were collected in vivo or from slaughterhouse ovaries and matured in culture media supplemented or not with 100 microM cysteamine. After nuclear stage assessment, oocytes were analyzed for GSH concentration and both oocytes and cumulus cells were analyzed for GPX and GAPDH mRNA. Our data showed that the maturation capability was similar in both in vivo aspirated oocytes and in those isolated from slaughterhouse ovaries. Moreover, the addition of cysteamine during IVM affected neither GSH content nor maturation rate. At the time of collection, intra-oocyte GSH content was not influenced by the chromatin status. GSH concentration was similar in in vivo and in vitro matured metaphase II (MII) stage oocytes, and was significantly higher in MII than immature germinal vesicle stage oocytes. Moreover, the presence of serum inhibited whereas its absence stimulated the accumulation of GSH within oocytes during IVM. After ICSI, a similar proportion of zygotes in each group developed beyond the two-cell stage after 72 hr of culture. Cumulus cells expressed GPX mRNA, while GPX transcript was absent in both immature and mature oocytes. Cumulus expression of GPX mRNA was significantly higher when analyzed at collection than after IVM. Taken together, our results demonstrate that in equine oocytes, GSH increases during IVM but the relative intra-oocyte content of this thiol does not affect maturation and early development efficiency after fertilization. We hypothesize that factor(s) other than GSH/GPX are responsible for the limited in vitro early developmental capability of equine oocytes.

Lambing rate using vitrified blastocysts is improved by culture with BSA and hyaluronan

Fatty acid-free bovine serum albumin (BSA(FAF)) can be added to supplement medium used in the culture of sheep embryos. BSA(FAF) was able to support blastocyst and subsequent embryo development at rates equivalent to that of fetal calf serum (FCS)-supplemented medium when fresh embryos were transferred. Furthermore, culture with BSA(FAF) significantly increased development of vitrified blastocysts transferred into synchronized sheep. The addition of the glycosaminoglycan, hyaluronan (HA) to the culture medium in the third and fifth day also increased cryo-tolerance of blastocysts and in turn lambing rate was improved.

Benefits of TEMPOL on ram semen motility and in vitro fertility: a preliminary study

Extending the preservation time of fresh semen is an important goal in artificial insemination programs particularly for ewes in natural oestrus, where insemination periods are longer than for ewes synchronized with hormonal treatments. The aim of this study was to evaluate the effect of the antioxidant TEMPOL (4-hydroxy-2,2,6,6-tetramethylpiperidine-1-oxyl) on the maintenance in long term storage of ram semen motility and fertility. Semen from Sarda breed rams was diluted in two extenders: sodium citrate buffer with TEMPOL and skimmed milk, used as control. Samples diluted with TEMPOL were cooled at either 15 degrees C or 22 degrees C, while those diluted with skimmed milk were cooled at 15 degrees C. Each sample was divided into four stocks, and stored for different times (5 min, 24, 48 and 72 h). Three aliquots were taken from each stock for every storage period. One was immediately evaluated under microscope; one was used for in vitro fertilization; one was incubated for 2 h in controlled humidified atmosphere (5% CO2, 7% O2 and 88% N2) at 39 degrees C, then evaluated for motility and utilized for in vitro fertilization. Ram semen diluted with media containing TEMPOL demonstrated increased motility, fertility and an improved protective effect when it was stored at 15 degrees C.

Intracytoplasmic Glutathione Levels in Heifer Oocytes Cultured in different Maturation Media and its Effect on Embryo Development

The present study was carried out to study the effect of different maturation media on embryo development of heifer oocytes and on their glutathione (GSH) synthesis during in vitro maturation (IVM). Immature heifer oocytes were matured in parallel in one of four maturation media: (i) Tissue Culture Medium (TCM)-199 supplemented with 10 ng/ml of epidermal growth factor (EGF); (i) TCM-199 supplemented with 10 ng/ml of EGF plus 1 microg/ml of FSH; (iii) TCM-199 supplemented with 10% of foetal bovine serum (FBS) and (iv) TCM-199 supplemented with 10% of FBS plus 1 microg/ml of FSH. Cow oocytes were used as control and were matured in TCM-199 supplemented with 10 ng/ml of EGF. No differences were observed in blastocyst rate among the different heifer oocyte groups (8.8, 7.5. 8.4 and 6.8%, respectively) however, the percentage of blastocysts obtained from cow oocytes was significantly higher (30%; p < 0.01) than those obtained from heifer oocytes. De novo GSH synthesis during oocyte maturation of heifer and cow oocytes was detected. No significant differences in intracytoplasmic GSH levels were observed among the experimental heifer oocyte groups or between heifer and cow oocytes both before and after IVM. In conclusion, the blastocyst yield obtained from heifer oocytes was lower than that from cow oocytes and this fact could not be explained by significant differences in intracytoplasmic GSH contents of oocytes before or after IVM.

Isolation, culture, and characterization of embryonic cell lines from vitrified sheep blastocysts

This study was conducted to isolate, to culture, and to characterize embryonic cell lines from in vitro produced vitrified sheep blastocysts. Embryos were produced and vitrified at the expanded blastocyst stage. Ten inner cell masses arising from day 6-7 blastocysts were isolated by immunosurgery, disaggregated, and cultured onto mitomocin-C-inactivated mouse STO fibroblasts (MIF). After 5 or 6 days of culture the primary cell colonies were disaggregated, seeded in a new MIF, and cultured for 3 or 4 days to form new colonies called Passage 1. These cells were then disaggregated and cultured for other two passages. The primary cell colonies and Passage 2 colonies expressed stage specific embryonic markers SSEA-1, SSEA-3, and SSEA-4, and were alkaline phosphatase positive. In the absence of feeder layer and human leukemia inhibitory factor (LIF), these cells differentiated into variety of cell types and formed embryoid bodies. When cultured for an extended period of time, embryoid bodies differentiated into derivatives of three embryonic germ (EG) layers. These were characterized by detection of specific markers for differentiation such early mesoderm (FE-C6), embryonic myosin (F1-652), neural precursor (FORSE-1), and endoderm (anti-cytokeratin 18). To our knowledge, this is the first time that embryonic cell lines from in vitro produced and vitrified ovine blastocysts have been isolated and examined for detection of SSEA markers, and embryoid bodies have been cultured and examined for specific cell surface markers for differentiation.

Comparison of different vitrification protocols on viability after transfer of ovine blastocysts in vitro produced and in vivo derived

We compare different vitrification protocols on the pregnancy and lambing rate of in vitro produced (IVP) and in vivo derived (IVD) ovine embryos. Ovine blastocysts were produced by in vitro maturation, fertilization and culture of oocytes collected from slaughtered ewes or superovulated and inseminated animals. Embryos were cryopreserved after exposure at room temperature either for 5 min in 10% glycerol (G), then for 5 min in 10% G + 20% ethylene glycol (EG), then for 30 s in 25% G + 25% EG (glycerol group), or for 3 min in 10% EG + 10% dimethyl sulphoxide (DMSO), then for 30s in 20% EG + 20% DMSO + 0.3 M sucrose (DMSO group). One group of in vitro produced embryos was cryopreserved similarly to the DMSO group, but with 0.75 M sucrose added to the vitrification solution (DMSO 0.75 group). Glycerol group embryos were then loaded into French straws or open pulled Straws (OPS) while the DMSO group embryos were all loaded into OPS and directly plunged into liquid nitrogen. Embryos were warmed with either a one step or three step process. In the one step process, embryos were placed in 0.5 M sucrose. The three-step process was a serial dilution in 0.5, 0.25 and 0.125 M sucrose. The embryos of DMSO 0.75 group were warmed directly by plunging them into tissue culture medium-199 (TCM-199) + 20% foetal bovine serum (FBS) in the absence of sucrose (direct dilution). Following these manipulations, the embryos were transferred in pairs into synchronised recipient ewes and allowed to go to term. The pregnancy and the lambing rate within each group of IVP and IVD embryos indicated that there was no statistical difference among the vitrification protocols.

State-of-the-art production, conservation and transfer of in-vitro-produced embryos in small ruminants

Today, although not efficient enough to replace multiple ovulation and embryo transfer, in vitro embryo production for small ruminants is a platform for new reproductive technologies, such as embryo sexing, transgenesis and cloning. The in vitro embryo-production system developed for sheep and goats is more efficient now than 15 years ago, but could still be improved. Laparoscopic collection of oocytes in live animals treated with gonadotrophin indicates a promising future for the application of this technology to genetic improvement programmes. Oocyte maturation in defined medium with epidermal growth factor and cysteamine appears as efficient as oocyte maturation in follicular fluid-supplemented medium and allows future study of the effect of other factors involved in the cytoplasmic maturation of oocytes from these species. Further efforts have to be made to standardise the semen-capacitating process and to improve the quality and freezability of in-vitro-produced (IVP) embryos. The optimisation of IVP procedures for deer species has required the study of the seasonal variation of oocyte competence and the development of a specific methodology to allow the culture of embryos up to the blastocyst stage.

Sexing of in vitro produced ovine embryos by duplex PCR

The aim of this article was to develop a fast and easy duplex polymerase chain reaction (PCR) method, for sex determination of ovine in vitro produced embryos prior to implantation. We tested the approach with 107 samples of autosomal cells (oviductal sheep cells and male lamb fibroblasts), divided into three groups for each sex according to the number of cells employed (30, 5, 2, respectively). We then used the test on 21 embryos at blastocyst stage. On the same day the embryos were transferred in pairs into 11 recipient synchronized ewes. The PCR utilized two different sets of primers: the first pair recognized a bovine Y-chromosome-specific sequence (SRY), that showed 100% homology with the corresponding sequence of the ovine Y-chromosome and is amplified in males only. The second pair recognized the bovine 1.715 satellite DNA (SAT) which was amplified in all ovine samples but, when submitted to the GenBank database did not show homology with any of the reported ovine sequences. However, after sequencing, ovine amplification product showed 98% homology with the bovine specific satellite sequence. The autosomal samples were amplified with 85.0% efficiency and 91.2% accuracy, while amplification was successful with all 21 embryos (100% efficiency). Eight lambs were born and the sex as determined by PCR corresponded to the anatomical sex in seven (87.5% accuracy). These results confirm that this method can be applied in ovine breeding programs to manipulate sex ratio of offspring.