Effect of Ca Ionophore On Blastocyst Production Following Intracytoplasmic Sperm Injection in Caprine Oocytes

Effect of chemical activators after intracytoplasmic sperm injection (ICSI) on embryo development in alpacas

Low motility and low sperm concentration are characteristics of alpaca semen. Thus, the intracytoplasmic sperm injection (ICSI) technique represents an alternative to improve the reproductive capacity of the male. However, the effect of post-ICSI activation in alpaca is not yet known. The aim of the present study was to compare the effect of chemical activators on alpaca embryo development after ICSI. Alpaca ovaries were collected from a local slaughterhouse and transported to the laboratory. Category I, II and III oocytes were matured for 30 h at 38.5 °C. After ICSI, injected oocytes were randomly divided and activated as follows: i) 5 μM ionomycin for 5 min, ii) 7% ethanol for 4 min, iii) 5 μM ionomycin for 5 min, window period 3 h plus 7% ethanol for 4 min, iv) 5 μM ionomycin for 5 min, window period 3 h, a second ionomycin treatment for 5 min, followed by 1.9 mM 6-DMAP for 3 h, v) 10 mM SrCl2 for 3 h. Culture was carried out for 5 days in SOFaa at 38.5 °C. The cleavage rate was the lowest in the SrCl2 group, morula development was the lowest in the SrCl2 and without activation groups, and blastocyst stage was not different between groups (P<0.05). The rates with SrCl2 were lower in total embryos produced, whereas in transferable embryos they were lower with 2Io/6-DMAP and with SrCl2 (P<0.05). In conclusion, alpaca oocyte activation is more efficient with ionomycin and ethanol to produce transferable embryos.

Oxidative Stress in Assisted Reproductive Techniques, with a Focus on an Underestimated Risk Factor

Based on current findings, the presence of oxidative stress has a significant impact on the quality of gametes and embryos when performing assisted reproductive techniques (ART). Unfortunately, in vitro manipulation of these cells exposes them to a higher level of reactive oxygen species (ROS). The primary goal of this review is to provide a comprehensive overview of the development of oxidative stress in female and male reproductive systems, as well as in the case of the pre-implantation embryo and its environment. This review also focuses on the origins of ROS and the mechanisms of oxidative stress-induced damage during ART procedures. A well-known but underestimated hazard, light exposure-related photo-oxidation, is particularly concerning. The effect of oxidative stress on ART outcomes, as well as the various strategies for preventing it, are also discussed. We emphasize the role and significance of antioxidants and light protection including forms, functions, and mechanisms in the development of gametes and embryos in vivo and in vitro.

Folate Receptor-1 is Vital for Developmental Competence of Goat Embryos

Folate is essential for DNA synthesis and methylation via one-carbon (C1) metabolism during embryonic development. It is transported into the developing oocytes via folate receptors (FOLR1 and FOLR2) and transporters (RFC1) for utilization during embryo development. However, the role of folate receptors during pre-implantation stages of embryos is not well known. Thus, the present study aimed to investigate the expression of folate transport genes and proteins in mature oocytes and pre-implantation embryos; and the effect of FOLR1 knockdown in zygotes on blastocyst outcome. For this, Immature goat oocytes were matured in maturation medium followed by in vitro fertilization and culture at standard conditions. A group of zygotes was transfected with esiRNA against FOLR1 and in vitro cultured for blastocyst outcome assessment. The transcripts and proteins for FOLR1, FOLR2 and RFC1 were present in oocytes as well as all the stages of pre-implantation embryos. Immunofluorescence revealed the presence of FOLR1 in the nuclei of embryos but not in the metaphase (matured) oocytes. The knockdown of FOLR1 in embryos was effective and significantly reduced the blastocyst production rate. The present study demonstrates the existence of active folate transport in oocytes and pre-implantation goat embryos. FOLR1 is vital for pre-implantation embryo development and may aid in the progression by functioning as a transcription factor.

Assessment of different stages of parthenogenetic embryos for production of embryonic stem cell like colonies

Parthenogenetic activation of oocytes has gained new interest in recent years as an alternative approach to create embryos with no reproductive purpose for research in areas such as assisted reproduction technologies itself and for derivation of clinical grade pluripotent embryonic stem cells for regenerative medicine. In this study, we described the production of goat parthenogenetic ES like cells from different stages of parthenogenetic embryos. We compared the source material on the pESCs outgrowth and culture. 8-16 cell stage embryos, morula, blastocysts and ICM (inner cell mass) from hatched blastocysts produced from chemical activation were cultured on goat fetal fibroblast monolayer in stem cell culture media. Colonies were passaged when signs of differentiation were visible. ESC like colonies were cultured on feeder cells in the presence of hLIF however, some ESC like colonies were also cultured in absence of hLIF for random differentiation. In our study, ESC like colony formation with ICM of hatched blastocyst was comparatively higher as compared to blastocysts while ESC like colony formation with blastocysts and ICM of hatched blastocyst was significantly higher as compared 8-16 cells and morula. It is observed that inner cell mass source is an important criterion for the ES like cells derivation in goats. Also, in comparison to the expanded blastocysts (80.10%), hatched blastocysts showed higher (86.06%) attachment rate and primary colony formation rate. ESC like colonies in absence of hLIF differentiated in vitro into epithelial like and neuronal like cells. Undifferentiated ESC like colonies stained positive for alkaline phosphatase, SSEA-3 and OCT-4.

Development of caprine chimeric embryos reconstructed through ES-tetraploid complementation assay

The aim of the present study was to evaluate the development of caprine chimeric embryos in different culture media, viz. RVCL and mCR2aa + 10% FBS. Inner cell mass (ICM) from hatched blastocysts of parthenogenetic activated embryos were used to produce ES cell-like cells (103) while 4-cell embryos obtained from IVF were utilized to produce tetraploid embryos (231). The aggregates prepared were randomly divided into 2 groups, viz. Gr 1 (RVCL) (53) and Gr 2 (mCR2aa +10% FBS) (50) followed by culture in humidified atmosphere of 5% CO2 at 38.5°C in a CO2 incubator. Outcome measures were aggregation, 8–16 cell, morula and blastocyst formation. The percentage of aggregation, 8–16 cell, morula and blastocyst in Gr 1 (RVCL) was 83.33±6.00%, 42.24±7.71%,29.59±7.64% and 11.49±5.36%, respectively while the percentage of aggregation, 8–16 cell, morula and blastocyst in Gr 2 (mCR2aa +10% FBS) was 91.66±4.32%, 54.76±7.75%, 22.32±5.75% and 14.58±5.18%, respectively. In conclusion, both the media supported the development of chimeric embryos up to blastocyst.

Optimization of caprine embryo production in different media for generation of embryonic stem cell-like cells

The aim of the present study was to optimize the production of blastocyst for obtaining caprine embryonic stem cell-like cells. A total of 4372 cumulus oocyte complexes (COCs) were recovered by slicing the 1187 caprine ovaries and were matured in maturation media for 27 h in humidified atmosphere at 38.5°C with 5% CO2 in CO2 incubator. After 27 h of maturation, oocytes were denuded and were co-incubated with buck semen in fertilization medium (TALP medium + 8 mg/ml fatty acid free BSA and 50 μg/ml heparin) for 18 h. Good quality zygotes (2483) were selected and randomly divided into 2 groups (experiment 1), viz. Group 1 (1312) wherein the presumptive zygotes were cultured in RVCL while in Group 2 (1171) the presumptive zygotes were cultured in mCR2aa medium. The cleavage rate, blastocyst and hatched blastocyst production was significantly higher in Gr 1 (47.45±2.93, 10.13±1.31 and 3.90±1.13%) than Gr 2 (37.75±2.46, 4.20±0.93 and 1.66±0.72%). In experiment 2, after in-vitro fertilization, morula stage embryos and inner cell mass (ICM) from blastocyst and hatched blastocyst were used to isolate ES cell-like cells. Thus the results indicated that the RVCL medium is the best medium as far as the embryonic development up to blastocyst stage in comparison to mCR2aa media. Furthermore, the formation of putative embryonic stem cell colonies were higher from hatched blastocysts (91.6%) as compared to that of blastocysts (82.1%) and it was significantly higher than that from morulas (34.3%).