The effects of various antioxidants on the development of parthenogenetic porcine embryos

N-(2-mercaptopropionyl)-glycine enhances in vitro pig embryo production and reduces oxidative stress

This study evaluated the effects of different concentrations (1, 10, 25, 50, and 100 µM) of the antioxidant N-(2-mercaptopropionyl)-glycine (NMPG), during the culture of in vitro-fertilized porcine oocytes. While the highest concentrations of NMPG (50 and 100 µM) were toxic to the developing embryos during the first two days of culture, 25 µM NMPG achieved cleavage rates that were similar to those achieved by the control but did not sustain blastocyst production by Day 7 of culture. Compared to the control culture medium, the culture medium supplemented with 10 µM NMPG increased (P < 0.05) the rates of blastocyst formation, decreased (P < 0.05) the intracellular levels of reactive oxygen substances, and downregulated (P < 0.05) the expression of the oxidative stress related gene GPX1. In conclusion, these results demonstrated that supplementation of porcine embryo culture medium with 10 µM NMPG can attenuate oxidative stress and increase the yield of in vitro production of blastocysts.

Improvement in the blastocyst quality and efficiency of putative embryonic stem cell line derivation from porcine embryos produced in vitro using a novel culturing system

Porcine embryonic stem cells (pESCs) have great potential for application in translational biomedical research, including xenotransplantation and disease models. Obtaining high-quality blastocysts is the most important factor in the isolation and colonization of primary ESCs and the establishment of ESC lines. In pigs, in vitro-derived blastocysts have a limited cell number compared to in vivo-derived blastocysts and show an indefinite inner cell mass, which may result in failure to establish pESC lines. In the present study, the effects of resveratrol (RES), granulocyte-macrophage colony stimulating factor (GM-CSF) and β-mercaptoethanol (β-ME) on the quality of blastocysts and the efficiency of colony derivation were investigated for the establishment of ESCs. A novel culturing system was developed in which 2 µM RES was added to the oocyte in vitro maturation (IVM) medium, and 10 ng/ml pGM-CSF and 10 µM β-ME were added to embryo in vitro culture (IVC) medium. This novel system showed significantly more parthenogenetic activation (PA) blastocysts (54.5 ± 1.8% vs. 43.4 ± 1.2%; P<0.05) and in vitro fertilization (IVF) blastocysts (36.9 ± 3.3% vs. 26.2 ± 2.9%; P<0.06) at day seven as compared with that in the control system. The PA and IVF blastocysts from the novel system showed a significantly greater hatching rate (P<0.05) and greater cell numbers (55.1 ± 2.0 vs. 45.6 ± 2.0; P<0.05 and 78.9 ± 6.8 vs. 58.5 ± 7.2; P<0.06, for PA and IVF, respectively) at day seven compared to that in the control system. After seeding on feeder cells, the PA blastocysts produced by the novel system showed a significantly increased rate of attachment (28.8 ± 3.9% vs. 17.2 ± 2.4%; P<0.062). Finally, two putative pESC lines from PA embryos produced by the novel system and one by the control system were established. In conclusion, the novel system improved blastocyst quality and increased the derivation efficiency of putative pESC lines from porcine PA and IVF embryos produced in vitro.

Effect of trans-ε-viniferin on in vitro porcine oocyte maturation and subsequent developmental competence in preimplantation embryos

Trans-ε-viniferin is a naturally occurring polyphenol belonging to the stilbenoid family that has been isolated from Vitis amurensis, one of the most common wild grapes in Asia. We investigated the effects of trans-ε-viniferin on in vitro maturation (IVM) and developmental competence after in vitro fertilization (IVF) or parthenogenesis (PA). We observed that trans-ε-viniferin treatment during IVM did not improve nuclear maturation rates of oocytes in any group, but significantly increased (P<0.05) intracellular glutathione (GSH) levels and reduced reactive oxygen species (ROS) levels in the 0.5 µM treatment group. Trans-ε-viniferin treatment during IVM of recipient oocytes promoted higher (P<0.05) expression of DNA methyltransferase-1 (DNMT1) mRNA in the 0.5 µM treatment group as compared with the control group. However, the expression of essential transcriptional and apoptosis-related genes did not significantly differ from that of the control. In cumulus cells, pro-apoptosis gene expressions were changed as apoptosis decreased. Oocytes treated with trans-ε-viniferin during IVM did not have significantly different cleavage rates or blastocyst formation rates after PA, but total cell numbers were significantly higher (P<0.05) in the 0.5 and 5.0 µM treatment groups compared with those in the control group. IVF embryos showed similar results. In conclusion, these results indicate that trans-ε-viniferin treatment during porcine IVM increased the total cell number of blastocysts, possibly by increasing intracellular GSH synthesis, reducing ROS levels, increasing DNMT1 gene expression of oocytes and decreasing pro-apoptosis gene expressions of cumulus cells.

The effect of intra-peritoneal administration of Papaver bracteatum Lindl. extract on development of NMRI mice oocytes treated with Doxorubicin

Purpose

The effect of water-alcohol Papaver bracteatum Lindl. extract on development of mice oocytes treated with Doxorubicin (dox) was examined in this study.

Methods

The mice were classified into four groups. Control group, mice injected intraperitoneally (IP) with saline. Extract group alone, mice treated with 200 mg/kg of body weight (bw), IP, twelve consecutive days. Dox group alone, mice were given dox, IP, 10 mg/kg bw. Experimental group treated with extract and dox together. Effect of the extract on the development of mice oocytes treated with dox were evaluated through assisted reproductive technology techniques (ARTs).

Results

Developmental rate and blastocyst formation was improved by using the extract. A significant increase in in vitro developmental competence in comparison with dox group (P < 0.05) was observed.

Conclusions

The results of this study indicated that P. bracteatum Lindl. extract could prevent dox toxicity of dox affecting both follicle or oocytes, and therefore it can result in improved embryo development which was observed in mice treated with dox plus P. bracteatum Lindl. compared to mice treated with dox alone.

Advances on in vitro production and cryopreservation of porcine embryos

There have been intensive attempts to establish reliable in vitro production (IVP) and cryopreservation methods of embryos in pigs. Although a great deal of progress has been made, current IVP systems and cryopreservation still suffer from insufficient cytoplasmic abilities of in vitro matured oocytes, polyspermic fertilization, poor quality of in vitro produced embryos and low efficiency of embryo cryopreservation. Compared to other mammalian species, pig oocytes and embryos are characterized by large amounts of lipid content stored mainly in the form of lipid droplets in the cytoplasm. This fact has a negative influence on biotechnological applications on porcine oocytes and embryos. In this review, we will discuss recent studies about methods and techniques for modifying porcine embryo IVP system and embryo cryopreservation that produces high quality of pig blastocysts using in vitro maturation, in vitro fertilization, in vitro culture, microsurgical manipulation, addition of protein, the use of cytoskeleton stabilizing agents and various physical methods. The presented methods and techniques make it possible to modify the characteristics of oocytes and embryos and thus may become major tools in mammalian gamete and embryo agricultural or biotechnological applications in the future.