C-C motif chemokine ligand 2 regulates prostaglandin synthesis and embryo attachment of the bovine endometrium during implantation.

C-C motif chemokine ligand 2 (CCL2) has been reported to be expressed in the bovine endometrium during pregnancy. However, the details of its functions involved in the implantation mechanism are still not clear. The purpose of this study is to analyze the functional properties of CCL2 in the bovine endometrium and embryos. The expression of CCR2 was not different between the luteal phase and implantation phase of their endometrial tissues, but was significantly high in IFNa treated bovine endometrial stromal (BES) cells in vitro. The expressions of PGES1, PGES2, AKR1C4, and AKR1C4 were high at the implantation stage compared with the luteal stage. On the other hand, PGES2 and AKR1B1 in BEE and PGES3 and AKR1A1 in BES were significantly increased by CCL2 treatment, respectively. The expressions of PCNA and IFNt were found significantly high in the bovine trophoblastic cells (BT) treated with CCL2 compared to the control. CCL2 significantly increased the attachment rate of BT vesicles to BEE in in vitro co-culture system. The expression of OPN and ICAM-1 increased in BEE, and ICAM-1 increased in BT by CCL2 treatment, respectively. The present results indicate that CCL2 has the potential to regulate the synthesis of PGs in the endometrium and the embryo growth. In addition, CCL2 has the possibility to regulate the process of bovine embryo attachment to the endometrium by modulation of binding molecules expression.

Gene expression of bovine endometrial epithelial cells cultured in matrigel.

Glandular epithelial cells (GE) in the endometrium are thought to support the elongation and survival of ruminant embryos by secreting histotrophs. In the present study, the gene expression of bovine endometrial epithelial cells cultured in matrigel was analyzed and examined whether it could be an in vitro model of GE. Bovine endometrial epithelial cells (BEE) and stromal cells (BES) were isolated from the slaughterhouse uteri and cultured in DMEM/F12 + 10% FBS. BEE showed the gland-like structure morphological changes when cultured in 15% matrigel but could not be identified in higher concentrations of the matrigel (30% or 60%). The expression of typical genes expressed in GE, SERPINA14 and GRP, was substantially high in matrigel-cultured BEE than in monolayer (P  <  0.05). P4 and INFα have no significant effect on the SERPINA14 expression of BEE cultured in matrigel without co-culture with BES. On the other hand, when BEE were co-cultured with BES in matrigel culture, the expression of FGF13 was increased by the P4 treatment (P  <  0.05). Furthermore, SERPINA14 and TXN expressions were increased by P4 + IFNα treatment (P  <  0.05). These results demonstrate the appropriate conditions for BEE to form glandular structures in matrigel and the effect of co-culture with BES. The present study highlighted the possible use of matrigel for the culture of BEE to investigate the expression of cell-specific glandular epithelial genes as well as P4 and type-I IFN as factors controlling endometrial function during the implantation period.

Analysis of novel embryonic factors of cattle and effects on endometrial cells in vitro.

Interferon tau (IFNT) is thought to have essential functions in maternal recognition and establishment of pregnancy in ruminants. There, however, is a lack of research on embryonic factors that affect pregnancy other than IFNT. The present study was conducted to determine what are other embryo-derived factors involved in pregnancy recognition and to identify effects on endometrial cells using an in vitro culture system. With use of LC-MS/MS procedures to evaluate the supernatant of elongating embryos of cattle in culture, there was detection of 78 secretary proteins including five cytokines and two growth factors. Then there was analysis for up-regulated genes using ingenuity pathway procedure, IFNT and MIF were identified as upstream regulators of 37 and five genes, respectively. The mRNA transcript of MIF receptors was identified in endometrial cells, however, not in embryos. Among genes induced by MIF, CCL2, IL7 and IL23A transcripts were identified in endometrial cells. When endometrial cells were treated with interferon alpha (IFNA) and MIF, the CCL2 transcript was in a larger abundance of endometrial epithelial and polymorphonuclear neutrophil cells, and there was a larger abundance of there mRNA transcripts as a result of MIF treatment of peripheral blood mononuclear cells. In conclusion, MIF secreted by elongating embryos of cattle synergistically regulates relative abundances of specific mRNA transcripts of endometrial cells when there is treatment with IFNA, indicating further there are several factors other than IFNT that have effects on gene expression in the endometrium during early stages of gestation in cattle.

Effect of Dipeptides on In vitro Maturation, Fertilization and Subsequent Embryonic Development of Porcine Oocytes.

The effects of amino acids and dipeptides on in vitro production of porcine embryos and accumulation of ammonia in culture medium during developmental stages were examined in this study. The maturation, fertilization and development of embryonic cultures were performed in modified Tissue culture medium (mTCM)-199 supplemented with 10% (v/v) porcine follicular fluid, modified Tyrode's albumin lactate pyruvate (mTALP) medium, and modified North Carolina State University (mNCSU)-23 medium, respectively. In addition, amino acids and dipeptides of different concentrations and combinations were used to treat the embryos. The addition of L-alanyl-L-glutamine (AlnGln)+L-glycyl-L-glutamine (GlyGln) significantly (p<0.05) improved oocyte maturation, fertilization and the incorporation and oxidation of (14)C(U)-glucose when compared to the control group and other treatment groups. Additionally, 2-4 cell, 8-16 cell, morula and blastocyst development increased significantly (p<0.05) following treatment with AlnGln+GlyGln when compared to the control group and other treatment groups, while this treatment reduced the accumulation of ammonia. Taken together, these findings suggest that treatment with AlnGln+GlyGln may play an important role in increasing the rate of porcine oocyte maturation, fertilization and embryonic development by reducing the level of accumulated ammonia measured in the culture media.

Selenium and vitamin E improve the in vitro maturation, fertilization and culture to blastocyst of porcine oocytes.

Selenium (Se) and vitamin E (Vit-E), as integral parts of antioxidant systems, play important roles for sperm and embryos in vitro. In this study, the effects of Se and Vit-E on the maturation, in vitro fertilization and culture to blastocysts of porcine oocytes and accumulation of ammonia in the culture medium during different development stages were investigated. The maturation was performed in modified tissue culture medium (mTCM)-199 supplemented with 10% (v/v) porcine follicular fluid, the fertilization medium was modified Tyrode's albumin lactate pyruvate (mTALP), and the embryo culture medium was modified North Carolina State University (mNCSU)-23. Se in the form of sodium selenite (SS) and seleon-L-methionine (SeMet) and Vit-E at different concentrations were also used. The incorporation and oxidation of (14)C(U)-glucose were assessed with a liquid scintillation counter. In this study, SeMet and SeMet+Vit-E increased oocyte maturation, fertilization and incorporation and oxidation of (14)C(U)-glucose significantly (P<0.05) compared with the control and other treatments. In addition, embryo development, specifically in terms of the numbers of morulae and blastocysts, significantly increased (P<0.05) with SeMet and SeMet+Vit-E. In contrast, the accumulation of ammonia was reduced with SeMet and SeMet+Vit-E compared with other treatments. These findings indicate that SeMet and SeMet+Vit-E may play important roles in reducing the accumulation of ammonia and subsequently in increasing the rate of maturation of porcine oocytes and fertilization, as well as development of the blastocyst and utilization of glucose in in vitro maturation, fertilization and culture to blastocysts of porcine oocytes.