Progesterone enhances in vitro development of bovine embryos

Exogenous progesterone-dependent modulation in the follicular dynamics of Bos indicus cattle undergoing repeated ovum pick-up sessions

The objective of the present study was to evaluate the role of serum progesterone (P4) in follicular dynamics, oocytes' recovery and quality and their in vitro developmental competence during consecutive ovum pick-up (OPU) sessions in Bos indicus dairy cows. Wave-synchronized Sahiwal cattle (n = 20) were randomly divided into treatment (n = 10) and control (n = 10) groups. CIDR was used as a source of external progesterone in the treatment group. Four consecutive OPU sessions at 96-hr intervals were conducted and repeated ultrasonography at 12-hr intervals was done to monitor follicular dynamics. The viable oocytes were processed for IVC following IVM and IVF until day 7. The serum P4 concentrations in the P4 and control groups were recorded as 2.31 ± 0.059 versus.0.32 ± 0.065 ng/ml, respectively (p < .05). In the treatment group, the total number of recorded follicles was higher (p < .05; 12.05 ± 0.37 versus. 10.87 ± 0.40), whilst the growth rate (mm/day) of follicles was lower (p > .05). Per session recovered oocytes (5.31 ± 0.19 versus. 3.58 ± 0.21; p < .0001) and recovery rate (54.23 versus. 42.53%; p < .05) were also higher in the treatment group compared to control. Similarly, the viable oocytes (4.54 ± 0.187 versus. 3.06 ± 0.199) and the number of grade I and II oocytes per session (3.37 ± 0.196 versus. 2.06 ± 0.21) were higher (p < .05) in the treatment group compared with the control group. However, the nuclear maturation, cleavage, and blastocyst rate did not differ (p > .05) between the groups. Taken together, during OPU sessions, serum P4 improves oocytes' recovery and quality, whilst does not affect the in vitro developmental competence of recovered oocytes.

Atlas of receptor genes expressed by the bovine morula and corresponding ligand-related genes expressed by uterine endometrium

Regulation of the mammalian embryo involves cell‐signaling molecules produced by the maternal oviduct and endometrium. Here, datasets on the transcriptome of the gestational Days 5 and 6 bovine morula and Day 5 maternal endometrium were examined to identify receptor genes expressed by the morula and expression of the corresponding ligand‐related genes in the endometrium. A total of 175 receptor genes were identified in the morula, including 48 encoding for growth factors or WNT signaling molecules, 25 for cytokines and chemokines, 35 involved in juxtacrine and matricellular signaling and 25 encoding for receptors for small molecules. Some of the highly‐expressed pairs of endometrial ligand and embryo receptor genes included MDK and its receptors ITGB1, SDC4 and LRP2, WNT5A (RYK), VEGFA (ITGB1), GPI (AMFR), and the hedgehog proteins IHH and DHH (HHIP). The most highly expressed receptors for small molecules were GPRC5C (retinoic acid receptor), PGRMC1 (progesterone), and CHRNB2 (acetylcholine). There were also 84 genes encoding for cell signaling ligands expressed by the morula, with the most highly expressed being GPI, AIMP1, TIMP1, IK, and CCN2. The atlas of receptor and ligand genes should prove useful for understanding details of the communication between the embryo and mother that underlies optimal embryonic development.

Progesterone modulates adhesion molecules in uterine epithelial cells and in vitro embryo production in buffalo

This study was undertaken to evaluate the role of progesterone (P4) in modulation of the expression profile of adhesion-related molecules in uterine epithelial cells (UECs) and in vitro blastocyst production in buffalo. UECs were isolated from slaughterhouse-derived uteri by enzymatic treatment, and cells were characterized by immunocytochemistry (ICC) and PCR assays. The well-characterized UECs were exposed to different concentrations of P4 (0, 0.314, 3.14 and 6.28 ng/ml) along with the basal level of oestradiol for 6 days. Thereafter, the relative mRNA expression of different biomolecules such as mucin 1 (MUC1), osteopontin, integrin alpha (α3, α6 and αV) and beta (β1 and β3) subunits, progesterone receptor (PR) and oestrogen receptor, was evaluated. Further, day 2 post-insemination embryos were cultured in mSOF supplemented with or without P4. UECs were found positive for cytokeratin expression and negative for vimentin expression. Progesterone treatment significantly enhanced the mRNA expression of most of the transcripts compared with the control group, and correspondingly, the immunofluorescence depicted higher protein expression of all these molecules. Further, the long-term exposure of UECs to P4 downregulated the expression of PR and, concomitantly, MUC1. Progesterone supplementation to embryo culture medium significantly (p < .05) improved the blastocyst rate. The study demonstrates the role of P4 hormone in modulation of the expression of early implantation-related biomolecules in uterine epithelial cells; hence, adequate level of steroids is crucial for normal embryo development and its implantation.

Progesterone receptor membrane component 1 (PGRMC1)-mediated progesterone effect on preimplantation development of in vitro produced porcine embryos

Progesterone is a steroid hormone well known for its significant role in the reproduction process of mammals. Numerous studies have reported on the regulation of progesterone during implantation, pregnancy and parturition, but there are fewer studies on progesterone in relation to the early stages of embryo development. In the present study, we investigated the effects of progesterone during the development of in vitro produced porcine embryos. First, gene expression of various progesterone receptors in the in vitro produced porcine embryos were analyzed. PGRMC1 and PGRMC2 (progesterone receptor membrane component 1 and 2) showed distinct expression. Next, the embryos were treated with two concentrations of progesterone (10 nM and 100 nM) for two different durations (from day 0 and from day 4) to compare the developmental rates, cell numbers, and apoptosis rates of day 7 blastocysts. The experimental groups in both durations showed similarly increased blastocyst cell numbers and decreased apoptosis rates when treated with 100 nM progesterone. Furthermore, the expression levels of PGRMC1, PGRMC2, PAIRBP1 (plasminogen activator inhibitor RNA-binding protein 1), and apoptosis-related genes were examined in blastocysts and showed significant increases in the 100 nM treatment group compared to the control group. Subsequently, the embryos were treated with the PGRMC1 inhibitor, AG-205, and developmental rates, cell numbers, and apoptosis rates of day 7 blastocysts were compared. In addition, 100 nM progesterone was treated simultaneously with AG-205 to test if the inhibition effect is relieved by progesterone. Groups treated with 1 μM and 2 μM AG-205 showed decreased cell numbers and increased apoptosis rates in day 7 blastocysts compared to the control group. We also confirmed the recovery of inhibition by 100 nM progesterone. In conclusion, the present study indicated that progesterone positively affects the development of in vitro produced preimplantation porcine embryos by increasing cell proliferation and decreasing apoptosis via PGRMC1-involved actions. However, the detailed mechanisms of PGRMC1 need further elucidation.

Intraoviductal concentrations of steroid hormones during in vitro culture changed phospholipid profiles and cryotolerance of bovine embryos

The objective of this study was to evaluate the effect of progesterone (P4), estradiol (E2), and cortisol (CO) at intraoviductal concentrations on bovine embryo development and quality in vitro. After fertilization of in vitro matured oocytes, zygotes were cultured for 8 days in synthetic oviductal fluid, supplemented with 55 ng/ml P4, 120 pg/ml E2, 40 ng/ml CO, or their combination (ALL). Control embryos were cultured with vehicle (0.1% ethanol). Exposure to steroids did not affect the embryo developmental rate nor the mean number of cells per blastocyst. However, at 24 hr after vitrification-warming, exposure to P4 improved the proportion of embryos that re-expanded and were viable while exposure to CO decreased the proportion of viable embryos. By intact cell MALDI-TOF mass spectrometry, a total of 242 phospholipid masses of 400-1000 m/z were detected from individual fresh blastocysts. Exposure to ALL induced the highest and most specific changes in embryo phospholipids, followed by P4, E2, and CO. In particular, the m/z 546.3 and 546.4 attributed to lysophosphatidylcholines were found less abundant after exposure to P4. In conclusion, exposure of bovine embryos to intraoviductal concentrations of steroid hormones did not affect in vitro development but changed blastocyst quality in terms of cryotolerance and phospholipid profiles.

Effect of plasma progesterone on oocyte recovery, oocyte quality, and early in-vitro developmental competence of embryos in Bos indicus dairy cows

The objective of present study was to determine the effect of plasma progesterone (P4) on oocyte recovery, oocyte quality, and early in-vitro developmental competence of embryos in Bos indicus dairy cows. The ovaries were collected in an abattoir. These ovaries (n = 750) were divided into two groups: 1) estrous CYCLIC (n = 318), and 2) estrous ACYCLIC (n = 432). Mean serum concentrations of P4 in a subset of (n = 85; 4.21 ± 0.4 ng/ml compared with 0.5 ± 0.2 ng/ml; P <  0.05) were greater in estrous CYCLIC as compared to ACYCLIC cows, respectively. The mean number of oocytes recovered per ovary (6.5 ± 0.5 compared with 4.0 ± 0.2; P <  0.05) was greater for estrous CYCLIC than ACYCLIC cows, respectively. The oocytes with grade I_+_II quality (55.3% compared with 47.6%; P <  0.05) were greater, whereas, there was lesser percentage with grade III_+_IV quality (44.5% compared with 52.4%; P <  0.05) from estrous CYCLIC as compared with ACYCLIC cows, respectively. Cleavage rate (70.9% compared with 52.8%; P < 0.05) was greater for embryos derived from estrous CYCLIC than ACYCLIC cows, respectively. Similarly, the embryo developmental rates to the 8- (38.5% compared with 20.8%; P < 0.05) and 16- (20.0% compared with 10.9%; P < 0.05) cell stage were greater for embryos derived from estrous CYCLIC as compared to ACYCLIC cows, respectively. In conclusion, the presence of greater plasma P4 has a beneficial effect on oocyte recovery, oocyte quality, and early IVEP outcomes in Bos indicus dairy cows.

Impact of foot-and-mouth disease on fertility performance in a large dairy herd in Kenya

This was a retrospective cohort study using data collected from a large-scale dairy herd in Kenya (n = 328 female animals), to investigate the effects of foot-and-mouth disease (FMD) on herd fertility performance following a confirmed outbreak in a regularly vaccinated herd. Kaplan-Meier graphs were used to depict differences in survival functions between exposure groups and Cox regression models were used to calculate hazard ratios (HR) for associations between being clinical FMD cases and the following fertility outcomes: age at first calving; fertility failure related culling (not in calf); time to first service; time to conception. Potential confounding variables investigated and controlled for were age, breed, parity, stage of lactation/gestation and eligibility for service. A case control study was nested within the cohort to investigate the effects of disease on conception HR following calving by comparing animals susceptible to fertility suppression at the time of the outbreak (cases) to animals that had conceived prior to the outbreak (controls). The median age of first calving in clinically affected young-stock was 2.7 months higher than non-clinical cases (adjusted HR = 0.37, 95%CI 0.21-0.67, P = 0.01). There was no evidence of a difference in fertility related culling and times to first service and conception. Animals susceptible to fertility suppression at the time of the outbreak had a lower hazard of conception compared to animals served prior to the outbreak (HR = 0.56, 95%CI 0.41-0.75, P = 0.01). Within the herd, the odds of being a case decreased with parity and age likely related to the lifetime number of vaccination doses received which may reduce the impact among older animals in the herd. Moreover, one would expect the impact to be higher in a non-vaccinating herd to be higher. Notwithstanding these limitations, the results of this study provide evidence that FMD outbreaks in endemic settings impact herd fertility performance. An increased age at first calving is likely to increase rearing costs and reduce an animal's lifetime productivity while poorer conception rates will likely extend calving intervals. Impaired herd fertility and production will incur higher costs to the farmer and society as animals are less productive which for FMD can extend beyond the outbreak period where economic studies tend to focus. These impacts of FMD on herd fertility should be considered when conducting benefit-cost analyses of FMD control to inform resource allocation.

Role of progesterone in embryo development in cattle

Progesterone (P4) from the corpus luteum is critical for the establishment and maintenance of pregnancy and plays a major role in regulating endometrial secretions essential for stimulating and mediating changes in conceptus growth and differentiation throughout early pregnancy in ruminants. Numerous studies have demonstrated an association between elevated systemic P4 and acceleration in conceptus elongation. A combination of in vivo and in vitro experiments found that the effects of P4 on conceptus elongation are indirect and mediated through P4-induced effects in the endometrium. Despite effects on elongation, data on the effects of post-insemination supplementation with P4 on pregnancy rates are conflicting. This review highlights the effects of P4 on conceptus development and examines strategies that have been undertaken to manipulate P4 concentrations to increase fertility.

Effects of oocyte donor age and embryonic stage of development on transcription of genes coding for enzymes of the prostaglandins and progesterone synthesis pathways in bovine in vitro produced embryos

The ability of early bovine embryos to produce prostaglandins (PGs) and progesterone (P4), and the role of these mediators in embryonic development and survival are poorly understood. In this study we tested the hypothesis that day 7 bovine embryos are able to transcribe genes coding for enzymes of the PGs (PTGS2, PGES, PGFS) and P4 (StAR, P450scc, 3β-HSD) synthesis pathways, and that transcription levels of these genes are associated with developmental progression and heifer age-related [pre-pubertal (PP) versus post-pubertal cyclic (C)] oocyte competence. Compared with C heifer oocytes, PP heifer oocytes showed a lower (P < 0.0001) in vitro blastocyst rate, but in embryos developing until day 7, heifer age had no effect on quality grade. Day 7 quality grade 1–2 embryos were selected for RNA extraction and gene transcription analysis by qRT-PCR, in a 2 × 2 factorial design [age (PP or C) × embryonic stage (compact morulae and early blastocysts, CM + EBL, or blastocysts and expanded blastocysts, BL + BEX); 15 embryos/group]. Transcription levels of PTGS2, PGES, PGFS, P450scc and 3β-HSD were not affected by heifer age but were higher (P < 0.01) in BL + BEX than in CM + EBL. In conclusion, the main limiting factor for embryo production from PP heifers is oocyte competence. Day 7 bovine embryos evidence transcription of genes coding for enzymes of PGs and P4 synthesis pathways, and transcription levels are associated with blastocyst differentiation. This prompts for an autocrine/paracrine action of PGs and P4 in early bovine embryonic development.

Oviductal, endometrial and embryonic gene expression patterns as molecular clues for pregnancy establishment

In higher animals, the beginning of new life and transfer of genetic material to the next generation occurs in the oviduct when two distinct gametes cells unite resulting in the formation of a zygote. The zygote then undergoes serial developmental processes in the oviduct and enters into the uterus where it faces challenges and scrutiny from the endometrial ecosystem. Thus, embryos that are able to establish an appropriate embryo-maternal dialogue are capable of developing to term whereas the incompetent ones can perish any time during the gestation period. Although several lines of evidences indicated that pregnancy loss is a multi-factorial phenomenon, the biochemical composition of the embryo and maternal environment are the main players to determine pregnancy outcome. Indeed, expression patterns of the genes are the driving forces that induce biochemical composition changes in embryo, oviduct and uterine environment. Thus, examining the molecular signals that are associated with oviductal or endometrial receptivity and embryo implantation is essential for establishing strategies to improve pregnancy success. Therefore, this review focuses on the contribution of oviduct and its transcriptome profile on early stage embryo development and the impact of endometrium and its transcriptome changes on peri and post embryo implantation. In addition, this paper integrates established facts about hormonal and molecular signatures associated with endometrial receptivity. Finally, the blastocyst and pre-conception endometrial gene expression profiles have been discussed in relation to the pregnancy outcome to highlight the potentials of blastocyst and pre-transfer endometrial transcriptome profile approach for selecting appropriate recipient and developmentally competent embryo.