Corpus Luteum Formation Research Articles

Selective effects of protein 4.1N deficiency on neuroendocrine and reproductive systems

Protein 4.1N, a member of the protein 4.1 family, is highly expressed in the brain. But its function remains to be fully defined. Using 4.1N−/− mice, we explored the function of 4.1N in vivo. We show that 4.1N−/− mice were born at a significantly reduced Mendelian ratio and exhibited high mortality between 3 to 5 weeks of age. Live 4.1N−/− mice were smaller than 4.1N+/+ mice. Notably, while there were no significant differences in organ/body weight ratio for most of the organs, the testis/body and ovary/body ratio were dramatically decreased in 4.1N−/− mice, demonstrating selective effects of 4.1N deficiency on the development of the reproductive systems. Histopathology of the reproductive organs showed atrophy of both testis and ovary. Specifically, in the testis there is a lack of spermatogenesis, lack of leydig cells and lack of mature sperm. Similarly, in the ovary there is a lack of follicular development and lack of corpora lutea formation, as well as lack of secretory changes in the endometrium. Examination of pituitary glands revealed that the secretory granules were significantly decreased in pituitary glands of 4.1N−/− compared to 4.1N+/+. Moreover, while GnRH was expressed in both neuronal cell body and axons in the hypothalamus of 4.1N+/+ mice, it was only expressed in the cell body but not the axons of 4.1N-/- mice. Our findings uncover a novel role for 4.1N in the axis of hypothalamus-pituitary gland-reproductive system.

The p38 signaling pathway mediates the TGF-β1-induced increase in type I collagen deposition in human granulosa cells.

Type I collagen, which is mainly composedof collagen type I alpha 1 chain (COL1A1), is the most abundant extracellular matrix (ECM) protein in the mammalian ovary; and the cyclical remodeling of the ECM plays an essential role in the regulation of corpus luteum formation. Our previous studies have demonstrated that TGF-β1 is a potent inhibitor of luteinization in human granulosa-lutein (hGL) cells. Whether TGF-β1 can regulate the expression of COL1A1 during the luteal phase remains to be elucidated. The aim of this study was to investigate the effect of TGF-β1 on the regulation of COL1A1 expression and the underlying molecular mechanisms using an immortalized hGL cell line (SVOG cells) and primary hGL cells (obtained from 20 consenting patients undergoing IVF treatment). The results showed that TGF-β1 significantly upregulated the expression of COL1A1. Using inhibition approaches, including pharmacological inhibition (a specific p38 inhibitor, SB203580, and a specific ERK1/2 inhibitor, U0126) and specific siRNA-mediated knockdown inhibition, we demonstrated that TGF-β1 promoted the expression and production of COL1A1 in hGL cells, most likely via the ALK5-mediated p38 signaling pathway. Our findings provide insights into the molecular mechanisms by which TGF-β1 promotes the deposition of type I collagen during the late follicular phase in humans.

Core clock gene Bmal1 deprivation impairs steroidogenesis in mice luteinized follicle cells.

Luteinization is the event of corpus luteum formation, a way of follicle cells transformation and a process of steroidogenesis alteration. As the core clock gene, Bmal1 was involved in the regulation of ovulation process and luteal function afterwards. Till now, the underlying roles of luteinization played by Bmal1 remain unknown. To explore the unique role of Bmal1 in luteal steroidogenesis and its underlying pathway, we investigated the luteal hormone synthesis profile in Bmal1 knockout female mice. We found that luteal hormone synthesis was notably impaired, and phosphorylation of PI3K/NfκB pathway was significantly activated. Then, the results were verified in in vitro cultured cells, including isolated Bmal1 interference granulosa cells (GCs) and theca cells (TCs), respectively. Hormones levels of supernatant culture media and mRNA expressions of steroidogenesis-associated genes (star, Hsd3β2, cyp19a1 in GCs, Lhcgr, star, Hsd3β2, cyp17a1 in TCs) were mutually decreased, while the phosphorylation of PI3K/NfκB was promoted during in vitro luteinization. After PI3K specific-inhibitor LY294002 intervention, mRNA expressions of Lhcgr and Hsd3β2 were partially rescued in Bmal1 interference TCs, together with significantly increased androstenedione and T synthesis. Further exploration in TCs demonstrated BMAL1 interacted directly but negatively with NfκB p65 (RelA), a subunit which was supposed as a mediator in Bmal1-governed PI3K signaling regulation. Taken together, we verified the novel role of Bmal1 in luteal steroidogenesis, achieving by negative interplay with RelA-mediated PI3K/NfκB pathway.

Novel Insights on the Corpus Luteum Function: Role of Vaspin on Porcine Luteal Cell Angiogenesis, Proliferation and Apoptosis by Activation of GRP78 Receptor and MAP3/1 Kinase Pathways.

Formation and limited lifespan of corpus luteum (CL) are important for proper ovarian periodicity and fertility. Failed vascularization, imbalance between proliferation and apoptosis leads to luteal phase deficiency and infertility. The aim of this study was to examine the effect of vaspin on angiogenesis, apoptosis and proliferation as well as the involvement of 78-kDa glucose-regulated protein receptor (GRP78) and mitogen-activated kinase (MAP3/1) in these processes. Porcine luteal cells were incubated with vaspin (0.1–10 ng/mL) for 24 h to 72 h and then mRNA and protein expression of angiogenesis: vascular endothelial growth factor (VEGFA), fibroblast growth factor 2 (FGF2), angiopoietin 1 (ANGPT1), VEGFA receptors (VEGFR1, VEGFR2), apoptosis: caspase 3, bcl-2-like protein 4 (BAX), B-cell lymphoma (BCL2), and proliferation: proliferating cells nuclear antigen (PCNA), cyclin A factors as well as secretion of VEGFA, FGF2, ANGT1 were measured by real-time polymerase chain reaction (PCR), immunoblotting and enzyme-linked immunosorbent assay (ELISA), respectively. Moreover, apoptosis was assessed by caspase activity using the Caspase-Glo 3/7 assay, while proliferation was by alamarBlue. We found that vaspin enhanced luteal cell angiogenesis, proliferation, and significantly decreased apoptosis. Additionally, using GRP78 siRNA and the pharmacological inhibitor of MAP3/1 (PD98059), we observed that the effect of vaspin was reversed to the control level in all investigated processes. Taken together, our results suggest that vaspin is a new regulator of female fertility by direct regulation of CL formation and maintenance of luteal cell function.

MALDI-TOF Mass Spectrometry Revealed Significant Lipid Variations in Follicular Fluid and Somatic Follicular Cells but Not in Enclosed Oocytes between the Large Dominant and Small Subordinate Follicles in Bovine Ovary.

Lipid metabolism in ovarian follicular cells supports the preparation of an enclosed oocyte to ovulation. We aimed to compare lipid composition of a dominant large follicle (LF) and subordinated small follicles (SFs) within the same ovaries. Mass spectrometry imaging displayed the differences in the distribution of several lipid features between the different follicles. Comparison of lipid fingerprints between LF and SF by Matrix Assisted Laser Desorption/Ionisation Time-Of-Flight (MALDI-TOF) mass spectrometry revealed that in the oocytes, only 8 out of 468 detected lipids (1.7%) significantly changed their abundance (p < 0.05, fold change > 2). In contrast, follicular fluid (FF), granulosa, theca and cumulus cells demonstrated 55.5%, 14.9%, 5.3% and 9.8% of significantly varied features between LF and SF, respectively. In total, 25.2% of differential lipids were identified and indicated potential changes in membrane and signaling lipids. Tremendous changes in FF lipid composition were likely due to the stage specific secretions from somatic follicular cells that was in line with the differences observed from FF extracellular vesicles and gene expression of candidate genes in granulosa and theca cells between LF and SF. In addition, lipid storage in granulosa and theca cells varied in relation to follicular size and atresia. Differences in follicular cells lipid profiles between LF and SF may probably reflect follicle atresia degree and/or accumulation of appropriate lipids for post-ovulation processes as formation of corpus luteum. In contrast, the enclosed oocyte seems to be protected during final follicular growth, likely due in part to significant lipid transformations in surrounding cumulus cells. Therefore, the enclosed oocyte could likely keep lipid building blocks and energy resources to support further maturation and early embryo development.

Immunoexpression of cytokine tumour necrosis factor-α suggesting its role in formation and regression of corpus luteum in Indian buffalo.

Tumour necrosis factor-α (TNF-α) is a cytokine that plays multiple important roles in corpus luteum (CL). Immunolocalization of expression of TNF-α in CL of buffalo was studied in different stages of its development and regression. Corpus luteum of healthy buffaloes (24) was collected from local slaughterhouses and categorized into early (stage I, 1-5days, n=6), mid (stage II, 6-11days, n=6), late luteal (stage III, 12-16days, n=6) and regressing phase (stage IV, 17-20days, n=6). In earliest phase of cyclic CL, per cent immunoexpression of TNF-α was significantly (p<.05) lower as compared to all phases with its expression being restricted to few developing luteal cells, usually in neutrophils. A significantly (p<.05) higher number of neutrophils with TNF-α immunoexpression were observed as compared to mid-luteal phase that indicated its role in initiation of angiogenesis at this stage. TNF-α immunoexpression almost doubled in mid-luteal phase, but the number of neutrophils exhibiting TNF-α was significantly (p<.05) lower with respect to all phases of CL. Immunoexpression percentage in late luteal phase increased sharply being significantly (p<.05) higher than earlier two phases of CL. In regressing phase, per cent immunostaining was maximum with highly significant (p<.05) difference as compared to all other stages, observed in all degrading luteal cells, abundant immune cells, that is neutrophils and macrophages which finally led to apoptosis and phagocytosis. Immunoexpression of TNF-α in early luteal phases served its role in initiation of angiogenesis, and its intense expression in regressing phase of CL suggested a shift in its role to apoptosis and structural luteal regression signifying both luteotropic and luteolytic roles in buffalo. This is probably the first study of its kind in buffaloes.

Mefenamic acid treatment to ward follicles development and progesterone level

Mefenamic acid is anti-inflammation non-steroid, which can hamper prostaglandin synthesis in the body tissue by hampering the siklooxigen enzyme. The purpose of this research is to find out the influence of Mefenamic acid toward the follicles development and progesterone level. This research is an experimental laboratory method. The subject of the research divided into five groups randomly selected and have been homogenized — one group as a control group and others as an experimental group with various dosages of Mefenamic acid treatment. The data is analyzed using a one-way Anova test. The results of this research are confirmed the significant difference of Grafian follicles, yellowish corpus luteum and progesterone level as the influence of Mefenamic acid. While there was no significant difference in tertiary follicles development. The decrease of corpus luteum is caused by Mephenamic acid activity to hamper the prostaglandin synthesis in the body tissue by hampering the siklooxigen enzyme. The prostaglandin can make follicles swelling and cause follicles fracture and make ovulation. The granulosis cell will make corpus luteum, which secreted progesterone hormone. Mefenamic acid was proven to avoid ovulation that blocked the formation of yellowish corpus luteum resulting in decreased blood progesterone level.

Newly Identified Regulators of Ovarian Folliculogenesis and Ovulation.

Each follicle represents the basic functional unit of the ovary. From its very initial stage of development, the follicle consists of an oocyte surrounded by somatic cells. The oocyte grows and matures to become fertilizable and the somatic cells proliferate and differentiate into the major suppliers of steroid sex hormones as well as generators of other local regulators. The process by which a follicle forms, proceeds through several growing stages, develops to eventually release the mature oocyte, and turns into a corpus luteum (CL) is known as “folliculogenesis”. The task of this review is to define the different stages of folliculogenesis culminating at ovulation and CL formation, and to summarize the most recent information regarding the newly identified factors that regulate the specific stages of this highly intricated process. This information comprises of either novel regulators involved in ovarian biology, such as Ube2i, Phoenixin/GPR73, C1QTNF, and α-SNAP, or recently identified members of signaling pathways previously reported in this context, namely PKB/Akt, HIPPO, and Notch.

Gliding into diapause: early embryo development in roe deer (Capreolus capreolus)

During mammalian diapause, the embryo is arrested at the blastocyst stage. In diapausing carnivores and marsupials, growth arrest of the blastocyst is coincident with a quiescent corpus luteum (CL). In the roe deer, progesterone is produced throughout diapause and the blastocyst exhibits very slow growth. To date, early roe deer embryos of known age have not been described. Therefore, it is not known at which stage and at what pace the roe deer embryo enters diapause. To collect multiple embryos of known gestational age, we performed cycle synchronization and superovulation in captive roe deer prior to artificial insemination (AI) and natural breeding (NB), respectively. Superovulatory responses were evaluated based on ultrasonographic detection of CL formation on the day of in vivo embryo flushing and on plasma progesterone (P4) analysis. In total, 33 superovulation treatments resulted in 6.6 ± 2.2 (mean ± SD) CL per doe on the day of embryo flushing. At days 6 and 7 after AI, 37 multicellular embryos up to the morula stage were retrieved from 8 does. At day 12 and 13 after natural breeding, 28 embryos, mainly at the blastocyst stage (n=20), were collected from 7 does. Multiple embryos could be collected from single animals, proving the feasibility of superovulation in this species. Compared to other diapausing and non-diapausing species where blastocysts have formed at days 6 – 8, roe deer embryo development appeared to be already decelerated prior to the blastocyst stage. The roe deer might therefore be well suited as a model to investigate mechanisms regulating embryonic growth velocity with respect to cell cycle control.

OR27-03 Duration of Testosterone-Induced Acyclicity Influences Corpora Lutea Formation and Stromal Changes in a Transgender Mouse Model

The impact and reversibility of long-term gender-affirming testosterone (T) therapy on the reproductive axis of transgender men has not been well-established. Little is known about outcomes for transgender men interested in pausing T therapy to harvest oocytes or get pregnant. We previously established a translational mouse model to investigate T-induced acyclicity and ovarian perturbations. We hypothesized that the duration of T-induced acyclicity would impact the reversibility of cyclic and ovarian changes. To test this hypothesis, T-treated mice were assigned to two groups: (SHORT) 6 weeks of T therapy with immediate reversibility (1.5 mg T propionate pellet implant/removal, n = 5) and (LONG) 6 weeks of T therapy with a prolonged T washout phase (subcutaneous oil injections of T enanthate at 0.9 mg once weekly, n = 5). Control groups (placebo pellets n = 5, sesame oil vehicle injections n = 5) were run in parallel. Estrous cycles were monitored using daily vaginal cytology. Following cessation of T therapy, mice were sacrificed in diestrus after resumption of cyclicity for 4 cycles and ovarian histology examined. Data were analyzed in GraphPad Prism using Welch’s t-test or Mann-Whitney where appropriate. T therapy led to persistent diestrus within a week after T administration for all T-treated mice and none of the controls. The total duration of acyclicity was 6±1 weeks for the SHORT group, which was significantly shorter than the 11±2 weeks for the LONG group (mean ± s.d., p = 0.0079). With resumption of cyclicity, both the SHORT and LONG groups had a significantly lower percentage of days in estrus and higher percentage of days in metestrus as compared to their parallel age-matched controls. Ovarian histology for the SHORT group all showed regular corpora lutea and minimal stromal changes, however, 3/5 mice in the LONG group lacked corpora lutea and 4/5 revealed marked stromal cell hypertrophy. Similar stromal cell changes were not seen in control mice. In conclusion, the length of time of T-induced acyclicity appears to impact the development of stromal cell hypertrophy and formation of corpora lutea even after resumption of cyclicity with similar alterations to the estrous cycles. These findings may have clinical relevance for transgender men interested in fertility, based on duration of gender-affirming T therapy. Future work will aim to separate out the respective contributions of T exposure and acyclicity to the stromal phenotype.

Granulosa cell proliferation is inhibited by PGE2 in the primate ovulatory follicle

ABSTRACT Prostaglandin E2 (PGE2) is a key paracrine mediator of ovulation. Few specific PGE2-regulated gene products have been identified, so we hypothesized that PGE2 may regulate the expression and/or activity of a network of proteins to promote ovulation. To test this concept, Ingenuity Pathway Analysis (IPA) was used to predict PGE2-regulated functionalities in the primate ovulatory follicle. Cynomolgus macaques underwent ovarian stimulation. Follicular granulosa cells were obtained before (0 h) or 36 h after an ovulatory dose of human chorionic gonadotropin (hCG), with ovulation anticipated 37–40 h after hCG. Granulosa cells were obtained from additional monkeys 36 h after treatment with hCG and the PTGS2 inhibitor celecoxib, which significantly reduced hCG-stimulated follicular prostaglandin synthesis. Granulosa cell RNA expression was determined by microarray and analyzed using IPA. No granulosa cell mRNAs were identified as being significantly up-regulated or down-regulated by hCG + celecoxib compared with hCG only. However, IPA predicted that prostaglandin depletion significantly regulated several functional pathways. Cell cycle/cell proliferation was selected for further study because decreased granulosa cell proliferation is known to be necessary for ovulation and formation of a fully-functional corpus luteum. Prospective in vivo and in vitro experiments confirmed the prediction that hCG-stimulated cessation of granulosa cell proliferation is mediated via PGE2. Our studies indicate that PGE2 provides critical regulation of granulosa cell proliferation through mechanisms that do not involve significant regulation of mRNA levels of key cell cycle regulators. Pathway analysis correctly predicted that PGE2 serves as a paracrine mediator of this important transition in ovarian structure and function.

Functions of Lysosomes in Mammalian Female Reproductive System

The lysosome is the most acidic membrane-bound intracellular organelle. Lysosomal acidity is primarily maintained by vacuolar H+-ATPase (V-ATPase) and counter ion channels. There are >60 hydrolytic enzymes in the lysosome for its fundamental digestive role. Lysosomes also play important roles in endocytosis, exocytosis, autophagy, and cell death. Studies that have implicated roles of lysosomes in the female reproductive system are reviewed here. In the ovary, lysosomes are implicated in the preparation of free cholesterol for steroidogenesis and degradation of regulators of steroidogenesis, regulation of follicular atresia, follicle rupture during ovulation, luteal cell survival, and luteal regression. In the oviduct, lysosomes are involved in endocytosis of both serum and oviductal luminal components. In the uterus during the menstrual/estrous cycle, lysosomes are associated with endometrial secretion, apoptosis, and menstruation. In the uterus during early pregnancy, lysosomes are involved in the temporal and directional changes of endocytosis, uterine epithelial acidification upon embryo implantation initiation, and embryo-maternal mutual communications via extracellular vesicles. In the placenta, lysosomes are implicated in nutrient transport and placental separation from the uterus for parturition. In the mammary gland, lysosomes are important for mammary gland development and involution. These findings suggest/demonstrate functions of lysosomes in multiple processes of female reproduction, from ovulation to ovarian steroidogenesis for pregnancy maintenance, and from essential in utero nurturing of developing embryos/fetuses via embryo/fetal-maternal communications, to optional postpartum nurturing of newborns via lactation. Future studies using genetically or modified animal models and pharmacological approaches will provide novel insights into the functions and mechanisms of lysosomes in the mammalian female reproductive system.

Induction and Formation of Accessory Corpus Luteum after Artificial Insemination (AI) Might Increase Pregnancy Rate per AI in Heat Stressed Dairy Cows

Abstract The present study aimed to evaluate whether the induction and the formation of an accessory corpus luteum (CL) after AI might increase the pregnancy per AI (P/AI) in heat stressed dairy cows. Starting at d 50±3 post-partum, 113 lactating Holstein cows from one commercial herd during summer were scored for body condition, blood sampled and examined by ultrasound. Those bearing a CL&gt;25mm and progesterone (P4) level&gt;2ng/mL were synchronized using a double PGF2α injection given 12 h apart and AI-ed at detected estrus. In total 18 cows, there were not any signs of estrus (n=10) nor a P4 level &lt;2ng/mL at the time of enrolment (n=8) and therefore they were excluded from the study, leading to 95 cows finally enrolled.. At d5 post-AI, cows were randomly allocated into 2 groups: control group (CON, n=45) without any additional treatment, and treatment group (GnRH, n=50), treated with 0.008 mg Buserelin – a GnRH agonist. Blood sampling and ultrasound examination were done at d5, d14 and at d21 after AI, whereas the pregnancy diagnosis was done at d21 and d30 after AI. Average daily temperature and relative humidity values were used to calculate the temperature-humidity index (THI). The average THI during the experiment was 79.5±0.6. At d5, no differences were observed neither between the number of the CL nor between the P4 level in both groups. At d14 and d21, 82% of the GnRH-treated cows had more than one CL versus 0% of the CON cows. Both at d14 and 21, GnRH-treated cows had higher P4 levels compared to the CON cows (p&lt;0.05). In addition, P/AI were higher in the GnRH group than in the CON group (65% vs. 48.3%, p&lt;0.05), whereas late embryonic losses were higher in CON in comparison to GnRH cows (10.6 vs. 4%, respectively). The BCS at the moment of insemination did not affect P/AI (p&gt;0.05). In conclusion, the induction of an accessory CL at d 5 after AI might increase P/AI in heat stressed dairy cows.

Medicinal Plants and Female Reproduction Disorders due to Oxidative Stress

Reactive oxygen species (ROS) are highly reactive oxidizing agents. Cells, under aerobic conditions, have a defence system against ROS, and in normal circumstances, there is an appropriate balance between pro?oxidants and antioxidants. When an overproduction of ROS develops or the body fails to eliminate ROS in excess, oxidative stress arises, during which ROS accumulate and damage cells and tissues. Besides their noxious effects, accumulating data have shown that controlled of adequate ROS concentrations exerts physiologic functions. Different studies have confirmed the presence of ROS and the transcripts of the various antioxidant enzymes in the female reproductive tract. When ROS production overwhelms antioxidant defenses, oxidative stress occurs, which may deeply threaten the anatomical and functional integrity of the genital tract. This review addresses the main physiological and pathological roles exerted by ROS and their scavenging systems in several processes involved in the main physiological functions of the female reproductive tract of domestic animals. Stress, of both physical and emotional origin, has effects on the reproductive system. Accordingly, impaired follicular development appears to be the most common cause of reproductive dysfunction attributable to stress in the human female. New developments in the understanding of the role of stress in reproduction must take into consideration the many differences between the hormonal responses to stress in the human and laboratory animals. Particularly, the involvement of the oxidant system in several reproductive processes is investigated, such as follicular development, ovarian steroidogenesis, ovulation, corpus luteum formation and function, luteolysis, germ cell function, maintenance of pregnancy and beginning of parturition. The use of medicinal plants has gained the world to solve health problems, notably reproductive disturbance. A large number of tropical plants and their extracts have shown beneficial therapeutic activities including fertility enhancement, antioxidant, anti-microbial and aphrodisiac activities.

Monitoring follicular dynamics to determine estrus type and timing of ovulation induction in captive brown bears (Ursus arctos).

It is important to understand ovarian physiology when developing an artificial insemination (AI) protocol. Brown bears (Ursus arctos) have a breeding season from May to July, although the type of estrus (polyestrus or monoestrus) is still contested. The present study aimed to define the ovarian dynamics, including follicular waves and ovulatory follicle size, and estrus type in brown bears. Six brown bears were used for ovarian ultrasonography; four were observed between April and October (before the start and after the end of the breeding season) and two in June (breeding season). In addition, we attempted to induce ovulation by administering a gonadotropin releasing hormone (GnRH) agonist. We observed follicular development in April in four bears, but follicles did not develop to greater than 6.0 mm in diameter until May. Thereafter, a group of follicles developed to more than 6.0 mm and grew as dominant follicles, except in one bear. After ovulation and subsequent corpus luteum (CL) formation, the follicular waves disappeared. Furthermore, in three bears treated with GnRH, follicles between 8.2 to 11.2 mm in diameter at the time of treatment ovulated and formed CLs. In two bears, follicles between 5.8 to 8.8 mm ovulated spontaneously within the observation interval. Our results suggest that brown bears may be monoestrous animals. Therefore, AI can only be performed once during the breeding season. Our results also suggest that dominant follicles larger than 8.0 mm are a suitable size for inducing ovulation.

Low invasive estrous synchronization protocol for wild animals: an example with melengestrol acetate in brown brocket deer (Mazama gouazoubira)

Deer are sensitive to stressful stimuli by handling and their reproductive physiology could be altered by these procedures, making it necessary to develop less invasive protocols for ART. Melengestrol acetate (MGA), a synthetic progestin administered orally, appears as an alternative for estrous synchronization protocols (ESP), such as reported in cattle. Firstly, we compared two MGA doses (0.5 and 1.0 mg/day/animal), which would have suppression effect in estrous behavior (EB). Eight females were randomly and equally distributed in Group 1 (G1) and Group 2 (G2), which received 0.5 and 1.0 mg/day/animal respectively for 15 days (D1 to D15). Two cloprostenol (CP) applications were performed on D0 and D11. Estrus detection (ED) was performed every day. All females from G1 displayed estrus during treatment period, whereas all females from G2 displayed estrus after treatment, suggesting a suppressive effect of 1.0 mg in the EB. Once the suppressive MGA dose (1.0 mg) was defined, we used this dose for assessing ESP. The same eight females received 1.0 mg/animal for eight days (D-8 to D-1), followed by 0.25 mg of estradiol benzoate on D-8 and 265 μg of CP on D0. Feces for fecal progesterone metabolites (FPM) measurement were collected from D0 until seven days after the last day of estrus. Seven females displayed estrus between 12 and 72 h after CP application, which was followed by a significant increase in FPM levels (except female MG6), suggesting the formation of corpus luteum. After ED, females were placed with a fertile male to assess the fertility of the protocol. Pregnancy was confirmed by ultrasound 30 days after mating in 3/6 individuals. Although the low effectiveness of MGA protocol, it should be considered as a promising alternative in deer ESP since this protocol has less stressful effect on the animal during reproductive management when compared to other ESP.

Fertility Improvement of Baladi Goats Using Dexamethasone and GnRH-dependant Protocols

This study aimed to evaluate the effect of dexamethasone and gonadotropin releasing hormone (GnRH) on improvement of the fertility of Baladi goats. To accomplish this study, twenty does were synchronized for estrus using PGF-2α agonist. Then, they were divided into four groups randomly (5/ each). Group-I was injected with dexamethasone, while, group-II was injected by three doses of gonadotropin releasing hormone (GnRH). Group-III, was injected by dexamethasone and GnRH, while group-IV was injected with saline to be used as control group. The fertile bucks were allowed to mount the does for fertilization. Ovarian response to the treatment and diagnosis of pregnancy were monitored using ultrasonography. Results revealed that compared to control group, all the treatment protocols have a significant intensifying and improving effect on the appearance of signs of estrous, the day of mount, day of pro-estrus, day of ovulation and day of mature corpus luteum formation. However, the treatment with dexamethasone seems to have more effect over the other treatment protocols. Also, the number of the detected mature corpora lutei was significantly increased upon application of the treatment protocols as compared to control group but this effect was more obvious in group I. Finally, the treatment protocols tend to have no significant effect on the number of the formed mature follicles, weights of feti at birth or their weights after 60 days, on the other hand the treatments protocols has proved to decrease the percent of fetal losses when compared to control group.

Doppler sonography of the corpus luteum during the oestrus cycle in dairy cows

Doppler ultrasound has recently emerged as one of the main innovations in cattle practice and has mainly found application in the evaluation of luteal blood perfusion (LBF). LBF has been evaluated during different phases of the oestrous cycle, but the technique is poorly standardized. The aim of the study was to evaluate visual and quantitative changes of size of corpus luteum (CL) and LBF in dairy cattle during an oestrous cycle at 2 follicular waves using colour flow mode (CFM) and power flow mode (PFM) doppler ultrasound. Ten Friesian cows were selected and synchronized. The CL was evaluated at 3/4-day intervals until the next oestrus onset. After identifying the spiral luteal artery entry at the base of the CL, multiple scans of the vertical plane at the maximum diameter of the CL from the apex to the base were recorded in B-mode, CFM and PFM for each cow and session. An Esaote Mylab vet 30 gold was employed with the following setting: pulse repetition frequency 2.1 (CFM) or 2.8 (PFM), gain 70%. The real area of CL (RACL) was calculated subtracting the area of the eventual inner cavity. The LBF was quantified off-line by means of a visual score and of an image analysis system (Digimizer 4.1). Student and Anova tests were used for statistical analysis. Data were presented as means and standard deviations. There were significant individual variations for the RACL and LBF when calculated in CFM. PFM minimized these variations, although, at day 15-16, it was also affected by individual factors (p &lt; 0.01). The combined study of RACL and LBF during a 2-wave oestrous cycle distinguished 3 phases: a phase of CL formation (3-4 days) with LBF of 0.3 ± 0.3 cm2 on a RACL of 3.1 ± 0.9 cm2, a central phase (7-16 days) with LBF of 0.7 ± 0.4 cm2 on a RACL of 4.8 ± 0.8 cm2 and a regression phase (19-20 days) with a minimum LBF of 0.1 ± 0.1 cm2 in a CL of 3.3 ± 0.6 cm2. According to this study, there is no significant difference of LBF from 7 to 16 days of the oestrus cycle; although the RACL significantly changes in this period, the dimensional variations are too thin to be clinically appreciated. However, this study contributed to defining the values of RACL and LBF during a 2-wave oestrous cycle of dairy cattle.

Contribution of Tissue Hypoxia to Corpus Luteum Formation

Corpus luteum is a temporary endocrine organ that is formed and regressed during the female reproductive cycle.It is developed from the residual follicular tissue after ovulation,which is associated with the rapid angiogenesis.Vascular endothelial growth factor(VEGF)is the most important stimulatory factor that regulates the luteal angiogenesis and also plays a key role during corpus luteum formation.VEGF is regulated by hypoxia-inducible factor(HIF)-1,which is a heterodimeric transcription factor consistent of HIF-1α and HIF-1β.The local hypoxia of ovary due to the ruptured follicle and the lack of new vascular networks induces HIF-1α expression and participates in the luteal formation through VEGF-dependent angiogenesis.The present article describes the functional and structural changes during the luteal formation from the local and hypoxic conditions immediately before and after ovulation,with an attempt to clarify the roles of hypoxia in luteal formation as well as ovarian physiology.

Secretion of equine chorionic gonadotropin and its association with supplementary corpus luteum formation and progesterone concentration in Hokkaido native pony recipient mares

The objectives of this study were to determine the plasma profile of equine chorionic gonadotropin (eCG) and its association with the formation of supplementary corpus luteum (CL) and plasma progesterone concentrations in embryo transfer Hokkaido native pony recipient mares. Blood samples and transrectal ultrasound examination of the reproductive tract were carried out weekly from the day of ovulation until week 32 of gestation (n = 4). Plasma concentrations of eCG and progesterone were measured by enzyme immunoassays. The eCG concentration was first detectable at week 5 for 2 mares and at week 6 for another 2 mares. Immediately after detection, the mean plasma eCG concentrations were observed to rise sharply and reach a peak at week 8. The concentrations then declined dramatically to a baseline (<0.5 IU/mL) by week 21. Plasma progesterone p=p concentrations increased in 2 phases. First, a sharp increase from 0.18 ± 0.05 ng/mL at ovulation to 15.9 ± 4.6 ng/mL at week 1 was observed, then a decrease to 9.69 ± 2.27 ng/mL by week 2, and maintained at this level until week 5 of gestation. The onset of the second rise occurred at week 6 and was observed to peak to 58.3 ± 21.8 ng/mL at week 10, then gradually declined to <10 ng/mL by week 26. The supplementary CLs were first detectable by pregnancy week 6 and 7 for 2 mares each. All supplementary and primary CLs regressed by week 26 for 3 mares and by week 30 for the remaining mare. The mean number of supplementary CL was 4.5 ± 0.8 and their formation in the right ovary (66.7%, 12/18) was higher (P < 0.05) than that in the left ovary (33.3%, 6/18). Among the mares, 1 mare that developed only 2 supplementary CL had 35% lower level of peak eCG and 65% lower concentration of peak progesterone compared with other 3 mares that had 5 or 6 supplementary CL. In conclusion, development of supplementary CL and blood concentrations of progesterone from around day 40 of gestation were associated with eCG concentration. The total number of supplementary CL formation in the present study in embryo transfer Hokkaido native pony recipient mares seemed higher than previously reported supplementary CL number in pregnant mares, with a greater rate in the right ovary than in left.