Corpus Luteum Formation Research Articles

Evaluation of minimally invasive estrus synchronization protocols in brown brocket deer (Subulo gouazoubira)

This study aimed to evaluate minimally invasive protocols for estrus synchronization in the brown brocket deer (Subulo gouazoubira). Females were submitted to Latin square design, in different treatments. All females received 0.25 mg of estradiol benzoate on the first day of treatment, concomitant with one of the following sources of progesterone: (1) DIP: an intravaginal progesterone releasing device for eight days, (2) MGA1x: once a day (in the morning) oral dose of 1 mg melengestrol acetate for eight days, (3) MGA2x: twice a day (morning and afternoon) oral doses of 0.5 mg of MGA for eight days, (4) P4LA: a single i.m. administration of 75 mg of long-acting progesterone (P4LA). Eight days after the beginning of each treatment, females received an i.m. administration of 265 µg of prostaglandin (PGF2α; cloprostenol). Treatment efficacy was evaluated by manifestation of behavioral estrus after treatment and concentration of fecal progesterone metabolites (FPM). The time to onset of estrus in treatment P4LA was significantly longer (180 ± 38.9 h) compared to DIP (63 ± 6.6 h), MGA1x (53 ± 14.4 h) and MGA2x (41 ± 10.1 h) (P = 0.008). According to individual baseline FPM and FPM concentration during the days after estrus, the corpus luteum formation was suggested in all females which responded to the treatments (93.75 %). Low synchrony, longer interval between PGF2α administration and onset of estrus suggest that the P4LA dose (75 mg) is too high and not effective for S. gouazoubira. DIP, MGA 1x and MGA 2x, were effective in estrus synchronization.

Determinación de la eficacia de la administración de hCG sobre el desempeño reproductivo, la placentación, el parto y los parámetros neonatales en diferentes días posteriores al apareamiento en ovejas Kangal inducidas sexualmente durante el anestro

This study aimed to determine the efficacy of post mating human Chorionic Gonadotropin (hCG) during anestrus on the formation of the accessory corpus luteum and some reproductive parameters. For this purpose. after synchronization of all the animal were divided into group 1 (n=100), group 2 (n=100), and group 3 (n=100) by applying 600 IU of hCG 6 d after sponge removal, 600 IU of hCG 8 d after sponge removal, and no hCG application (Control), respectively. The difference between groups in terms of reproductive parameters such as estrus, pregnancy, multiple pregnancy, litter size, and productivity was not statistically significant. The live birth weight of lambs was evaluated for singletons, twins, and triplets. The difference between group 1 and the control group was statistically significant in singleton lambs (P=0.04). The difference between group 1 and control (P<0.001) and between group 2 and control (P<0.001) was statistically significant for twins. In triplets, group 1 was different from both groups (P<0.001) and group 2 was different from the control group (P<0.001). In addition, when the placenta weight and the daily body weight gain of singleton lamb in the neonatal stage were examined, the values of both groups that were administered with post mating hCG were higher than the control group (P<0.001). The Progesterone (P4) level in blood samples taken on the 21st d of pregnancy was found to be different between all groups. Furthermore, P4 levels were found to be higher in group 1 compared to the other two groups (P<0.001). In the light of these findings, it was determined that hCG administration after mating contributed to placenta and offspring development by elevating P4 levels. It was concluded that hCG should be administered 6 d after the sponge will be removed (on d 5 postmating) for optimal efficacy.

Lipopolysaccharide accelerates tryptophan degradation in the ovary and the derivative kynurenine disturbs hormone biosynthesis and reproductive performance

Lipopolysaccharide (LPS), also known as endotoxin, is a component of the outer membrane of gram-negative bacteria. LPS is released into the surrounding environment during bacterial death and lysis. Due to its chemical and thermal stability, LPS can be detected anywhere and easily exposed to humans and animals. Previous studies have shown that LPS causes hormonal imbalances, ovarian failure, and infertility in mammals. However, the potential mechanisms remain unclear. In this study, we investigated the effects and mechanisms of LPS on tryptophan degradation, both in vivo and in vitro. The effects of kynurenine, a tryptophan derivative, on granulosa cell function and reproductive performance were explored. Results showed that p38, NF-κB, and JNK signaling pathways were involved in LPS-induced Ido1 expressions and kynurenine accumulation. Furthermore, the kynurenine decreased estradiol production, but increased granulosa cell proliferation. In vivo, experiments showed that kynurenine decreased estradiol and FSH production and inhibited ovulation and corpus luteum formation. Additionally, pregnancy and offspring survival rates decreased considerably after kynurenine treatment. Our findings suggest that kynurenine accumulation disrupts hormone secretion, ovulation, corpus luteal formation, and reproductive performance in mammals.

Ultrasonographic and Doppler characteristics of corpus luteum luteogenesis in Remonta Argentino jennies

The corpus luteum (CL) plays a crucial role in maintaining pregnancy and preparing the uterus for implantation of the fertilized egg. Transrectal Doppler ultrasonography of the ovary can be used as a diagnostic tool to assess the reproductive status and functionality of the CL. Our aim was to characterize size, echogenicity and degree of vascularization of the corpus luteum over five days after ovulation in Remonta Argentino jennies. Five healthy cycling jennies aged 9 to 14 years were monitored transrectally using the MyLabTMOne ultrasound (ESAOTE, InMed, Argentina) with a 5-10 MHz linear array transducer. After a preovulatory follicle was detected, jennies were monitored daily for ovulation (day 0) and ultrasonographic evaluation of the CL until day 5. Two ovulations and the respective CL formation were analyzed in each jenny (n=10 CL). Size and echogenicity were evaluated using B mode and CL vascularization using the Doppler-color function, with a pulse repetition frequency of 1.2 MHz. All ultrasound examinations were video recorded for analysis. Adobe Premiere Pro CS6® was used to collect three images from each video where the largest area of the CL and the highest Doppler signal were detected. Image J. version 1.52i software (National Institute of Health, USA) was used to analyze images and to determinethe area, number of gray pixels (echogenicity) and color area within the CL in Doppler mode. The average value from the three images was used to determine CL size (area in cm2), echogenicity (average gray pixel intensity) and the proportion of vascularized area (AV; area with blood flow/total CL area x 100). Spearman's test was used to correlate the variables and the changes recorded between days 1 and 5 of diestrus. The results obtained on each day were the following (values expressed as mean±SEM): Day 0: area 3.26±0.5; echogenicity 84.2±4.86; AV 5.54±1.75; Day 1: area 4.86±0.32; echogenicity 91.25±7.42; AV 1.84±0.26; Day 2: area 4.83±0.41; echogenicity 88.72±7.89; AV 3.51±0.81; Day 3: area 4.64±0.43; echogenicity 89.69±4.9; AV 4.54±0.67; Day 4: area 4.38±0.48; echogenicity 97.78±7.61; AV 5.8±1.06; Day 5: area 4.24±0.49; echogenicity 89.18±9.25; AV 8.66±1.15. No statistical correlation was observed either between variables or with the day of diestrus (p>0.05). Blood samples were collected daily between day 0 and day 5 of diestrus and progesterone determinations are ongoing. Our results contribute to a better understanding of CL formation in Remonta Argentino donkeys that could potentially be used to determine CL age and function.

Review: Role and regulatory mechanism of inhibin in animal reproductive system.

Inhibin (INH) is a glycoprotein hormone secreted by the gonads that inhibit the synthesis and secretion of follicle-stimulating hormone (FSH). Increasing evidence indicates that INH plays a significant role in the development of the reproductive system including follicle development, ovulation rate, corpus luteum formation and ablation, steroid hormone synthesis and spermatogenesis, subsequently affecting the reproductive capacity of animals such as litter size and egg production. There are currently three main views on how INH inhibits FSH synthesis and secretion: influencing the activity of adenylate cyclase, the expression of follicle-stimulating hormone receptor or gonadotropin-releasing hormone receptor, and the competition system of inhibin-activin. This review discusses the current findings on the structure, function, and mechanism of action of INH in the reproductive system of animals.

Impact of Accessory Corpus Luteum Induced by Gonadotropin-Releasing Hormone or Human Chorionic Gonadotropin on Pregnancy Rates of Dairy Cattle following Embryo Transfer: A META-Analysis.

The circulation of progesterone (P4) concentrations of recipients has positive correlations with embryo survival and pregnancy success of embryo transfer (ET) in dairy cows. One strategy to improve P4 concentration is the administration of gonadotropin-releasing hormone (GnRH) or human chorionic gonadotropin (hCG), thereby inducing the formation of accessory corpus luteum (CL). This study aimed at determining the efficacy of GnRH or hCG treatment regarding embryo transfer (ET) and providing a better clinical veterinary practice guidance. A meta-analysis was conducted on the data from 2048 treated recipient cows and 1546 untreated cows. By inducing the formation of accessory CL with GnRH (100 µg), GnRH analogue Buserelin (8-10 µg), or hCG (≥1500 IU) 5-11 days after synchronized ovulation, hCG alone achieved an improvement (RR = 1.39, p < 0.05), while GnRH and GnRH analogue did not result in significant changes (RR = 1.04, p = 0.26). Treatment with GnRH or hCG 5-7 days after synchronized ovulation was associated with increased chances of pregnancy compared with later treatment (11-14 days). Owing to the treatment, the pregnancy rate of cows with very poor fertility (<40%) was improved, while that of cows with good fertility (≥40%) was not affected. Treatment with GnRH or hCG greatly improved pregnancy rates of parous lactating cows (RR = 1.32, p < 0.05) compared with heifers (RR = 1.02, p > 0.05). Additionally, as indicated by pregnancy loss analysis, the treatment had no benefit on late embryo/early fetus survival at days 28-81. In conclusion, the induction of accessory CL with GnRH or hCG may benefit fertility and have important implications for the management of reproductive performance in the dairy industry.

Effects of apoptosis by 20α-hydroxysteroid dehydrogenase activity on corpus luteum formation during early pregnancy in cattle

20α-hydroxysteroid dehydrogenase (20α-HSD) is a member of the aldo-keto reductase family. These enzymes play a pivotal role in regulating steroid hormones, such as androgens, oestrogen, and progesterone, and are, therefore, considered vital targets for determining whether a pregnancy is maintained. In this study, we investigated the association between 20α-HSD and apoptosis-related genes in luteal tissues (at 30, 60, and 90 days of gestation) and cells from early gestation in cattle. The corpus luteum altered the number of large lutein cells from 30–90 days. The change in the junction of the connective tissue appeared to affect the density of the corpus luteum. In addition, 20α-HSD was detected in the corpus luteum and cultured cells during early pregnancy, in contrast to the results of previous studies. The overall expression pattern of the 20α-HSD and Casp-3 proteins was lower on day 50 of gestation than on days 30 and 90. However, the 20α-HSD expression gradually increased from 30 to 90 days of gestation. When the 20α-HSD protein was increased to 0.5 μg/ml, 1 μg/ml, and 1.5 μg/ml in the luteal cells collected on day 30 of pregnancy, apoptosis was analysed after 48 hours. 20α-HSD generated in the cells was confirmed, and the concentration gradually decreased as the concentration increased. However, the expression of Casp-3 showed an overall similar expression pattern. Notably, the 20α-HSD and Casp-3 proteins were lowest at 1.5 μg/ml supplemented with 20α-HSD, with higher levels in the cytosol than in the cytoplasm. These results suggest that 20α-HSD plays a role in maintaining normal pregnancy, particularly by regulating the progesterone concentrations during luteal cell development.

Effect of inducing accessory corpus luteum formation with gonadotropin-releasing hormone or human chorionic gonadotropin on the day of embryo transfer on fertility of recipient dairy heifers and lactating cows

The objective was to determine the effect of inducing an accessory corpus luteum (CL) using GnRH or human chorionic gonadotropin (hCG) on the day of in vitro-produced (IVP) embryo transfer (ET) on pregnancy per ET (P/ET) and calving/ET in dairy heifers and lactating cows. Dairy heifers (11–15 mo of age; n = 1,547) and lactating cows (n = 1,480) detected in estrus by tail chalk (d 0) were used as recipients. Before ET, the presence of a CL was evaluated by transrectal palpation from d 6 to 9 of the estrous cycle. Animals with a CL were randomly assigned to receive 1 of 3 treatments immediately before ET: control (no treatment; n = 1,009), GnRH (86 µg of GnRH; n = 1,085) and hCG (2,500 IU; n = 1,069). Embryos were implanted in the uterine horn ipsilateral to the ovary with a CL (fresh IVP embryos, n = 2,544; vitrified IVP embryos n = 545; slow-freezing IVP embryos, n = 74). Pregnancy diagnosis was performed on d 37 ± 3 of gestation by transrectal palpation. Pregnancy loss data and calving records were collected from the dairy farm management software. Treatment did not affect P/ET, calving/ET, or pregnancy loss either overall or within parity. When treatments inducing CL formation were combined (GnRH + hCG), heifers tended to have greater P/ET than controls (67.7 vs. 63.5%, respectively). Yet, calving/ET were similar. Response variables were also analyzed within embryo type and parity. For heifers receiving stage 6 (blastocyst) fresh IVP embryos, hCG had greater P/ET than controls (74.5 vs. 51.1%, respectively). In addition, GnRH tended to have greater P/ET than controls (67.8 vs. 51.2%, respectively). However, calving/ET in heifers receiving blastocyst fresh IVP embryos was similar among treatments. When only stage 7 (expanded blastocyst) fresh IVP embryos were considered, primiparous GnRH cows had greater P/ET (59.3 vs. 47.1%) and calving/ET (48.6 vs. 38.1%) than hCG. Moreover, hCG showed decreased calving/ET compared with controls in primiparous cows transferred with expanded blastocyst fresh IVP embryos. In summary, the effects of hCG or GnRH at ET on P/ET and calving/ET were inconsistent according to different embryo characteristics (e.g., embryo stage) and parity of recipients. Furthermore, treatment did not improve the overall fertility outcomes for recipient animals receiving IVP embryos.

Prolactin Relationship with Fertility and In Vitro Fertilization Outcomes-A Review of the Literature.

Hyperprolactinemia is a known cause of amenorrhea and infertility. However, there is an increasing body of evidence suggesting that prolactin is involved in multiple physiological aspects of normal reproduction. Thus, the present paper aims to review the current literature regarding the relationship between serum prolactin level and in vitro fertilization (IVF)/intracytoplasmic sperm injection outcome and the role of dopamine agonists treatment in IVF success. Moreover, the mechanisms by which prolactin may exert its role in fertility and infertility were summarized. Although not all studies agree, the available evidence suggests that higher prolactin levels in follicular fluid are associated with increased oocytes competence, but also with positive effects on corpus luteum formation and survival, endometrial receptivity, blastocyst implantation potential and survival of low-motile sperm. Transient hyperprolactinemia found in IVF cycles was reported in most of the studies not to be related to IVF outcome, although a few reports suggested that it may be associated with higher implantation and pregnancy rates, and better-cumulated pregnancy outcomes. Administration of dopamine agonists for hyperprolactinemia preceding IVF treatment does not seem to negatively impact the IVF results, while treatment of transient hyperprolactinemia during IVF might be beneficial in terms of fertilization rates and conception rates. Due to limited available evidence, future studies are necessary to clarify the optimal level of circulating prolactin in patients performing IVF and the role of dopamine agonist treatment.

Enhanced progesterone support during stimulated cycles of transvaginal follicular aspiration improves bovine in vitro embryo production

The in vitro production (IVP) of cattle embryos requires that germinal-vesicle stage oocytes undergo a period of maturation in vitro prior to fertilization and culture to the blastocyst stage. Success of IVP in taurine cattle is enhanced following ovarian stimulation prior to oocyte retrieval (OPU), particularly if preceded by a short period of FSH withdrawal (‘coasting’). However, evidence regarding the importance of progesterone (P4) support during OPU-IVP is equivocal. The current study, therefore, determined the effects of increased peripheral P4 concentrations during FSH-stimulated (‘coasted’) cycles of OPU. Progesterone support was provided by either an active corpus luteum (CL) and/or one of two intravaginal P4 releasing devices (i.e., CIDR® [1.38 g P4] or PRID® Delta [1.55 g P4]). Expt. 1 established an initial estrus prior to OPU, allowing CL formation (single luteal phase) spanning the first two of five cycles of OPU; the remaining three cycles were supported by either a CIDR® or PRID® Delta. Expt. 2 commenced with two cycles of dominant follicle removal (including prostaglandin F2α) undertaken seven days apart prior to six cycles of OPU. The absence of a CL meant that these cycles were supported only by a CIDR® or PRID® Delta. As each experiment involved several sequential cycles of OPU, the cumulative effects of device use on vaginal discharges were also assessed. Each experiment involved 10 sexually mature Holstein heifers. In the absence of a CL, peak plasma P4 concentrations were greater (P = 0.002) for the PRID® Delta (4.3 ± 0.22) than for the CIDR® (2.9 ± 0.22). In Expt. 1 there was an interaction (P < 0.05) between CL presence at OPU and P4 device on Day 8 blastocyst yields, indicating an effect of P4 device only when the CL was absent. The percentage hatching/hatched blastocysts of matured oocytes for the CIDR® and PRID® Delta was 44.3 ± 5.04 and 41.0 ± 5.40 in the presence, and 17.1 ± 3.48 and 42.2 ± 3.76 in the absence, of a CL (P = 0.018). Combined analyses of data from Expt. 1 and 2, when no CL was present, confirmed that Day 8 blastocyst yields were greater (P = 0.022) for the PRID® Delta than the CIDR®. Vaginal discharge scores were higher (P < 0.001) for the PRID® Delta than the CIDR® in Expt. 1 but not in Expt 2; however scores were low, did not increase with repeated use, and thus were deemed of no clinical or welfare concern. In conclusion, enhanced P4 support during FSH-stimulated cycles of OPU-IVP can improve in vitro embryo development.

TGF-β1 induces type I collagen deposition in granulosa cells via the AKT/GSK-3β signaling pathway-mediated MMP1 down-regulation.

Type I collagen is the most abundant extracellular matrix (ECM) protein in the mammalian ovary, and comprises two COL1A1 subunits and one COL1A2 subunit. Matrix metalloproteinase 1 (MMP1) is a typical collagenase of type I collagen, that can be detected in ovarian follicles and early corpus luteum. Previous studies demonstrated that MMP1-mediated degradation of type I collagen plays a functional role in regulating corpus luteum formation, and transforming growth factor β1 (TGF-β1) inhibits luteinization and progesterone production in granulosa cells (GCs). Whether TGF-β1 regulates the expression of MMP1, COL1A1, or the deposition of type I collagen during corpus luteum formation remains to be elucidated. This study aimed to investigate the molecular mechanisms through which TGF-β1 regulates MMP1 expression and type I collagen deposition in GCs. Our results show that TGF-β1 upregulates COL1A1 expressions and downregulates MMP1 expression. Inhibition approaches, including pharmacological inhibitors such as p38 inhibitor (SB203580), ERK1/2 inhibitor (U0126), AKT inhibitor (LY294002), and GSK-3β inhibitor (LiCl), as well as knockdown using siRNA specific to these genes, were used. Our results suggest that TGF-β1 decreases MMP1 production via an ALK5-mediated AKT/GSK-3β-dependent signaling pathway, and a decrease in MMP1 levels and an increase in COL1A1 levels synergistically promote type I collagen deposition in GCs. Collectively, these findings provide novel insights into the underlying molecular mechanisms by which TGF-β1 upregulates type I collagen deposition in GCs.

Development of relugolix combination therapy as a medical treatment option for women with uterine fibroids or endometriosis

Treatment of uterine fibroids (UF) and endometriosis (EM) has relied on the surgical skills of gynecologists to improve symptoms and potentially alter the course of these debilitating diseases. Medical management of symptoms for both diseases leverages combined hormonal contraceptives used off label as a first-line treatment, with nonsteroid anti-inflammatory drugs and opioids to manage pain as needed. Gonadotropin-releasing hormone (GnRH) receptor agonists (peptide analogs) have been used as short-term therapy to manage severe symptoms of UF or EM, treat anemia, and reduce fibroid size before surgery. The introduction of oral GnRH receptor antagonists opened the door for the development of new treatment options for UF, EM, and other estrogen-driven diseases. Relugolix is an orally active, nonpeptide, GnRH receptor antagonist that competitively binds to GnRH receptors, preventing the release of follicle-stimulating hormone and luteinizing hormone (LH) into the systemic circulation. In women, the reduction in follicle-stimulating hormone concentrations prevents natural follicular development, suppressing ovarian production of estrogen, and together with reductions in LH concentrations, prevent ovulation, corpus luteum formation, and, thereby, the production of progesterone (P). By reducing circulating concentrations of estradiol (E2) and P, relugolix improves heavy menstrual bleeding and other symptoms associated with UF and moderate to severe pain associated with EM, including dysmenorrhea, nonmenstrual pelvic pain (NMPP) and dyspareunia. However, as monotherapy, the use of relugolix is associated with signs and symptoms of a hypoestrogenic state, including bone mineral density loss and vasomotor symptoms. The clinical development of relugolix incorporated the addition of a 1 mg dose of E2 and a 0.5-mg dose of norethindrone acetate (NETA) to achieve systemic E2 concentrations that remain in a therapeutic range while mitigating the risk for bone mineral density loss and vasomotor symptoms, enabling the longer-term treatment and reducing the impact of symptoms on quality of life, and potentially delaying or preventing the need for surgery. Relugolix 40 mg in combination with estradiol (E2) 1 mg and NETA 0.5 mg as a single fixed-dose combination tablet (relugolix combination therapy [relugolix-CT]) approved in the United States as MYFEMBREE is the first and only once daily oral GnRH antagonist combination therapy indicated for the management of heavy menstrual bleeding associated with UF and moderate to severe pain associated with EM. In the European Union (EU) and the United Kingdom (UK), relugolix-CT is approved as RYEQO for the management of symptoms associated with UF. In Japan, relugolix 40 mg, as monotherapy, was the first GnRH receptor antagonist approved to improve symptoms associated with UF or pain associated with EM under the brand name RELUMINA. In men, relugolix suppresses testosterone production. Relugolix 120 mg (ORGOVYX) was developed by Myovant Sciences and is approved in the United States, EU, and UK as the first and only oral androgen-deprivation therapy for the treatment of advanced prostate cancer. This review is focused on the development of relugolix and relugolix-CT in women's health indications.

Single-Step Protocol for Isolating the Recombinant Extracellular Domain of the Luteinizing Hormone Receptor from the Ovis aries Testis.

The luteinizing hormone receptor (LHR) is a glycoprotein member of the G protein-coupled receptors superfamily. It participates in corpus luteum formation and ovulation in females and acts in testosterone synthesis and spermatogenesis in males. In this study, we extracted RNA from sheep testicles and synthetized the cDNA to amplify the gene lhr-bed. This gene consists of 762 bp and encodes 273 amino acids of the extracellular domain of LHR. The lhr-bed was cloned into pJET1.2/blunt, then subcloned into pCOLD II, and finally, transformed in E. coli BL21 (DE3) cells. Because the induced rLHR-Bed protein was found in the insoluble fraction, we followed a modified purification protocol involving induction at 25 °C, subjection to denaturing conditions, and on-column refolding to increase solubility. We confirmed rLHR-Bed expression by means of Western blot and mass spectrometry analysis. It is currently known that the structure stem-loop 5'UTR on pCOLD II vector is stable at 15 °C. We predicted and obtained RNAfold stability at 25 °C. We successfully obtained the recombinant LHR extracellular domain, with protein yields of 0.2 mg/L, and purity levels of approximately 90%, by means of a single chromatographic purification step. The method described here may be used to obtain large quantities of rLHR-Bed in the future.

Ovarian contrast-enhanced ultrasonography and Doppler fluxometry in bitches during the postovulatory estrus and corpora lutea formation

The aim of the present study was to evaluate the vascularization features of canine ovaries during the follicular phase and the formation of the corpora lutea by using Doppler ultrasonography and Contrast-Enhanced Ultrasound (CEUS). Eight healthy bitches were enrolled in the study and were evaluated at five different timepoints (T1 – T5) of the estrous cycle established by vaginal cytology and serum progesterone concentration. Ultrasonographic examinations were performed by a single operator using the ACUSON S2000/SIEMENS machine equipped with a linear multifrequency transducer (9.0 MHz). Color-coded Doppler evaluation of the ovarian parenchyma was performed to investigate the aspects of the signal detection throughout the different timepoints. Pulsed-wave Doppler of the intraovarian arteries was performed to evaluate spectral waveform and doppler velocimetric parameters of Systolic Peak Velocity (SPV cm/s), End Diastolic Velocity (EDV cm/s), Resistivity Index (RI) and Pulsatility Index (PI). CEUS evaluation of the ovaries was performed using a vascular contrast agent (SonoVue®, Bracco, Sao Paulo, Brazil) and the CADENCE™ Contrast Pulse Sequencing (CPS, Siemens) software, in order to perform both qualitative and quantitative analysis. Perfusion parameters of pixel number, peak intensity (PPI in %), time to peak intensity (TTP in s), mean transit time (MTT in s) and area under the curve (AUC in %). Colour-coded Doppler evaluation demonstrated an increase in signal detection as cycle progressed, with blood flow initially detected with few coloured pixels and mainly at the ventral surface of the ovaries. Further on, the number of coloured pixels increased and spreading to the central region, resulting in a circular-like pattern around the corpora hemorrhagica. The spectral waveform was consistent at all timepoints. SPV (cm/s) and EDV (cm/s) presented a numeric trend and a slight statistical difference at all timepoints, whereas no difference was found for RI and PI. CEUS evaluation demonstrated an increase in pixel intensity across all the timepoints. Quantitative CEUS analysis revealed a statistical difference in PPI (%), MTT (s) and AUC (%) at T5. CEUS evaluation of the ovaries was feasible and demonstrated a marked increase in perfusion parameters in the late postovulatory period, demonstrating its applicability in the assessment of canine corpora lutea development.

A single-cell atlas of the cycling murine ovary.

The estrous cycle is regulated by rhythmic endocrine interactions of the nervous and reproductive systems, which coordinate the hormonal and ovulatory functions of the ovary. Folliculogenesis and follicle progression require the orchestrated response of a variety of cell types to allow the maturation of the follicle and its sequela, ovulation, corpus luteum formation, and ovulatory wound repair. Little is known about the cell state dynamics of the ovary during the estrous cycle and the paracrine factors that help coordinate this process. Herein, we used single-cell RNA sequencing to evaluate the transcriptome of >34,000 cells of the adult mouse ovary and describe the transcriptional changes that occur across the normal estrous cycle and other reproductive states to build a comprehensive dynamic atlas of murine ovarian cell types and states.

Possible Role of Hypoxia-Inducible Factor-1Alpha and Vascular Endothelial Growth Factor During Periovulation and Corpus Luteum Formation in Cows

Possible Role of Hypoxia-Inducible Factor-1Alpha and Vascular Endothelial Growth Factor During Periovulation and Corpus Luteum Formation in Cows

Increased luteal tissues after secondary corpus luteum formation leads to enhanced progesterone concentrations and improved fertility in repeat-breeder dairy cows during heat stress condition in tropical climate.

Relatively, little is known about the corpus luteum (CL) function in early pregnancy after the successful treatment of luteal phase deficiency in repeat-breeder dairy cows when exposed to extreme environments under tropical climate. To investigate the influence of increased tissues of corpora lutea (CLs) by inducing secondary CL based on progesterone (P4) concentration and fertility in repeat-breeder dairy cows undergoing the fixed-time artificial insemination (FTAI) protocol, 32 cows were treated with gonadotropin releasing hormone (GnRH) on day 5 post-induction (experiment 1). In experiment 2, 213 cows were bred using the short-term FTAI protocol. On day 5 post-FTAI, cows were divided into two groups: treatment with (GnRH5-treated group) or without (GnRH5-untreated group) GnRH. The temperature-humidity index ranged from 77.3 to 82.8. Cows bearing two CLs had greater P4 concentrations than cows bearing only one CL on their ovaries (P < 0.05). Pregnancy rates were greater in GnRH5-treated group than the GnRH5-untreated group (P < 0.01). Moreover, repeat-breeder cows bearing two CLs had a greater likelihood of pregnancy (odds ratio = 20.86) than cows bearing only one CL on their ovaries (P < 0.01). Under heat stress condition, the results highlighted that increasing luteal tissues by creating secondary CL leads to enhanced peripheral P4 concentrations and improved pregnancy outcomes in repeat-breeder dairy cows.

Characterization of the roles of amphiregulin and transforming growth factor β1 in microvasculature-like formation in human granulosa-lutein cells.

Vascular endothelial-cadherin (VE-cadherin) is an essential component that regulates angiogenesis during corpus luteum formation. Amphiregulin (AREG) and transforming growth factor β1 (TGF-β1) are two intrafollicular factors that possess opposite functions in directing corpus luteum development and progesterone synthesis in human granulosa-lutein (hGL) cells. However, whether AREG or TGF-β1 regulates the VE-cadherin expression and subsequent angiogenesis in the human corpus luteum remains to be elucidated. Results showed that hGL cells cultured on Matrigel spontaneously formed capillary-like and sprout-like microvascular networks. Results of specific inhibitor treatment and small interfering RNA-mediated knockdown revealed that AREG promoteed microvascular-like formation in hGL cells by upregulating the VE-cadherin expression mediated by the epidermal growth factor receptor (EGFR)-extracellular signal-regulated kinase1/2 (ERK1/2) signaling pathway. However, TGF-β1 suppressed microvascular-like formation in hGL cells by downregulating VE-cadherin expression mediated by the activin receptor-like kinase (ALK)5-Sma- and Mad-related protein (SMAD)2/3/4 signaling pathway. Collectively, this study provides important insights into the underlying molecular mechanisms by which TGF-β1 and AREG differentially regulate corpus luteum formation in human ovaries.

Relationship of TNF-α levels in the Placenta with Blood Pressure, Urinary Albumin, and Fetal Weight Balb/c Strain Mice in Pregnant SLE Models

Systematic Lupus Erythematosus (SLE) is one of the autoimmune diseases which, if it occurs at reproductive age, can cause problems during Pregnancy. Tumor Necrosis Factor Alpha (TNF-α) is a proinflammatory cytokine that develops follicles during ovulation, corpus luteum formation, and endometrial function. Therefore, if the Pregnancy increases, it will affect the output results. This study aims to determine the relationship between TNF-α placenta levels with blood pressure, urinary albumin, and fetal body weight in mice of the BALB/c strain of the lupus bunting model. This study was a true experimental (actual experimental) conducted in vivo using balb/c mice experimental animals. The treatment group was given an intraperitoneal injection of 0.5 ml pristane.TNF-α levels were measured using the ELISA method, blood pressure mice with a tail-cuff computerized system tool, and weighing fetal body weight with analytical scales. The result of this study was that there was a significant difference between TNF-α levels between the control and treatment groups. There were significant differences in pregnancy outcomes in the form of blood pressure and urinary albumin in the control and treatment groups. TNF- α levels were associated with increased urine albumin (p=0.01&lt;a). It can be concluded that there is a relationship between the levels of TNF- α in the placenta to the increase in urinary albumin.

History, insights, and future perspectives on studies into luteal function in cattle.

The corpus luteum (CL) forms following ovulation from the remnant of the Graafian follicle. This transient tissue produces critical hormones to maintain pregnancy, including the steroid progesterone. In cattle and other ruminants, the presence of an embryo determines if the lifespan of the CL will be prolonged to ensure successful implantation and gestation, or if the tissue will undergo destruction in the process known as luteolysis. Infertility and subfertility in dairy and beef cattle results in substantial economic loss to producers each year. In addition, this has the potential to exacerbate climate change because more animals are needed to produce high-quality protein to feed the growing world population. Successful pregnancies require coordinated regulation of uterine and ovarian function by the developing embryo. These processes are often collectively termed "maternal recognition of pregnancy." Research into the formation, function, and destruction of the bovine CL by the Northeast Multistate Project, one of the oldest continuously funded Hatch projects by the USDA, has produced a large body of evidence increasing our knowledge of the contribution of ovarian processes to fertility in ruminants. This review presents some of the seminal research into the regulation of the ruminant CL, as well as identifying mechanisms that remain to be completely validated in the bovine CL. This review also contains a broad discussion of the roles of prostaglandins, immune cells, as well as mechanisms contributing to steroidogenesis in the ruminant CL. A triadic model of luteolysis is discussed wherein the interactions among immune cells, endothelial cells, and luteal cells dictate the ability of the ruminant CL to respond to a luteolytic stimulus, along with other novel hypotheses for future research.