Increase In Follicle Diameter Research Articles

Effect of one or two fixed glutamate doses on follicular development, ovarian-intraovarian blood flow, ovulatory rate, and corpus luteum quality in goats with a low body condition score.

This study aimed to investigate the effect of a short glutamate supply on the ovarian response in goats with low body condition scores. Twenty-one goats had their estrus and follicular waves synchronized using three injections of prostaglandin analog at seven-day intervals. Goats were allocated to groups receiving 10 mg/kg LW (iv) of glutamate administered in a single dose (group LBCG1, n = 7) or in two doses five days apart (group LBCG2, n = 7). The control group (LBC; n = 7) received saline solution. Glutamate treatment did not affect glucose, cholesterol, or glutathione peroxidase levels, body weight, or adipose deposits. During the experimental period, the LBCG2 group showed a higher (P < 0.05) number of follicles (> 3 mm) and an increase in follicle diameter (P < 0.05). Glutamate supply improved (P < 0.05) the intraovarian Doppler blood area size in the LBCG groups, and the second dose in LBCG2 also induced a higher (P < 0.05) systolic and diastolic peak of the ovary artery. After ovulation induction, LBCG2 exhibited a high (P < 0.05) volume of the corpus luteum and vascularized area. We concluded that the supply of two doses of glutamate five days apart was efficient in ovarian stimulation in goats with a low body condition.

Expression analysis of POSTN gene in ovine follicles

The purpose of this study was to explore the potential expression regularity of POSTN in ovarian tissue. In this study, the uterus, ovarian follicles, heart, liver, spleen, lung, kidney, and muscle tissues of Merino sheep (10) were collected and detected by Western blot, real-time quantitative polymerase chain reaction, immunohistofluorescence, and fluorescence staining, respectively. The expression of POSTN in various organizations was analyzed. The results showed that the POSTN in Merino sheep had close homology with Bos mutus and Bos taurus. The expression of POSTN was detected in the uterus, follicle, heart, liver, spleen, lung, kidney, and muscle tissue, among which the expression of POSTN was highest in ovarian tissue. In addition, the expression of POSTN gradually increased with the increase of follicle diameter, among which POSTN was highly expressed in the granulosa cells (GCs) of follicles. Meanwhile, POSTN were distributed throughout the nucleus and cytoplasm of GCs, suggesting that POSTN may be involved in the regulation of follicle development.

The ovarian and uterine responses of Baixadeiro mares to prostaglandin synchronization during the dry and rainy seasons.

This study aimed to evaluate the effect of synchronization with prostaglandin F2α in Baixadeiro mares during the rainy and dry seasons. Fourteen mares were synchronized by administering two doses of 1 mL prostaglandin PGF 2α and monitored by rectal palpation and ultrasound for the assessment of follicular development and uterine echotexture. Of this total, nine mares allowed the collection of blood, in which the blood was collected by venipuncture of the jugular vein to determine progesterone (P4) by ELISA. Mares showed no differences (P > 0.05) in weight, body score condition (BSC), tone, uterine edema, frequency of ovulation, synchronization interval, estrus, and the total number of follicles between periods. However, there was a difference in large increased follicle diameter (P < 0.05) during the dry season. The average concentrations of P4 in mares differed (P < 0.05) between the pre- and post-ovulatory phases for both seasons and after ovulation, with higher concentrations in the rainy season. Furthermore, statistical differences in daily light (P < 0.05) were observed between the dry and rainy periods. Thus, we conclude that mares from the genetic grouping Baixadeiro showed no reproductive seasonality, though there was a difference in luminosity between the rainy and dry seasons. The treatment with two doses of PGF 2α was effective in synchronizing the mares, promoting the return of estrus in the dry and rainy periods. The mares remaining cyclically active throughout the year provided there were appropriate forage availability and quality levels to allow for normal values of body weight and condition.

Phenanthrene disrupting effects on the thyroid system of Arabian seabream, Acanthopagrus arabicus: In situ and in vivo study

Phenanthrene, a polycyclic aromatic hydrocarbon (PAH), is one of the endocrine disrupting chemicals (EDCs). The present study aimed to evaluate the effects of phenanthrene on histophysiology of thyroid in Arabian seabream (Acanthopagrus arabicus). In this regards, different concentrations of phenanthrene (2, 20 and 40 pg/gbw) were injected to Acanthopagrus arabicus and changes in thyroid tissue structure and the serum levels of triiodothyronine (T3) and Thyroxine (T4) were assessed. The experiment lasted 21 days. Alterations in thyroid tissue structure and T3 and T4 serum levels also were assessed in Acanthopagrus arabicus caught from different stations of the Persian Gulf (Jafari, Samail, Arvand, Zangi, Bahrakan). In addition, the concentration of phenanthrene was measured in the fish muscle and sediment samples from the stations. Phenanthrene concentration reached the maximum level in the muscle of all injected fish after 4 days and then decreased by the end of the experiment. The highest and lowest concentrations of phenanthrene were recorded in the fish muscle and sediment samples collected from Jafari and Bahrakan, respectively. The levels of T3 and T4 decreased dose dependently in phenanthrene-injected fish up to day 7 and then increased by the end of the experiment. The serum level of T3 and T4 in fish collected from different stations was as follows: Jafari<Samail<Arvand<Zangi≤Bahrakan. Some tissue changes observed in fish included decrease in the thickness of thyroid follicle epithelium and increase in follicle diameter. In conclusion, according to the results, phenanthrene significantly affected thyroid function in fish.

FACTORS AFFECTING EMBRYO DEVELOPMENTAL PACE

Ovarian follicle size reportedly correlates with oocyte maturity and embryo morphology. The day of blastulation (day 5, 6, or 7) has been correlated with embryo implantation potential. The objective of this study was to identify factors, including follicle diameter, that might influence the day of embryo blastulation. In this prospective observational study, patients underwent routine ovarian stimulation with exogenous gonadotropins. Each aspirated follicle was sonographically measured during oocyte collection. Embryos were cultured to the blastocyst stage. The day of blastulation was recorded for blastocysts of transferable quality (no CC grades). Blastocysts forming after day 5 were considered delayed. Logistic regressions were run to determine if patient age, follicle diameter, and the total number of eggs collected correlated with blastocyst formation on day 5. Because of the potential for biopsy to artificially influence blastulation, separate logistic regression models were developed for biopsied and non-biopsied blastocysts. P<0.05 was considered significant. The day of blastulation was recorded for 514 blastocysts derived from measured follicles, 221 of which formed on day 5, 249 on day 6, and 44 on day 7. Two logistic regression models were constructed. The first logistic model was developed predicting day 5 blastulation among the 170 biopsied blastocysts. The only significant predictor of day 5 blastulation in this model was follicle diameter (P=0.0038). The second logistic model was developed for 344 blastocysts that were not biopsied. In this second model, the only significant predictor of day 5 blastulation was, again, follicle diameter (P=0.0067). In both models, increasing follicle diameter corresponded with increased risk of delayed blastulation (day 6 or day 7 blastulation). Regardless of biopsy for PGT-A, larger follicles were significantly associated with delayed blastulation. Patient age and the number of eggs collected were not significant predictors of delayed blastulation.

109 Pre-synchronization and reutilization of progesterone devices during a 6-day CO-Synch protocol for fixed-time artificial insemination in beef heifers

Ovulatory response to the initial gonadotrophin-releasing hormone (GnRH) of the CO-Synch protocol is affected by circulating progesterone (P4) and follicle size. In addition, heifers that ovulate to the initial GnRH treatment have greater fertility after AI. Thus, this study determined the effect of (1) presynchronization (Presynch) before a 6-day CO-Synch protocol and (2) circulating [RCE1] (P4) on ovulatory response, oestrus expression, and pregnancies per AI (P/AI) in beef heifers. Yearling beef heifers (n=233) at three locations were randomly assigned in a 2×2 factorial design to the following treatments: (1) Presynch+6-day CO-Synch with a new P4 device; (2) Presynch+6-day CO-Synch with a once-used P4 device; (3) 6-day CO-Synch with a new P4 device; and (4) 6-day CO-Synch with a once-used P4 device. Presynch consisted of insertion of a new P4 intravaginal device (1.38g of P4) on Day −17 and removal of P4 device on Day −11 concurrently with 500µg of cloprostenol sodium (PGF). On Day −9, all heifers received either a new (New) or once-used (Used) CIDR and 100µg of gonadorelin acetate (GnRH). Six days later (Day −3), CIDRs were removed, 1000µg of PGF was administered and an oestrous detection patch applied (Estrotect). At 72h after CIDR removal, AI was performed concurrently with administration of 100µg of GnRH. Pregnancy was determined by transrectal ultrasonography 31 days after AI. A subset of heifers (n=155) was examined on Day −9 and Day −3 by ultrasonography to determine ovulation to Day −9 GnRH. Data were analysed using generalized linear mixed models (SAS 9.4; SAS Institute Inc.). Presynch heifers had larger follicle diameter on Day −9 (12.7±0.3 vs. 10.1±0.3 mm; P&amp;lt;0.001), greater ovulatory response to Day −9 GnRH (82.5%; 66/80 vs. 56%; 42/75; P&amp;lt;0.001), greater expression of oestrus (90.6%; 106/117 vs. 78.4%; 91/116; P&amp;lt;0.02), and earlier oestrus (49.8±1 vs. 53.1±1 h; P&amp;lt;0.01) compared with controls. There was a treatment×CIDR interaction on oestrous expression, such that a lesser (P&amp;lt;0.05) percentage of control heifers with new CIDR expressed oestrus compared with all other groups (Table 1). Heifers with a used CIDR during the 6-day CO-Synch tended (P=0.08) to have greater P/AI (52.1%; 61/117) than those with a new CIDR (40.5%; 47/116). In conclusion, presynchronization before initiation of a 6-day CO-Synch increased follicle diameter, enhanced ovulatory response and oestrous expression, but did not affect fertility. The earlier onset of oestrus in presynchronized heifers suggests that the timing of AI may need to be modified. Table 1. Oestrous expression and pregnancy per AI (P/AI) in beef heifers with or without presynchronization and treated with a new or used CIDR during a 6-day CO-Synch Treatment CIDR Oestrus (%; n/n) Time of oestrus (h) P/AI (%; n/n) Control New 67.8a (40/59) 53.7±1.5a 33.9 (20/59) Used 89.5b (51/57) 52.7±1.6a 50.9 (29/57) Presynch New 94.7b (54/57) 50.9±1.4b 47.4 (27/57) Used 86.7b (52/60) 48.7±1.3b 53.3 (32/60) P-value Treatment 0.03 0.01 0.21 CIDR 0.62 0.19 0.08 Interaction 0.003 0.75 0.38 a,bValues with different superscripts differ (P&amp;lt;0.05).

115 Presynchronization and reutilization of progesterone devices during a 6-day CO-Synch protocol for fixed-time artificial insemination in beef heifers

Ovulatory response to the initial gonadotrophin-releasing hormone (GnRH) of the CO-Synch protocol is affected by circulating progesterone (P4) and follicle size. In addition, heifers that ovulate to initial GnRH treatment have greater fertility after AI. Thus, the aim of this study was to assess the effect of (1) presynchronization (Presynch) before a 6-day CO-Synch protocol and (2) P4 device reuse (new vs. second use) on ovulatory response, oestrous expression, and pregnancy per AI (P/AI) in beef heifers. Yearling beef heifers (n=233) were randomly assigned in a 2×2 factorial design to the following treatments: (1) Treatment (Presynch): (1a) Presynch+6-day CO-Synch with new P4 device; (1b) Presynch+6-days CO-Synch with a once-used P4 device; (2) Control (no Presynch): (2a) 6-day CO-Synch with new P4 device; (2b) 6-day CO-synch with once-used P4 device. Presynch consisted of insertion of a new P4 intravaginal device (CIDR, 1.38g of P4; Zoetis) on Day −17 and removal of the CIDR on Day −11 concurrently with 500µg of cloprostenol sodium. On Day −9, all heifers received either a new or once-used (used) CIDR and 100µg of gonadorelin acetate (GnRH, Parnell Inc.). Six days later (Day −3) CIDRs were removed, 1000µg of PGF was administered, and an oestrous detection patch applied (Estrotect, Rockway Inc.). At 72h after CIDR removal, 100µg of GnRH and AI using 3 different sires was performed. Pregnancy was determined by ultrasonography 31 days after AI. A subset of heifers (n=151) were examined on Day −9 and Day −3 by ultrasonography to assess ovulation to Day −9 GnRH. Data were analysed using GLIMMIX (SAS 9.4; SAS Institute Inc.). Presynch heifers had larger follicle diameter on Day −9 (12.7±0.3 vs. 10.4±0.3 mm; P&amp;lt;0.0001), greater ovulatory response (84.6%; 66/78 vs. 52.05%; 38/73; P&amp;lt;0.0001), greater oestrus expression (90.6%; 106/117 vs. 78.4%; 91/116; P=0.03), and expressed oestrus earlier (49.8±1.0 vs. 53.1±1.1 h; P=0.01) compared with controls. There was an interaction for treatment and CIDR on oestrous expression, whereas a lesser (P=0.003) percentage of control heifers with new CIDR showed oestrus compared with all other groups (Table 1). Heifers treated with a used P4 device tended (P=0.08) to have greater P/AI (52.1%; 61/117) than those with a new CIDR (40.5%; 47/116). In conclusion, presynchronization before initiation of a 6-day CO-Synch increased follicle diameter, ovulatory response, and oestrous expression, but did not affect fertility. The earlier onset of oestrus in Presynch heifers warrants further study on timing of AI. Table 1. Oestrous expression and pregnancy per AI (P/AI) in beef heifers with or without presynchronization and treated with a new or used CIDR Treatment CIDR Oestrus (%; n/n) Time of oestrus (h) P/AI (%; n/n) Control New 67.8a (40/59) 53.7±1.5a 33.9 (20/59) Used 89.5b (51/57) 52.7±1.6a 50.9 (29/57) Presynch New 94.7b (54/57) 50.9±1.4b 47.4 (27/57) Used 86.7b (52/60) 48.7±1.3b 53.3 (32/60) P-value Treatment 0.03 0.01 0.21 CIDR 0.62 0.18 0.08 Interaction 0.003 0.78 0.38 a,bValues with different superscripts differ (P &amp;lt; 0.05).

Effects of inorganic selenium injection on the performance of beef cows and their subsequent calves

Sixty-seven pregnant Angus cows and their subsequent calves were used in a randomized design to evaluate the effect of inorganic Se injection from 80 d of gestation until weaning on cow reproductive parameters, BW and BCS evolution, milk yield and quality, calf growth and calf hematology parameters. The treatments were as follows: 1) Se+: cows were administered Se as sodium selenite at doses of 0.05 mg/Kg of BW at 80, 140, 200, 260 d of gestation and 30, 90, 150 and 240 d of lactation. Calves from Se + cows were Se as sodium selenite subcutaneously injected with a dose of 0.05 mg/Kg of BW at 70, 104, 144 d of age; 2) Control: cows and calves were administered sterile NaCl solution (9 g/l) at the same volume and intervals as Se + treatment. At the start of the experiment, forage Se concentration was 58.6 ppb ± 7.6 ppb, and cow whole blood Se concentration was similar (P > 0.10) between treatments (Se+, 29.3 ± 0.3 ppb; Control, 28.1 ± 0.5 ppb). After Se injection, cow whole blood Se concentration was increased (P < 0.01) in Se + cows in relation to control cows until the end of the experiment. Calf whole blood Se concentration was increased (P < 0.01) at birth and 30 d of age in calves from Se + cows compared to calves from Control cows. However, calf whole blood Se concentration was not different (P > 0.10) between treatments at d 70 after birth. After the first Se injection (70 d of age), calf whole blood Se concentration was increased (P < 0.01) at 104 and 144 d of age in calves from Se + cows compared to calves from Control cows. Cow BW and BCS did not differ (P > 0.10) between treatments throughout the experiment. Ovarian follicle diameter measured by ultrasound 47 d postpartum was greater (P = 0.03) in Se + cows compared to Control cows. Pregnancy rate to fixed time artificial insemination (FTAI), overall pregnancy rate (P > 0.10) and pregnancy loss (P = 0.19) did not differ between groups. Selenium injection did not affect (P > 0.10) milk yield and composition. Calf morphometric parameters, BW at birth and growth rate during lactation were not affected (P > 0.10) by treatments. No significant effect (P > 0.10) was observed between treatments on hematological results of blood samples from calves at weaning. Results of this study shown that inorganic Se injection was an efficient tool to improve Se-status in cow-calf operation under extensive management. Selenium injection increased follicle diameter in postpartum beef cow, however, did not affect the rest of the variables studied.

Comparative effects of TiO2 and ZnO nanoparticles on growth and ultrastructure of ovarian antral follicles

Titanium dioxide (TiO2) and zinc oxide (ZnO) nanoparticles (NP) have been demonstrated to reach the ovary. However, the potential detrimental effects of these metal-based NP on ovarian antral follicles and whether they can be directly taken up by follicular cells are unknown. The aim of this study was to evaluate whether TiO2 and ZnO NP internalize into the antral follicle, and further compared any potential detrimental effects of either NP on growth, ultrastructure and viability of antral follicles. It has been described that TiO2 and ZnO NP induce oxidative stress, thus this study indirectly assessed whether oxidative stress was involved. Antral follicles were cultured with TiO2 (5, 25 and 50 μg/mL) or ZnO (5, 15 and 25 μg/mL) NP for 96 h. TiO2 NP were internalized and agglomerated into cells, increased follicle diameter and disrupted the cytoskeleton arrangement, effects that were partially prevented by a co-exposure with trolox. Moreover, ZnO NP partially dissolved into culture media, decreased follicle diameter, and disrupted cytoskeletal arrangement, and these effects were not prevented by trolox. Ultrastructural alterations induced by exposure to both NP were evidenced by impaired transzonal projections and swelling mitochondria. Oxidative stress mediates TiO2 NP-induced effects but not those from ZnO NP in antral follicle development. Our results suggest that both NP induced ovarian follicle toxicity through different toxic mechanisms, possibly due to a stimulation of ZnO NP solubility and agglomeration of TiO2 NP into the follicular cells.

Effects of Stachys sylvatica hydroalcoholic extract on the ovary and hypophysis-gonadal axis in a rat with polycystic ovary syndrome

BackgroundPolycystic ovary syndrome (PCOS) is the most common endocrinopathy affecting women. The purpose of this study is to evaluate the effects of Stachys sylvatica hydroalcoholic extract on biochemical and histological parameters in a rat model of polycystic ovary syndrome. Thirty adult female Wistar rats with an average weight of 180 g were divided into five groups of six rats. Animals were divided into groups of control, PCOS (intramuscular injection of 2 mg estradiol valerate, Aburaihan Co., Iran/rat, once), and treated with hydroalcoholic extract of Stachys sylvatica. After 60 days of PCOS induction, 100, 250, and 500 mg/kg BW Stachys sylvatica hydroalcoholic extract were injected intraperitoneally. The control group was just injected with olive oil as a solvent. After 10 days of treatment, animals were weighed and then sacrificed and blood samples were taken from their heart for hormonal studies. Ovaries of all groups were cut for histological studies and fixed in formaldehyde, and 7-μm sections were prepared by microtome and stained using hematoxylin–eosin. The data were analyzed by one-way ANOVA and Tukey-Kramer post hoc test with the SPSS software. The significant level was p < 0.05.ResultsThe Stachys sylvatica extract can improve obesity in the PCOS group. The histological and hormonal results showed that PCOS induction can decrease the number of preantral, antral, and Graafian follicles as well as corpus luteum in comparison with the control (p < 0.001), whereas the number of cystic follicles increased significantly (p < 0.001). After treatment with Stachys sylvatica hydroalcoholic extract (500 mg/kg), a significant increase was observed in all these parameters. In addition, the number of cystic follicles decreased significantly (p < 0.001). The level of LH and FSH hormones decreased significantly (p < 0.01) in the PCOS group compared with the control. In contrast, the estrogen level increased significantly (p < 0.01). In the 250 and 500 mg/kg group, treatment with the extract could increase FSH and decrease estrogen concentration significantly relative to the PCOS group (p < 0.01). Results of antral follicle morphometry indicated an increase in follicle diameter and theca thickness, but the thickness of the granulosa layer decreased significantly. An improvement in these measurements was observed in the treated PCOS groups with all doses.ConclusionsIt can be concluded that Stachys sylvatica hydroalcoholic extract can improve some symptoms of polycystic ovary syndrome because of components such as iridoids, flavonoids, and sesquiterpenes with antioxidant and anti-inflammatory effects. In this experiment, 500 mg/kg dose of extract was considered as the most effective dose.

Transition to the ovulatory season in mares: An investigation of antral follicle receptor gene expression in vivo.

The inability to obtain in vivo samples of antral follicle wall layers without removing the ovaries or sacrificing the animals has limited more in-depth studies on folliculogenesis. In this study, a novel ultrasound-guided follicle wall biopsy (FWB) technique was used to obtain in vivo follicle wall layers and follicular fluid samples of growing antral follicles. The expression of proliferative, hormonal, angiogenic, and pro-/antiapoptotic receptors and proteins in the follicular wall among three follicle classes were compared during the spring transitional anovulatory (SAN) and spring ovulatory (SOV) seasons in mares. The main findings observed in the granulosa, theca interna, and/or all follicle layers during the SOV season compared with the SAN season were (a) small-sized follicles (10-14 mm) had greater epidermal growth factor receptor (EGFR) and Bcl-2 expression; (b) medium-sized follicles during the expected deviation/selection diameter (20-24 mm) had greater expression of EGFR, Ki-67, luteinizing hormone receptor (LHR), and Bcl-2; and (c) dominant follicles (30-34 mm) had greater EGFR, Ki-67, vascular endothelial growth factor, LHR, and Bcl-2 expression. Estradiol related receptor alpha expression and intrafollicular estradiol concentration increased, along with an increase in follicle diameter in both seasons. In this study, the application of the FWB technique allowed a direct comparison of different receptors' expression among follicles in different stages of development and between two seasons using the same individuals, without jeopardizing their ovarian function. The successful utilization of the FWB technique and the mare as an experimental animal offer a great combination for future folliculogenesis studies on mechanisms of follicle selection, development, and ovulation in different species, including women.

Profile of melatonin and its receptors and synthesizing enzymes in cumulus\u2013oocyte complexes of the developing sheep antral follicle\u2014a potential estradiol-mediated mechanism

BackgroundMelatonin is an amine hormone that plays an important role in regulating mammalian reproduction. This study aimed to investigate the expression pattern of melatonin synthesis enzymes AANAT and HIOMT and melatonin receptors MT1 and MT2 in sheep cumulus–oocyte complexes (COCs) as well as the change of melatonin level in follicular fluid (FF) during antral follicle development. In this research, we also study the effect of β-estradiol (E2) on MT1 and MT2 expression as well as melatonin synthesis in COCs so as to lay the foundation for further exploration of the regulation mechanism of melatonin synthesis in the ovary.MethodsCOCs and FF were collected from different size (large follicles (diameter ≥ 5 mm), medium follicles (diameter 2–5 mm), and small follicles (diameter ≤ 2 mm)) of antral follicles in sheep ovaries. To assess whether E2 regulates melatonin synthase and its receptors expression in sheep COCs and whether it is mediated through estrogen receptor (ER) pathway. The collected COCs were cultured in vitro for 24 h and then treat with 1 μM E2 and/or 1 μM ICI182780 (non-selective ER antagonist). The expression of AANAT, HIOMT, MT1 and MT2 mRNA and protein were determined by qRT-PCR and western blot. The melatonin level was determined by ELISA.ResultsThe expression of AANAT, HIOMT, MT1 and MT2 were significantly higher expression in the COCs of small follicles than in those of large follicles (P < 0.05). However, the melatonin level was significantly higher in large follicle FF than in small follicle FF (P < 0.05). Further, the expression of AANAT, HIOMT, MT1, and MT2 and melatonin production were decreased by E2 treatment (P < 0.05), but when ICI182780 was added, the expression of AANAT, HIOMT, MT1, and MT2 and melatonin production recovered (P < 0.05).ConclusionsWe suggest that sheep COCs can synthesize melatonin, but this ability is decreased with increasing follicle diameter. Furthermore, E2 play an important role in regulated the expression of MT1 and MT2 as well as melatonin synthesis in sheep COCs through the ER pathway.

The presence of two ovulatory follicles at timed artificial insemination influences the ovulatory response to GnRH in high-producing dairy cows

This study sought to examine the impact of the presence of two co-dominant (ovulatory) follicles at the time of artificial insemination (AI) on the ovulatory response to GnRH given in a fixed-time AI protocol. The study population comprised 622 lactating dairy cows: 306 (49.2%) with a single follicle, 198 (31.8%) with two bilateral follicles (one follicle per ovary) and 118 (19%) with two unilateral follicles (same ovary). Based on odds ratios, cows with two bilateral or unilateral follicles were less likely (by factors of 0.09 and 0.11, respectively) to undergo ovulation failure compared with cows with one follicle (P = 0.01 and P = 0.02, respectively); the likelihood of ovulation failure decreased 0.75 times with every one-mm increase in follicle diameter for cows with a single follicle, whereas individual follicle diameter was not related to ovulation failure in cows with two bilateral follicles (P = 0.001). The likelihood of double ovulation decreased 0.7 times with every one-mm diameter difference between the larger and smaller follicle for all cows with two follicles (P = 0.001), whereas cows with two unilateral follicles showed a higher (P < 0.05) double ovulation rate than cows with two bilateral follicles. In 116 (58.6%) of the cows with two bilateral follicles, only the larger follicle ovulated in 59.5% cows, whereas only the smaller one ovulated in the remaining 40.5% cows. In these cows, a one-mm size difference between the larger and the smaller follicle gave rise to a 1.12-fold increase in the ovulation failure rate for the larger follicles (P = 0.0001). Cows with two bilateral follicles were more likely (by a factor of 1.5) to conceive than cows with one follicle (P = 0.001). Significant right-left differences were not found in cows with two bilateral follicles, whereas the right ovary was more active than the left in the remaining cows. Our results indicate that cows with two co-dominant follicles at AI show different ovulation patterns to those with one dominant follicle. A higher rate of ovulation failure was observed among cows with one follicle than cows with two follicles, whereas the conception rate was higher for cows with two bilateral follicles than for the remaining cows. In cows with two follicles, double ovulations along with ovulation of the smaller follicle were related to the least size difference between the larger and smaller follicle.

Follicular localization of growth differentiation factor 8 and its receptors in normal and polycystic ovary syndrome ovaries.

Polycystic ovary syndrome (PCOS) is the most common endocrine disorder in women of reproductive age and its etiology has not been characterized. Growth differentiation factor 8 (GDF8) is a member of the transforming growth factor-β superfamily that plays a critical role in the regulation of ovarian functions. However, the expression pattern of GDF8 in the human ovary is not yet clear. This study examined the cellular distribution of GDF8 and its putative cellular receptors (ACVR2A, ACVR2B, and ALK5) in a series of normal (n=34) and PCOS ovaries (n=14). The immunostaining of GDF8, ACVR2A, ACVR2B, and ALK5 was detected in the oocytes regardless of the developmental stage. All these proteins were localized in antral follicles in normal and PCOS ovaries, and the expression of these proteins increased with increasing follicle diameter. A significantly higher expression of GDF8 was detected in the granulosa cells than in the matched theca cells (TCs). These proteins were also localized in the luteal cells of the corpus luteum. Granulosa cells and TCs of large antral follicles in PCOS ovaries display a higher expression of these proteins. The higher expression levels of GDF8 and its functional receptors (ACVR2A, ACVR2B, and ALK5) in antral follicles of PCOS ovaries than those in normal ovaries suggest the possible involvement of dysregulated GDF8 in the pathogenesis of PCOS.

Reproductive performance of lactating dairy cows after inducing ovulation using hCG in a five-day progesterone-based fixed-time AI protocol

This study compares the effects of inducing ovulation using human chorionic gonadotropin (hCG) or gonadotropin releasing hormone (GnRH) at the end of a 5-day progesterone(P4)-based protocol for fixed-time artificial insemination (FTAI) in lactating dairy cows on ovarian dynamics and fertility. A P4 intravaginal device (PRID) was fitted for five days and GnRH administered upon PRID insertion and a double dose (24 h apart) of prostaglandin F2α upon PRID removal. Cows received either GnRH (GnRH group; n = 98), 1000 IU hCG (hCG-1 group; n = 97), or 3000 IU hCG (hCG-2 group; n = 104) 36 h after PRID removal and were inseminated 50–56 h after PRID removal. Based on Tukey-Kramer tests, cows in hCG-1 and hCG-2 showed a larger follicle diameter at AI than cows in GnRH (P < 0.05). HCG-2 treatment increased corpus luteum (CL) size on Day 7 post-AI compared with the GnRH and hCG-1 treatments (P < 0.05). Based on odds ratios, the likelihood of ovulation failure decreased with increasing follicle diameter at AI (P = 0.002). Cows in hCG-1 or hCG-2 that did not become pregnant were more likely to return to estrus than cows in GnRH (P < 0.01). A larger CL size post-AI was related to an increased conception rate at FTAI (P = 0.003). Cows given hCG-2 treatment showed a 1.9-fold cumulative pregnancy rate after two rounds of AI compared to cows receiving GnRH. Our results indicate that hCG treatment hCG treatment used to induce ovulation at the end of a short protocol for FTAI improves follicular/luteal dynamics compared to GnRH treatment. Of the two hCG treatments tested, better results were obtained with the 3000 IU dose.

Ovulation time in suckled beef cows is anticipated by use of low doses of progesterone and temporary calf removal on fixed timed AI protocol

This study was designed to evaluate the effect of concentrations of P4 during a fixed-time artificial insemination (TAI) protocol and 48 hours temporary calf removal (CR; i.e., calves were temporally weaned for 48 hours) or treatment with 300 IU of eCG on ovulation time in suckled beef cows. One hundred and fourteen Nellore cows were estrous synchronized by receiving an intravaginal P4 releasing device containing 1.9 g of P4 (CIDR) plus 2.0-mg estradiol benzoate on Day 0, 12.5-mg dinoprost tromethamine on Day 7, and CIDR removal plus 0.5-mg estradiol cypionate on Day 9. Concentrations of P4 (P4 conc.) were manipulated by insertion of a new CIDR containing 1.9 g of P4 (CIDR1) or a CIDR previously used for 9 days (CIDR2), 18 days (CIDR3), or 27 days (CIDR4). On Day 9, within CIDR uses, cows received either CR or eCG. On Day 11 (48 hours after CIDR removal), all cows received a single TAI. Estrus was observed twice, a day between Day 9 and TAI. Ovulation by 60 hours or 72 hours after CIDR removal was defined as the disappearance of the largest follicle (LF) detected on Day 11 and presence of CL on Day 18, determined by transrectal ultrasonography. Cows ovulating after 72 hours were deemed to have a dominant follicle at 60 hours and 72 hours but also had a CL on Day 18. Serum P4 conc. were evaluated on Days 9, 11, and 18. Cows from CIDR4 + CR treatment ovulated at 60 hours (53.3%) tended to be greater (P = 0.07) than CIDR4 + eCG (21.4%). For the remaining treatments, this effect was not detected (CIDR1 + eCG: 6.3% vs. CIDR1 + CR: 0.0%; CIDR2 + eCG: 6.7% vs. CIDR2 + CR: 12.5%; CIDR3 + eCG: 0.0% vs. CIDR3 + CR: 25%). As a consequence, the percentage of cows from CIDR4 + CR treatment ovulating by 72 hours (26.7%) was lesser (P < 0.05) than that of cows in the CIDR4 + eCG treatment (78.6%), but for the remaining CIDR uses ovulation was not affected. The analysis of ovulating time revealed that earlier ovulation was associated (P < 0.01) to: (a) lesser P4 conc. on Day 9 (2.69b, 3.36a, and 3.82a ng/mL, standard error of the mean [SEM]: 0.12); (b) greater LF on Day 11 (12.46a, 12.09a, and 11.06b mm, SEM: 0.34); (c) greater estrus rate (94.1%a, 80.0%a, and 28.6%b), for ovulation at 60 hours, 72 hours, or >72 hours, respectively. Thereafter, previously used CIDR resulted (P < 0.01) in lesser P4 conc. on Day 9 (4.84a, 3.24b, 3.00b, and 2.50c ng/mL, SEM: 0.12), greater LF (10.50b, 12.07a, 11.98a, and 12.33a mm, SEM: 0.18) but only CIDR4 increased (P < 0.05) estrus rate (53.1%b, 65.6%b, 57.9%b, and 90.3%a), for CIDR1, CIDR2, CIDR3, and CIDR4, respectively. In conclusion, cows with low concentrations of P4 during a TAI protocol exhibited increased follicle diameter and an increased rate of estrus. This resulted in a greater percentage of cows ovulating by 60 hours when they had experienced calf removal.

Morphometric characteristics of preantral and antral follicles and expression of factors involved in folliculogenesis in ovaries of adult baboons (Papio anubis).

Baboons are commonly utilized as an animal model for studies of human reproduction. However, folliculogenesis in this species has not been fully documented. The aim of this study was to assess follicle morphometry and expression of essential proteins involved in folliculogenesis in baboons. Ovaries were recovered from four adult baboons and processed for histological evaluation and immunohistochemical analyses. Follicle proportion, follicle and oocyte diameter, theca layer thickness, number of granulosa cells, and follicle density were calculated. Immunohistochemical staining was also carried out for connexin 43 (Cx43), aromatase, and zona pellucida 3 (ZP3). A total of 2221 follicles were counted and measured. Proportions of primordial, primary, secondary, small antral, and large antral follicles were 49, 26, 23, 1, and 1%, respectively. The increase in follicle diameter was due not only to the increase in oocyte diameter but also to granulosa cell proliferation. Almost all antral follicles were positive for Cx43 (89.8%), aromatase (84.8%), and ZP3 (100%). Most secondary follicles were positive for Cx43 (65%) and ZP3 (64.5%), and some primary follicles were positive only for Cx43. No primordial follicles stained positive in any of these immunohistochemical analyses. Only antral follicles showed aromatase activity. On the basis of these results, we can conclude that folliculogenesis in baboons appears to be similar to that in humans, and this animal therefore constitutes a valuable model.

Mammalian target of rapamycin/eukaryotic initiation factor 4F pathway regulates follicle growth and development of theca cells in mice.

The aim of the present study was to clarify the roles of the mammalian target of rapamycin (mTOR) signalling pathway in follicular growth and development of thecal cells. Using in vivo-grown and in vitro-cultured ovaries, histological changes were evaluated using haematoxylin and eosin (HE) staining. Differentially expressed genes (DEGs) from 0 day post partum (d.p.p.) to 8 d.p.p. ovaries were screened by microarray and verified by quantitative real-time polymerase chain reaction. Forty-two DEGs related to cell proliferation and differentiation were screened out, with most DEGs being related to the to mTOR signalling pathway. Then, 3 d.p.p. ovaries were retrieved and used to verify the role of mTOR signalling in follicle and thecal cell development using its activators (Ras homologue enriched in brain (Rheb) and GTP) and inhibitor (rapamycin). The development of follicles and thecal cells was significantly impaired in ovaries cultured in vitro Day 3 to Day 8. In in vitro-cultured ovaries, Rheb and GTP (is 100ngmL-1 Rheb and 500ngmL-1 GTP for 48h) significantly increased follicle diameter, the percentage of primary and secondary follicles and the umber of thecal cells, and upregulated expression of mTOR, phosphorylated eukaryotic translation initiation factor 4E-binding protein 1 (4EBP1), eukaryotic initiation factor (eIF) 4F and cytochrome P450, family 17, subfamily A, polypeptide 1 (CYP17A1). Rapamycin (10nM rapamycin for 24h) had opposite effects to those of Rheb and GTP, and partly abrogated (significant) the effects of Rheb and GTP when added to the culture in combination with these drugs. Thus, mTOR signalling plays an important role in follicle growth and thecal cell development.

Relationships between follicle and corpus luteum diameter, blood flow, and progesterone production in beef cows and heifers: preliminary results

The aim of the present study in beef cattle was to investigate potential differences in follicle size and follicle wall-blood flow between cows and heifers and to compare follicle wall-blood flow between smaller and larger follicles. Cows and heifers were treated with a synchronization protocol and follicles and CLs were measured and evaluated for blood flow. Pregnancy diagnosis was performed on day 50 of the protocol. Cows had larger (P 0.05) in CL diameter, CL blood flow, and plasma progesterone concentrations. Moderate correlations between follicle diameter and follicle blood flow were observed for cows (r = 0.51; P 0.05) among all follicle diameter categories. In conclusion, synchronized beef cows and pregnant cows had larger follicles and greater blood flow than heifers and non-pregnant cows, and follicle wall blood flow was closely associated with increasing follicle diameter

Effects of administration of prostaglandin F at initiation of the seven-day CO-Synch+controlled internal drug release ovulation synchronization protocol for suckled beef cows and replacement beef heifers.

Two experiments were conducted to determine the effect of administering PGF at the initiation of the 7-d CO-Synch+controlled internal drug release (CIDR) fixed-timed AI (TAI) protocol on pregnancy rates of suckled beef cows and replacement heifers. Within location, cows were stratified by days postpartum (DPP), BCS, and parity (Exp. 1; = 1,551) and heifers were stratified by BCS (Exp. 2; = 999) and randomly assigned to 1 of 2 treatments: 1) CO-Synch+CIDR (100-μg injection of GnRH at CIDR insertion [d -10] with a 25-mg injection of PGF at CIDR removal [d -3] followed by injection of GnRH and TAI on d 0) or 2) PG-CO-Synch+CIDR (a 25-mg injection of PGF on d -10 of the CO-Synch+CIDR protocol). Follicle diameter and corpus luteum (CL) development were assessed on d -10 and -3, and pregnancy status was determined on d 30 to 35. Blood was collected on d -20, -10, -3, and 0 relative to TAI to determine concentrations of progesterone (P4). In Exp. 1, TAI pregnancy rates did not differ ( = 0.667) between treatments and were affected by BCS ( = 0.003) and DPP ( = 0.006). Concentrations of P4 were greater ( < 0.0001) on d -3 for CO-Synch+CIDR than for PG-CO-Synch+CIDR (4.1 ± 0.2 and 3.4 ± 0.2 ng/mL, respectively). Follicle diameter on d -3 differed ( = 0.05) between PG-CO-Synch+CIDR (13.4 ± 0.3 mm) and CO-Synch+CIDR (12.5 ± 0.3 mm) treatments. Cows with P4 > 2.5 ng/mL on d -10 had greater ( = 0.024) pregnancy rate to TAI (56.5%) compared with cows with 2.5 ng/mL < P4 > 1 (43.0%), whereas cows with P4 < 1 ng/mL were intermediate (51.6%). Cows with a CL on d -10 had greater ( = 0.012) pregnancy rates to TAI than cows without a CL (66.3 vs. 39.4%, respectively). In Exp. 2, TAI pregnancy rates did not differ ( = 0.316) between treatments. Concentrations of P4 differed ( < 0.0001) on d -3 with greater concentrations of P4 for CO-Synch+CIDR than for PG-CO-Synch+CIDR (3.75 ± 0.20 ng/mL and 3.60 ± 0.21 ng/mL, respectively). Follicle diameter was similar ( = 0.749) between treatments on d -10 and -3. Regardless of treatment, cyclic status tended ( = 0.062) to improve pregnancy rates to TAI (55 vs. 45%, for cycling and noncycling heifers, respectively). We concluded that addition of PGF to the 7-d CO-Synch+CIDR protocol decreased concentrations of P4 in cows and heifers and increased follicle diameter at CIDR removal in cows but failed to increase TAI pregnancy rates.