Number Of Preantral Follicles Research Articles

An extreme model of fertility in sheep demonstrates the basis of controversies surrounding antral follicle count and circulating concentrations of anti-Müllerian hormone as predictors of fertility in ruminants

Ovarian ultrasonography and measurement of circulating concentrations of anti-Müllerian hormone (AMH) have been used to estimate follicle number and predict fertility in mammalian females, but no study has evaluated follicle number and circulating concentrations of AMH in ewes known to differ in fertility. We tested the hypothesis that ewes that had failed to lamb (BARREN) in four consecutive annual breeding seasons of 21–35 d have fewer follicles and diminished circulating concentrations of AMH compared to closely matched ewes that consistently produced lambs (FERTILE) under the same breeding protocols. Once identified, BARREN ewes (n = 19) were paired by breed and sire to a FERTILE control ewe (n = 19) and reproductive tracts were recovered at necropsy. Visible antral follicles in both ovaries were counted and a representative cross section of one ovary was embedded for histological evaluation of pre-antral follicle numbers. Paired t-tests indicated that BARREN ewes had fewer antral follicles, fewer primordial follicles, and decreased circulating concentrations of AMH compared to FERTILE ewes (P ≤ 0.01), but there were ewes in each fertility classification that had ovarian phenotypes like the opposite fertility classification. The best technologies we have currently for estimating follicle numbers are ultrasonography and measurement of circulating concentrations of AMH, but no single technique is perfect for predicting fertility. A better understanding of the under-lying biological mechanisms linking AMH, folliculogenesis, and fertility is required to improve the use of measurements of follicle number for predicting fertility in livestock.

Value of Assessing AMH in the Management of Polycystic Ovarian Syndrome (PCOS)

Polycystic ovary syndrome (PCOS) is the most common endocrinopathy in reproductive age affecting 5 “ 10% of women and is the leading cause of ovulatory dysfunction. Anti-mullerian hormone (AMH) is a dimeric glycoprotein releases from the granulosa cells of small preantral and antral follicles and these concentrations have shown to be proportional to the number of developing follicles in the ovaries. In women with PCOS serum levels are elevated 2- to 3- fold in comparison with normo-ovulatory women, consistent with the increased number of small antral follicles in these women. AMH production per granulosa cell is increased on average 75-fold in anovulatory PCOS compared with normal ovaries. AMH is a marker for ovarian reserve of the women. It also can be used for diagnosis of PCOS. The high level of PCOS has negative effect on reproduction. It inhibits the function of FSH and causes follicular arrest and anovulation. In presence of high AMH there is poor response to oral ovulation inducing agent, gonadotropin and laparoscopic ovarian drilling. Quality of embryo, implantation rate and live birth rate are significantly reduced in presence of high AMH. High LH, hyperandrogenism, hyperinsulinemia have association with high AMH. Androgen is responsible for increasing the number of preantral follicles, hence AMH. Adjuvant therapy like metformin can correct hyperandrogenism, reduce the serum level of AMH and improve ovulation, pregnancy and live birth rate. Pre-treatment AMH level 7.77ng/ml is a cutoff level to predict the response to fertility treatment in PCOS. Ovulation, pregnancy and live birth rate are significantly lower when AMH level is >7.77ng/ml. So, to predict response to treatment and to fix the treatment plan value of assessment of AMH is important in case of PCOS. Bangladesh J Obstet Gynaecol, 2022; Vol. 37(1): 47-62

Preantral follicle numbers and size in heifers carrying Trio, a bovine high fecundity allele.

The bovine high fecundity allele, Trio, results in the occurrence of multiple ovulations and is characterized by antral follicles that develop slower and acquire ovulatory capacity at smaller sizes. This study provides novel information on the effect of the Trio allele on early folliculogenesis. The bovine high fecundity allele, Trio, causes overexpression in granulosa cells (GCs) of SMAD6, an inhibitor of BMP15-activated SMAD signalling. Furthermore, the Trio allele results in antral follicles that develop slower, acquire ovulatory capacity at smaller sizes, and have three-fold greater ovulation rate compared to half-sib non-carriers. The present study was designed to determine preantral follicle numbers and size in Trio carrier and non-carrier cattle testing the hypothesis that inhibition of SMAD signalling would alter preantral follicle activation and/or growth. Ovarian tissues from Trio carrier (n = 12) and non-carrier (n = 12) heifers were obtained by laparotomy after follicle wave synchronization. Follicle numbers and dimensions were determined for each stage of development (primordial, transitional, primary, and secondary) from paraffin-embedded sections. There were no differences in the number of primordial, transitional, or secondary follicles or in antral follicle count, circulating AMH, or ovarian volume between carriers and non-carriers. Trio carriers had ~2.5-fold greater (P < 0.01) number of primary follicles than non-carriers, and transitional and primary follicles were larger (~1.2-fold; P < 0.1) in Trio carriers. Oocyte volume of primordial and transitional follicles was not different between genotypes; however, oocytes were larger (P < 0.05) in primary (~1.3-fold) and secondary (~1.8-fold) follicles for Trio carriers. Granulosa cell numbers were not different (P > 0.3) between carriers and non-carriers, irrespective of the stage of development. These results suggest that, after primordial follicle activation, follicles in Trio carrier cattle have slower progression through the primary stage, hence the larger oocyte and greater number of primary follicles.

Identification of royal jelly as a potential new drug to protect the ovarian reserve and uterus against cyclophosphamide in rats.

The aim of this study was to investigate the effect of royal jelly (RJ), a powerful natural antioxidant, on cyclophosphamide-induced ovarian damage. Thirty-two Wistar albino rats were divided into four groups. Oral treatment was administered to all rats for 16 days after a single intraperitoneal injection. The control group received intraperitoneal and oral saline; the RJ group received intraperitoneal saline and 100 mg/kg/day oral RJ; the cyclophosphamide group received intraperitoneal 100 mg/kg cyclophosphamide and oral saline; and the treatment group received intraperitoneal 100 mg/kg cyclophosphamide and 100 mg/kg/day oral RJ. The groups were compared in terms of ovarian reserve tests and histopathological changes in the ovary and uterus. All follicle counts were higher in the treatment group than in the cyclophosphamide group. The increase in the number of preantral follicles (p=0.001) and the decrease in the number of atretic follicles (p=0.004) were statistically significant. RJ treatment significantly improved follicular degeneration and cortical fibrosis in the ovary and epithelial and gland degeneration in the uterus due to cyclophosphamide toxicity. According to these results, RJ reduces cyclophosphamide-related ovarian and endometrial damage in rats. For this reason, it should be further investigated to determine its effects on reproductive function.

Spatial distribution of preantral follicles in ovarian parenchyma of bovine species.

The goal of this study was to determine the distribution of preantral follicles in bovine ovaries. Follicular distribution in the ovaries (n = 12) was evaluated in the region of the greater curvature of the ovary (GCO) and the region close to the ovarian pedicle (OP) of Bos taurus indicus heifers of the Nelore breed. Two fragments were obtained from each region of the ovary (GCO and OP). The mean weight of the ovaries was 4.04 ± 0.32 g. The mean antral follicle count (AFC) was 54.58 ± 3.55 follicles (minimum and maximum variation of 30 and 71 follicles, respectively). In total, 1123 follicles were visualized in the region of the GCO; 949 (84.5%) of them were primordial follicles and 174 (15.5%) were developing follicles. The region close to the OP contained 1454 follicles, of which 1266 (87%) were primordial follicles and 44 (12.9%) were developing follicles. The OP region showed a higher proportion of intact follicles in the primordial (P < 0.0001) and primary (P = 0.042) stages compared with the GCO region. The proportion of secondary follicles was similar in the OP and GCO regions. The ovaries of two bovine females (16%; 2/12) contained multi-oocytes follicles, which were characterized as primary follicles. Therefore, the distribution of preantral follicles in the bovine ovary was heterogeneous, with the region close to the OP containing a greater number of preantral follicles compared with the GCO region (P < 0.05).

Differential Strain-dependent Ovarian and Metabolic Responses in a Mouse Model of PCOS.

Several mouse models have been developed to study polycystic ovarian syndrome (PCOS), a leading cause of infertility in women. Treatment of mice with DHT for 90 days causes ovarian and metabolic phenotypes similar to women with PCOS. We used this 90-day DHT treatment paradigm to investigate the variable incidence and heterogeneity in 2 inbred mouse strains, NOD/ShiLtJ and 129S1/SvlmJ. NOD mice naturally develop type 1 diabetes, and recent meta-analysis found increased androgen excess and PCOS in women with type 1 diabetes. The 129S1 mice are commonly used in genetic manipulations. Both NOD and 129S1 DHT-treated mice had early vaginal opening, increased anogenital distance, and altered estrus cycles compared with control animals. Additionally, both NOD and 129S1 mice had reduced numbers of corpora lutea after DHT exposure, whereas NOD mice had decreased numbers of preantral follicles and 129S1 mice had reduced numbers of small antral follicles. NOD mice had increased body weight, decreased white adipocyte size, and improved glucose sensitivity in response to DHT, whereas 129S1 mice had increased body weight and white adipocyte size. NOD mice had increased expression of Adiponectin, Cidea, Srebp1a, and Srebp1b and 129S1 mice had decreased Pparg in the white adipose tissues, whereas both NOD and 129S1 mice had increased expression of Glut4 and Prdm16, suggesting DHT may differentially affect glucose transport, thermogenesis, and lipid storage in white adipose tissue. DHT causes different ovarian and metabolic responses in NOD and 129S1 mice, suggesting that strain differences may allow further elucidation of genetic contributions to PCOS.

Characterization of preantral follicle clustering and neighborhood patterns in the equine ovary.

Understanding the transition from quiescent primordial follicles to activated primary follicles is vital for characterizing ovarian folliculogenesis and improving assisted reproductive techniques. To date, no study has investigated preantral follicle crowding in the ovaries of livestock or characterized these crowds according to follicular morphology and ovarian location (portions and regions) in any species. Therefore, the present study aimed to assess the crowding (clustering and neighborhood) patterns of preantral follicles in the equine ovary according to mare age, follicular morphology and developmental stage, and spatial location in the ovary. Ovaries from mares (n = 8) were collected at an abattoir and processed histologically for evaluation of follicular clustering using the Morisita Index and follicular neighborhoods in ovarian sections. Young mares were found to have a large number of preantral follicles with neighbors (n = 2,626), while old mares had a small number (n = 305). Moreover, young mares had a higher number of neighbors per follicle (2.6 ± 0.0) than old mares (1.2 ± 0.1). Follicle clustering was shown to be present in all areas of the ovary, with young mares having more clustering overall than old mares and a tendency for higher clustering in the ventral region when ages were combined. Furthermore, follicles with neighbors were more likely to be morphologically normal (76.5 ± 6.5%) than abnormal (23.5 ± 6.5%). Additionally, morphologically normal activated follicles had increased odds of having neighbors than normal resting follicles, and these normal activated follicles had more neighbors (2.6 ± 0.1) than normal resting follicles (2.3 ± 0.1 neighbors). In the present study, it was demonstrated that preantral follicles do crowd in the mare ovary and that clustering/neighborhood patterns are dynamic and differ depending on mare age, follicular morphology, and follicular developmental stage.

P-154 growth hormone supplementation decline quality of maternally aged oocytes via reducing aneuploidy

Abstract Study question Does growth hormone (GH) supplementation ameliorate the quality of oocytes in aged mice via reducing aneuploidy? Summary answer Daily injections of growth hormone for 2 months improve the age-related decline in ovarian reserve, and promote oocyte quality by reducing the aneuploidy rate. What is known already Women of advanced maternal age, particular over 35 years, could consequently bear poor quality oocytes, which are mainly caused by chromosomal aneuploidy. Age-related decline in GH levels may be related to the insufficient reproductive potential in women of advanced maternal age. To date, the role of GH in in vitro fertilization remains controversial. GH has been reported to affect oocyte quality, and studies in vivo have shown that intraperitoneal administration of GH reduces the occurrence rate of spindle/chromosome defects. Study design, size, duration The young (6-week-old) and aged (8-month-old) C57BL/6J mice were used in the study. In the in vivo experiment, aged mice were intraperitoneally injected daily with GH (1.6 mg/kg body weight, n = 85) or the equivalent volume of NS (n = 81) for consecutive for two months. In the in vitro experiment, GV oocytes from aged mice were treated with GH (Gene Science Pharmaceuticals, Changchun, China) (200ng/ml) in M16 medium for 14∼16 hours. Participants/materials, setting, methods We analyzed the number of oocytes and hormone levels to assess ovarian reserve, by immunohistochemistry and ELISA methods. The expression of GHR was measured by real-time quantitative RT-PCR and immunofluorescence. Time–lapse incubator was utilized to record the developmental potential of oocytes and embryos. Immunofluorescence was performed to assess parameters of oocyte quality (mitochondrial functions, ROS level, spindle/chromosome defects, and DNA damage). Chromosome spread and single-cell DNA sequencing were used to analyze chromosome aneuploidy rate. Main results and the role of chance The expression of GHR decreased in aged oocyte (21.68±1.08) and increased after GH treatment(30.64±0.70, P &amp;lt; 0.001). GH ameliorated decline in ovarian reserve of aged mice, with increased ovarian index (0.040%±0.0031 vs 0.023%±0.0019, P &amp;lt; 0.01), number of preantral follicles (7.33±0.89 vs 4.12±0.58, P &amp;lt; 0.05) and antral follicles (8.67±1.2 vs 3.33±0.88, P &amp;lt; 0.05) compared to the aged controls, but no other hormonal differences were detected. After GH supplementation, aged oocyte showed better quality and developmental potential, including restored mitochondrial functions (P &amp;lt; 0.05) and decreased ROS level (19.83±1.50 vs 23.6±1.72, P &amp;lt; 0.05). As expected, GH effectively promoted the fertilization rate (39.9%±1.10 vs 14.4%±0.62, P &amp;lt; 0.001) and early embryo development (P &amp;lt; 0.01). In addition, the spindle/chromosome defects (31.6%±2.12 vs 48.9%±1.83, P &amp;lt; 0.01), DNA damage (16.37±1.76 vs 49.35±2.52, P &amp;lt; 0.001) and aneuploidy rate (21.5%±1.61 vs 34.6%±1.84, P &amp;lt; 0.01) were lower in GH group than that in control group. Overall, GH treatment restored age-related decline in ovarian reserve, and decreased the occurrence rate of aneuploidy caused by spindle/chromosome defects, inducing a better oocyte quality in aged mice. Limitations, reasons for caution The molecular and mechanism of GH to regulate spindle/chromosome function remains to be determined. Besides, future work should be extended to human oocyte to determine whether this mechanism is conserved between mice and humans. Wider implications of the findings Our work expounds a theoretical basis for application of GH to improve the fertility of aged women. Besides, the results also feed new ideas for the prevention and treatment of oocyte quality decline in assisted reproductive technology. Trial registration number not applicable

Effect of ZhuLian's type Ⅱ inhibition needling technique on endocrine metabolism in rats with polycystic ovary syndrome and insulin resistance

To observe the effect of ZhuLian's type Ⅱ inhibition needling technique on sex hormones, insulin resistance and ovarian morphology in rats with polycystic ovary syndrome (PCOS), so as to explore its mechanism on regulating endocrine and metabolic dysfunction of PCOS. Twenty-four female SD rats were randomly divided into control, model and ZhuLian acupuncture groups (n=8 in each group). The PCOS model was established by continuous gavage of letrozole combined with high-fat diet. Rats of the ZhuLian acupuncture group were stimulated at "Guanyuan"(CV4) and bilateral "Guilai"(ST29), "Zusanli"(ST36), "Sanyinjiao"(SP6), and "Fenglong"(ST40) by ZhuLian's type Ⅱ inhibition needling technique for 30 min, continuously intervented for 28 days. The body weight was measured before and after modeling and after intervention. The ovarian volume was calculated. HE staining was used to observe the changes of ovarian histology. Plasma levels of luteinizing hormone (LH), follicle stimulating hormone (FSH) and fasting insulin (FINS) were measured by ELISA. LH/FSH ratio and insulin resistance index (HOMA-IR) were calculated. After modeling, the rats' body weight and the ovarian volume were increased (P<0.05), and the ovaries showed polycystic changes in the model group compared with the control group. And the FINS level, HOMA-IR, LH content and LH/FSH ratio were significantly increased (P<0.05), while the FSH level was decreased (P<0.05). After the intervention, the rats' body weight and ovarian volume were decreased (P<0.05), and a small number of preantral follicles and more antral follicles were observed under microscope, and the levels of LH, LH/FSH, FINS and HOMA-IR were significantly decreased (P<0.05), while FSH content was increased (P<0.05) in the ZhuLian acupuncture group than in the model group. ZhuLian's type Ⅱ inhibition needling technique can improve the endocrine and metabolic disorders in PCOS rats, which may be related to the regulation of endocrine system.

The antioxidant effect of Michauxia campanuloides on rat ovaries

This study investigated how Michauxia campanuloides affects the Proliferating Cell Nuclear Antigen (PCNA) expression in granulosa cells, the ovarian histomorphology and serum total antioxidant capacity (TAC) in rats. Rats were divided into control (C), treatment 1 (T 1) and treatment 2 (T 2) groups. The rats in the T 1 and T 2 groups received aqueous extract of M. campanuloides at doses of 20 mg/kg/day and 40 mg/kg/day orally for 21 days, respectively. Serum TAC levels, follicles counts including primordial, primary, preantral, antral and atretic follicles, and PCNA expression in granulosa cells were evaluated. Numbers of preantral follicles increased in T 1 and T 2 groups compared to C group (P &lt; 0.05). TAC and numbers of preantral and antral follicles increased in T 2 group compared to T 1 and C groups (P &lt; 0.05). PCNA expression in granulosa cells was increased in T 2 group compared to T 1 and C groups (P &lt; 0.01). In conclusion, treatment with M. campanuloides had positive effects on antioxidant activity, follicular dynamics, and PCNA expression of granulosa cell in rats.

87 Population estimate and morphology of ovarian preantral follicles in fetal and adult alpacas (Vicugna pacos)

Preantral follicles are the largest ovarian follicle population and represent an important source of potentially competent oocytes. During the lifespan of the female this large population becomes atretic during their growth. In alpacas, there are few studies that estimate the number of preantral follicles. Therefore, the objective of the present study was to compare the population and morphology of preantral follicles in the ovaries of fetal and adult alpacas. Ovaries from alpacas in fetal (fetus during the last third of gestation, n=5) and adult stage (3–4 years, n=5) were collected at a local slaughterhouse. The whole ovaries were individually fixed overnight at room temperature, and later dehydrated in alcohol, cleared with xylene, and embedded in paraffin. Tissue were sectioned at 7μm with a rotating microtome. Then, sections were processed and stained with periodic acid Schiff and haematoxylin. Preantral follicles were classified for their development stage as primordial, transitional, primary, or secondary, according to the layer number and form of granulosa cells. Estimation of the number of preantral follicles was made by counting all follicles in each histological section. Only follicles in which the oocyte nucleus was visible were counted. In addition, for each follicle category (n=30 per group), oocyte and follicle diameters were measured using Motic Images Plus 2.0 software. The population estimate and follicular diameter were compared using Kruskal–Wallis test with significance set at P ≤ 0.05 using SPSS v.2 2 software (IBM Corp.). A total of 2174 histologic sections were analysed. The results showed a higher (P=0.045) number of preantral follicles (80 516.1±3623.9) for fetal alpacas compared with adult alpacas (67 870.8±2267.4). Also, primordial follicles population (31 543.4±2690) and morphologically normal follicles (98.2%) were higher (P=0.04) in fetus compared with those in the adult stage (2244.7±355.37; 76.35%) respectively. On the contrary, the diameters of primordial, transitional, and primary follicles (45.34±3.76; 52.38±6.22; 59.79±5.22µm) from adult alpaca were greater (P=0.04) than those of fetal preantral follicles (33.305±7.2; 36.715±3; 77.985±15.8µm). In conclusion, the preantral follicle population declines dramatically in adult alpaca and animals of this age show an increased percentage of degenerate primordial follicles.

The Effects of Foeniculum vulgare Seed Extract on Fertility Results of Assisted Reproductive Technology in Women With Poor Ovarian Response

Objectives: Foeniculum vulgare due to phytoestrogens is important in the treatment of female sexual dysfunction including infertility. Accordingly, this study was conducted to investigate the effect of the F. vulgare seed extract on the fertility results of assisted reproductive technology (ART) in women with a poor ovarian response (POR). Materials and Methods: In this before-after intervention, 19 infertile women with POR were enrolled by a convenience sampling method. T h e amounts of luteinizing hormone ( LH) and follicle-stimulating hormone (FSH), ovarian ultrasound volume, the number of preantral follicles, and the size of the prominent ovary were measured before treatment with F. vulgare. Then, patients were treated with F. vulgare for two months, followed by initiating the in vitro fertilization (IVF) cycle. The number of embryos transferred in previous and current cycles was investigated after IVF. Finally, the data were analyzed in SPSS 16. Results: There was a significant difference in the serum LH level (P=0.002), LH/FSH (P=0.049), the number of follicles and ovules (P=0.003), endometrial thickness (P=0.04), and ovarian volume (P=0.03) between before and after treatment with F. vulgare. Moreover, a significant difference regarding the decreased number of required days for induction was observed between before and after treatment with F. vulgare (P=0.022). Conclusions: In general, the use of F. vulgare had positive effects on improving t h e quality of oocytes and female fertility indices in women with POR.

128 Study of preantral ovarian follicular population in fetal alpaca (Vicugna pacos) ovaries

In mammals, folliculogenesis begins at the fetal stage and is a complex, dynamic process that involves follicular quiescence, activation, growth, follicular migration, and cell interactions. At birth, the preantral ovarian follicular population, drastically reduced, constitutes &amp;gt;90% of all ovarian follicles, representing the ovarian reserve that will be used throughout the reproductive life. In alpacas, changes in follicular wave growth patterns and ovulation are different from other species; thus, it is important to know the ovarian reserve at fetal stage, as a starting point for future studies. Therefore, the aim of the present study was to establish the morphological characterisation and estimate the population of alpaca preantral follicles in the fetal stage. Ovaries from alpacas (n=5) in the fetal stage (fetus during the last third of gestation) were collected at a local slaughterhouse. Whole ovaries were individually fixed in 4% paraformaldehyde phosphate-buffered saline overnight at room temperature for routine histology. Ovaries were dehydrated in alcohol, cleared with xylene, and embedded in paraffin, and all tissue was serially sectioned at 7μm with a rotating microtome (Leica). The histological sections were mounted and stained with periodic acid-Schiff and hematoxylin. Preantral follicles were classified according to their developmental stage: primordial (one layer of flattened granulosa cells surrounding the oocyte), primary follicle transition (flattened cuboidal granulosa cells surrounding the oocyte), primary (single layer of cuboidal granulosa cells around the oocyte), or secondary (oocyte surrounded by more than one complete layer of cuboidal granulosa cells). We estimated the number of preantral follicles by counting all follicles in each histological section. Only follicles in which the oocyte nucleus was visible were counted. In addition, for each follicle category (n=40 per group), oocyte and follicle diameters were measured using an ocular micrometer. The variable means were compared using unpaired Student's t-test analysis, with significance set at P ≤ 0.05. Estimation of preantral follicular population (mean±standard deviation) was 80 516±14 575 in the ovaries of alpaca fetuses. Most of the follicles found belong to the primordial (49.2%) or primary follicle transition (39.2%) categories, followed by primary (10.8%) and secondary (0.8%) stages. Follicle and oocyte diameters of primordial (33.3±7.2; 21.5±4.6μm) and primary follicle transition stages (36.7±3.0; 23.4±2.6μm) were significantly (P&amp;lt;0.05) smaller than those of primary-stage follicles (77.9±15.8; 50.02±11.1μm). Finally, preantral follicles classified with normal morphological integrity appearance for each developmental stage were 98.2% (primordial), 96.7% (primary follicle transition), 91.5% (primary), and 88.1% (secondary), respectively. In conclusion, this study shows for the first time an estimation of the population of preantral follicles in alpaca fetal ovaries and establishes follicle and oocyte diameters and their normal morphological integrity.

Ovarian follicle resilience in mice orally dosed with methoxychlor: Are reproductive impacts possible in mammals as ecological receptors?

Abstract Mammals are routinely evaluated with chemical exposure modeling in ecological risk assessments for contaminated terrestrial properties, such as sites managed under the U.S. EPA’s Superfund program. Despite modeling outcomes frequently indicating that site mammals are experiencing severe reproductive impacts, there are virtually no known instances of site mammal populations being either unhealthful or reduced in size. This observation has triggered the development of the one-time patented and recently ASTM International-certified Rodent Sperm Analysis method that directly assesses male reproductive health, and thereby the overall health of mammals that occur at sites. Just as experimentation has led to an understanding of the degree of sperm count reduction, sperm motility reduction, and increase in morphologically altered sperm that need occur for reproduction to be impacted, the degree of ovarian follicle count reduction to similarly impact reproductive success should be able to be determined. Thus, adult female CD-1 mice were orally exposed to vehicle control or methoxychlor at 32 and 64 mg/kg/day for 30 days. Pursuant to resting periods of 30 and 60 days post-dosing, half of the treated animals were euthanized and their ovaries were collected and subjected to histological evaluations of follicle numbers and health. The other half of the animals were mated to proven breeder males to enable evaluation of breeding success. At 30 days post-dosing, primary and pre-antral follicle numbers were increased at both methoxychlor doses compared to controls. Further, the number of atretic follicles nearly doubled at both methoxychlor doses compared to controls. In contrast, at 60 days post-dosing, follicle numbers did not differ between methoxychlor treatment and control groups. These results were corroborated by 60-day mated and non-mated mice displaying an increase in serum anti-Mullerian hormone level, a recognized marker for the quantitative aspect of ovarian reserve. At both 30 day and 60 days post-dosing, pup weights and litter sizes in methoxychlor exposed animals were the same as those of controls. Collectively, these data indicate that oral exposure to methoxychlor did not increase follicle atresia or reduce follicle numbers enough to compromise female fertility. These outcomes may be indicators of ovarian follicle resiliency to chemical exposure, a capability that could benefit mammals in the wild. Ovarian follicle resiliency could, in part, explain the recurrent discovery at contaminated terrestrial sites, of rodent populations that are identical (in terms of size, sex ratio, and age distribution) to those of nearby (non-contaminated) reference locations.

Prenatal and Neonatal Exposure to Glyphosate-Based Herbicide Reduces The Primordial to Primary Follicle Transition in The Newborn Rat Ovary: A Preliminary Study

This study investigated how a glyphosate-based herbicide (GBH) affects the proportional distribution of ovarian follicles that develop from the 18 th day of the embryo period (E18) to the 7 th postnatal day (PND7) in newborn female rats. A total of 6 pregnant rats that were used in the study were divided into two groups so that there would be 3 pregnant rats in the control group and 3 pregnant rats in the GBH group. Starting from E21 to E18 the pregnant rats in the experimental group were administered at 50 mg/kg/day GBH subcutaneously (s.c.) and the physiological saline was administered as vehicle to the control group. Subsequently, female pups received vehicle or 2 mg/kg GBH from PND1 to PND7. On PND8, all female offspring (neonatal period, 6 newborn female rats from each group) were sacrificed by light ether anesthesia. For the histological examination of the dissected ovaries, the primordial, primary, secondary and preantral follicle numbers were determined using Crossman's modified triple staining method and Periodic Acid-Shiff (PAS) staining methods. The percentage of primordial follicles was significantly higher in the ovaries of female rats in GBH exposed group compare to the control group. However, the percentage of primary, secondary and preantral follicles was lower. Thus, it was observed that prenatal and neonatal GBH exposure decreased the transition of primordial follicle to primary follicle.

SAT-LB042 Effect of Dehydroepiandrosterone on the Perimenopausal Ovary

Dehydroepiandrosterone (DHEA) supplementation can improve oocyte quality in women with diminished ovarian function1-2. However, it is unclear if similar beneficial effects of DHEA supplementation can be obtained during the perimenopause, a period when the number of ovarian follicles shows a marked age-associated decline. To address this question we examined the impact of 2.5-months of daily oral DHEA supplementation (5 mg) on the number of ovarian follicles as well as on the concentration of anti-Müllerian hormone (AMH) – a marker of ovarian function. The study used perimenopausal adult rhesus monkeys; like women, these long-lived nonhuman primates show ~28-day menstrual cycles and eventually undergo menopause. Furthermore, they show similar age-related neuroendocrine changes, including a marked decrease in circulating DHEA concentrations3-4. Our experimental design involved the following three groups (N = 6 per group): Young adult (mean age = 11.6 years), Old control (mean age = 23.1 years), and Old DHEA-treated (mean age = 23.5 years). Histological examination of the ovaries revealed a significant (P<0.05) age-related decrease in the mean number of pre-antral follicles but no obvious beneficial effect of DHEA supplementation. Similarly, AMH concentrations within the ovaries and serum, assessed by Western analysis and ELISA respectively, showed a significant (P<0.05) age-related decrease but no obvious beneficial effect of DHEA supplementation. Taken together, the results indicate that short-term DHEA supplementation alone is insufficient to enhance ovarian function during the perimenopause and they complement findings from our earlier studies, which showed no obvious benefit of DHEA supplementation on cognitive function5. On the other hand, it remains plausible that chronic DHEA supplementation, earlier DHEA intervention, and supra-physiological DHEA doses may have more therapeutic potential. 1Gleicher N et al.Reprod Biomed Online, 21:360-365, 2010. 2Yilmaz N et al. Eur J Obstet Gynecol Reprod Biol, 169:257-260, 2013. 3Downs JL & Urbanski HF. Biol Reprod, 75: 539-546, 2006. 4Sorwell KG et al. Neurobiol Aging, 33:1487.e1-e13, 2012. 5Sorwell KG et al. Genes Brain Behav, 16:361-368, 2017. Unless otherwise noted, all abstracts presented at ENDO are embargoed until the date and time of presentation. For oral presentations, the abstracts are embargoed until the session begins. s presented at a news conference are embargoed until the date and time of the news conference. The Endocrine Society reserves the right to lift the embargo on specific abstracts that are selected for promotion prior to or during ENDO.

Folliculogenesis in the sheep as influenced by breed, season and oestrous cycle

Summary. In the sheep the total duration of folliculogenesis, i.e. from the start of development of a primordial follicle to ovulation, is thought to be about 6 months. The initiation of follicular growth as follicles enter the growth phase is influenced by gonadotrophins and, in the sheep, by factors such as breed, season and nutrition. Preantral follicles are characterized by a slow growth rate and no atresia. The number of preantral follicles is influenced by gonadotrophins, age, nutrition, season and unilateral ovariectomy. Antral follicles grow rapidly and produce steroids in response to gonadotrophins. The number of antral follicles varies according to factors such as breed of sheep, season, cycle, unilateral ovariectomy and gonadotrophins. Ovulation rate can be influenced in the short term by factors such as PMSG stimulation, short-term nutrition and unilateral ovariectomy that probably act by changing the number of follicles undergoing atresia. Factors such as breed, age and season probably act by changing the number of follicles entering the growth phase.

Spatial distribution of preantral follicles in the equine ovary.

Comprehensive studies on spatial distribution of preantral follicles in the ovary are scarce. Considering that preantral follicles represent the main ovarian reserve, harvesting of these follicles is crucial for the development/use of assisted reproductive techniques. Therefore, knowledge on follicle spatial distribution can be helpful for targeting areas with richer number of preantral follicles through biopsy procedures. The aim of this study was to assess the distribution and localization of equine preantral follicles according to: (i) age, (ii) ovarian portion (lateral and intermediary) and region (dorsal and ventral), (iii) distance from the geometric center, and (iv) follicular class. Ovaries from young and old mares (n = 8) were harvested in a slaughterhouse and submitted to histological processing for further evaluation. For data analyses, a novel methodology was developed according to the geometric center of each histological section for a precise determination of preantral follicle distribution. Results indicated that (i) equine preantral follicles are clustered and located near to the ovarian geometric center, and that aging induced their dispersion through the ovarian cortex; (ii) the distance from the geometric center was shorter for developing follicles than primordial; and (iii) secondary follicles were more distant from the geometric center but closer to the ovulation fossa. In conclusion, the spatial distribution of preantral follicles was successfully determined in the equine ovary and was affected by age, region, and portion.

Hydroalcoholic extract of flaxseed improves polycystic ovary syndrome in a rat model.

Objective(s):Herbal medicines are an alternative choice for treatment or controlling of polycystic ovary syndrome (PCOS). Effect of hydroalcoholic extract of flaxseed was evaluated on ovarian hormones and histological changes of uterus and ovary in a PCOS-induced rat model.Materials and Methods:Twenty four rats divided into four groups including negative control, positive control, PCOS and treatment groups. Positive control group received hydroalcoholic extract of flaxseed for 30 days. PCOS was induced by single intramuscular injection of estradiol valerate. Treatment group was treated with flaxseed extract 7 weeks after induction of PCOS for 30 days. Ovaries and uterus were dissected out and their sections were used for histomorphometric study. Levels of estradiol, progesterone, testosterone and dehydroepiandrosterone (DHEA) were measured in the serum.Results:In the treatment group, flaxseed extract increased level of progesterone (P<0.05), while decreased testosterone (P<0.05) compared with the PCOS group. Concentrations of estrogen and DHEA did not change significantly in comparison with the PCOS group. Histomorphometric study showed that in the treatment group, the number of preantral follicles, antral follicles and corpus luteum increased compared with the PCOS group (P<0.05), but the number of cystic follicles and diameter of antral follicles decreased (P<0.05), and the number of primary follicle did not alter significantly. In the treatment group, the thickness of granulosa layer increased, but the thickness of theca layer and tunica albuginea decreased compared to the PCOS group (P<0.05).Conclusion:Hormonal profile and histomorphometric features of ovary that were disturbed by PCOS induction were ameliorated by hydroalcoholic extract of flaxseed.

Characterization of the ovarian preantral follicle populations and its correlation with age and nutritional status in Brazilian Northeastern donkeys (Equus assinus)

This study aimed to characterize the ovarian follicular population and to determine its correlations with the age and nutritional status of donkeys of the Northeastern Brazilian breed. A total of 10 females with a mean age of 5.1±3.2years were submitted to ovariectomy by videolaparoscopy to obtain the ovaries. In the laboratory, the ovaries were sectioned into 6–12 fragments of approximately 7mm in diameter, which were fixed in Carnoy, dehydrated in increasing concentrations of alcohol (85%, 95% and absolute), clarified using xylol and embedded in blocks of histological paraffin. The blocks were cut in sections of 7μm and each 120th section was mounted on a slide for observation using optical microscopy. The follicle counting and identification allowed the characterization of the population of the preantral follicles. A total of 21.135±10.821 preantral follicles was counted, of which, 91.3% were primordial, 8.3% were primary follicles and 0.4% were secondary follicles. There were no differences between the two ovaries of each animal regarding the follicular population (P>0.05). There was a rate of 9.77% degenerated follicles. Values of 0.99% follicles containing two oocytes were also identified and classified as multi-oocyte follicles, always of the primordial category. The thickness of the granulosa cell layer was 1.85μm±1.39, 3.56μm±2.08 and 21.85μm±17.27, for primordial, primary and secondary follicles, respectively. There was a significant inverse correlation (r=−0.66; P<0.001) between the age of the animals and the population of ovarian follicles. A negative influence of the weight and body score on the ovarian follicular population was also observed, when donkeys had very little or a great amount of body condition. This is the first study to describe the morphometric characteristics and estimation of the population of preantral ovarian follicles in Northeastern Brazilian donkey, showing that number of preantral follicles decreased with increasing age of the animals and this finding may be affected by nutritional status of the animals.