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Taylor PD, Wilson H, Hillier SG, Wiegand SJ, Fraser HM. Effects of inhibition of vascular endothelial growth factor at time of selection on follicular angiogenesis, expansion, development and atresia in the marmoset. Mol Hum Reprod 2007; 13:729-36. [PMID: 17804434 DOI: 10.1093/molehr/gam056] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
This study determined the effects of inhibiting vascular endothelial growth factor (VEGF) at follicle selection. Marmosets were given an injection of VEGF antagonist, the VEGF Trap on Day 5 of the follicular phase and ovaries were evaluated on Day 10 or 15. Ovaries from controls were assessed on Day 5 (time of selection), Day 10 (peri-ovulatory) and Day 15 (luteal phase). At Day 10, ovaries of four of the five controls contained dominant follicles, while one had ovulated. VEGF Trap-treated ovaries also contained large follicles on Day 10, but VEGF inhibition had suppressed endothelial cell proliferation, leading to reductions in the thecal vascularization and plasma estradiol relative to controls. By Day 15, ovaries of controls contained active corpora lutea whereas ovaries of four of the five treated animals still contained large antral follicles similar in size to pre-ovulatory follicles, and one had small, avascular corpora lutea. However, these follicles had a restricted vasculature, increased incidence of activated caspase-3 staining and morphological features indicating they would become degenerative non-functional cysts. These results show that after follicle selection, VEGF is essential for angiogenesis and the generation of healthy ovulatory follicles and corpora lutea, but fluid accumulation can still occur in selected follicles in the absence of VEGF.
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Burke CR, Cárdenas H, Mussard ML, Gasser CL, Day ML. Steroidogenic changes and steady state amount of messenger RNA encoding steroidogenic enzymes, gonadotropin receptors and cell-death signalling in the dominant ovarian follicle during estradiol-induced atresia in cattle. Anim Reprod Sci 2007; 99:244-57. [PMID: 16842941 DOI: 10.1016/j.anireprosci.2006.05.019] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2005] [Accepted: 05/23/2006] [Indexed: 11/27/2022]
Abstract
Changes in steroidogenic function and associated gene expression were characterized in dominant ovarian follicles (DF) of cattle where follicles were induced to become atretic by systemic administration of estradiol benzoate (EB). In experiment 1, follicular fluid (FF) steroid concentrations in the DF were measured at 12-hourly time points for 48 h in heifers treated with 1 mg EB i.m./500 kg body weight (EB; n=20) as compared with untreated controls (C; n=19). Treatment with EB promoted a transient reduction in circulating FSH, a rapid (12 h) and sustained reduction in FF estradiol, a rapid (12 h) but transient reduction in FF progesterone and a delayed (36 h) increase in FF testosterone concentrations. In experiment 2, whole follicular wall tissue was collected from DF of mature non-lactating cows allocated to a 0 h control group (0 HC: n=7), a 24h control group (24 HC; n=7) or an EB-treated group where tissue was collected 24 h after administration of 1 mg EB i.m./500 kg body weight (EB; n=8). As for experiment 1, EB promoted a transient reduction in circulating FSH, a pronounced reduction in FF estradiol and a smaller but significant reduction in FF progesterone concentrations. Semi-quantitative RT-PCR on follicular wall tissue revealed that the loss in estrogen activity at 24 h after EB was associated with two-fold reduction in aromatase mRNA, with an apparent acceleration in loss of 17alpha-hydroxylase mRNA. Expression of genes for gonadotropin receptors (LHR and FSHR) and a cell-death signalling pathway (Fas antigen and Fas ligand) were unchanged during the initial 24h of EB-induced atresia. These results suggest that EB initiates atresia in dominant ovarian follicles through a rapid suppression of follicular estradiol synthesis, an effect associated with down-regulation of the aromatase gene. A transient suppression in circulating FSH following administration of EB appears to have initiated these events, and it is suggested that subsequent processes involved in atresia follow this loss in estrogenic function.
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Hoyer PB, Sipes IG. Development of an animal model for ovotoxicity using 4-vinylcyclohexene: a case study. ACTA ACUST UNITED AC 2007; 80:113-25. [PMID: 17342769 DOI: 10.1002/bdrb.20103] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
BACKGROUND The occupational chemical 4-vinylcyclohexene (VCH) has been shown to cause destruction of small pre-antral follicles in ovaries of mice. Further, its monoepoxide metabolites, 1,2-VCH epoxide, 7,8-VCH epoxide, and the diepoxide, VCD, have been shown to cause pre-antral follicle loss in rats as well as mice. Chemicals that destroy small pre-antral follicles are of concern to women because exposure can result in premature ovarian failure (early menopause). METHODS Studies working with these chemicals over the past decade have determined a number of aspects of the mechanism(s) of small pre-antral destruction, and a variety of questions have been answered. RESULTS Specifically, it has been determined that the diepoxide (VCD) is the bioactive form and it directly targets the ovary in mice and rats. Mice are more susceptible to VCH than rats because they are capable of its metabolic bioactivation. Follicle destruction by VCD is selective for primordial and primary follicles. Mechanistic studies in rats have determined that VCD causes ovotoxicity by accelerating the natural process of atresia (apoptosis) and this requires repeated exposures. Pro-apoptotic signaling events in the Bcl-2 and mitogen activated protein kinase families have been shown to be selectively activated in fractions of small pre-antral follicles (targets for VCD). Finally, a whole ovarian culture system using neonatal mouse and rat ovaries has been developed to expand the potential for more in depth investigations into ovotoxicity caused by VCD. CONCLUSIONS This article provides an overview of the questions asked and the approaches taken in studying VCH and VCD to support these conclusions.
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Minervini F, Giannoccaro A, Fornelli F, Dell'Aquila ME, Minoia P, Visconti A. Influence of mycotoxin zearalenone and its derivatives (alpha and beta zearalenol) on apoptosis and proliferation of cultured granulosa cells from equine ovaries. Reprod Biol Endocrinol 2006; 4:62. [PMID: 17137489 PMCID: PMC1697814 DOI: 10.1186/1477-7827-4-62] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/26/2006] [Accepted: 11/30/2006] [Indexed: 02/08/2023] Open
Abstract
BACKGROUND The mycotoxin zearalenone (ZEA) and its derivatives, alpha and beta-zearalenol (alpha and beta-ZOL), synthesized by genera Fusarium, often occur as contaminants in cereal grains and animal feeds. The importance of ZEA on reproductive disorders is well known in domestic animals species, particularly in swine and cattle. In the horse, limited data are available to date on the influence of dietary exposure to ZEA on reproductive health and on its in vitro effects on reproductive cells. The aim of this study was to evaluate the effects of ZEA and its derivatives, alpha and beta-ZOL, on granulosa cells (GCs) from the ovaries of cycling mares. METHODS The cell proliferation was evaluated by using the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) test after 3 days exposure at different concentrations of ZEA and its derivatives (from 1 x 10-7 to 0.1 microM). The apoptosis induction was evaluated after 1 day exposure, by DNA analysis using flow cytometry. RESULTS An increase in cell proliferation with respect to the control was observed in the presence of ZEA at 1 x 10-3 and 1 x 10-4 microM and apoptosis was induced by all mycotoxins at different concentrations. CONCLUSION The simultaneous presence of apoptosis and proliferation in GC cultures treated with zearalenones could indicate that these mycotoxins could be effective in inducing follicular atresia. These effects of zearalenones may result from both direct interaction with oestrogen-receptors as well as interaction with the enzymes 3alpha (beta)-hydroxysteroid dehydrogenase (HSD), involved in the synthesis and metabolism of endogenous steroid hormones. These cellular disturbances, described for the first time in equine GCs cultured in vitro, could be hypothesized as referred to reproductive failures of unknown ethiology in the mare.
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Slot KA, Kastelijn J, Bachelot A, Kelly PA, Binart N, Teerds KJ. Reduced recruitment and survival of primordial and growing follicles in GH receptor-deficient mice. Reproduction 2006; 131:525-32. [PMID: 16514195 DOI: 10.1530/rep.1.00946] [Citation(s) in RCA: 73] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
GH influences female fertility. The goal of the present study was to obtain more insight into the effect of loss of GH signalling, as observed in humans suffering from Laron syndrome, on ovarian function. Therefore, serial paraffin sections of ovaries of untreated and IGF-I-treated female GH receptor knock-out (GHR/GHBP-KO) mice were examined to determine the follicular reserve and the percentage of follicular atresia in each ovary. Our observations demonstrate that the amount of primordial follicles was significantly elevated in GHR/GHBP-KO mice, while the numbers of primary, preantral and antral follicles were lower compared with wild-type values. The reduced number of healthy growing follicles in GHR/GHBP-KO mice was accompanied by a significant increase in the percentage of atretic follicles. IGF-I treatment of GHR/GHBP-KO mice for 14 days resulted in a reduced number of primordial follicles, an increased number of healthy antral follicles, and a decreased percentage of atretic follicles. The results of the present study suggest that GH may play a role, either directly or indirectly, via for instance IGF-I, in the recruitment of primordial follicles into the growing pool. Furthermore, GH seems to protect antral follicles, directly or indirectly from undergoing atresia.
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Chanda D, Krishna A. Hormonal induction of ovulation stimulates atresia of antral follicles in a vespertilionid bat, Scotophilus heathi. ZOOLOGY 2006; 109:208-16. [PMID: 16814533 DOI: 10.1016/j.zool.2006.02.001] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2005] [Revised: 11/24/2005] [Accepted: 02/05/2006] [Indexed: 11/19/2022]
Abstract
Scotophilus heathi is a seasonally monoestrous subtropical vespertilionid bat found at Varanasi, India. Although the antral follicles remain present in the ovaries of S. heathi from November till March, ovulation is delayed in this species until early March. In order to understand the mechanism of ovulation suppression during this period of delayed ovulation, the effects of human chorionic gonadotropin (hCG), pregnant mare's serum gonadotropin (PMSG), follicle stimulating hormone (FSH) and gonadotropin releasing hormone agonist (GnRH agonist) on ovarian morphology and steroid concentration were investigated. Hormonal treatments were given as a single i.p. dose 24 h after capture. The bats were sacrificed 48 h after the injection. Treatment with hCG, PMSG, FSH and GnRH agonist failed to induce ovulation in S. heathi, although these hormones produced a high degree of ovarian stimulation. The administration of hCG and PMSG induced ovarian enlargement, intense hyperemia, marked changes in the interstitial cells (ICs), development of several antral follicles and a varying degree of abnormalities in the oocytes of most of the antral follicles. In the bats treated with hCG, PMSG and GnRH agonist, androstenedione concentration increased significantly to extraordinarily high levels, whereas estradiol concentration decreased. Administration of FSH caused regression of ICs and pyknosis of granulosa cells in the majority of antral follicles. FSH did not enhance androstenedione concentration. The results of the present study suggest that the failure of hormonal treatments to induce ovulation during the period of delayed ovulation might be due to a seasonal desensitization of ovarian follicles in S. heathi. The hormonal treatment instead stimulated the ICs to produce a high level of androstenedione resulting in atretic changes of the antral follicles.
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Gupta RK, Miller KP, Babus JK, Flaws JA. Methoxychlor Inhibits Growth and Induces Atresia of Antral Follicles through an Oxidative Stress Pathway. Toxicol Sci 2006; 93:382-9. [PMID: 16807286 DOI: 10.1093/toxsci/kfl052] [Citation(s) in RCA: 88] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
The mammalian ovary contains antral follicles, which are responsible for the synthesis and secretion of hormones that regulate estrous cyclicity and fertility. The organochlorine pesticide methoxychlor (MXC) causes atresia (follicle death via apoptosis) of antral follicles, but little is known about the mechanisms by which MXC does so. Oxidative stress is known to cause apoptosis in nonreproductive and reproductive tissues. Thus, we tested the hypothesis that MXC inhibits growth and induces atresia of antral follicles through an oxidative stress pathway. To test this hypothesis, antral follicles isolated from 39-day-old CD-1 mice were cultured with vehicle control (dimethylsulfoxide [DMSO]), MXC (1-100 microg/ml), or MXC + the antioxidant N-acetyl cysteine (NAC) (0.1-10 mM). During culture, growth was monitored daily. At the end of culture, follicles were processed for quantitative real-time polymerase chain reaction of Cu/Zn superoxide dismutase (SOD1), glutathione peroxidase (GPX), and catalase (CAT) mRNA expression or for histological evaluation of atresia. The results indicate that exposure to MXC (1-100 microg/ml) inhibited growth of follicles compared to DMSO controls and that NAC (1-10 mM) blocked the ability of MXC to inhibit growth. MXC induced follicular atresia, whereas NAC (1-10 mM) blocked the ability of MXC to induce atresia. In addition, MXC reduced the expression of SOD1, GPX, and CAT, whereas NAC reduced the effects of MXC on their expression. Collectively, these data indicate MXC causes slow growth and increased atresia by inducing oxidative stress.
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Shimizu T. Promotion of ovarian follicular development by injecting vascular endothelial growth factor (VEGF) and growth differentiation factor 9 (GDF-9) genes. J Reprod Dev 2006; 52:23-32. [PMID: 16538032 DOI: 10.1262/jrd.17072] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Ovarian follicular development in mammals is the complex process including endocrine, paracrine and autocrine. There is the development of four basic stages of ovarian follicles, i.e. the primordial, primary, secondary and tertiary or Graafian follicles. There are few blood vessels in the cortical area where primordial and primary follicles are assembled. The development of these follicles is stimulated by oocytes derived factor including growth differentiation factor 9 (GDF-9) or bone morphogenetic protein 15 (BMP-15). Porcine GDF-9 complementary DNA (cDNA) cloned, and then injected its gene into the ovary in gilts. The injection of porcine GDF-9 gene resulted in an increase in the number of primary, secondary and tertiary follicles, concomitant with a decrease in the number of primordial follicles, indicating that exogenous GDF-9 can promote early folliculogenesis in the porcine ovary. On the other hand, the development of antral follicles is associated with increased density of blood vessels within the theca cell layers surrounding the follicles. A recent study reported that vascular endothelial growth factor (VEGF) play an important role in the process of thecal angiogenesis during follicular development. To investigate whether additional induction of thecal angiogenesis would support subsequent follicular development, miniature gilts were directly injected VEGF gene into the ovary. Injection of VEGF gene increased the levels of mRNA expression of VEGF 120 and VEGF 164 isoforms in the granulosa cells and VEGF protein contents in the follicular fluid. The number of preovulatory follicles and the capillary density in the theca interna increased significantly in the ovaries injected with VEGF gene compared with those treated with eCG alone, indicating that the regulation of thecal angiogenesis during follicular development is a very important factor in the development of ovulatory follicles. This technique may be an innovative technique for enhanced induction of follicular development in the ovary through gene and hormonal treatment, which may lead to prevention of infertility caused by ovarian dysfunction.
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Schirling M, Jungmann D, Ladewig V, Ludwichowski KU, Nagel R, Köhler HR, Triebskorn R. Bisphenol A in artificial indoor streams: II. Stress response and gonad histology in Gammarus fossarum (Amphipoda). ECOTOXICOLOGY (LONDON, ENGLAND) 2006; 15:143-56. [PMID: 16374667 DOI: 10.1007/s10646-005-0044-2] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Accepted: 08/09/2005] [Indexed: 05/05/2023]
Abstract
The effects of the world wide-distributed chemical bisphenol A (BPA) on the endocrine system of vertebrates have been demonstrated in several studies. Here, we report on the impact of BPA (0, 5, 50 and 500 microg/l nominally, deduced effective concentrations 0, 0.24, 2.4, and 24.1 microg/l, respectively, all at 15 degrees C) on the 70 kD stress protein family (hsp70), the 90 kD stress protein family (hsp90), and gonad histology of the crustacean Gammarus fossarum exposed in artificial indoor streams. The animals were exposed for a maximum of 103 days and samples were taken at the beginning and at days 34, 69 and 103 of the experiment. Exposure to BPA resulted in accelerated maturation of oocytes in females and in a decline in the number and size of early vitellogenic oocytes. The level of hsp90, which plays a pivotal role in vertebrate sex steroid signal transduction, was significantly reduced by BPA. In all five streams, measured parameters did not indicate any captivity stress for a period of 69 days. Beyond this time, the mortality rate and proteotoxic effects, the latter measured by hsp70 expression, were found to be elevated.
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Olatinwo MO, Bhat GK, Stah CD, Mann DR. Impact of gonadotropin administration on folliculogenesis in prepubertal ob/ob mice. Mol Cell Endocrinol 2005; 245:121-7. [PMID: 16337737 DOI: 10.1016/j.mce.2005.11.003] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/28/2005] [Revised: 10/31/2005] [Accepted: 11/07/2005] [Indexed: 01/01/2023]
Abstract
Female leptin deficient (ob/ob) mice exhibit abnormal ovarian folliculogenesis resulting in an impaired ability to reproduce. This effect may be related to the hypogonadotropic state of these animals, or leptin may directly modulate ovarian follicle development. In the present study we assessed whether exogenous gonadotropin administration would normalize folliculogenesis and induce ovulation in immature ob/ob animals. Eight 26-day-old ob/ob and eight control mice were injected sc with pregnant mare serum gonadotropin followed 48 h later with a sc injection of human chorionic gonadotropin. Animals were killed 24 h later. Gonadotropin (GTH) administration increased both ovarian and uterine weights in control mice, but this effect was attenuated in leptin deficient animals. The number of preantral follicles was greater in ob/ob mice than controls, but in GTH-treated animals the number of antral follicles was subnormal in the ovaries of leptin deficient animals. Ob/ob animals also failed to ovulate in response to GTH, and the protective actions of GTH against granulosa cell apoptosis and follicular atresia were attenuated in these animals. Interestingly, however, serum levels of estradiol and progesterone were higher in ob/ob mice than controls, regardless of whether or not the animals received GTH treatment. We conclude that the ovarian responsiveness to GTH is subnormal in leptin deficient animals suggesting that leptin may modulate the process of folliculogenesis by directly altering the sensitivity of the ovary to GTH.
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Miller KP, Gupta RK, Greenfeld CR, Babus JK, Flaws JA. Methoxychlor Directly Affects Ovarian Antral Follicle Growth and Atresia through Bcl-2- and Bax-Mediated Pathways. Toxicol Sci 2005; 88:213-21. [PMID: 16081520 DOI: 10.1093/toxsci/kfi276] [Citation(s) in RCA: 68] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Methoxychlor (MXC) is an organochlorine pesticide and reproductive toxicant. While in vivo studies indicate that MXC exposure increases antral follicle atresia, in part by altering apoptotic regulators (Bcl-2 and Bax), they do not distinguish whether MXC does so via direct or indirect mechanisms. Therefore, we utilized an in vitro follicle culture system to test the hypothesis that MXC is directly toxic to antral follicles, and that overexpression of anti-apoptotic Bcl-2, or deletion of pro-apoptotic Bax, protects antral follicles from MXC-induced toxicity. Antral follicles were isolated from wild-type (WT), Bcl-2 overexpressing (Bcl-2 OE), or Bax deficient (BaxKO) mice, and exposed to dimethylsulfoxide (control) or MXC (1-100 microg/ml) for 96 h. Follicle diameters were measured every 24 h to assess growth. After 96 h, follicles were histologically evaluated for atresia or collected for quantitative PCR analysis of Bcl-2 and Bax mRNA levels. MXC (10-100 microg/ml) significantly inhibited antral follicle growth at 72 and 96 h, and increased atresia (100 microg/ml) compared to controls at 96 h. Furthermore, MXC increased Bax mRNA levels between 48-96 h and decreased Bcl-2 mRNA levels at 96 h. While MXC inhibited growth of WT antral follicles beginning at 72 h, it did not inhibit growth of Bcl-2 OE or BaxKO follicles until 96 h. MXC also increased atresia of small and large WT and BaxKO antral follicles over controls, but it did not increase atresia of large Bcl-2 OE antral follicles over controls. These data suggest that MXC directly inhibits follicle growth partly by Bcl-2 and Bax pathways, and increases atresia partly through Bcl-2 pathways.
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Ankley GT, Jensen KM, Durhan EJ, Makynen EA, Butterworth BC, Kahl MD, Villeneuve DL, Linnum A, Gray LE, Cardon M, Wilson VS. Effects of Two Fungicides with Multiple Modes of Action on Reproductive Endocrine Function in the Fathead Minnow (Pimephales promelas). Toxicol Sci 2005; 86:300-8. [PMID: 15901916 DOI: 10.1093/toxsci/kfi202] [Citation(s) in RCA: 139] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Many chemicals that adversely affect reproduction and/or development do so through multiple pathways within the reproductive tract and hypothalamic-pituitary-gonadal axis. Notable in this regard are fungicides, such as prochloraz or fenarimol, which in mammals have the potential to impact endocrine function through inhibition of CYP enzymes involved in steroid metabolism, as well as through antagonism of the androgen receptor(s). The objective of our studies was to assess the effects of prochloraz and fenarimol on reproductive endocrine function in a model small fish species, the fathead minnow (Pimephales promelas), using both in vitro and in vivo assays. The two fungicides inhibited in vitro CYP19 aromatase activity in brain and ovarian homogenates from the fish, with prochloraz exhibiting a greater potency than fenarimol. Prochloraz and fenarimol also bound competitively to the cloned fathead minnow androgen receptor expressed in COS-1 cells. The two fungicides significantly reduced fecundity of the fish in a 21-day reproduction assay at water concentrations of 0.1 (prochloraz) and 1.0 (fenarimol) mg/l. The in vivo effects of prochloraz on plasma steroid (17beta-estradiol, testosterone, 11-ketotestosterone) and vitellogenin (an estrogen-responsive protein) concentrations, as well as on gonadal histopathology, were consistent with inhibition of steroidogenesis. Fenarimol also affected several aspects of endocrine function in vivo; however, the suite of observed effects did not reflect either aromatase inhibition or androgen receptor antagonism. These studies contribute to a better mechanistic understanding of the extrapolation of effects of endocrine-disrupting chemicals across vertebrate classes.
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Burke CR, Cárdenas H, Mussard ML, Day ML. Histological and steroidogenic changes in dominant ovarian follicles during oestradiol-induced atresia in heifers. Reproduction 2005; 129:611-20. [PMID: 15855624 DOI: 10.1530/rep.1.00384] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Histological and steroidogenic changes within dominant ovarian follicles (DFs) undergoing atresia following systemic administration of oestradiol benzoate (ODB) were characterized in beef heifers. At 5.6 ± 0.1 days after the onset of oestrus, heifers received 1 mg ODB i.m./500 kg body weight (ODB; n = 15) or served as controls (n = 15). Timing of treatment initiation was designated as hour (h) 0 on day (d) 0, and coincided with the presence of the DF of the first follicular wave (DF1). Within treatments, the DF1 was collected following ovariectomy in four animals at h 12, h 36 or after ultrasonic detection of a new wave (NW) of ovarian follicular development. In heifers of the NW groups (n = 7 per treatment), blood samples were collected at intervals of 20 min for 12 h beginning at h − 12, 0, 24 and 48 to characterize circulating LH patterns. Administration of ODB suppressed (P < 0.01) mean concentrations of LH at h 24 and h 48 by preventing (P < 0.05) the increase in LH pulse amplitude observed in controls, but had no effect on FSH. Follicular fluid (FF) concentrations of androgens and oestradiol were reduced at h 36 in the ODB-treated group. The diameter of the DF1 and the number of granulosa cell layers were also reduced in ODB-treated as compared with control heifers. Treatment differences were not observed in the proportion of apoptotic granulosa cells as assessed using the TUNEL assay method, and timing of a new wave of follicular development (d 4.6 ± 0.2) was similar (P > 0.1) among treatments. A prominent characteristic of oestradiol-induced atresia of the DF1 of the oestrous cycle in heifers was a loss in oestrogenic function associated with reduced LH support. However, the timing of new follicular development may be influenced by a factor(s) other than the status of the DF undergoing oestradiol-induced atresia.
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Birtch RL, Baerwald AR, Olatunbosun OA, Pierson RA. Ultrasound image attributes of human ovarian dominant follicles during natural and oral contraceptive cycles. Reprod Biol Endocrinol 2005; 3:12. [PMID: 15829004 PMCID: PMC1087505 DOI: 10.1186/1477-7827-3-12] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/09/2005] [Accepted: 04/13/2005] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Computer-assisted analyses were used to examine ultrasound image attributes of human dominant ovarian follicles that developed during natural and oral contraceptive (OC) cycles. We hypothesized that image attributes of natural cycle follicles would quantitatively differ from those in OC cycles and that OC cycle follicles would possess image attributes indicative of atresia. METHODS Dominant ovarian follicles of 18 clinically normal women were compared using transvaginal ultrasonography for the 7 days before ovulation during a natural cycle (n = 9) or the 7 days before peak estradiol in women using OC (n = 11). Follicles were analyzed using region and line techniques designed to compare the image attributes numerical pixel value (NPV), pixel heterogeneity (PH) and area under the curve (AUC). RESULTS NPV was higher in OC cycle follicles with region analysis and tended to be higher with line analysis (p = 0.005 and p = 0.06, respectively). No differences were observed in two other image attributes (AUC and PH), measured with either technique, between natural and OC cycle follicles. CONCLUSION The increased NPV value of OC cycle follicles and lack of differences in PH and AUC values between natural cycle and OC cycle follicles did not support the hypothesis that OC cycle follicles would show ultrasonographically detectable signs of atresia. Image attributes observed in OC cycle follicles were not clearly indicative of atresia nor were they large enough to preclude preovulatory physiologic status in OC cycle follicles.
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Thompson KE, Bourguet SM, Christian PJ, Benedict JC, Sipes IG, Flaws JA, Hoyer PB. Differences between rats and mice in the involvement of the aryl hydrocarbon receptor in 4-vinylcyclohexene diepoxide-induced ovarian follicle loss. Toxicol Appl Pharmacol 2005; 203:114-23. [PMID: 15710172 DOI: 10.1016/j.taap.2004.07.010] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2004] [Accepted: 07/26/2004] [Indexed: 11/23/2022]
Abstract
Repeated dosing with the occupational chemical 4-vinylcyclohexene diepoxide (VCD) selectively depletes small pre-antral follicles in the ovaries of rats and mice via apoptosis. The aryl hydrocarbon receptor (AhR) plays a role in mediating the effects of several xenobiotics. Therefore, this study was designed to investigate a potential role of the AhR in VCD-induced ovotoxicity. Female F344 rats, C57BL/6 mice, or AhR-deficient (-/-, AhRKO) mice were dosed daily (15 days) with vehicle, VCD (80 mg/kg, i.p.) and/or the AhR antagonist, alpha-naphthoflavone (ANF; 80 mg/kg, i.p.). Compared with controls, VCD caused a 60% reduction (P < 0.05) in primordial and primary follicles in mice and rats. Concurrent dosing with ANF protected against the VCD-induced follicle loss in rats, but not in mice. As with AhR-intact mice and rats, VCD induced a 70% loss (P < 0.05) of small pre-antral follicles in AhRKO mice. AhR mRNA expression was increased (P < 0.05) by VCD dosing in small pre-antral follicles isolated from ovaries of rats but not mice. AhR protein in rats was increased by VCD dosing in oocyte nuclei in primordial and primary follicles when measured by immunofluorescence and confocal microscopy. In rat small pre-antral follicles, apoptosis-associated caspase-3-like activity was increased (P < 0.05) by VCD treatment, decreased (P < 0.05) by ANF treatment, and unaffected by VCD plus ANF treatment. VCD had no effect on expression of GST Ya1 or GST Ya2 mRNA or CYP 1A1 protein in rats. Taken together, these findings demonstrate a difference between rats and mice in the potential involvement of AhR as related to VCD-induced ovotoxicity. Whereas, AhR appears to be involved in rats, no evidence for a similar role in mice was obtained. Overall, these findings point out that there can be mechanistic species differences in ovarian responses to xenobiotic chemicals.
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Borgeest C, Miller KP, Gupta R, Greenfeld C, Hruska KS, Hoyer P, Flaws JA. Methoxychlor-Induced Atresia in the Mouse Involves Bcl-2 Family Members, but Not Gonadotropins or Estradiol1. Biol Reprod 2004; 70:1828-35. [PMID: 14973267 DOI: 10.1095/biolreprod.103.022889] [Citation(s) in RCA: 48] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/01/2022] Open
Abstract
Methoxychlor (MXC) is an organochlorine pesticide that increases the rate of ovarian atresia. To date, little is known about the mechanism by which MXC induces atresia. Because Bcl-2 (an antiapoptotic factor), Bax (a proapoptotic factor), gonadotropins, and estradiol are important regulators of atresia in the ovary, the purpose of this study was first to examine whether MXC-induced atresia occurred through alterations in Bcl-2 or Bax, and second, to examine the effect of MXC on gonadotropins, estradiol, and their receptors. CD-1 mice were dosed with 8-64 mg kg(-1) day(-1) MXC or vehicle (sesame oil). Ovaries were subjected to analysis of antral follicle numbers, Bcl-2, Bax, estrogen receptor, and follicle-stimulating hormone receptor levels. Blood was used to measure gonadotropins and estradiol. In some experiments, mice that overexpressed Bcl-2 or mice that were deficient in Bax were dosed with MXC or vehicle and their ovaries were analyzed for atresia. MXC caused a dose-dependent increase in the percentage of atretic antral follicles compared with controls at the 32 and 64 mg kg(-1) day(-1) doses of MXC. MXC treatment did not result in changes in Bcl-2 levels, but it did result in an increase in Bax levels in antral follicles. MXC treatment did not affect gonadotropin or estradiol levels, nor did it affect the levels of follicle-stimulating hormone or estrogen receptors. Mice that overexpressed Bcl-2 or mice that were deficient in Bax were protected from MXC-induced atresia. These data suggest that MXC induces atresia through direct effects on the Bax and Bcl-2 signaling pathways in the ovary.
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Letterie GS. Anovulation in the prevention of cytotoxic-induced follicular attrition and ovarian failure. Hum Reprod 2004; 19:831-7. [PMID: 15033951 DOI: 10.1093/humrep/deh120] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
BACKGROUND Gonadal failure secondary to alkylating agents may be related to ovulatory status. The objective of this investigation was to evaluate whether anovulation protected ovarian follicles during treatment with cyclophosphamide. METHODS Four groups (n = 20 mature female Sprague-Dawley rats per group) were studied: control (group I), 5 mg/kg/day cyclophosphamide only (group II), 5 mg/kg/day cyclophosphamide and the combination of 50 micro g ethinyl estradiol/2 mg norgestrel (group III) and 5 mg/kg/day cyclophosphamide and 2.5 micro g leuprolide acetate daily (group IV). Animals were sacrificed after 4 weeks of treatment. Follicles were classified as medium (300-450 micro m) and large (>450 micro m) per section of ovary. RESULTS Group II developed a significantly greater number of medium and large follicles [15.1 +/- 6.1 and 4.9 +/- 1.9 (mean +/- SD), respectively] compared with group I [7.1 +/- 2.1 and 1.0 +/- 0.7 (mean +/- SD), respectively] (P </= 0.05). Groups III and IV developed a significantly greater number of medium follicles [13.2 +/- 2.5 and 10.8 +/- 2.3 (mean +/- SD), respectively) compared with group I (P < or = 0.05). There was a trend toward a greater number of large follicles in groups III and IV when they were compared with group I. There were no differences in medium follicles in groups II, III and IV. No differences were noted in the number of large follicles between groups III and IV (2.9 +/- 1.2 and 2.3 +/- 1.0, respectively). CONCLUSIONS These results suggest that in the rat model, cyclophosphamide exerts a stimulatory effect on the ovary resulting in the greater development of both medium and large follicles. Anovulation conferred no protection against cyclophosphamide-induced gonadal toxicity. These data suggest that in the rat model, cyclophosphamide may result in ovarian failure by enhancing recruitment of follicles regardless of ovulatory status or hormonal milieu.
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Liu ZH, Yue KZ, Ma SF, Sun XS, Tan JH. Effects of pregnant mare serum gonadotropin (eCG) on follicle development and granulosa-cell apoptosis in the pig. Theriogenology 2003; 59:775-85. [PMID: 12517381 DOI: 10.1016/s0093-691x(02)01122-6] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The effect of eCG on follicular development and granulosa-cell apoptosis in sexually mature and immature gilts and on granulosa-cell apoptosis in vitro were studied. The sexually mature gilts were treated with eCG on Day 11 of the estrous cycle, and effects were analyzed at different times after treatment with untreated animals at corresponding stages of the cycle as controls. Apoptosis was determined by terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling (TUNEL), hematoxylin and eosin staining, and DNA ladder. The proportion of apoptotic cells in atretic follicles (39%) was significantly higher (P<0.01) than that in healthy follicles (9%). At 24h after eCG treatment in mature gilts, the total number of follicles visible on the ovarian surface (57 per ovary), the number of small (<3mm) follicles (31.5 per ovary) and the number of medium-sized (3-5mm) follicles (23 per ovary) were significantly higher (P<0.05) than those of control animals (28, 20 and 6.5 per ovary, respectively), and declined gradually thereafter to below the level of control animals. The number of large (>or=5mm) follicles began to show a marked increase at 72h after eCG (8.5 versus 2.5, P<0.05). At 24h after eCG treatment, the proportions of apoptotic cells in small (7.2%) and medium-sized follicles (7.4%) were markedly lower (P<0.01) than those in controls (21.5 and 21%, respectively) and increased gradually thereafter to approach the level in controls. The percentage of apoptotic cells in large follicles (10% at 24h post-eCG) did not change significantly. Before eCG treatment, there were markedly fewer follicles of all types on ovaries of immature gilts than of mature gilts (9 versus 25 per ovary) and the proportion of apoptotic cells in small and medium follicles was high (25 and 34%, respectively). After eCG treatment, the changes in follicle number and proportion of apoptotic cells in the immature gilts followed a similar pattern to that of the mature gilts. Equine chorion gonadotropin inhibited apoptosis of granulosa cells cultured either in vitro or in intact follicles in a dose-dependent manner. Thus, follicular atresia in the pig, as in other animals, was characterized by apoptosis of large numbers of granulosa cells, and eCG promoted follicular development by inhibition of granulosa-cell apoptosis.
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Kim HH, Shaipanich M, Hasselblatt K, Yeh J. Induction of apoptosis and ovarian cyst formation in the mouse ovary by dehydroepiandrosterone (DHEA). JOURNAL OF MEDICINE 2003; 34:101-12. [PMID: 17682316] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 05/16/2023]
Abstract
Exogenous dehydroepiandrosterone (DHEA) produces ovarian cysts and atretic follicles in mice. We sought to test the hypothesis that the abnormal follicular development found after DHEA administration in mice results from aberrant ovarian apoptosis. DHEA was injected subcutaneouly for 15 days. Controls received an equivalent volume of vehicle. Follicle size was measured, and the proportion of ovarian follicles containing apoptotis was assessed by in situ end-labeling of DNA. DHEA resulted in a greater proportion of follicles with evidence of apoptosis (62.4% in the DHEA group [n = 789 follicles] vs. 53.0% in the vehicle group [n = 440 follicles]; p = 0.031). DHEA also produced larger follicles (mean diameter: 234.7um +/- 24.6um in the DHEA group vs. 204.6um +/- 11.4um in the vehicle group; p < 0.01). All of the DHEA-treated mice contained follicles > 500um while only one of the mice in the vehicle group contained a follicle > 500um in diameter (p < 0.001). We conclude that DHEA administration results in increased ovarian apoptosis and in larger follicle size, thereby producing a characteristic cystic and atretic appearance in the mouse ovary. This may be the mechanism by which androgens cause ovarian cyst formation.
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Hiremath MB, Kaliwal BB. Effect of endosulfan on ovarian compensatory hypertrophy in hemicastrated albino mice. Reprod Toxicol 2002; 16:783-90. [PMID: 12401506 DOI: 10.1016/s0890-6238(02)00060-6] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
Endosulfan, a chlorinated cyclodiene insecticide, was administered orally at 1.5, 3, 6, and 9 mg/kg per day to normal hemicastrated virgin mice for 15 consecutive days to examine the effect on ovarian function. Sham-operated and hemicastrated control mice were administered a similar volume of olive oil. The vaginal smear and body weight of the mice were recorded daily and mice were sacrificed on day 16. The remaining left ovary, uterus, kidney, adrenal, liver, thymus, and thyroid were removed and weighed. The left ovary from each animal was serially sectioned and stained for histologic studies. The hemicastrated control mice had a 40.5% increase in weight of the remaining left ovary and a significant increase in healthy and atretic follicles when compared with sham-operated controls. The remaining left ovaries of mice treated with 1.5mg endosulfan had a 37.2% increase in weight with no significant difference in ovarian weight and or in the healthy and atretic follicles when compared with hemicastrated olive oil-treated controls. However, treatment with 3, 6, and 9 mg endosulfan resulted in weight increases in the remaining left ovary of only 14.9, 7.4, and 0.8% and a significant decrease in healthy follicles with a concomitant increase in the number of atretic follicles compared to the olive oil-treated controls. There was no significant change in the number of estrous cycles or the duration of each phase of the estrous cycle with 1.5 and 3mg/kg per day endosulfan. However, there was a significant decrease in the number of estrous cycles, and the duration of estrus and metestrus with a concomitant significant increase in the duration of the diestrus phase with 6 and 9 mg/kg per day endosulfan treatment when compared with hemicastrated olive oil-treated controls. There were no significant change in body weight or the weights of the uterus, kidney, adrenal, liver, thymus, or thyroid after endosulfan treatment. These observations show that endosulfan treatment caused a significant decrease in compensatory ovarian hypertrophy. An increase in the number of atretic follicles and disruption of the estrous cycle may have been due to a direct effect on the ovary or to effects on the hypothalamo-hypophysial-ovarian axis.
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Mayer LP, Pearsall NA, Christian PJ, Devine PJ, Payne CM, McCuskey MK, Marion SL, Sipes IG, Hoyer PB. Long-term effects of ovarian follicular depletion in rats by 4-vinylcyclohexene diepoxide. Reprod Toxicol 2002; 16:775-81. [PMID: 12401505 DOI: 10.1016/s0890-6238(02)00048-5] [Citation(s) in RCA: 104] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
4-Vinylcyclohexene diepoxide (VCD) destroys preantral ovarian follicles in rats. Female 28-day Fisher 344 (F344) rats were dosed (30 days) with VCD (80 mg/kg per day, i.p.) or vehicle, and animals were evaluated for reproductive function at subsequent time points for up to 360 days. At each time point animals were killed, and ovaries and plasma collected. VCD reduced (P<0.05) the number of preantral follicles by day 30 relative to control. There were no ultrastructural differences in morphology between VCD-treated and control ovaries. Circulating FSH levels in VCD-treated animals were greater (days 120, 240, and 360, P<0.05) than in controls. Cyclicity was disrupted in the VCD-treated group by day 360. These results show that VCD-induced follicular destruction in rats is associated with a sequence of events (loss of preantral follicles, increased plasma FSH, and cyclic disruption) preceding premature ovarian senescence that is similar to events that occur during the onset of menopause in women.
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Hu X, Flaws JA, Sipes IG, Hoyer PB. Activation of mitogen-activated protein kinases and AP-1 transcription factor in ovotoxicity induced by 4-vinylcyclohexene diepoxide in rats. Biol Reprod 2002; 67:718-24. [PMID: 12193377 DOI: 10.1095/biolreprod.102.004259] [Citation(s) in RCA: 40] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/01/2022] Open
Abstract
Previous studies have demonstrated that ovotoxicity induced in small preantral (primordial and primary) ovarian follicles by 4-vinylcyclohexene diepoxide (VCD) in rats is likely via acceleration of the normal process of atresia (apoptosis). This acceleration is associated with increased activities of caspase cascades, changes in subcellular distribution of Bcl-2 family members, and alteration of estrogen receptor-mediated signaling pathways. The present study was designed to investigate possible effects of VCD dosing on the mitogen-activated protein kinases (MAPK)/AP-1 signaling pathways in rat ovarian small follicles. Female F344 rats were given a single dose of VCD (80 mg/kg i.p., 1 day--a time when ovotoxicity has not been initiated) or dosed daily for 10 or 15 days (80 mg/kg i.p.; 10 days--a time when the earliest signs of impending follicular destruction is seen, 15 days--a time when significant ovotoxicity is underway). Four hours following the final dose, ovaries and livers were collected. Ovarian small (25-100 microm) and large (100-250 microm) preantral follicles were isolated, and cytosolic or nuclear extracts were prepared from follicles and livers for analyses. Activities of MAPKs, including extracellular signal-regulated kinase, c-Jun N-terminal protein kinase (JNK), and p38 kinase, were determined in follicular and liver cytosolic extracts, and AP-1 DNA binding activity was determined in follicular and liver nuclear extracts. Compared with control, a single dose of VCD caused a decrease in JNK activity and an increase of AP-1 binding activity in isolated small ovarian follicles. After repeated daily dosing with VCD for 10 or 15 days, JNK and p38 kinase activities in small ovarian follicles were increased (p38 kinase: 1.64 +/- 0.14 for 10 days, 1.48 +/- 0.11 for 15 days, VCD/control, P < 0.01; JNK: 1.44 +/- 0.11 for 10 days, 1.37 +/- 0.06 for 15 days, VCD/control, P < 0.01) and AP-1 binding activity in small ovarian follicles was decreased (10 days, 0.29 +/- 0.04; 15 days, 0.51 +/- 0.04, VCD/control, P < 0.01). VCD did not affect any of these measurements in large preantral follicles or liver. Phosphorylation status of c-Jun protein as measured by Western blotting was increased (1.22 +/- 0.1, VCD/control, P < 0.05) after the 15-day daily dosing with VCD, but total c-Jun protein levels were unaffected. Using antibodies against c-Jun or phospho-c-Jun for supershift DNA binding assay, c-Jun and phospho-c-Jun were identified in the AP-1-DNA binding complex, and the binding activity was reduced in tissues with increased phospho-c-Jun protein levels. Taken together, these data provide evidence that accelerated atretic signals induced by VCD is associated with MAPK/AP-1 signaling pathways and phosphorylation of c-Jun plays a significant role in transmitting the apoptotic signals.
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48
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Borgeest C, Symonds D, Mayer LP, Hoyer PB, Flaws JA. Methoxychlor may cause ovarian follicular atresia and proliferation of the ovarian epithelium in the mouse. Toxicol Sci 2002; 68:473-8. [PMID: 12151644 DOI: 10.1093/toxsci/68.2.473] [Citation(s) in RCA: 102] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Methoxychlor (MXC) is currently used to protect agricultural products from insects. Previous studies show that MXC adversely affects the ovary, but the target cells were not revealed by those studies. Therefore, the purpose of this study was to test the hypothesis that MXC induces ovarian changes by adversely affecting the antral follicles and the ovarian surface epithelium in the mouse. To test this hypothesis, cycling female CD-1 mice (39 days) were dosed with MXC (8, 16, or 32 mg/kg/day), kepone (KPN, 8 mg/kg/day, positive control), or sesame oil (vehicle control) via intraperitoneal injection for 10 or 20 days. Estrous cyclicity was evaluated daily via vaginal lavage. After dosing, ovaries were collected for histological evaluation of follicle numbers, atresia, and surface epithelial height. The results indicate that at the 20-day time point, MXC (32 mg/kg) and KPN (8 mg/kg) increased the percentage of atretic antral follicles (n= 4-9,p<or= 0.001). MXC (32 mg/kg) also increased the height of the ovarian surface epithelium compared with controls (n= 7-10,p<or= 0.045), and KPN increased the percentage of days in estrus (n= 6-10,p<or= 0.0001). These data suggest that MXC and KPN increase antral follicle atresia, MXC increases surface epithelial height, and KPN affects vaginal cytology.
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Homady MH, Khleifat KM, Tarawneh KA, Al-Raheil IA. Reproductive toxicity and infertility effect of Ferula hornonis extracts in mice. Theriogenology 2002; 57:2247-56. [PMID: 12141574 DOI: 10.1016/s0093-691x(02)00900-7] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
The anti-fertility, anti-implantation, and ovarian histological alterations of the ethanolic extract of Ferula hormonis have been investigated in female mice. The intragastric application of 3 mg/kg per day of such extract for 6 weeks resulted in a significant reduction in female mice fertility. Furthermore, it caused a decrease in the number of mated females, the total number of implantations, and the number of viable fetuses. These changes were also associated with ovarian atrophy and a concomitant increase in the connective tissue. The ova showed degeneration while most of the ovarian follicles suffered follicular atresia.
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Thompson KE, Sipes IG, Greenstein BD, Hoyer PB. 17beta-estradiol affords protection against 4-vinylcyclohexene diepoxide-induced ovarian follicle loss in Fischer-344 rats. Endocrinology 2002; 143:1058-65. [PMID: 11861533 DOI: 10.1210/endo.143.3.8665] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Repeated dosing with 4-vinylcyclohexene diepoxide (VCD) accelerates atresia via apoptosis in primordial and primary follicles in ovaries of rats. The mechanisms that control atresia and VCD-induced toxicity are unknown; however, they could involve 17beta-E2. Atresia slows as animals enter puberty, whereas circulating E2 levels increase with the the onset of cyclicity. This inverse relationship suggests that E2 may be involved in the control of atresia. Therefore, this study was designed to determine whether treatment of immature rats with E2 could protect follicles normally destroyed by VCD-induced apoptosis. Female F344 rats were treated daily with E2, ER analogs, and/or VCD for 15 d. VCD alone caused a 50% reduction in primordial and primary follicles. Coinjection of E2 (0.1 mg/kg) and VCD (80 mg/kg) selectively protected primary follicles from VCD-induced follicle loss. This protection was mimicked by an ER agonist, genistein (0.1 mg/kg), and prevented by an ER antagonist, 4-hydroxytamoxifen (2 mg/kg). VCD treatment increased caspase-3-like activity, whereas concurrent treatment with genistein and VCD restored caspase-3-like activity to control levels. VCD treatment had no effect on circulating E2 levels, uterine weight, or E2 binding to the ER, nor could it directly displace E2 from ERbeta. These observations support the idea that ER-mediated protection against VCD-induced follicle toxicity is obtained by reducing apoptosis in small preantral follicles, although VCD does not appear to directly interact with ER.
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