Circulating miRNAs as Potential Alternative Cell Signaling Associated with Maternal Recognition of Pregnancy in the Mare

During early pregnancy, the conceptus and mare communicate to establish pregnancy. Cell-secreted vesicles (e.g., exosomes) have been reported in serum. Exosomes contain bioactive materials, such as miRNA, that can mediate cell responses. We hypothesized that a) exosomes are present in mare circulation and quantity varies with pregnancy status, b) exosomes contain miRNAs unique to pregnancy status, and c) miRNAs target pathways in endometrium based upon pregnancy status of the mare. First, serum samples were obtained from mares in a crossover design, with each mare providing samples from a pregnant and nonmated control cycle (n = 3/sample day) on Days 12, 14, 16, and 18 postovulation. Flow cytometry revealed the presence of serum microvesicles in mares in two different-sized populations (greater than or less than 100 nm), validated by transmission electron microscopy. Second, serum was collected on Days 9, 11, and 13 (n = 4/day), and endometrial biopsies were collected on Days 11 and 13 (n = 3/day) from pregnant and nonmated mares. Total RNA from serum exosomes was evaluated with quantitative RT-PCR using equine-specific miRNA sequences. A total of 12 miRNAs were found in different quantities on the specified days. Pathway analysis suggested that miRNAs targeted focal adhesion molecules (FAMs). Transcripts corresponding to FAMs were evaluated in endometrial biopsies. Protein levels and localization for PAK6 and RAF1 were further evaluated. Our data suggest that serum exosomes contain miRNA that differ based upon pregnancy status, and may affect mRNA expression related to focal adhesion pathway in the endometrium, with a potential role in maternal recognition of pregnancy.

Prenatal exposure to vinclozolin disrupts selective aspects of the gonadotrophin-releasing hormone neuronal system of the rabbit

Developmental exposure to the agricultural fungicide vinclozolin can impair reproductive function in male rabbits and was previously found to decrease the number of immunoreactive-gonadotrophin-releasing hormone (GnRH) neurones in the region of the organum vasculosum of the lamina terminalis and rostral preoptic area by postnatal week (PNW) 6. In the present study, in an aim to further examine the disruption of GnRH neurones by foetal vinclozolin exposure, pregnant rabbits were dosed orally with vinclozolin, flutamide or carrot paste vehicle for the last 2 weeks of gestation. Offspring were euthanised at birth (males and females), PNW 6 (females), PNW 26 (adult males) or PNW 30 (adult females) of age. At birth and in adults, brains were sectioned and processed for immunoreactive GnRH. The numbers of immunoreactive GnRH neuronal perikarya were significantly decreased in vinclozolin-treated rabbits at birth and in adult littermates. By contrast, there was an increase in GnRH immunoreactivity in the terminals in the region of the median eminence. Analysis of PNW 6 female brains by radioimmunoassay revealed a two-fold increase in GnRH peptide content in the mediobasal hypothalamus in vinclozolin-treated rabbits. This finding was complemented by immunofluorescence analyses, which revealed a 2.8-fold increase in GnRH immunoreactivity in the median eminence of vinclozolin compared to vehicle-treated females at PNW 30. However, there was no difference between treatment groups in the measures of reproduction that were evaluated: ejaculation latency, conception rates or litter size. These results indicate that sub-acute, prenatal vinclozolin treatment is sufficient to create perdurable alterations in the GnRH neuronal network that forms an important input into the reproductive axis. Finally, the effect of vinclozolin on the GnRH neuronal network was not comparable to that of flutamide, suggesting that vinclozolin was not acting through anti-androgenic mechanisms.

Testicular microlithiasis and neoplastic lesions in wild eland (Tragelaphus oryx): possible effects of exposure to environmental pollutants?

The purpose of the study was to compare wildlife in the proximity and away from the sources of known industrial pollution. Macroscopic, focal, gritty areas that appeared white were observed in the testes of all 24 South African eland (Tragelaphus oryx) culled in the Rietvlei Nature Reserve (RNR; n=17) between 2001 and 2003 and Suikerbosrand Nature Reserve (SNR; n=7) in 2004. Histopathological evaluation of testes showed multiple intratubular dystrophic calcifications, focal areas of sperm stasis and interstitial chronic cell infiltrates with fibrosis. Spermatogenesis was generally impaired; a few atypical germ cells were also encountered. Sertoli cell vacuolization and sloughing of the seminiferous epithelium were evident. Adenomatous changes of the rete testis, reflective of possible chronic estrogenic exposure, were found. In testes collected from three reference eland in 2007 from the Molopo Nature Reserve (MNR) in the Kalahari/Kgalagadi Desert, except for one focal area of sperm stasis and another with microcalcification, the seminiferous epithelium as well as collecting/rete tubules were normal. Analyses of fat tissue for environmental pollutants showed that 11 out of 17 RNR eland contained a detectable estrogenic chemical p-nonylphenol (mean+/-SD: 184.8+/-24.6 microg/kg fat); no organochlorine chemicals or polychlorinated biphenyls were detected. Of the 7 SNR eland, 5 had detectable octylphenol residues (50.2+/-30.9 microg/kg fat), 3 had detectable p-nonylphenol (137.8+/-77.9 microg/kg fat), 3 had o-p'-DDT (114.9+/-31.1 microg/kg fat), 3 had p-p'-DDT (127.3+/-49.9 microg/kg(79.5+/-30.4 microg/kg fat) and 5 contained o-p'-DDE (27.7+/-9.9 microg/kg fat). One eland from the MNR contained one 70.6 microg o-p'-DDT/kg fat and another p-p'-DDE 61.3 microg/kg fat. Therefore, in eland with testicular abnormalities, significant amounts of various estrogenic chemicals were bioaccumulated in fat samples. It therefore seems likely that the lesions found in RNR and SNR were associated with the relatively high body-burden of environmental pollutants (phenols), although the possibility of systemic infections cannot be ruled out. No testicular abnormalities were found in reference eland. These findings are the first indication of mammalian wildlife being affected by environmental pollution of endocrine disrupting chemicals in South Africa.

Characterization of a biphasic neoplasm in a Madagascar tree boa (Sanzinia madagascariensis)

We describe a disseminated biphasic neoplasm in a young Madagascar tree boa utilizing transmission electron and light microscopy. Discrete neoplastic cells identified within pulmonary capillaries and hepatic sinusoids represented the leukemic phase. Spindloid cells represented the sarcomatous phase, which comprised hepatic and fat body nodules. A zone of transition of the neoplastic cells, from discrete to spindloid, was noted along the periphery of the hepatic and fat body nodules. Ultrastructural examination elucidated similar nuclear features in the discrete and spindloid neoplastic cells and revealed collagen fibers within the spindloid neoplastic cells. These ultrastructural findings indicate that the discrete and spindloid cells represent a single neoplastic process with a subpopulation of cells exhibiting mesenchymal differentiation.

Cryptorchidism in common eutherian mammals

Cryptorchidism is failure of one or both testes to descend into the scrotum. Primary fault lies in the testis. We provide a unifying cross-species interpretation of testis descent and urge the use of precise terminology. After differentiation, a testis is relocated to the scrotum in three sequential phases: abdominal translocation, holding a testis near the internal inguinal ring as the abdominal cavity expands away, along with slight downward migration; transinguinal migration, moving a cauda epididymidis and testis through the abdominal wall; and inguinoscrotal migration, moving a s.c. cauda epididymidis and testis to the bottom of the scrotum. The gubernaculum enlarges under stimulation of insulin-like peptide 3, to anchor the testis in place during gradual abdominal translocation. Concurrently, testosterone masculinizes the genitofemoral nerve. Cylindrical downward growth of the peritoneal lining into the gubernaculum forms the vaginal process, cremaster muscle(s) develop within the gubernaculum, and the cranial suspensory ligament regresses (testosterone not obligatory for latter). Transinguinal migration of a testis is rapid, apparently mediated by intra-abdominal pressure. Testosterone is not obligatory for correct inguinoscrotal migration of testes. However, normally testosterone stimulates growth of the vaginal process, secretion of calcitonin gene-related peptide by the genitofemoral nerve to provide directional guidance to the gubernaculum, and then regression of the gubernaculum and constriction of the inguinal canal. Cryptorchidism is more common in companion animals, pigs, or humans (2–12%) than in cattle or sheep (≤1%). Laboratory animals rarely are cryptorchid. In respect to non-scrotal locations, abdominal testes predominate in cats, dogs, and horses. Inguinal testes predominate in rabbits, are common in horses, and occasionally are found in cats and dogs. S.c. testes are found in cattle, cats and dogs, but are most common in humans.

Chronic Exposure to Low Levels of Dibromoacetic Acid, a Water Disinfection By-product, Adversely Affects Reproductive Function in Male Rabbits

Four groups (minimum of 10/dose group) of male Dutch-belted rabbits were treated daily with dibromoacetic acid (DBA) via drinking water beginning in utero from gestation day 15 to adulthood; target dosages were 1, 5, and 50 mg DBA/kg body weight. Developmental, prepubertal as well as postpubertal reproductive sequelae were evaluated. One (out of 22), 2 (out of 32), and 1 (out of 21) male offspring in the 1, 5, and 50 mg DBA/kg groups were unilaterally cryptorchid. There were no significant differences in serum follicle-stimulating hormone, luteinizing hormone, and testosterone (basal concentrations or in response to exogenous gonadotropin-releasing hormone) in both prepubertal and adult rabbits. Chronic exposure to DBA adversely affected the mating abilities of some rabbits. The number of sperm produced was not affected, but spermiogenesis was disrupted, resulting in unique sperm acrosomal-nuclear malformations even at the 1-mg dose level. Concentrations of SP22, a specific sperm membrane fertility protein, in detergent extracts of ejaculated sperm were significantly lower (P < .05) in all DBA-treated groups compared with controls. The conception rates following artificial insemination of a constant number of sperm for 1, 5, and 50 mg DBA/kg groups were 55% (10/18), 65% (13/20), and 55% (9/16), respectively, vs 85% (17/20) for control group. Histologic lesions in testes characterized by spermatogenic arrest predominantly at the round spermatid stage, pyknosis of differentiating germ cells, and ultimate degeneration and desquamation leaving focal vacuolation in seminiferous epithelium were evident in DBA-treated groups. Thus, male rabbits exhibit reproductive toxicity with exposure to DBA during reproductive development at dosages as low as 1 mg/kg body weight.

Sequelae in male rabbits following developmental exposure to p,p'-DDT or a mixture of p,p'-DDT and vinclozolin: cryptorchidism, germ cell atypia, and sexual dysfunction

Rabbit does (7-9 per group) were treated daily per orum from gestation day 15 through post-natal week 4 to provide per kg body wt 25 micaromol (low) or 250 micromol (high) p,p'-DDT or a mixture of DDT and vinclozolin (12.5 and 125 micromol each). Developmental as well as post-pubertal reproductive sequelae of male progeny were studied. Testicular descent in some pups was impaired by DDT. Serum LH or testosterone was not affected. FSH was lower in mixture- but not in DDT-exposed rabbits. Lack of sexual interest, penile erection and ejaculation were observed in some mixture rabbits. Sperm counts were unaffected, but morphologically normal spermatozoa were fewer; nuclear and acrosomal morphogenesis was disrupted. Atypical germ cells resembling carcinoma in situ were found. Also considering data for vinclozolin [Veeramachaneni DNR, Palmer JS, Amann RP, Kane CM, Higuchi TT, Pau K-YF. Disruption of sexual function, FSH secretion, and spermiogenesis in rabbits following developmental exposure to vinclozolin, a fungicide. Reproduction 2006;131:805-16], we concluded that DDT causes cryptorchidism and germ cell atypia, vinclozolin permanently disrupts FSH secretion and sexual function, and the mixture causes the full spectrum of dysgenesis.

Disruption of sexual function, FSH secretion, and spermiogenesis in rabbits following developmental exposure to vinclozolin, a fungicide

We studied sequelae of prenatal plus infantile exposure of male rabbits to vinclozolin, because it is ingested by women and children. Female Dutch-Belted rabbits (7–10/group) were treated daily per orum from gestation day 15 through post-natal week 4 to provide 0, 7.2, or 72 mg vinclozolin/kg dam’s body weight/day. Vinclozolin had no effect on maintenance of pregnancy, growth of pups, age at testicular descent or weight of organs. Concentrations of serum LH or testosterone at 6, 12, or 24 weeks of age were unaffected. However, FSH was lower (P< 0.05) in both vinclozolin groups at all three ages. Following injection of GnRH at 12 or 24 weeks, the increase in FSH was less (P< 0.05) in both vinclozolin groups, as was testosterone at 12 weeks of age. After full sexual maturity, 2 of 7 low dose rabbits were uninterested in female or male teasers and never achieved erection or ejaculation. Overall, rates of ejaculation failure were: control 0% (0/48), low dose 29% (12/42), and high dose 5% (3/60). Daily sperm production per gram of testis and total number of sperm per ejaculate in both vinclozolin groups were similar (P> 0.1) to controls. However, semen from vinclozolin rabbits contained over two times more (P< 0.05) morphologically abnormal spermatozoa, mostly nuclear and acrosomal defects, than semen from controls. Seminiferous tubules with degenerative changes were more frequent (P< 0.05) in vinclozolin rabbits than in controls. Lesions included syncytia of spherical spermatids and desquamation of germ cells. Hence, developmental exposure to vinclozolin caused presumably permanent changes in copulatory ability, secretion of FSH, and spermiogenesis.

Sub-chronic exposure to dibromoacetic acid, a water disinfection by-product, does not affect gametogenic potential in mice

Water disinfection by-products, such as dibromoacetic acid (DBA), are formed when drinking water is treated with chlorination, bromination, or ozonation. Epidemiological studies have linked these byproducts to adverse effects in humans such as cancer, developmental defects, and reproductive toxicities. DBA has been shown to produce reproductive toxicity in rodents at relatively high doses. The present study used a mouse model to determine the developmental and reproductive effects of sub-chronic, low-dose exposure to DBA. Pregnant mice (10/dose group) were exposed with DBA in drinking water at 0, 5, or 50 mg/kg/day from gestation day 15 though nursing. Upon weaning at 3 weeks, one group of pups (pre-pubertal group: 7-10 pups of each gender/treatment group) were euthanized and weights of liver, paired kidneys, testes, and ovaries were measured. In the 50 mg dose group, weights of testes and liver in males and weights of liver and kidneys in females were significantly higher (p < 0.05). The remaining pups (15-17 of each gender/dose group) continued to be dosed similarly through adulthood. At 7 weeks of age (neo-pubertal group), animals were euthanized and tissues weighed and processed for evaluation of reproductive organs and gametogenic potential. Except for decreased (p < 0.05) testes and kidney weights in 50 mg dose group males, there were no differences in organ weights. No significant differences were noted between control and dosed animals in daily sperm production, testicular sperm counts, epididymal sperm reserves, morphology of seminiferous epithelium, or ovarian follicle counts.

Chronic exposure to dibromoacetic acid, a water disinfection byproduct, diminishes primordial follicle populations in the rabbit

To determine if dibromoacetic acid (DBA) affects ovarian folliculogenesis, four groups of female Dutch-belted rabbits were exposed daily to 0, 1, 5, or 50 mg DBA/kg body weight in drinking water beginning in utero from gestation day 15 throughout life. Functionality of the endocrine axis was assessed by measuring serum concentrations of gonadotropins following an im injection of 10 microg GnRH at 12 (prepubertal; n = 6/dose group) and 24 (postpubertal; n = 10/dose group) weeks of age. A day after GnRH challenge, number of ovulation sites and ovarian weights were determined at necropsy. Left ovaries were processed for histopathology, serially sectioned at 6 microm, and every twelfth section stained with hematoxylin and eosin was evaluated. All healthy follicles were categorized as primordial, primary, small preantral, large preantral, or small antral follicles. The area of each section evaluated was measured and the number of follicles in each category expressed per mm2 unit area. In prepubertal animals, DBA caused a reduction in number of primordial follicles (p < 0.05) and total healthy follicles (p < 0.05) at 50 mg/kg dose level. In adult animals, there were fewer primordial follicles in both the 5 (p < 0.01) and 50 (p = 0.1) mg/kg dose groups. No profound changes in gonadotropin profiles were observed. Although chronic exposure to DBA did not appear to have an effect on late follicular development or ovulation, DBA did reduce the population of primordial follicles. The long-term health consequences of diminished primordial follicles are unknown, but it is very likely that reproductive senescence would occur earlier.

Quantitative assessment of foetal exposure to trenbolone acetate, zeranol and melengestrol acetate, following maternal dosing in rabbits

1. Residues of commonly used growth-promoting agents found in animal meat can be hormonally active and they have been implicated as possible endocrine disruptors in man. Although these compounds could be potentially detrimental to the developing foetus, it is not clear whether and to what extent they pass through placental barrier. 2. This issue was addressed using the rabbit as an animal model. Pregnant rabbits were treated with trenbolone acetate, zeranol or melengestrol acetate beginning at gestation day 14. Levels of active substances in plasma were screened by means of specific ELISA systems. The residues of parent compounds and their metabolites were quantified in maternal and foetal tissues on gestation day 27 using validated, sensitive HPLC/ELISA methods. 3. All three compounds crossed the placental barrier and were detectable in foetal tissues. The extent of tissue concentration varied depending on the compound and tissue analysed. Gender differences were observed in some instances.