Structural and functional changes in rat uterus induced by neonatal androgenization.

Fetal or neonatal androgen exposure has a programming effect on ovarian function inducing a polycystic ovarian syndrome-like condition. Its effects on uterine structure and function are poorly studied. The aim of this work was to characterize the temporal course of changes in the rat uterine structure induced by neonatal exposure to aromatizable or not aromatizable androgens. Rats were daily treated with testosterone, dihydrotestosterone or vehicle during follicle assembly period (postnatal days 1 to 5). Uterine histoarchitecture, hormonal milieu, endometrial stromal collagen and capillary density were analyzed at prepubertal, pubertal and adult ages. Our data shows that neonatal androgen exposure induces early and long-lasting deleterious effects on uterine development, including altered adenogenesis and superficial epithelial alterations and suggest a role for altered serum estradiol levels in the maintenance and worsening of the situation. Our results suggest that alterations of the neonatal androgenic environment on the uterus could be responsible for alterations in the processes of implantation and maintenance of the embryo in women with polycystic ovary syndrome.

Pathophysiological and molecular considerations of viral and bacterial infections during maternal-fetal and -neonatal interactions of SARS-CoV-2, Zika, and Mycoplasma infectious diseases.

During pregnancy, a series of physiological changes are determined at the molecular, cellular and macroscopic level that make the mother and fetus more susceptible to certain viral and bacterial infections, especially the infections in this and the companion review. Particular situations increase susceptibility to infection in neonates. The enhanced susceptibility to certain infections increases the risk of developing particular diseases that can progress to become morbidly severe. For example, during the current pandemic caused by the SARS-CoV-2 virus, epidemiological studies have established that pregnant women with COVID-19 disease are more likely to be hospitalized. However, the risk for intensive care unit admission and mechanical ventilation is not increased compared with nonpregnant women. Although much remains unknown with this particular infection, the elevated risk of progression during pregnancy towards more severe manifestations of COVID-19 disease is not associated with an increased risk of death. In addition, the epidemiological data available in neonates suggest that their risk of acquiring COVID-19 is low compared with infants (<12 months of age). However, they might be at higher risk for progression to severe COVID-19 disease compared with older children. The data on clinical presentation and disease severity among neonates are limited and based on case reports and small case series. It is well documented the importance of the Zika virus infection as the main cause of several congenital anomalies and birth defects such as microcephaly, and also adverse pregnancy outcomes. Mycoplasma infections also increase adverse pregnancy outcomes. This review will focus on the molecular, pathophysiological and biophysical characteristics of the mother/placental-fetal/neonatal interactions and the possible mechanisms of these pathogens (SARS-CoV-2, ZIKV, and Mycoplasmas) for promoting disease at this level.

Neonatal androgenization in rats affects oocyte maturation.

Androgens are relevant in order to achieve a normal growth and maturation of the follicle and oocyte, since both excess and absence of androgens may affect the correct ovarian function. The current study analyzes the impact of neonatal androgenization in the first ovulation and oocyte maturation in response to exogenous gonadotrophin stimulation. Neonatal rats were daily treated with testosterone, dihydrotestosterone, or vehicle during follicle assembly period (days 1 to 5). At juvenile period, rats were stimulated sequentially with PMSG and hCG. Ovulation, ovarian histology, hormonal milieu, morphological characteristics of meiotic spindle, and in vitro fertilization rate in oocytes were analyzed. Our data shows that oocytes from androgenized rats displayed a major proportion of aberrant spindles and altered meiotic advance that control animals. These alterations were accompanied with an increase in both fertilization rate and aberrant embryos after 48 h of culture. Our findings showed a direct impact of neonatal androgens on oocyte development; their effects may be recognized at adulthood, supporting the idea of a programming effect exerted by neonatal androgens. These results could be relevant to explain the low fertility rate seen in polycystic ovary syndrome patients after in vitro fertilization procedures.

Distribution of sperm antigen 6 (SPAG6) and 16 (SPAG16) in mouse ciliated and non-ciliated tissues.

The cilia and flagella of eukaryotic cells serve many functions, exhibiting remarkable conservation of both structure and molecular composition in widely divergent eukaryotic organisms. SPAG6 and SPAG16 are the homologous in the mice to Chlamydomonas reinhardtii PF16 and PF20. Both proteins are associated with the axonemal central apparatus and are essential for ciliary and flagellar motility in mammals. Recent data derived from high-throughput studies revealed expression of these genes in tissues that do not contain motile cilia. However, the distribution of SPAG6 and SPAG16 in ciliated and non-ciliated tissues is not completely understood. In this work, we performed a quantitative analysis of the expression of Spag6 and Spag16 genes in parallel with the immune-localization of the proteins in several tissues of adult mice. Expression of mRNA was higher in the testis and tissues bearing motile cilia than in the other analyzed tissues. Both proteins were present in ciliated and non-ciliated tissues. In the testis, SPAG6 was detected in spermatogonia, spermatocytes, and in the sperm flagella whereas SPAG16 was found in spermatocytes and in the sperm flagella. In addition, both proteins were detected in the cytoplasm of cells from the brain, spinal cord, and ovary. A small isoform of SPAG16 was localized in the nucleus of germ cells and some neurons. In a parallel set of experiments, we overexpressed EGFP-SPAG6 in cultured cells and observed that the protein co-localized with a subset of acetylated cytoplasmic microtubules. A role of these proteins stabilizing the cytoplasmic microtubules of eukaryotic cells is discussed.

First ovarian response to gonadotrophin stimulation in rats exposed to neonatal androgen excess.

This study analyzes the effects of neonatal androgenization on follicular growth and first ovulation in response to gonadotrophins, using a model of exogenous stimulation or the use of subcutaneous ovary grafts in castrated animals to replace the hypothalamus-pituitary signal. Neonatal rats (days 1-5) were treated with testosterone, dihydrotestosterone or vehicle. At juvenile period, rats were stimulated with PMSG, hCG (alone or combined) or used as ovarian donors to be grafted on castrated adult female rats. Ovulation and ovarian histology were analyzed in both groups. Animals treated with vehicle or dihydrotestosterone stimulated with gonadotrophins (pharmacological or by using an ovary graft) ovulated, showing a normal histological morphology whereas rats exposed to testosterone and injected with the same doses of gonadotrophins did not it. In this group, ovulation was reached using a higher dose of hCG. Ovaries in the testosterone group were characterized by the presence of follicles with atretic appearance and a larger size than those observed in control or dihydrotestosterone groups. A similar appearance was observed in testosterone ovary grafts although luteinization and some corpora lutea were also identified. Our findings suggest that neonatal exposure to aromatizable androgens induces a more drastic signalling on the ovarian tissue that those driven by non-aromatizable androgens in response to gonadotrophins.

Ovarian follicular dynamics after aromatizable or non aromatizable neonatal androgenization.

The effects of neonatal testosterone or dihydrotestosterone exposure on ovarian follicular dynamics were analysed at prepubertal, pubertal or adult age in Wistar rats. Both androgens induced a transitory increase on follicular endowment that was partially corrected at puberty. At adult age testosterone prevented ovulation, without significant modifications on follicular dynamics. An increased number of cystic structures were observed from puberty to adult age. However, ovaries of rats treated with dihydrotestosterone showed follicles with evident morphological alterations in granulosa and thecal layers although several corpora lutea were observed. A significant increase in preantral follicles and few cystic structures were detected at advanced adulthood. The size of cyst increased with age. No immunohistochemical changes on growth factors or enzymes related to steroidogenesis in growing follicles were obvious in any group. In both androgenized groups, cysts shared immunohistochemical characteristics exhibited by preovulatory follicles but they were unable to ovulate spontaneously. Our results provide an insight into the role of different androgens in female reproductive system development, indicating a direct effect of dihydrotestosterone on ovarian tissues whereas a central effect would be the main feature of neonatal testosterone exposure. Heterogeneous clinical manifestations seen in pathologies such as polycystic ovary syndrome among women could be associated with subtle hormonal changes during follicular population development.

Neonatal testosterone exposure induces early development of follicular cysts followed by sympathetic ovarian hyperinnervation.

This study analysed the temporal association between ovarian cyst development induced by neonatal androgenisation and sympathetic innervation. Neonatal rats (postnatal Days 1 to 5) were treated with testosterone or dihydrotestosterone and the effects were evaluated at postnatal Days 20, 40, 90 or 180. Ovulation rate, number of cystic follicles and density of sympathetic fibres were analysed. The effects of surgical denervation or gonadotrophin stimulation were also assessed. Rats exposed to testosterone showed no oestrous cycle activity and did not ovulate, maintaining a polycystic ovarian morphology at all ages studied. Also, a significant increase in ovarian density of noradrenergic fibres was detected at postnatal Days 90 and 180. Sympathectomy was unable to re-establish ovarian activity; however, human chorionic gonadotrophin stimulation was enough to induce ovulation. The impact of dihydrotestosterone on ovarian function was less noticeable, showing the coexistence of corpora lutea and cystic structures without changes in sympathetic innervation. Our findings suggest that a remodelling of ovarian sympathetic innervation occurs as a response to modifications in the pattern of follicular growth induced by testosterone. A role of sympathetic innervation in the maintenance of the polycystic condition is suggested.

Involvement of the oestrogenic receptors in superior mesenteric ganglion on the ovarian steroidogenesis in rat.

Oestradiol (E(2)) is a key hormone in the regulation of reproductive processes. The aims of this work were a) to examine the distributions of oestrogen receptor α (ERα) and ERß in the neurons of the superior mesenteric ganglion (SMG) in the oestrus stage by immunohistochemistry, b) to demonstrate whether E(2) in the SMG modifies progesterone (P(4)), androstenedione (A(2)) and nitrite release in the ovarian compartment on oestrus day and c) to demonstrate whether E(2) in the ganglion modifies the activity and gene expression in the ovary of the steroidogenic enzymes 3ß-hydroxysteroid dehydrogenase (3ß-HSD) and 20α-hydroxysteroid dehydrogenase (20α-HSD). The ex vivo SMG-ovarian nervous plexus-ovary system was used. E(2), tamoxifen (Txf) and E(2) plus Txf were added in the ganglion to measure ovarian P(4) release, while E(2) alone was added to measure ovarian A(2) and nitrites release. Immunohistochemistry revealed cytoplasmic ERα immunoreactivity only in the neural somas in the SMG. E(2) increased ovarian P(4) and A(2) release at 15, 30 and 60 min but decreased nitrites. The activity and gene expression of 3ß-HSD increased, while the activity and gene expression of 20α-HSD did not show changes with respect to the control. Txf in the ganglion diminished P(4) release only at 60 min. E(2) plus Txf in the ganglion reverted the effect of E(2) alone and the inhibitory effect of Txf. The results of this study demonstrate that ERα activation in the SMG has an impact on ovarian steroidogenesis in rats, thus providing evidence for the critical role of peripheral system neurons in the control of ovarian functions under normal and pathological conditions.

Prepubertal estrogen exposure modifies neurotrophin receptor expression in celiac neurons and alters ovarian innervation.

Estradiol is a key hormone in the regulation of reproductive processes acting both on peripheral organs and sympathetic neurons associated to reproductive function. However, many of its regulatory effects on the development and function on the sympathetic neurons have not been completely clarified. Sympathetic neurons located in the celiac ganglion projects to visceral, vascular and glandular targets, and contribute to ovarian innervation, being the main source of sympathetic fibers. In the present study, we analyze the effects of elevated levels of exogenous estrogen during the prepubertal period in post-ganglionic sympathetic neurons. Estrogen exposure induced a significant increase in sympathetic celiac neuronal size and modified the expression of neurotrophin receptor p75. This change affected mainly small and medium size neurons. The effect of estrogens on innervation of celiac target organs was heterogeneous, inducing a significant increase in catecholaminergic innervation of the ovary, but not of the pyloric muscular layers. These findings further support the role of estrogen as a modulator of neuronal plasticity and suggest that estrogen could modify some features involved in the relation between sympathetic immature peripheral neurons and their target organs throughout a neurotrophin-dependent mechanism.

Echinococcus granulosus: the establishment of the metacestode is associated with control of complement-mediated early inflammation.

In this work we studied the evolution of early inflammation, complement activation and parasite survival/death along the establishment phase of Echinococcus granulosus metacestode. Using a chamber model of infection in mice, we examined cell infiltration and C3 deposition on individual parasites during their development from protoscoleces to cystic forms. We found that the intensity of the initial inflammation decreased around undamaged but not around damaged parasites: at 43dpi undamaged parasites were mostly associated with poor/mild inflammation while damaged parasites with a strong inflammation. In addition, whereas complement activation participated in the induction of early inflammation, the deposition of C3 on undamaged parasites progressively diminished. Interestingly, we observed some parasites in pre-cystic stage with no/poor C3 deposition at 3dpi. Overall, these results indicated that the establishment and survival of the hydatid cyst is associated with the control of complement and, consequently, of local inflammation at the initial phases of infection.

Involvement of nitric oxide on kainate-induced toxicity in oligodendrocyte precursors.

The vulnerability of oligodendrocytes to excitatory amino acids may account for the pathology of white matter occurring following hypoxia/ischemia or autoimmune attack. Here, we examined the vulnerability of immature oligodendrocytes (positively labeled by galactocerobroside-C and not expressing myelin basic protein) from neonatal rat spinal cord to kainate, an agonist of excitatory amino acid receptors that induces long-lasting inward currents in immature oligodendrocytes. In particular, we studied whether kainate toxicity was linked to the endogenous production of nitric oxide. We found cultured oligodendrocytes to be highly sensitive to 24-48 h exposure to 0.5-1 mM kainate. The toxin induced striking morphological changes in oligodendrocytes, characterized by the disruption of the process network around the cell body and the growth of one or two long, thick and non-branched processes. A longer exposure to kainate resulted in massive death of oligodendrocytes, which was prevented by 6,7, dinitroquinoxaline-2,3-dione (DNQX) (30 micro M), the antagonist of AMPA (alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropionic/kainate receptors. Remarkably, we found that those oligodendrocytes displaying bipolar morphology following kainate exposure, also expressed the inducible form of nitric oxide synthase (iNOS) and nitrotyrosine immunoreactivity, suggesting that peroxynitrite could be formed by the reaction of nitric oxide with superoxide. Moreover, kainate toxicity was significantly prevented by addition of the NOS inhibitor nitro-L-arginine methyl ester (L-NAME), further suggesting that nitric oxide-derived oxidants contribute to excitotoxic mechanisms in immature oligodendrocytes.

Intrinsic neurons in the mammalian ovary.

Mammalian ovarian function is under endocrine and neural control. Although the extrinsic innervation of the ovary has been implicated in the control of both ovarian development and mature function, it is now clear that, from rats to humans, the ovary is endowed with a network of intrinsic neurons displaying diverse chemical phenotypes. This article describes the presence of these intrinsic neurons in the ovary of different mammalian species, and discusses the possible functions that they may have in the regulation of ovarian physiology.