Suppression of uterine and placental ferroptosis by N-acetylcysteine in a rat model of polycystic ovary syndrome.

The mechanisms that link hyperandrogenism and insulin (INS) resistance (HAIR) to the increased miscarriage rate in women with polycystic ovary syndrome (PCOS) remain elusive. Previous studies demonstrate that increased uterine and placental ferroptosis is associated with oxidative stress-induced fetal loss in a pre-clinical PCOS-like rat model. Here, we investigated the efficacy and molecular mechanism of action of the antioxidant N-acetylcysteine (NAC) in reversing gravid uterine and placental ferroptosis in pregnant rats exposed to 5α-dihydrotestosterone (DHT) and INS. Molecular and histological analyses showed that NAC attenuated DHT and INS-induced uterine ferroptosis, including dose-dependent increases in anti-ferroptosis gene content. Changes in other molecular factors after NAC treatment were also observed in the placenta exposed to DHT and INS, such as increased glutathione peroxidase 4 protein level. Furthermore, increased apoptosis-inducing factor mitochondria-associated 2 mRNA expression was seen in the placenta but not in the uterus. Additionally, NAC was not sufficient to rescue DHT + INS-induced mitochondria-morphological abnormalities in the uterus, whereas the same treatment partially reversed such abnormalities in the placenta. Finally, we demonstrated that NAC selectively normalized uterine leukemia inhibitory factor, osteopontin/secreted phosphoprotein 1, progesterone receptor, homeobox A11 mRNA expression and placental estrogen-related receptor beta and trophoblast-specific protein alpha mRNA expression. Collectively, our data provide insight into how NAC exerts beneficial effects on differentially attenuating gravid uterine and placental ferroptosis in a PCOS-like rat model with fetal loss. These results indicate that exogenous administration of NAC represents a potential therapeutic strategy in the treatment of HAIR-induced uterine and placental dysfunction.

The Use of Atomic Force Microscopy in Comprehensive Assessment of the "Mother-Placenta-Fetus" System in Obstetric and Endocrine Pathology during Pregnancy.

Atomic force microscopy is not very popular in practical health care, therefore, its potential is not studied enough, for example, in obstetrics when studying the "mother-placenta-fetus" system. Our study summarizes the possibilities of using atomic force microscopy for detection of various circulatory disorders and vascular changes at the microscopic level in the uterus (endometrium and myometrium), placenta, and umbilical cord in the main variants of obstetric and endocrine pathology. For instance, in the case of endocrine pathologies, changes in the form of stasis, sludge, diapedesis, ischemia, destruction and separation of endotheliocytes in villous blood vessels were found in the mother. The oxygen content in erythrocytes also naturally decreased in pathologies; poikilo- and anisocytosis were observed.

Structure of the paraplacenta and the yolk sac placenta of the viviparous Australian sharpnose shark, Rhizoprionodon taylori.

INTRODUCTION: Viviparity (live-birth) has evolved from oviparity (egg-laying) multiple times in sharks. While most transitions from oviparity to viviparity have resulted in non-placental forms of viviparity, some sharks develop a yolk sac placenta during pregnancy. The Australian sharpnose shark (Rhizoprionodon taylori) is a placental species that suspends embryonic development in a diapause for most of pregnancy. METHODS: To identify structures involved in supporting rapid embryonic growth in late pregnancy, we examined uterine and placental morphology by light and electron microscopy. RESULTS: Paraplacental uterine regions have morphological specialisations consistent with secretion and fluid transport between uterine tissues and the lumen. Uterine secretions in the lumen may be absorbed by the outgrowths on the embryonic umbilical cord ('appendiculae'), which are densely covered by microvilli. The placenta consists of uterine villi that interdigitate with the yolk sac and enhance the surface area available for fetomaternal exchange. The yolk sac does not invade the uterine epithelium, and the egg capsule remains intact at the placental interface, separating maternal and fetal tissues. Some placental uterine epithelial cells are secretory, and endocytic vesicles in the opposing yolk sac ectodermal cells suggest that nutrient transport is by histotrophic uterine secretion followed by fetal absorption. Respiratory gases, water and possibly small nutrients likely diffuse across the placenta, where maternal and fetal blood vessels are ~2 µm apart. DISCUSSION: Placental structure in R. taylori is similar to most other sharks, but there are differences in cellular structures between species that may indicate species-specific placental transport mechanisms.

Preservation of Mesenchymal Stem Cell-Derived Extracellular Vesicles after Abdominal Delivery in the Experiment.

Light luminescent microscopy was used to study the distribution of extracellular microvesicles with PKH26-stained membranes secreted by placenta-derived mesenchymal stromal cells in the uterine tissues at different terms after injections to intact rats and after abdominal delivery (a model of cesarian section). Microvesicles migrated through the uterine tissues and were detected for at least 8 days after injection. In some cases, microvesicles were more numerous in the uterus after cesarian section modeling, which can be related to blockade of microcirculation and lymph flow due to inflammation accompanying surgical intervention. The content of microvesicles in the uterine tissues gradually declined due to macrophage phagocytosis and, probably, due to their migration into the vascular bed. Despite their size, properly stained extracellular microvesicles can be detected by light microscopy in tissues after injections.

Preliminary Assessment of the Mucosal Toxicity of Tea Tree (Melaleuca alternifolia) and Rosemary (Rosmarinus officinalis) Essential Oils on Novel Porcine Uterus Models.

Antimicrobial resistance, an ever-growing global crisis, is strongly linked to the swine production industry. In previous studies, Melaleuca alternifolia and Rosmarinus officinalis essential oils have been evaluated for toxicity on porcine spermatozoa and for antimicrobial capabilities in artificial insemination doses, with the future perspective of their use as antibiotic alternatives. The aim of the present research was to develop and validate in vitro and ex vivo models of porcine uterine mucosa for the evaluation of mucosal toxicity of essential oils. The in vitro model assessed the toxicity of a wider range of concentrations of both essential oils (from 0.2 to 500 mg/mL) on sections of uterine tissue, while the ex vivo model was achieved by filling the uterine horns. The damage induced by the oils was assessed by Evans Blue (EB) permeability assay and histologically. The expression of ZO-1, a protein involved in the composition of tight junctions, was assessed through immunohistochemical and immunofluorescence analysis. The results showed that low concentrations (0.2-0.4 mg/mL) of both essential oils, already identified as non-spermicidal but still antimicrobial, did not alter the structure and permeability of the swine uterine mucosa. Overall, these findings strengthen the hypothesis of a safe use of essential oils in inseminating doses of boar to replace antibiotics.

Intraluminal vesicles of binucleate trophoblast cell granules are a possible source of placental exosomes in ruminants.

INTRODUCTION: Exosomes are membrane-bound small extracellular vesicles, which play important roles in intercellular communication, including the feto-maternal communication. Placenta-derived exosomes have been identified in maternal blood of a variety of species, including cattle and sheep. METHODS: Transmission electron microscopy is used to characterize intraluminal vesicles in binucleate trophoblast cell secretory granules and extracellular vesicles in placentome samples from eight ruminant species of the bovidae and cervidae clades. RESULTS: In all species the secretory granules of binucleate cells contain intraluminal vesicles of 40-70 nm diameter. After fusion of the binucleate trophoblast cells with cells of the uterine epithelium these vesicles are exocytosed together with the granule's secretory proteins. The vesicles are located at the basement membrane of the uterine epithelium and in the connective tissue underneath. DISCUSSION: We suggest that these vesicles function as exosomes. Their function might be either locally in the maternal endometrial stroma or they could have systemic functions after entering the maternal blood. Earlier electron microscopical studies in other ruminants, including species of the most basic ruminant clade (tragulidae), indicate that the intraluminal vesicles are a general feature of ruminant binucleate trophoblast cell granules. Our findings suggest that ruminant BNC are a source of exosomes, which are released into the maternal organism and are thus a newly described type of feto-maternal communication in ruminants.

Ultrastructure of the uterus, embryonic envelopes and the coracidium of the enigmatic tapeworm Tetracampos ciliotheca (Cestoda: Bothriocephalidea) from African sharptooth catfish (Clarias gariepinus).

Transmission electron microscopy (TEM) was used to study the ultrastructure of the uterus and egg morphology in the enigmatic bothriocephalidean tapeworm Tetracampos ciliotheca. The uterine wall, underlain by well-developed muscle bundles, consists of a syncytial epithelium which is characterized by the abundance of free ribosomes, mitochondria and cisternae of granular endoplasmic reticulum (GER). On the apical surface of the uterine epithelium, there is an abundant network of cytoplasmic microlamellae projecting into the uterine lumen. The lumen is filled with freely lying eggs which are located close to the uterine wall but do not contact with the microlamellae of the uterine epithelium. The developed eggs possess an oncosphere surrounded by four envelopes: (1) a thin egg shell; (2) an outer envelope; (3) a syncytial, ciliated inner envelope; and (4) the oncospheral membrane. The mature hexacanth is armed with three pairs of oncospheral hooks, as well as somatic and hook muscles and five types of cells (1) binucleated subtegumental cell, (2) somatic cells, (3) penetration gland cells, (4) nerve cells and (5) germinative cells. Considering the relative scarcity of descriptive and comparative studies on the ultrastructure of the uterus and egg morphology in the order Bothriocephalidea, we concluded that Tet. ciliotheca displays a unique type of egg development. Based on these results, we discuss plausible ideas relating to the function of these structures for consideration in future studies.

Ultrastructural markers of tissue endometrial receptivity in patients with recurrent implantation failure.

The scanning electron microscopy of the endometrial surface epithelium during the 'implantation window' was performed in 119 patients with uterine factor of infertility or recurrent miscarriage due to endometrial hypoplasia. Ultramorphological picture of the surface endometrial epithelium was characterized by aplasia and hypoplasia of pinopodes (67.39%), dense cell - cell contacts (69.53%), heteromorphy of secretory cells (15.22%) in combination with atypia of microenvironment cells (50%) in patients with infertility. The asynchronous development of pinopodes (46.67%) and the absence of intercellular contacts separation during the 'implantation window' (84.44%) was observed in patients with recurrent miscarriage. The revealed disturbance determines the mechanisms of the blastocyst adhesion violation and trophoblast invasion in the different stages of implantation in patients with uterine factor of infertility and recurrent miscarriage.

Ultrastructural study of uterine epithelium in the domestic cat during prenatal development.

The study describes the sequence of ultrastructural changes of the endometrial lining epithelium, first in the primordial paramesonephric ducts, then in the differentiating uterine horns, and finally in the mature uterus. The research material comprised female fetuses of the domestic cat, aged 33-63 days post conceptionem (p.c.), and mature females. The ultrastructural observations of the developing epithelium were conducted using transmission electron microscopy (TEM) and light microscopy (LM). The results revealed two basic stages in the development of the uterine mucosal epithelium in the domestic cat: the development of the epithelium of the uterine segment of the paramesonephric ducts, lasting from day 33 to day 42 p.c., and the differentiation of this epithelium into the mucosal epithelium of the uterus, starting after day 42 p.c. and lasting until the end of the prenatal period. The epithelium of the uterine segments of the paramesonephric ducts is pseudostratified with a flat surface, all cells being characterized by the same distribution of desmosomes, ribosomes, rough endoplasmic reticulum (rER) cisternae, and mitochondria in the cytoplasm. The differentiating epithelium of the uterus after day 51 p.c. is pseudostratified with a varied height. In the epithelial cells there are increases of (i) the number and complexity of the junctional complexes, (ii) the number of invaginations of the lateral cell membranes, and (iii) the number of elongated mitochondria, and also there appear distended cisternae of the rER, lipid droplets and clusters of glycogen, which suggest increasing metabolism and secretory activity of the cells during the transformation of the epithelium.

The orientation of a decellularized uterine scaffold determines the tissue topology and architecture of the regenerated uterus in rats†.

A decellularized uterine scaffold (DUS) prepared from rats permits recellularization and regeneration of uterine tissues when placed onto a partially excised uterus and supports pregnancy in a fashion comparable to the intact uterus. The underlying extracellular matrix (ECM) together with an acellular, perfusable vascular architecture preserved in DUS is thought to be responsible for appropriate regeneration of the uterus. To investigate this concept, we examined the effect of the orientation of the DUS-preserving ECM and the vascular architecture on uterine regeneration through placement of a DUS onto a partially defective uterine area in the reversed orientation such that the luminal face of the DUS was outside and the serosal face was inside. We characterized the tissue structure and function of the regenerated uterus, comparing the outcome to that when the DUS was placed in the correct orientation. Histological analysis revealed that aberrant structures including ectopic location of glands and an abnormal lining of smooth muscle layers were observed significantly more frequently in the reversed group than in the correct group (70% vs. 30%, P < 0.05). Despite the changes in tissue topology, the uteri regenerated with an incorrectly oriented DUS could achieve pregnancy in a way similar to uteri regenerated with a correctly oriented DUS. These results suggest that DUS-driven ECM orientation determines the regenerated uterus structure. Using DUS in the correct orientation is preferable when clinically applied. The disoriented DUS may deteriorate the tissue topology leading to structural disease of the uterus even though the fertility potential is not immediately affected.

Detailed endometrial immune assessment of both normal and adverse reproductive outcome populations.

PURPOSE: Using a comprehensive flow cytometric panel, do endometrial immune profiles in adverse reproductive outcomes such as repeat implantation failure (RIF) and repeat pregnancy loss (RPL) differ from each other and male-factor controls? METHODS: Six-hundred and twelve patients had an endometrial biopsy to assess the immunophenotype. History on presentation was used to subdivide the population into recurrent implantation failure (RIF) [n = 178], recurrent pregnancy loss (RPL) [n = 155], primary infertility [n = 130] and secondary infertility [n = 114]. A control group was utilised for comparative purposes [n = 35] and lymphocyte subpopulations were described. RESULTS: Distinct lymphocyte percentage differences were noted across the populations. Relative to controls and RPL, patients with a history of RIF had significantly raised uterine NKs (53.2 vs 45.2 & 42.9%, p < 0.0001). All sub-fertile populations had increased percentage peripheral type NKs (p = 0.001), and exhibited increased CD69+ activation (p = 0.005), higher levels of B cells (p < 0.001), elevated CD4:CD8 ratio (p < 0.0001), lower T-regs (p = 0.034) and a higher proportion of Th1+ CD4s (p = 0.001). Patient aetiology confers some distinct findings, RPL; pNK, Bcells and CD4 elevated; RIF; uNK and CD56 raised while CD-8 and NK-T lowered. CONCLUSIONS: Flow cytometric endometrial evaluation has the ability to provide a rapid and objective analysis of lymphocyte subpopulations. The findings show significant variations in cellular proportions of immune cells across the patient categories relative to control tissue. The cell types involved suggest that a potential differential pro-inflammatory bias may exist in patients with a history of adverse reproductive outcomes. Immunological assessment in appropriate populations may provide insight into the underlying aetiology of some cases of reproductive failure.

The first ultrastructural observations of the egg-forming complex of Calicotyle affinis, an endoparasitic monocotylid monogenean which lacks a uterus.

This ultrastructural study of the female reproductive system of Calicotyle affinis, a monogenean without a uterus, demonstrates, for the first time in a monogenean, the presence of accessory cells located in the peripheral region of the ovary and a single large cell whose surface is penetrated by deep invaginations which restrict the passage of oocytes through the lumen of the distal extremity of the ovary. The cytoarchitecture of the epithelial lining of the two vaginae is a syncytium formed by an anucleate epithelial lining with sunken epithelial perykaria. The wall of the seminal receptacle is an enlarged prolongation of the vaginal epithelial lining. Fertilization occurs in the fertilization chamber and fertilized oocytes retain cortical granules within their cytoplasm, a characteristic known to occur in free-living flatworms. Our study also highlights concentrations of two distinct groups of Mehlis' gland cell ducts on either side of the proximal end of the ootype distinguished by ultrastructural characteristics of their secretory granules. The epithelial wall of the ootype is formed by a single layer of regular, columnar, glandular epithelial cells; these cells are closely adjacent, conjoined towards their apical region by septate junctions and produce rounded, electron-dense granules which are discharged into the ootype lumen via a merocrine or holocrine mechanism. Released granules concentrate around the eggshell and form an additional fibrous coat. The morphological diversity observed in the female reproductive system of the Monogenea is commented on it relation to clarifying patterns in monogenean evolution and for understanding the phylogeny of the Neodermata.

Uterine Receptivity in Merriam's Kangaroo Rat (Dipodomys merriami).

The uterine surface undergoes significant remodeling, termed the "plasma membrane transformation," during pregnancy to allow for implantation of the blastocyst and formation of the placenta in viviparous amniote vertebrates. Unlike other species within the superorder Euarchontoglires, which have a hemochorial (highly invasive) placenta, kangaroo rats (Dipodomys spp.) exhibit a less invasive endotheliochorial placenta. We characterized the changes that occur to membrane molecules and the cellular ultrastructure of the uterine epithelium during early pregnancy in Merriam's kangaroo rat, Dipodomys merriami using electron microscopy and immunofluorescence microscopy. Epithelial cadherin (E-cadherin) is an adhesion protein that forms the adherens junction and is localized to the lateral plasma membrane of uterine epithelium during the nonreproductive state but localizes nonspecifically in the uterine epithelium immediately preceding implantation. Desmosomes are a type of cadherin that form junctional complexes along the lateral plasma membrane of epithelium. Dsg-2, a marker for desmosomes, is localized along the lateral plasma membrane in non-pregnant animals but redistributes to the apical region of the lateral plasma membrane during early pregnancy. The shift in desmosome and cadherin distribution before implantation suggests that there is a reduction in lateral adhesion between epithelial cells to allow for invasion by the blastocyst. Surprisingly, although Kangaroo rats form a less invasive placenta, these same changes occur during pregnancy in species with highly invasive placentation, such as the laboratory rat and human. These commonalities suggest that it is not through the retention of lateral adhesion that the blastocyst is prevented from further invasion in this rodent species. Anat Rec, 301:1928-1935, 2018. © 2018 Wiley Periodicals, Inc.

Endometrial pinopode biomarkers: Molecules and microRNAs.

Ultrastructural changes on the apical surface of the luminal epithelium of the uterus are known as pinopodes. Their morphology in species and in special species is associated with different results about size, duration, and percentage of surface area covered by pinopodes. The content of pinopodes is different in rodents and humans. In mice and rats pinopodes have many vacuoles and no organelle that extends to the actin stalk above the microvilli. Human pinopodes do not have a large vacuole and contain the golgi complex, a rough endoplasmic reticulum, secretory vesicles, and mitochondria that extend from the entire cell surface. It has been suggested that pinopodes are good markers of endometrial receptivity and implantation window. There are several molecular markers related to the presence of pinopodes, including integrins, leukemia inhibiting factor (LIF), l-selectin, HOXA10, glutaredoxin, glycodelinA, heparin-binding epidermal growth factor, mucins, and microRNAs (miRNAs). Multiple lines of evidence have indicated that miRNAs could affect the expression of LIF and pinopodes in the endometrium and these molecules play key roles in implantation window processes. Here, we have summarized the morphology and function of pinopodes. Moreover, we have highlighted several molecules in relation to pinopodes that could be used as biomarkers.

Changes in mucins and matrix metalloproteases in the endometrium of early pregnant alpacas (Vicugna pacos).

South American Camelids (SAC) have unique reproductive features, one of which is that 98% of the pregnancies develop in the left uterine horn. Furthermore, early pregnancy is an uncharacterized process in these species, especially in regard to the ultrastructural, biochemical and genetic changes that the uterine epithelial surface undergoes to allow embryo implantation. The present study describes the uterine horn luminal surface and the characteristics of the mucinous glycocalyx in non-pregnant and early pregnant (15 days) female alpacas. In addition, the relative abundance of Mucin 1 and 16 genes (MUC1 and MUC16) was determined, as well as the relative mRNA abundance of matrix metalloproteinases (MMPs) that could be involved in MUC shedding during early pregnancy. Noticeable changes were detected in the uterine luminal epithelium and glycocalyx of pregnant alpacas in comparison to non-pregnant ones, as well as presence of MUCs and MMPs in the endometrial environment. The decrease in glycocalyx staining and in the relative abundance of MUC 1 and MUC 16 transcripts in pregnant females would allow embryo attachment to the luminal epithelium and its subsequent implantation, as has been described in other mammals. These results suggest a crucial role of MUC1 and MUC16 and a possible role of MMPs in successful embryo implantation and survival in alpacas.

Investigation of the uterine structural changes in the experimental model with polycystic ovary syndrome and effects of vitamin D treatment: An ultrastructural and immunohistochemical study.

In this study, we aimed to investigate the structural changes seen in the endometrium in experimental PCOS rat model and the effects of vitamin D treatment on these changes at immunohistochemical and electron microscopic levels. 24 prepubertal female rats were divided into three groups. Two groups were injected with dehydroepiandrosterone and one of them was treated with 1,25(OH)2 D3 at the same time. The control group was injected with sesame oil. At the end of the 28th day, the blood samples were collected. Uterus tissues were prepared for light and electron microscopic examinations. Epithelial, stromal and endometrial thickness measurements were investigated. Immunohistochemical staining was applied against caspase-3 and Ki-67. Serum AMH and estradiol levels were higher in PCOS group compared to the control group. Serum progesterone levels were similar in all groups. Endometrial, epithelial and stromal thickness measurements were increased in PCOS group compared to the control group, and decreased in the vitamin D treatment group compared to the PCOS group. Light and electron microscopic results of PCOS group showed an increase in apoptosis and proliferation. In the PCOS group, immunohistochemical staining of caspase-3 and Ki-67 were found to be higher than in the control group, but stainings were decreased with vitamin D treatment compared to PCOS group. Structural changes observed in endometrium may be related to implantation problems seen in patients with PCOS. Our studies suggest that vitamin D therapy may be beneficial in these patients.

Ultrastructure of digenean trematode eggs (Platyhelminthes: Neoophora): A review emphasizing new comparative data on four European Microphalloidea.

Despite their tremendous diversity and their medical and veterinary importance, details of egg ultrastructure among the digenean trematodes has been studied rather little. The available literature is spread over several decades and several species, but has not been adequately reviewed to reveal patterns of similarity and divergence. We present this review to synthesize and analyse what is known from the available literature reporting studies using both transmission electron microscopy (TEM) and scanning electron microscopy (SEM). To support our general review of existing literature, we also have synthesized our own previously published descriptions, and present herein our new previously unpublished data. From these new electron micrographs, we provide a comparative analysis of the intrauterine eggs of four digenean species, representing four genera and three families of the superfamily Microphalloidea, collected from four different host wildlife species in four European countries: 1) Mediogonimus jourdanei (Prosthogonimidae) from Myodes glareolus (Mammalia: Rodentia), collected in France; 2) Maritrema feliui (Microphallidae) from Crocidura russula (Mammalia: Soricimorpha), collected in Spain; 3) Brandesia turgida (Pleurogenidae) from Pelophylax ridibundus (Amphibia: Anura: Ranidae), collected in Russia; and 4) Prosotocus confusus (Pleurogenidae) from Rana lessonae (Amphibia: Anura: Ranidae), collected in Belarus. All were studied by preparing whole worms by various techniques for TEM, so that eggs could be studied in situ within the uterus of the parent worm. Based on the literature review and the new data presented here, we describe basic similarities in patterns of embryogenesis and egg formation among all trematode species, but substantial variations in timing of larvigenesis, sculpturing of egg shell surfaces, and some other features, especially including accessory cocoon coverings outside the egg shells of B. turgida and P. confusus. In the future, many more studies are needed to explore egg ultrastructure in other digenean taxa, to explore potential phylogenetic patterns in egg development and structure, and to correlate structure with function in the life cycle.

Intrauterine exosomes are required for bovine conceptus implantation.

Exosomes, extracellular vesicles, are present in uterine flushing fluids (UFs), which are involved in conceptus-endometrial interactions during peri-implantation periods. Despite several studies on intrauterine exosomes conducted, the roles conceptus and endometrial exosomes play during peri-implantation periods have not been well characterized. To investigate the effect of bovine intrauterine exosomes on conceptus implantation, exosomes isolated from bovine UFs during peri-implantation periods were subjected to global protein analysis. The analysis detected 596 exosomal proteins, including ruminants' pregnancy recognition factor IFNT, and 172 differentially expressed proteins with more than 1.5-fold changes in UFs on days 17, 20 and 22 pregnancy (day of conceptus implantation is initiated on days 19-19.5). Treatment of primary bovine endometrial epithelial cells with exosomes from day 17 UFs up-regulated the expression of apoptosis-related genes, and treatment with exosomes from day 20 and 22 UFs up-regulated the expression of adhesion molecule. Based on these findings, intrauterine exosomes should be considered as an essential constituent for successful implantation.

Prominin-2 Prevents the Formation of Caveolae in Normal and Ovarian Hyperstimulated Pregnancy.

During early pregnancy, uterine epithelial cells (UECs) become less adherent to the underlying basal lamina and are subsequently removed so the blastocyst can invade the underlying stroma. This process involves the removal of focal adhesions from the basal plasma membrane of UECs. These focal adhesions are thought to be internalized by caveolae, which significantly increase in abundance at the time of blastocyst implantation. A recent in vitro study indicated that prominin-2 prevents the formation of caveolae by sequestering membrane cholesterol. The present study examines whether prominin-2 affects the formation of caveolae and loss of focal adhesions in UECs during normal and ovarian hyperstimulation (OH) pregnancy in the rat. At the time of fertilization during normal pregnancy, prominin-2 is distributed throughout the basolateral plasma membrane. However, at the time of implantation and coincident with an increase in caveolae, prominin-2 is lost from the basal plasma membrane. In contrast, prominin-2 remains in the basolateral plasma membrane throughout OH pregnancy. Transmission electron microscopy showed that this membrane contained few caveolae throughout OH pregnancy. Our results indicate that prominin-2 prevents the formation of caveolae. We suggest the retention of prominin-2 in the basal plasma membrane during OH pregnancy prevents the formation of caveolae and is responsible for the retention of focal adhesions in this membrane, thereby contributing to the reduced implantation rate observed after such treatments.

Gold and Female Reproductive Organs: an Ultrastructural Study.

Gold, a heavy yellow-colored metal, is usually found in nature as a metallic element or as salts. This noble metal historically had a reputation as an anti-inflammatory medicine for rheumatoid arthritis, a nervine, and a remedy for nervous disorders, as well as a potential anticancer agent. It has also been used as component in dental restorations and in implant materials. The present study was undertaken to point out histological and ultrastructural effects of gold, administered by intraperitoneal route, in pregnant female reproductive organs (ovary and uterus), in order to clarify its side effects on the reproductive function. Using the transmission electron microscopy (TEM), the ultrastructural investigations of both ultrathin ovarian and uterine sections of treated pregnant rats revealed the existence of numerous heterogeneous clusters with very electron-dense inclusions characterized by various aspects in the lysosomes of granulosa, theca interna cells, and theca externa cells. Degeneration of these tissues, like cell vacuolization, marked expansion of the endoplasmic reticulum, mitochondrial alterations, and necrotic foci, were also highlighted. Moreover, huge phagolysosomes and high numbers of eosinophils as signs of inflammation were also identified especially in endometrial and myometrial cells of gold-treated rats. The ultrastructural investigations of reproductive organ sections of control pregnant rats showed a normal ultrastructural aspect and no loaded lysosomes. These results speculated the toxicity of gold at the used dose. The observed signs of toxicity allowed concluding that the important role of lysosome in the sequestration of this element under an insoluble form in all categories of cells in the studied tissues does not seem to be efficient.