Supplementation of granulosa cells conditioned medium with pyruvate and testosterone could improve early follicular development in cultured 1-day-old mouse ovaries.

In vitro activation of primordial follicles could serve as a safe method to preserve fertility in patients with cancer subjected to ovarian tissue cryopreservation during oncotherapy, however the culture medium for this purpose requires to be optimized. Granulosa cell conditioned medium (GCCM) has been recognized to enhance primordial follicle activation and the present study was conducted to understand whether addition of pyruvate, a combination of insulin, transferrin and selenium (ITS) or testosterone to GCCM could improve its efficiency in this regard. To this end, 1-day-old mouse ovaries were cultured in four different media including CON (control; containing GGCM only), PYR (containing GCCM plus pyruvate), ITS (containing GCCM plus ITS) or TES (containing GCCM plus testosterone) for 11 days. Furthermore, follicular dynamics and gene expression of factors involved in follicular development were assessed using histological examination and RT-PCR, respectively, on days 5 and 11 of culture. Pyruvate decreased follicular activation, but it enhanced the progression of follicles to the primary stage. Moreover, it upregulated Bmp15 and Cx37 (P < 0.05). In the ITS group, activation of follicles was not affected and total number of follicles was reduced by day 11 of culture. Additionally, ITS downregulated Pi3k, Gdf9, Bmp15 and Cx37 (P < 0.05). Although testosterone did not affect primordial follicle activation, it enhanced the development of follicles up to the preantral stage (P < 0.05). Furthermore, testosterone inhibited the expression of Pten but stimulated the expression of Gdf9 and Cx37 (P < 0.05). In conclusion, the present study revealed that inclusion of pyruvate and testosterone into GCCM could enhance the early development of follicles in cultured 1-day-old mouse ovaries.

High Doses of D-Chiro-Inositol Alone Induce a PCO-Like Syndrome and Other Alterations in Mouse Ovaries.

Administration of 1000-1500 mg/day D-Chiro-Inositol (DCIns) or a combination of Myo-Inositol (MyoIns) and DCIns in their plasma molar ratio (40:1) for three or more months are among recommended treatments for metabolic syndrome and/or Polycystic Ovary Syndrome (PCOS). We previously confirmed the efficacy of this formulation (8.2 mg/day MyoIns and 0.2 mg/day DCIns for 10 days) in a mouse PCOS model, but also observed negative effects on ovarian histology and function of formulations containing 0.4-1.6 mg/day DCIns. We therefore analyzed effects of higher doses of DCIns, 5, 10 and 20 mg/day, administered to young adult female mice for 21 days, on ovarian histology, serum testosterone levels and expression of the ovarian enzyme aromatase. Five mg/day DCIns (human correspondence: 1200 mg/day) altered ovarian histology, increased serum testosterone levels and reduced the amount of aromatase of negative controls, suggesting the induction of an androgenic PCOS model. In contrast, 10-20 mg/day DCIns (human correspondence: 2400-4800 mg/day) produced ovarian lesions resembling those typical of aged mice, and reduced serum testosterone levels without affecting aromatase amounts, suggesting a failure in steroidogenic gonadal activity. Notwithstanding physiological/biochemical differences between mice and humans, the observed pictures of toxicity for ovarian histology and function recommend caution when administering DCIns to PCOS patients at high doses and/or for periods spanning several ovulatory cycles.

Efficiently accumulating germ-like stem cells from mouse postnatal ovary by in situ tissue culture.

Although recent studies have revealed that germline stem cells (GSCs) exist in the mouse postnatal ovary, how to efficiently obtain GSCs for regenerating neo-oogenesis is still a technical challenge. Here, we report that using in situ tissue culture we can efficiently accumulate large amounts of proliferating germ-like cells from mouse postnatal ovaries. Usually, more than 10,000 germ-like cells can be derived from one ovary by this method, and over 20% of these cells can grow into germ-like cells with self-renewal, which thus can serve as a good cell pool to isolate GSCs by other cell assorting methods such as FACS. This method is simple and time-saving, which should be useful for in future studies on mouse GSCs.

Evaluation of vitrification protocol of mouse ovarian tissue by effect of DNA methyltransferase-1 and paternal imprinted growth factor receptor-binding protein 10 on signaling pathways.

Transplantation of cryopreserved ovarian tissue has been considered as a promising way of fertility preservation for women. however, this cryopreservation method is prone to post-resuscitation follicle proliferation and oocyte development stagnation, affecting late transplant survival. To evaluate current vitrification works, we investigated the critical pathway alternations in vitrified-warmed juvenile 10-day-old mouse ovary. We showed a significant decrease of protein kinase B (Akt) and Mitogen-activated protein kinase (Mapk) phosphorylation, during which serine/threonine kinases play central roles in coordinating follicle and oocyte development and stress response. Inhibition of Akt and Mapk activity were associated with one of the imprinted insulin pathway negative regulatory genes, Growth factor receptor-binding protein 10 (Grb10) which remarkably increased in vitrified-warmed juvenile mouse ovary than that of fresh group (p < 0.05). RNAi-induced Grb10 down-regulation reversed the decrease in Akt and Mapk phosphorylation. The increase of Grb10 expression was partially caused by the hyper-methylation of the promoter region, associated with the decrease of follicular DNA methyltransferase (Dnmt) 1 protein in different stages of vitrified-warmed group, compared to fresh group (p < 0.05). The mRNA and protein expression of Dnmt1 in ovary of vitrified-warmed juvenile mouse were remarkably lower than those in fresh group (p < 0.05). Dnmt1 overexpression dramatically reversed Grb10 up-regulation and Akt and Mapk phosphorylation reduction. Taken together, our findings suggest that Grb10 expression might be helpful in evaluation of effectiveness of vitrification, and considered as a potential target for further vitrification protocols improvement in the future.

Germ stem cells are active in postnatal mouse ovary under physiological conditions.

STUDY HYPOTHESIS: Are active ovarian germ stem cells present in postnatal mouse ovaries under physiological conditions? STUDY FINDING: Active ovarian germ stem cells exist and function in adult mouse ovaries under physiological conditions. WHAT IS KNOWN ALREADY: In vitro studies suggested the existence of germ stem cells in postnatal ovaries of mouse, pig and human. However, in vivo studies provided evidence against the existence of active germ stem cells in postnatal mouse ovaries. Thus, it remains controversial whether such germ stem cells really exist and function in vivo in postnatal mammalian ovaries. STUDY DESIGN, SAMPLES/MATERIALS, METHODS: Octamer-binding transcription factor 4 (Oct4)-MerCreMer transgenic mice were crossed with R26R-enhanced yellow fluorescent protein (EYFP) mice to establish a tamoxifen-inducible tracing system so that Oct4-expressing potential ovarian germ stem cells in young adult mice (5-6 weeks old) can be labeled with EYFP. The germ cell activities of DNA replication, mitotic division, entry into meiosis and progression to primordial follicle stage were investigated by means of immunofluorescent staining of ovarian tissues collected at different time points post-tamoxifen injection (1 day, 3 days, 2 months and 4 months). Meiosis entry and primordial follicle formation were also measured by EYFP-labeled single-cell RT-PCR. Germ cell proliferation and mitotic division were examined through 5-bromodeoxyuridine triphosphate incorporation assay. At each time point, ovaries from two to three animals were used for each set of experiment. MAIN RESULTS AND THE ROLE OF CHANCE: By labeling the Oct4-expressing small germ cells and tracing their fates for up to 4 months, we observed persistent meiosis entry and primordial follicle replenishment. Furthermore, we captured the transient processes of mitotic DNA replication as well as mitotic division of the marked germ cells at various time periods after tracing. These lines of evidence unambiguously support the presence of active germ stem cells in postnatal ovaries and their function in replenishing primordial follicle pool under physiological conditions. Moreover, we pointed out that Oct4(+) deleted in azoospermia-like (Dazl)(-) but not Oct4(+)Dazl(+) or Oct4(+) DEAD (Asp-Glu-Ala-Asp) Box Polypeptide 4 (Ddx4)(+) cells contain a population of germ stem cells in mouse ovary. LIMITATIONS, REASONS FOR CAUTION: This study was conducted in mice. Whether or not the results are applicable to human remain unclear. The future work should aim at identifying the specific ovarian germ stem cell marker and evaluating the significance of these stem cells to normal ovarian function. WIDER IMPLICATIONS OF THE FINDINGS: Clarifying the existence of active germ stem cells and their functional significance in postnatal mammalian ovaries could provide new insights in understanding the mechanism of ovarian aging and failure. LARGE SCALE DATA: Not applicable. STUDY FUNDING/COMPETING INTERESTS: This work was supported by the National Key Basic Research Program of China (grant number 2012CBA01300) and the National Natural Science Foundation of China to P.Z. (31571484). No competing interests are reported.

Effect of Cadmium on Cellular Ultrastructure in Mouse Ovary.

This study aimed at analyzing the cytotoxicity and pathological effects of cadmium on the ovary. Our studies revealed that cadmium was deposited in the mouse ovary after 8 d cadmium injection in vivo. Also, the increase in the rate of body weight was slowed, while the gonadosomatic index was reduced in the CdCl2 group, compared with the control group. Meanwhile, cadmium affected the maturation of follicles, the degradation of corpus luteum, the arrangement of follicles and corpus luteum, and increased the number of atresia follicles. Besides, under the electron microscope, chromatin margination, karopyknosis, swelling of mature cisternae of Golgi apparatus, mitochondrial cristae disappearance, and swelling of the rough endoplasmic reticulum can be observed in the CdCl2 group mice. Collectively, our findings elucidated the morphological mechanism that the exposure of cadmium changed the ultrastructure of cells in ovary tissues.

Reconstruction of ovarian follicular-like structure by recellularization of a cell-free human ovarian scaffold with mouse fetal ovarian cells.

The present study assessed the supportive roles of the decellularized human ovarian tissue in homing of mouse fetal ovarian cells into the scaffold as well as the formation of the follicular-like structure. The human ovarian cortical tissues were decellularized by three freeze-thaw cycles and then, treated with Triton X-100 for 15 h and 0.5% sodium dodecyl sulfate for 72 h. After isolation and preparation of mouse fetal ovarian cells (19 dpc) they were seeded into the decellularized scaffolds and cultured for 7 days, then using a light microscope, laser confocal scanning microscope, and scanning electron microscope these scaffolds were studied. Analysis of gene expression related to oocyte and follicular cells such as Ddx4, Nobox, Gdf9, and Connexin37 was assessed by real-time RT-PCR and the DDX4 and GDF9 proteins were detected by immunohistochemistry. The result showed that the human ovarian tissue was decellularized properly and the tissue elements and integrity were well preserved. After 7 days of in vitro culture, the fetal ovarian cells attached and penetrated into different sites and depths of the scaffold. The formed organoid within the scaffold showed large round, small polyhedral, and elongated spindle cells similar to the follicle structure. The molecular analysis and immunohistochemistry were confirmed an increase in the expression of genes and proteins related to oocyte and follicular cells in these reconstructed structures. In conclusion, the recellularization of human ovarian scaffolds by mouse fetal ovarian cells could support the follicular-like structure formation and it provides an in vitro model for follicle reconstitution and offers an alternative approach for clinical usage.

Dietary Supplementation of Flaxseed (Linum usitatissimum L.) Alters Ovarian Functions of Xylene-Exposed Mice.

The aim of the performed study was to examine the ability of xylene, flaxseed, and their combinations to affect morphological and endocrine indexes of murine ovaries. The 72 indexes of secondary and tertiary follicular cells, oocytes, corpora lutea, and ovarian stroma have been quantified: diameter, markers of proliferation PCNA and apoptosis caspase 3, receptors to FSH, oxytocin, estrogen (alpha and beta), and progesterone. In addition, concentrations of the ovarian hormones progesterone, estradiol, and IGF-I in the blood, as well as their production by isolated ovaries cultured with and without gonadotropins (FSH + LH mixture), were determined using histological, immunohistochemical, and immunoassay analyses. The character of xylene and flaxseed effects on ovarian functions in mice depended on the stage of ovarian folliculogenesis. It was shown that flaxseed could mitigate and prevent the major (63%) effects of xylene on the ovary. In addition, the ability of gonadotropins to affect ovarian hormone release and prevent its response to xylene has been shown. The effects of these additives could be mediated by changes in the release and reception of hormones. These observations suggest that flaxseed and possibly gonadotropins could be natural protectors of a female reproductive system against the adverse effects of xylene.

High steroid content in conditioned medium of granulosa cells may disrupt primordial follicles formation in in vitro cultured one-day-old murine ovaries.

This study was conducted to investigate the main and interactive effects of two methods of culture medium preparation [base medium vs granulosa cells conditioned medium (GCCM)] and two nutrient supplements [fetal bovine serum (FBS) vs knock-out serum replacement (KSR)] on formation and activation of primordial follicles and gene expression of corresponding factors during a seven-day culture period. One-day-old mouse ovaries were cultured with four different culture media including base medium containing FBS (BMF), base medium containing KSR (BMK), GCCM prepared with FBS (CMF) and GCCM prepared with KSR (CMK), and samples for histological and molecular assessments were collected on days 3 and 7 of culture. Further, steroid content of media was measured. Histological examination showed that KSR enhanced follicular formation and the number of follicular count was greater in BMK than CMF group (P < 0.05). Moreover, follicular activation was higher in CMK group than BMK and CMF groups (P < 0.05). Additionally, RT-PCR revealed that KSR upregulated Gdf9 gene expression (P < 0.05), while GCCM diminished expression of Gdf9, Bmp15, Notch2, Figla and Foxl2 (P < 0.05). GCCM decreased expression of Pten and increased expression of Pi3k (P < 0.05). Besides, hormonal assays indicated higher concentrations of estradiol and progesterone in GCCM compared with base media (P < 0.0001). In conclusion, the present study showed base medium containing KSR could serve as a proper medium for in vitro culture of neonatal mouse ovary since it could better support formation of primordial follicles. Yet BMK did not promote follicular activation as well as GCCM prepared with KSR did, and therefore, requires modifications.

Expression and localisation of ephrin-B1 and EphB4 in steroidogenic cells in the naturally cycling mouse ovary.

Ephrin receptors and ligands are membrane-bound molecules that modulate diverse cellular functions such as cell adhesion, epithelial-mesenchymal transition, motility, differentiation and proliferation. We recently reported the co-expression of ephrin-B1 and EphB4 in adult and foetal Leydig cells of the mouse testis, and thus speculated that their co-expression is a common property in gonadal steroidogenic cells. Therefore, in this study we examined the expression and localisation of ephrin-B1 and EphB4 in the naturally cycling mouse ovary, as their expression patterns in the ovary are virtually unknown. We found that ephrin-B1 and EphB4 were co-expressed in steroidogenic cells of all kinds, i.e. granulosa cells and CYP17A1-positive steroidogenic theca cells as well as in 3ß-HSD-positive luteal cells and the interstitial glands; their co-expression potentially serves as a good marker to identify sex steroid-producing cells even in extra-gonadal organs/tissues. We also found that ephrin-B1 and EphB4 expression in granulosa cells was faint and strong, respectively; ephrin-B1 expression in luteal cells was weak in developing and temporally mature corpora lutea (those of the current cycle) and likely strong in regressing corpora lutea (those of the previous cycle) and EphB4 expression in luteal cells was weak in corpora lutea of the current cycle and likely faint/negative in the corpora lutea of the previous cycle. These findings suggest that a luteinising hormone surge triggers the upregulation of ephrin-B1 and downregulation of EphB4, as this expression fluctuation occurs after the surge. Overall, ephrin-B1 and EphB4 expression patterns may represent benchmarks for steroidogenic cells in the ovary.

Increasing telomerase enhanced steroidogenic genes expression and steroid hormones production in rat and human granulosa cells and in mouse ovary.

Telomerase, a ribonucleoprotein responsible for telomere re-elongation, is important for male and female fertility. Several factors, including the steroid hormone estrogen, regulate the expression of Telomerase Reverse Transcriptase (TERT), which one of its non-canonical functions is gene expression regulation. The steroidogenesis process is regulated principally by transcription of genes encoding steroidogenic enzymes, but it is not clear if TERT non-canonical functions affect the expression of steroidogenic genes. Here we investigated this new notion by increasing TERT expression and activity in granulosa cells (GCs) derived from rat and from women that underwent in vitro fertilization (IVF) procedures and in vivo in mouse ovary. We show that gonadotropin enhanced the expression of TERT in rat GCs. Overexpression of human- TERT enhanced the expression of steroidogenesis genes in gonadotropin-stimulated rat GCs. Moreover, treatment with TERT increasing compounds (AGS) alone enhanced the expression of the steroidogenic genes in both rat and human GCs and in vivo in mouse ovary, while telomerase inhibitor reduced their expression. Treatment with AGS compounds, together with gonadotropin stimulation, additively increased steroidogenic gene expression. Enhancing TERT expression and activity increased the level of progesterone in mouse blood and in the medium of rat GCs and estrogen in women derived pre-ovulatory luteinized GCs. These data suggest that increasing TERT in GCs by pharmaceutical compounds enhanced steroidogenesis and the production of steroid hormones that are essential processes in human and animal reproduction. These data also suggest a novel possible strategy for the enhancement of the production of steroid hormones.

Immunohistochemistry of Paraffin Sections from Mouse Ovaries.

Immunohistochemistry (IHC) is an efficient technique to detect cellular localizations of the proteins in paraffin-embedded tissues. It allows specific proteins to be visualized by the interaction of antibodies with an enzyme-substrate-chromogen system. Here, we describe indirect immunohistochemistry method for paraffin-embedded mouse ovaries fixed with Bouin's Fixative.