Zinc oxide nanoparticles functionalized with curcumin supplementation during in vitro embryo culture impaired in a concentration-dependent-manner blastocyst production in cattle.

This work investigated the effect of zinc oxide nanoparticles functionalized with curcumin (ZnO(np) + CUR) supplementation during the in vitro embryo culture (IVC) on the bovine in vitro embryo production, and the cellular antioxidant response. The cumulus-oocyte complexes (COCs) were matured, fertilized and then the presumptive zygotes were cultured in the medium in the absence (0 µM-control) or presence of different concentrations of ZnO(np) + CUR (3, 6 or 12 µM). After IVC, the embryos were destined either to assay intracellular ROS levels and mitochondrial membrane potential. The results demonstrated that only the addition of 12 µM ZnO(np) + CUR during IVC decreased intracellular ROS production and the rate of blastocyst production when compared to the control (p < .05). In conclusion, ZnO(np) + CUR addition during the IVC impaired in concentration-dependent-manner bovine in vitro embryo production.

How origin of ovaries influences the vitrification outcome of bovine ovarian tissue: effects of side of ovaries and corpus luteum.

Although cryopreservation of ovarian tissue has advanced greatly, it remains a challenge, and protocols should be optimized to handle the heterogeneous nature of ovarian samples. In an effort to address this factor, the present study evaluated the effects of corpus luteum (CL) and side of ovaries (right versus left) on cellular morphology and viability of vitrified bovine ovarian fragments in a closed system. The ovaries were categorized according to whether they had a CL and which side they were on, and then divided into six groups: 1) CL+ (with CL) group; 2) CL- (without CL) group; 3) right ovaries group; 4) left ovaries group; 5) fresh control group (ovaries without vitrification or culture that were not selected for CL or ovarian side) and 6) In vitro culture medium control group (non-vitrified ovaries that were not selected for the presence or absence of CL or side of the ovaries). The current study shows that the CL- and right groups had the greatest percentage of follicles with normal morphology compared to other vitrified-warmed groups. Furthermore, the levels of necrosis and tissue damage of the right cultured group were the lowest compared to other groups. It was shown that bovine ovarian tissues derived from right ovaries and ovaries without a corpus luteum can be functionally and morphologically preserved after vitrification. For the first time, the present study suggests that bovine ovarian tissue vitrification can be improved by considering the origin of the ovaries.

Ultra-diluted Folliculinum 6 cH impairs ovine oocyte viability and maturation after in vitro culture.

This study investigated the effect of Folliculinum 6 cH on the oocyte meiosis resumption and viability rates, progesterone production and mitochondrial activity after in vitro maturation of cumulus-oocyte complexes (COCs) in sheep. Sheep ovaries were collected at a local slaughterhouse and COCs were recovered by slicing technique. The selected COCs were maturated in TCM199 (Control treatment), or control medium supplemented with 0.05% ethanol (v/v) (the vehicle of the homeopathic preparation - Ethanol treatment) or with Folliculinum 6 cH. After 24 h of in vitro maturation (IVM), oocytes were mechanically denuded and incubated with Hoechst 33342 and MitoTracker (0.5 µM) Orange CMTMRos for analysis of viability and chromatin configuration, and mitochondrial activity, respectively. The results showed that Folliculinum 6 cH addition increased oocyte degeneration and reduced meiotic resumption compared to the control (P < 0.05). Interestingly, the percentages meiotic resumption and oocyte maturation were lower in the Folliculinum 6 cH treatment compared to its vehicle (Ethanol treatment) (P < 0.05). On the other hand, when the treatments were compared, higher mitochondrial activity was observed in the Ethanol treatment (P < 0.05). In conclusion, contrary to its vehicle, the addition of Folliculinum 6 cH to the IVM medium promoted oocyte degeneration and affected negatively the mitochondrial distribution, impairing meiosis resumption.

Impacts of different synthetic polymers on vitrification of ovarian tissue.

Type and concentration of cryoprotective agents (CPAs) are important factors which influence the likelihood of a successful ovarian tissue vitrification outcome. In an attempt to address this factor, the present study was conducted to evaluate the impacts of different synthetic polymers (Supercool X-1000, Supercool Z-1000 and PVP K-12) on vitrification of bovine ovarian tissue. From each ovarian pair, fragments were recovered and immediately fixed for analysis (fresh control) or submitted to vitrification, either or not followed by in vitro culture for one or five days. Vitrification was performed using the ovarian tissue cryosystem (OTC) system. The ovarian tissues were intended for histological and viability analysis [Reactive oxygen species (ROS) production and degenerate cells assay (Ethidium homodimer-1)], as well as immunolocalization of AQP3 and AQP9 were measured. The results showed that during almost all the periods after warming, in treatment groups which contain polymer (X-1000, Z-1000 and PVP), the percentage of morphologically normal follicles was the highest in the X-1000 samples. Furthermore, post-thawed X-1000 group revealed stronger labeling for AQP9 in primordial and transitional follicles, when compared with others. However, morphology after cryopreservation did not correlate with follicle viability and function where the levels of degeneration and tissue damage of PVP K-12 group were lower in comparison with X-1000 group and only in PVP K-12 group, ROS level was similar to that of the fresh control group. We believe that in addition to permeating CPAs, the addition of one (Supercool X-1000) or maybe a combination (Supercool X-1000 and PVP K-12) of non-permeating polymers could be useful to improve the outcome for vitrified bovine ovarian tissue.

Advances in in vitro folliculogenesis in domestic ruminants.

The in vitro follicle culture (IVFC) represents an outstanding tool to enhance our understanding of the control of folliculogenesis and to allow the future use of a large number of immature oocytes enclosed in preantral follicles (PFs) in assisted reproductive techniques in humans as well as in others mammalian species including the ruminants. So far, the best results of IVFC were reported from mice with the production of live offspring from primordial follicles cultured in vitro. Live birth has been obtained after the in vitro culture of bovine early antral follicles. However, in other ruminant species, these results have been limited to the production of a variable number of mature oocytes and low percentages of embryos after in vitro culture of goat, buffalo and sheep isolated secondary preantral follicles. The present review presents and discusses the main findings, limitations, and prospects of in vitro folliculogenesis in ruminants focusing on bovine, caprine, and ovine species.

Response of preantral follicles exposed to quinoxaline: A new compound with anticancer potential.

The culture of preantral follicles as an in vitro model to evaluate the toxicity of new anticancer drug has being established. Therefore, the aim of this study was to evaluate the effect of quinoxaline derivative the 2 2- (XYZC 6H 3 -CH=N-NH)-quinoxaline, 1 (QX) on caprine preantral follicles. We evaluate the follicular morphology and activation, proliferation and apoptosis of granulosa cells and finally the protein (ABCB1) and genes expression (cyclin/Cdks), respectively involved in multidrug resistance and cell cycle progression. Ovarian fragments containing primordial and developing follicles were exposed (in vitro culture) to different concentrations of QX (QX1.5, QX3.0 or QX6.0 µM/mL) during 6 days. To evaluate the effect of QX, the ovarian tissue was exposed to Paclitaxel 0.1 µg/mL (PTX - negative control) or in culture media without QX (MEM). At the end of exposure time, we realized that the QX (all concentrations) increased (P < .05) the normal morphology of preantral follicles compared to control (not treated ovarian tissue) or MEM. However, QX6.0 showed a enhanced (P < .05) on follicular activation (burnout) and apoptosis than QX1.5 and QX3.0. Expression of ABCB1 was similar between QX1.5 and QX6.0 and both were lower than control, MEM and PTX. Interestingly, the apoptosis rate in QX3.0 was similar to control and MEM and lower then QX1.5; QX6.0 and PTX. We conclude that quinoxaline may be a promising chemotherapeutic agent, however, other concentrations within a defined range (2-5.5 µM) could be widely investigated.

In vitro study of Withanolide D toxicity on goat preantral follicles and its effects on the cell cycle.

The Withanolide D is a chemotherapeutic potential against the human tumor cell. However, there is no report on the effect of this compound on ovarian function, especially on preantral folliculogenesis. The aim of this study was to evaluate the toxicity of a new candidate to anticancer drug, Withanolide D (WD) on morphologic integrity, development (activation and granulosa cell proliferation) and gene expression of ABCB1 protein of caprine preantral follicles. Ovarian fragments were cultured in vitro for 2 or 6 days in α-MEM or α-MEM added with paclitaxel (PTX -0.1 µg/mL; negative control) and different concentrations of WD (WD1.5, WD3.0 or WD6.0). The higher dose of WD showed a toxic effect similar to PTX and higher (P < 0.05) than other treatments after 2 and 6 days. In addition, WD6.0 reduced the cell proliferating compared to PTX or mild dose. The expression of ABCB1 remained unchanged in the presence of the chemotherapeutic agents (PTX and WD) throughout the culture period. In conclusion, WD exerted a toxic effect observed by decreasing follicular survival and cell proliferation, on the preantral caprine follicles similar to PTX, whose negative effect on folliculogenesis is already widely known.

ATP-binding cassette (ABC) transporters in caprine preantral follicles: gene and protein expression.

The multidrug resistance proteins ABCB1, ABCC2 and ABCG2 are an energy-dependent efflux pump that functions in systemic detoxification processes. Physiologically expressed in a variety of tissues, most abundantly in the liver and intestinal epithelia, placenta, blood-brain barrier and various stem cells, until now, these pumps were not identified in goat ovarian tissue. Therefore, the aim of this study is to analyze ABCB1, ABCC2, and ABCG2 mRNA and protein expression in goat preantral follicles. Fragments (3 × 3 × 1 mm) from five pairs of ovary (n = 10) obtained from five goat were collected and immediately submitted to qPCR, Western blot, and immunofluorescence assay for mRNA detection and identification and localization of the ABC transporters, respectively. mRNA for ABCB1, ABCC2, and ABCG2 and the presence of their proteins were observed on ovarian tissue samples. Positive marks were observed for the three transport proteins in all follicular categories studied. However, the marks were primarily localized in the oocyte of primordial, transition and primary follicle categories. In conclusion, goat ovarian tissue expresses mRNA for the ABCB1, ABCC2 and ABCG2 transporters and the expression of these proteins in the preantral follicles is a follicle-dependent stage.

Control of growth and development of preantral follicle: insights from in vitro culture.

The regulation of folliculogenesis involves a complex interaction among endocrine, paracrine and autocrine factors. The mechanisms involved in the initiation of the growth of the primordial follicle, i.e., follicular activation and the further growth of primary follicles up to the pre-ovulatory stage, are not well understood at this time. The present review focuses on the regulation and development of early stage (primordial, primary, and secondary) folliculogenesis highlighting the mechanisms of primordial follicle activation, growth of primary and secondary follicles and finally transition from secondary to tertiary follicles. We also discuss the importance of in vitro follicle culture for the understanding of folliculogenesis during the preantral phase. Studies suggest that follicular development from primordial to early antral stages is primarily controlled by intra-ovarian ligands but it can also be influenced by many extra-ovarian factors. The control of early folliculogenesis is, therefore, extremely complex because several ligands act through distinct signaling pathways that form sophisticated information networks responding to multiple, often opposing, stimuli. The balance among different stimuli determines follicular survival or death as well as quiescence or activation (growth). The distribution of the ligands and their corresponding receptors varies among follicular compartments and species, and significant changes in gene expression pattern among follicular categories have been reported. Knowing that follicular requirements during early folliculogenesis can be stage-specific and species-specific, in vitro culture studies offer an alternative to evaluate single and combined factors during a specific period of follicular development. Herewith we summarize the main findings obtained in vitro together with the mechanisms regulating folliculogenesis.

Ovine secondary follicles vitrified out the ovarian tissue grow and develop in vitro better than those vitrified into the ovarian fragments.

Cryopreservation of preantral follicles is a promising technique to preserve female fertility. The aim of this study was to evaluate the effect of vitrification on the development of secondary follicles included in ovarian tissue or isolated after microdissection. An important end point included is the capacity of grown oocytes to resume meiosis. Sheep ovarian cortexes were cut into fragments and split into three different groups: (1) fresh (control): secondary follicles isolated without any previous vitrification; (2) follicle-vitrification (follicle-vit): secondary follicles vitrified in isolated form; and (3) tissue-vitrification (tissue-vit): secondary follicles vitrified within fragments of ovarian tissue (in situ former) and subsequently subjected to isolation. From the three groups, isolated secondary follicles were submitted to IVC for 18 days. After IVC, cumulus-oocyte complexes (COCs) were harvested from follicles. As an additional control group, in vivo grown, in vivo-grown COCs were collected from antral ovarian follicles. All, recovered COCs were matured and the chromatin configuration was evaluated. Data were analyzed by ANOVA, and the means were compared by Student-Newman-Keuls test, and by chi-square. Differences were considered to be significant when P < 0.05. Isolated preantral follicles from all treatments had normal morphology, antrum formation, and low follicle degeneration after IVC. The growth rate between control and follicle-vit did not differ (P > 0.05), and was higher (P < 0.05) than for tissue-vit. The percentage of follicles that decreased diameter during IVC was significantly higher in tissue-vit than the in follicle-vit. Recovery rate of oocytes from normal follicles was higher in follicle-vit than in tissue-vit. Furthermore, oocyte viability was lower in tissue-vit than other treatments, and follicle-vit did not differ from control and in vivo grown. The percentage of oocytes meiosis resuming was not different between treatments except for in vivo grown. After vitrification, only follicle-vit showed metaphase I oocyte. We conclude that secondary follicles vitrified after isolation displayed a better follicular growth rate, oocyte viability, percentage of oocytes reaching the metaphase I stage, and fewer follicles with decreased diameter after IVC.

Connexin 37 and 43 gene and protein expression and developmental competence of isolated ovine secondary follicles cultured in vitro after vitrification of ovarian tissue.

Cryoinjuries caused by vitrification of tissues and organs lead to the loss of membrane proteins that mediate intercellular communications, such as connexins 37 (Cx37) and 43 (Cx43). Thus, the present study aimed to evaluate ovine Cx37 and Cx43 gene and protein expressions and developmental competence by in vitro-cultured secondary follicles retrieved from vitrified ovarian tissue. Ovarian fragments for the same ovary pair were distributed into six treatments: (1) fresh ovarian tissue (FOT); (2) vitrified ovarian tissue (VOT); (3) isolated follicles from fresh ovarian tissue (FIF); (4) isolated follicles from vitrified ovarian tissue; (5) isolated follicles from fresh ovarian tissue followed by in vitro culture (CFIF); (6) isolated follicles from vitrified ovarian tissue followed by in vitro culture (CVIF). In all treatments, Cx37 and Cx43 gene and protein expression patterns were evaluated by reverse transcription polymerase chain reaction and immunocytochemistry. In addition, secondary follicles were analyzed according to follicular integrity and growth, apoptosis, and cell proliferation. In vitro-cultured secondary follicles (CFIF and CVIF) were evaluated based on morphology (extruded follicles), antrum formation, and viability. The percentage of intact follicles was higher, whereas antrum formation, oocyte extrusion rate, and follicle viability were lower in CVIF than in CFIF treatment (P < 0.05). Terminal deoxynucleotidyl transferase-mediated biotinylated deoxyuridine triphosphates nick end-labeling assay demonstrated that apoptosis was absent in FIF, whereas follicles from all other treatments showed positive labeling. Cell proliferation index was higher in isolated follicles from vitrified ovarian tissue and CVIF treatments than in follicles from FIF. Expression of Cx43 messenger RNA was lower in CVIF treatment when compared with follicles from all other treatments (P < 0.05). Follicle Cx37 messenger RNA levels did not show alterations in any treatment (P > 0.05). Cx37 and Cx43 immunolabeling was localized mainly on granulosa cells and oocytes, respectively. In conclusion, isolation of ovine secondary follicles could be done successfully after vitrification of ovarian tissue, and the basement membrane integrity remained intact after in vitro culture. Although the gene and protein expression of Cx37 did not change after vitrification of ovarian tissue, Cx43 turned out to be altered in secondary follicles after vitrification and in vitro culture.

Vitrified sheep isolated secondary follicles are able to grow and form antrum after a short period of in vitro culture.

The risk of reintroducing malignant cells after ovarian graft into patients following post-cancer treatment is an obstacle for clinical applications (autotransplantation). In this context, in vitro follicle culture would be an alternative to transplantation in order to minimize such risks. Therefore, the aim of this study was to compare the development of secondary follicles after vitrification in isolated form (without stroma) with vitrification in in situ form (within fragments of ovarian tissue). Follicles were first isolated from ovarian fragments from mixed-breed ewes and then vitrified; these comprised the Follicle-Vitrification group (Follicle-Vit), or fragments of ovarian tissue were first vitrified, followed by isolation of the follicles, resulting in the Tissue-Vitrification group (Tissue-Vit). Control and vitrified groups were submitted to in vitro culture (6 days) and follicular morphology, viability, antrum formation, follicle and oocyte diameter, growth rate, ultrastructural characteristics and cell proliferation were evaluated. The percentages of morphologically normal follicles and antrum formation were similar among groups. Follicular viability and oocyte diameter were similar between Follicle-Vit and Tissue-Vit. The follicular diameter and growth rate of Follicle-Vit were similar to the Control, while those of Tissue-Vit were significantly lower compared to the Control. Both vitrified groups had an augmented rate of granulosa cellular proliferation compared to Control. Secondary follicles can be successfully vitrified before or after isolation from the ovarian tissue without impairing their ability to survive and grow during in vitro culture.

Expression and localization of Aquaporin 3 (AQP3) in folliculogenesis of ewes.

The mRNA expression and localization of Aquaporin 3 (AQP3) were investigated in the ovarian follicles of ewes at different stages of development (primordial, primary, secondary, small, and large antral). The gene expression was quantified by qPCR, while the protein identification and localization were determined by Western blot and immunohistochemistry, respectively. Analysis revealed that AQP3 mRNA was detected only in the antral follicles, whereas the protein expression was detected in the oocyte and granulosa cells in all stages of follicular development. The latter observation suggests that the presence of AQP3 in follicles of all categories, especially in the antral follicles, provides novel insights on the mechanisms that regulate the flow of water between cells during the formation of antral follicles in sheep.