Effect of epidermal growth factor and insulin-like growth factor I on porcine preantral follicular growth, antrum formation, and stimulation of granulosal cell proliferation and suppression of apoptosis in vitro

Influence of ovarian stromal cells on human ovarian follicle growth in a 3D environment

STUDY QUESTION

Do ovarian stromal cells (OSCs) influence the viability and growth of human preantral follicles in vitro?

SUMMARY ANSWER

A feeder layer of OSCs promotes the growth and transition of low developmental stage follicles to the primary/secondary stage while maintaining a high proportion of viable follicles.

WHAT IS KNOWN ALREADY

In the ovary, follicles rely on the support of ovarian cells, which secrete essential factors for their survival and development. This phenomenon has also been demonstrated in vitro through the 3D culture of isolated mouse primary and secondary follicles on a feeder layer of OSCs. This co-culture notably enhances follicle survival and growth.

STUDY DESIGN SIZE DURATION

Pre-antral follicles were isolated from human frozen-thawed ovarian tissue biopsies and then encapsulated in 1% alginate scaffolds. These embedded preantral follicles were either placed directly on the OSCs feeder layer or at the bottom of a culture dish for a 7-day in vitro culture (control). The study compared follicle viability, growth, and hormone production between the different groups.

PARTICIPANTS/MATERIALS SETTING METHODS

Primordial/intermediate and primary follicles were isolated from frozen-thawed ovarian tissue of cancer patients (n = 6). OSCs were then isolated from ovarian tissue of post-menopausal women and cultured as a feeder layer. Follicle diameter was measured on Days 0 and 7 using an inverted microscope to assess their development based on the increase in diameter. Viability was evaluated by staining a subset of follicles (n = 87) with calcein AM and ethidium homodimer-I, followed by classification into healthy/minimally damaged and damaged/dead follicles using confocal fluorescence microscopy. Additionally, estradiol levels were measured using ELISA.

MAIN RESULTS AND THE ROLE OF CHANCE

A total of 382 human preantral follicles (370 primordial/intermediate and 12 primary) with a mean diameter of 40.8 ± 9.9 µm (mean ± SD) were isolated, embedded in 1% alginate hydrogel, and placed either on a monolayer of OSCs or directly on the plastic. By Day 7, the preantral follicles showed a significant size increase under both culture conditions (P < 0.0001 for D0 vs D7). The mean diameter of follicles (quiescent and growing) cultured on the feeder layer was 80.6 ± 11.0 μm compared to 67.3 ± 7.2 μm without it (P = 0.07). During the 7-day in vitro culture, the viability of the follicles significantly decreased only in the group without an OSCs monolayer compared to the D0 viability (P < 0.05). Additionally, more follicles transitioned to a higher developmental stage in the presence of OSCs (D0 primordial/intermediate: 184, primary: 7 vs D7 primordial/intermediate: 51, primary/secondary: 93) compared to those cultured without OSCs (D0 primordial/intermediate: 186, primary: 5 vs D7 primordial/intermediate: 84, primary/secondary: 65; P < 0.001). Specifically, 66 and 44 follicles reached the secondary stage (75< x <200 μm) in the presence and absence of OSCs, respectively. Moreover, the estradiol level was significantly higher (P = 0.006) in the alginate beads containing primordial and growing follicles cultured on the OSCs (54.1 ± 14.2 pg/ml) compared to those cultured without OSCs (29.9 ± 4.0 pg/ml).

LARGE SCALE DATA

N/A.

LIMITATIONS REASONS FOR CAUTION

This study was conducted using a short-term culture, and none of the primordial/intermediate/primary follicles reached the antral stage. Further in vitro studies are required to investigate follicular developmental capacity, physiology, and steroidogenesis in alginate scaffolds with human OSCs.

WIDER IMPLICATIONS OF THE FINDINGS

Activating and growing human primordial/intermediate follicles to a secondary stage in in vitro short-term culture has posed a longstanding challenge. However, co-culturing with human OSCs has shown the potential to overcome this limitation.

STUDY FUNDING/COMPETING INTERESTS

This study was supported by grants from the Fonds National de la Recherche Scientifique de Belgique (FNRS-PDR Convention grant number T.0004.20 awarded to C.A.A., PhD scholarship awarded to H.V.), Fondation Louvain (awarded to C.A.A.; PhD scholarship awarded to S.M., as part of a legacy from Mr Frans Heyes, and PhD scholarship awarded to A.D. as part of a legacy from Mrs Ilse Schirmer), Foundation Against Cancer (grant 2018-042 awarded to A.C.), and the European Community Structural Funds and Lithuanian Research Council (Agreement registration No. D-19-0874). The authors have no conflicts of interest to declare.

Genome-wide selective signatures mining the candidate genes for egg laying in goose

BACKGROUND

Improving the egg production of goose is a crucial goal of breeding, because genetics is the key factor affecting egg production. Thus, we sequenced the genomes of 55 Chinese indigenous geese from six breeds, which were divided into the high egg-laying group (ZE, HY, and SC) and low egg-laying group (ZD, LH, and ST). Based on the results of the inter-population selection signal analysis, we mined the selected genome regions in the high egg-laying germplasm population to identify the key candidate genes affecting the egg-laying traits.

RESULTS

According to the whole-genome sequencing data, the average sequencing depth reached 11.75X. The genetic relationships among those six goose breeds coincided with the breed's geographical location. The six selective signal detection results revealed that the most selected regions were located on Chr2 and Chr12. In total, 12,051 single-nucleotide polymorphism (SNP) sites were selected in all six methods. Using the enrichment results of candidate genes, we detected some pathways involved in cell differentiation, proliferation, and female gonadal development that may cause differences in egg production. Examples of these pathways were the PI3K-Akt signaling pathway (IGF2, COMP, and FGFR4), animal organ morphogenesis (IGF2 and CDX4), and female gonad development (TGFB2).

CONCLUSION

On analyzing the genetic background of six local goose breeds by using re-sequencing data, we found that the kinship was consistent with their geographic location. 107 egg-laying trait-associated candidate genes were mined through six selection signal analysis. Our study provides a critical reference for analyzing the molecular mechanism underlying differences in reproductive traits and molecular breeding of geese.

Menstrual blood-derived endometrial stem cell, a unique and promising alternative in the stem cell-based therapy for chemotherapy-induced premature ovarian insufficiency

Chemotherapy can cause ovarian dysfunction and infertility since the ovary is extremely sensitive to chemotherapeutic drugs. Apart from the indispensable role of the ovary in the overall hormonal milieu, ovarian dysfunction also affects many other organ systems and functions including sexuality, bones, the cardiovascular system, and neurocognitive function. Although conventional hormone replacement therapy can partly relieve the adverse symptoms of premature ovarian insufficiency (POI), the treatment cannot fundamentally prevent deterioration of POI. Therefore, effective treatments to improve chemotherapy-induced POI are urgently needed, especially for patients desiring fertility preservation. Recently, mesenchymal stem cell (MSC)-based therapies have resulted in promising improvements in chemotherapy-induced ovary dysfunction by enhancing the anti-apoptotic capacity of ovarian cells, preventing ovarian follicular atresia, promoting angiogenesis and improving injured ovarian structure and the pregnancy rate. These improvements are mainly attributed to MSC-derived biological factors, functional RNAs, and even mitochondria, which are directly secreted or indirectly translocated with extracellular vesicles (microvesicles and exosomes) to repair ovarian dysfunction. Additionally, as a novel source of MSCs, menstrual blood-derived endometrial stem cells (MenSCs) have exhibited promising therapeutic effects in various diseases due to their comprehensive advantages, such as periodic and non-invasive sample collection, abundant sources, regular donation and autologous transplantation. Therefore, this review summarizes the efficacy of MSCs transplantation in improving chemotherapy-induced POI and analyzes the underlying mechanism, and further discusses the benefit and existing challenges in promoting the clinical application of MenSCs in chemotherapy-induced POI.

The role of macrophages in polycystic ovarian syndrome and its typical pathological features: A narrative review

Polycystic ovarian syndrome (PCOS) is the most common endocrine and metabolic disorder in women of childbearing age, with ovulatory dysfunction, hyperandrogenism, and polycystic ovarian morphology (PCOM) as the clinical features. Androgen excess, insulin resistance, obesity, adipose tissue dysfunction, ovulatory dysfunction, and gut microbiota dysbiosis are the main pathological features and pathogenesis of PCOS and are related to systemic chronic low-grade inflammation and chronic ovarian tissue inflammation in PCOS. With the advances in immune-endocrine interaction studies, research on the role of immune cells in the occurrence and development of PCOS is gradually increasing. As the core of innate immunity, macrophages play an indispensable role in systemic inflammatory response. Meanwhile, they are involved in maintaining the stability and function of the ovary as the most abundant immune cells in ovarian tissue. Studies in humans and mice have found that the polarization of macrophages into M1 type plays multiple roles in the pathogenesis of PCOS. This review describes the distribution characteristics of macrophage subpopulations in patients and animal models with PCOS, discusses the role of macrophage-related metabolic inflammation in PCOS, and summarizes the relationship between macrophages and PCOS-related pathological features and its possible mechanisms, to further understand the pathogenesis of PCOS and reveal the role of macrophages in it. In addition, research on immune-endocrine interactions can also provide direction for finding new therapeutic targets for PCOS.

The FSH-mTOR-CNP signaling axis initiates follicular antrum formation by regulating tight junction, ion pumps, and aquaporins

The initial formation of the follicular antrum (iFFA) serves as a dividing line between gonadotropin-independent and gonadotropin-dependent folliculogenesis, enabling the follicle to sensitively respond to gonadotropins for its further development. However, the mechanism underlying iFFA remains elusive. Herein, we reported that iFFA is characterized by enhanced fluid absorption, energy consumption, secretion, and proliferation and shares a regulatory mechanism with blastula cavity formation. By use of bioinformatics analysis, follicular culture, RNA interference, and other techniques, we further demonstrated that the tight junction, ion pumps, and aquaporins are essential for follicular fluid accumulation during iFFA, as a deficiency of any one of these negatively impacts fluid accumulation and antrum formation. The intraovarian mammalian target of rapamycin-C-type natriuretic peptide pathway, activated by follicle-stimulating hormone, initiated iFFA by activating tight junction, ion pumps, and aquaporins. Building on this, we promoted iFFA by transiently activating mammalian target of rapamycin in cultured follicles and significantly increased oocyte yield. These findings represent a significant advancement in iFFA research, further enhancing our understanding of folliculogenesis in mammals.

Effects of Ginsenoside Rg1 on the Biological Behavior of Human Amnion-Derived Mesenchymal Stem/Stromal Cells (hAD-MSCs)

Ginsenoside Rg1 (Rg1) is purified from ginseng with various pharmacological effects, which might facilitate the biological behavior of human amnion-derived mesenchymal stem/stromal cells (hAD-MSCs). This study is aimed at investigating the effects of Rg1 on the biological behavior, such as viability, proliferation, apoptosis, senescence, migration, and paracrine, of hAD-MSCs. hAD-MSCs were isolated from human amnions. The effects of Rg1 on the viability, proliferation, apoptosis, senescence, migration, and paracrine of hAD-MSCs were detected by CCK-8, EdU, flow cytometry, SA-β-Gal staining, wound healing, and ELISA assays, respectively. The protein expression levels were detected by western blot. Cell cycle distribution was evaluated using flow cytometry. We found that Rg1 promoted hAD-MSC cycle progression from G0/G1 to S and G2/M phases and significantly increased hAD-MSC proliferation rate. Rg1 activated PI3K/AKT signaling pathway and significantly upregulated the expressions of cyclin D, cyclin E, CDK4, and CDK2 in hAD-MSCs. Inhibition of PI3K/AKT signaling significantly downregulated the expressions of cyclin D, cyclin E, CDK4, and CDK2, prevented cell cycle progression, and reduced hAD-MSC proliferation induced by Rg1. hAD-MSC senescence rate was significantly increased by D-galactose, while the elevated hAD-MSC senescence rate induced by D-galactose was significantly decreased by Rg1 treatment. D-galactose significantly induced the expressions of senescence markers, p16^INK4a, p14^ARF, p21^CIP1, and p53 in hAD-MSCs, while Rg1 significantly reduced the expressions of those markers induced by D-galactose in hAD-MSCs. Rg1 significantly promoted the secretion of IGF-I in hAD-MSCs. Rg1 reduced the hAD-MSC apoptosis rate. However, the difference was not significant. Rg1 had no influence on hAD-MSC migration. Altogether, our results demonstrate that Rg1 can promote the viability, proliferation, and paracrine and relieve the senescence of hAD-MSCs. PI3K/AKT signaling pathway is involved in the promotive effect of Rg1 on hAD-MSC proliferation. The protective effect of Rg1 on hAD-MSC senescence may be achieved via the downregulation of p16^INK4A and p53/p21^CIP1 pathway.

Epidermal growth factor regulates autophagy activity and endocytosis of yak cumulus cells in a concentration-dependent manner

Introduction

Autophagy and endocytosis are crucial biological activities in mammalian follicle development and oocyte maturation, which are easily affected by external environmental factors. Epidermal growth factor (EGF), as an important component of follicular fluid, regulates the growth and apoptosis of follicular cells. However, its regulatory mechanism of autophagy and endocytosis in mammals, especially in large domestic animals such as plateau yak, remains unclear. This study aimed to investigate the regulatory mechanism of EGF on autophagy and endocytosis in yak cumulus cells.

Methods

Yak cumulus cells were treated with different concentrations of EGF and appropriate concentrations of EGFR inhibitor gefitinib (10 μM). The dynamic expression levels of Atg5, Beclin1, LC3, Cav1 and Cav2 were detected by immunofluorescence staining, qRT-PCR and Western-blot.

Results

EGF inhibited autophagy in yak cumulus cells by down-regulating the expression of Atg5, Beclin1, and LC3. The level of autophagy varied with the concentration of ligands, and the inhibition was most significant at 100 ng/mL. Noteworthy, EGF can promote endocytosis by regulating the expression of Cav1 and Cav2, but the EGFR-mediated signaling pathway is not the main way to regulate the expression of these proteins.

Discussion

These results provide a reference for further exploring the effects of growth factors on livestock germ cells and the regulatory role of autophagy-endocytosis crosstalk mechanism in follicle development and oocyte maturation, to improve the fecundity of yaks.

Drug-free in vitro activation combined with 3D-bioprinted adipose-derived stem cells restores ovarian function of rats with premature ovarian insufficiency

BACKGROUND

Emerging drug-free in vitro activation (IVA) technique enables patients with premature ovarian insufficiency (POI) to restore ovarian function and conceive their own genetic offspring. However, various issues have greatly restricted its clinical application. Transplantation of adipose-derived stem cells (ADSCs) has promising roles in restoring ovarian function of rats with POI, but insufficient retention has greatly hampered their efficiency. Here, we designed a 3D-bioprinted engineering ovary composed of drug-free IVA and ADSCs, which may prolong the retention of ADSCs and construct an early vascular microenvironment, thus compensating for the disadvantages of drug-free IVA to some extent and ameliorating impaired ovarian function in the POI rats.

METHODS

After intraperitoneal injection of cyclophosphamide, the POI model rats were randomized into 5 groups: (1) POI group; (2) ovarian fragments group; (3) 3D scaffold combined with ovarian fragments group; (4) ovarian fragments combined with ADSCs group; (5) 3D scaffold with ADSCs combined with ovarian fragments as 3D-bioprinted engineering ovary group. Normal rats were identified as the control group. The localization of CM-Dil-labeled ADSCs and co-localization with CD31 were observed to examine the distribution and underlying mechanism of differentiation. Histomorphological and immunohistochemical analyses were performed to calculate follicle number and assess proliferation and apoptosis of granulosa cells (GCs). Immunofluorescence staining was used to evaluate angiogenesis. Hormone levels were measured to evaluate the restoration of endocrine axis. Western blot analysis and RT-PCR were conducted to explore the potential mechanism.

RESULTS

CM-Dil-labeled ADSCs were distributed in the interstitium of ovaries and had significantly higher retention in the 3D-bioprinted engineering ovary group. Several regions of the co-staining for CM-Dil and CD31 were in the area of vascular endothelial cells. Meanwhile, the follicle counts, GCs proliferation, neoangiogenesis, and hormone levels were significantly improved in the 3D-bioprinted engineering ovary group, as compared with other groups. Furthermore, the ovarian function was ameliorated and angiogenesis was promoted through regulating the PI3K/AKT pathway.

CONCLUSION

Our results suggested that 3D-bioprinted engineering ovary had great potential for restoring impaired ovarian function of rats with POI, which could compensate for the disadvantages of drug-free IVA to some extent.

The study of candidate genes in the improvement of egg production in ducks – a review

Duck is the second-largest poultry species aside from chicken. The rate of egg production is a major determinant of the economic income of poultry farmers. Among the reproductive organs, the ovary is a major part of the female reproductive system which is highly important for egg production. Based on the importance of this organ, several studies have been carried out to identify candidate genes at the transcriptome level, and also the expression level of these genes at different tissues or egg-laying conditions, and single nucleotide polymorphism (SNPs) of genes associated with egg production in duck. In this review, expression profile and association study analyses at SNPs level of different candidate genes with egg production traits of duck were highlighted. Furthermore, different studies on transcriptome analysis, Quantitative Trait Loci (QTL) mapping, and Genome Wide Association Study (GWAS) approach used to identify potential candidate genes for egg production in ducks were reported. This review would widen our knowledge on molecular markers that are associated or have a positive correlation to improving egg production in ducks, for the increasing world populace.

Effects of EGF and melatonin on gene expression of cumulus cells and further in vitro embryo development in bovines

Despite previous research demonstrating the benefits of including growth factors and antioxidants to maturation medium to support embryo production, to date the effect of epidermal growth factor (EGF) and melatonin (Mel) on oocyte competency has not been studied. This study supplemented in vitro maturation (IVM) medium with EGF (10 ng/ml) and Mel (50 ng/ml) alone, or in combination, and evaluated cumulus cell (CC) gene expression and the development and quality of parthenogenetic blastocysts. No differences in CC gene expression levels indicative of developmental potential were found among the treatment groups. Antioxidant gene CuZnSOD was significantly (P < 0.05) decreased in CCs from the Mel group. Moreover, blastocyst rates on day 7 were significantly increased in EGF or Mel (P < 0.05), but not EGF+Mel. Significant decrease (P < 0.05) in GPX1, CuZnSOD, SLC2A1 and HSPA1A (P = 0.07) mRNA levels was observed in blastocysts from the Mel group. OCT4 gene expression was significantly increased (P < 0.05) in EGF+Mel and confirmed using immunofluorescence. Our results indicate that, despite the lack of changes of competence-related genes in CCs, IVM medium supplemented with Mel improved the culture environment sufficiently, resulting in improved blastocysts. Moreover, EGF and Mel combined during maturation increased OCT4 gene and protein expression in blastocysts, indicating its potential for stem cells.

Follicle-stimulating hormone mediates the consumption of serum-derived glycogen by bovine cumulus-oocyte complexes during in vitro maturation

Background and Aim:

Oocyte in vitro maturation (IVM) is an appealing approach for several assisted reproductive technologies and dissecting oocyte maturation. Nonetheless, IVM leads to lower developmental competence and usually relies on undefined, serum-containing media. Therefore, biochemical profiling aimed to explore fluctuations in IVM media content during the acquisition of oocyte developmental competence.

Materials and Methods:

Bovine cumulus-oocyte complexes (COCs) underwent IVM in TCM199 medium with Earle’s salts, supplemented with 2.0 mM L-glutamine, 10% fetal bovine serum, antibiotics, and 0.05 IU/mL porcine follicle-stimulating hormone (FSH+) or vehicle control (CTL) medium for 22 h.

Results:

FSH withdrawal (CTL) diminished several processes associated with the acquisition of oocyte developmental competence, such as reduced cumulus cell expansion, diminished estradiol synthesis (FSH+: 116.0±0.0 pg/mL vs. CTL: 97.6±18.0 pg/mL), and lower oocyte nuclear maturation rate (FSH+: 96.47% vs. CTL: 88.76%). Fresh media formulations (i.e., TCM199 with FSH or vehicle) were indistinguishable under biochemical profiling threshold conditions. Biochemical profiling showed similar total protein and lipid concentrations between groups. Further, total sugar concentrations diminished from fresh media to their post-IVM counterparts, albeit in an FSH-independent manner. Glycogen concentrations remained unaltered after IVM within CTL media, albeit were substantially lower after IVM under FSH+ conditions.

Conclusion:

FSH mediates the consumption of serum-derived glycogen by bovine COCs during IVM and implies that serum-free media should contain increased glucose concentrations to facilitate the acquisition of oocyte developmental competence.

The Roles of Different Stem Cells in Premature Ovarian Failure

Premature ovarian failure (POF) is characterized by amenorrhea, hypergonadotropism and hypoestrogenism before the age of 40, which affects 1% of women in the general population. POF is complex and heterogeneous due to its pathogenetic mechanisms. It is one of the significant causes of female infertility. Although many treatments are available for POF, these therapies are less efficient and trigger many side effects. Therefore, to find effective therapeutics for POF is urgently required. Due to stem cells having self-renewal and regeneration potential, they may be effective for the treatment of ovarian failure and consequently infertility. Recent studies have found that stem cells therapy may be able to restore the ovarian structure and function in animal models of POF and provide an effective treatment method. The present review summarizes the biological roles and the possible signaling mechanisms of the different stem cells in POF ovary. Further study on the precise mechanisms of stem cells on POF may provide novel insights into the female reproduction, which not only enhances the understanding of the physiological roles but also supports effective therapy for recovering ovarian functions against infertility.

Adult Stem Cell Therapy for Premature Ovarian Failure: From Bench to Bedside

Premature ovarian failure (POF) is a devastating condition for women of childbearing age with serious health consequences, including distress, infertility, osteoporosis, autoimmune disorders, ischemic heart disease, and increased mortality. In addition to the mainstay estrogen therapy, stem cell therapy has been tested as the result of rapid progress in cell biology and reprogramming research. We hereby provide a review for the latest research and issues related with stem cell-based therapy for POF, and provide a commentary on various methods for enhancing its effect. Large amount of animal studies have demonstrated an extensive benefit of stem cells for failed ovarian recovering. As shown by such studies, stem cell therapy can result in recovery of hormonal levels, follicular activation, ovarian angiogenesis, and functional restoration. Meanwhile, a study of molecular pathways revealed that the function of stem cells mainly depends on their paracrine actions, which can produce multiple factors for the promotion of ovarian angiogenesis and regulation of cellular functions. Nevertheless, studies using disease models also revealed certain drawbacks. Clinical trials have shown that menstrual cycle and even pregnancy may occur in POF patients following transplantation of stem cells, although the limitations, including inadequate number of cases and space for the improvement of transplantation methodology. Only with its safety and effect get substantial improvement through laboratory experiments and clinical trials, can stem cell therapy really bring benefits to more patients. Additionally, effective pretreatment and appropriate transplantation methods for stem cells are also required. Taken together, stem cell therapy has shown a great potential for the reversal of POF and is stepping from bench to bedside. Impact statement Premature ovarian failure (POF) is a devastating condition with serious clinical consequences. The purpose of this review was to summarize the current status of stem cell therapy for POF. Considering the diversity of cell types and functions, a rigorous review is required for the guidance for further research into this field. Meanwhile, the challenges and prospect for clinical application of stem cell treatment, methodological improvements, and innovations are addressed.

Macrophages: an indispensable piece of ovarian health

Macrophages are the most abundant immune cells in the ovary. In addition to their roles in the innate immune system, these heterogeneous tissue-resident cells are responsive to tissue-derived signals, adapt to their local tissue environment, and specialize in unique functions to maintain tissue homeostasis. Research in the past decades has established a strong link between macrophages and various aspects of ovarian physiology, indicating a pivotal role of macrophages in ovarian health. However, unlike other intensively studied organs, the knowledge of ovarian macrophages dates back to the time when the heterogeneity of ontogeny, phenotype, and function of macrophages was not fully understood. In this review, we discuss the evolving understanding of the biology of ovarian tissue-resident macrophages, highlight their regulatory roles in normal ovarian functions, review the association between certain ovarian pathologies and disturbed macrophage homeostasis, and finally, discuss the technologies that are essential for addressing key questions in the field.

Proteomic analysis of healthy and atretic porcine follicular granulosa cells

Follicular atresia is initiated with the apoptosis of granulosa cells (GCs) after birth in mammals. The molecular mechanisms underlying GC apoptosis during follicular selection are unclear at present. The objective of this study is to identify the proteins and pathways that may be involved in porcine follicular atresia. Proteins isolated from GCs collected from healthy and atretic follicles were detected by tandem mass tag (TMT) protein labeling and LC-MS/MS. A total of 4591 proteins in the healthy follicle granulosa cell (HFGC) and atretic follicle granulosa cell (AFGC) groups were identified, and 399 differentially abundant proteins were found between the HFGC and AFGC groups; of which 262 proteins were significantly up-regulated and 137 proteins were significantly down-regulated. Differential protein enrichment analysis showed that proteins involved in proteolysis, protein destabilization, phagocytosis, and engulfment were more abundant in the AFGC group. Also, these proteins were mainly involved in the lysosome, phagosome, autophagy, and apoptosis pathways. Specially, PTGFRN is potential important regulated protein in the development of the antral follicle, and down-regulation of PTGFRN in GCs may lead to follicular atresia. Our study shows that the identified proteins and their related signaling pathways may play crucial roles during health follicle develop to atretic follicle. SIGNIFICANCE: Follicular atresia during 'selection' reduces the reproductive potential of sows. In this study, we found 399 proteins differentially abundant. between the HFGC and AFGC groups. These results establish a foundation for elucidating the mechanism of follicular atresia in swine.

Intrafollicular growth differentiation factor 9: bone morphogenetic 15 ratio determines litter size in mammals†

We previously showed that rat, pig, sheep, and red deer oocytes express species-specific ratios of GDF9: BMP15 mRNA (3.7, 0.5, 1.26, and 0.1, respectively), and with the exception of the pig, they are directly correlated to litter size. The purpose of this study was to determine the alternative mechanism that enables pig oocytes to secrete low ratios whilst maintaining a large litter size. Herein, we performed same- and cross-species coincubations of oocytes with granulosa cells (GCs) of rat, pig, sheep, and red deer to compare the proliferation rate, mRNA expression levels of growth factor receptors, and downstream signalling pathways in GCs. A decreased proliferation rate, lower Bmpr1b and Bmpr2 mRNA expression levels, and higher SMAD1/5/8 protein levels were exhibited in rat GCs cocultured with red deer oocytes, compared to all other species. Pig GCs unequivocally expressed GDF9 mRNA, suggesting that, similar to rat GCs, the proliferation of pig GCs is regulated mainly by GDF9, despite lower intraoocyte expression of GDF9 mRNA. In support, a higher basal proliferation, and their ability to proliferate readily when coincubated with red deer oocytes, was observed in pig GCs. In contrast, red deer GC proliferation is likely to be mainly regulated by BMP15 in vivo with only red deer oocytes capable of altering SMAD1/5/8 and pSMAD2/3 levels, while both GDF9 and BMP15 appear important for sheep GC proliferation. In summary, this study strengthens our hypothesis that the ratio of GDF9: BMP15 in the intrafollicular milieu is directly correlated with litter size, and that the GCs of each species have evolved to respond to these unique ratios.

Supportive techniques to investigate in vitro culture and cryopreservation efficiencies of equine ovarian tissue: A review

During the reproductive lifespan of a female, only a limited quantity of oocytes are naturally ovulated; therefore, the mammalian ovary possesses a substantial population of preantral follicles available to be handled and explored in vitro. Hence, the manipulation of preantral follicles enclosed in ovarian tissue aims to recover a considerable population of oocytes of high-value animals for potential application in profitable assisted reproductive technologies (ARTs). For this purpose, the technique of preantral follicle in vitro culture (IVC) has been the most common research tool, achieving extraordinary results with offspring production in the mouse model. Although promising outcomes have been generated in livestock animals after IVC of preantral follicles, the quantity and quality of embryo production with those oocytes are still poor. In recent years, the mare has become an additional model for IVC studies due to remarkable similarities with women and livestock animals regarding in vivo and in vitro ovarian folliculogenesis. For a successful IVC system, several factors should be carefully considered to provide an optimum culture environment able to support the viability and growth of preantral follicles enclosed in ovarian tissue. The cryopreservation of the ovarian tissue is another important in vitro manipulation technique that has been used to preserve the reproductive potential in humans and, in the future, may be used in highly valuable domestic animals or endangered species. Several improvements in cryopreservation protocols are necessary to support the utilization of ovarian tissue of different species in follow-up ARTs (e.g., ovarian fragment transplantation). This review aims to provide an update on the most current advances regarding supportive in vitro techniques used in equids to evaluate and manipulate preantral follicles and ovarian tissue, as well as methodological approaches used during IVC and cryopreservation techniques.

Effects of epidermal growth factor and progesterone on development, ultrastructure and gene expression of bovine secondary follicles cultured in vitro

The aims of this study were to investigate the effects of epidermal growth factor (EGF) and progesterone on the development, viability and the gene expression of bovine secondary follicle culture in vitro for 18 days. Secondary follicles (∼0.2 mm) were isolated from ovarian cortex and individually cultured at 38.5 °C, with 5% CO₂ in air, for 18 days, in TCM-199⁺ (n = 63) alone (control medium) or supplemented with 10 ng/mL progesterone (n = 64), 10 ng/mL EGF (n = 61) or both EGF and progesterone (n = 66). The effects of these treatments on growth, antrum formation, viability, ultrastructure and mRNA levels for GDF-9, c-MOS, H1foo and cyclin B1 were evaluated, significantly different (p < 0.05). The results showed that there was a progressive increase in follicular diameter in all treatments, but only follicles cultured in medium supplemented with EGF had increased significantly in diameter when compared to follicles cultured in the control medium at the end of the culture period, significantly different (p < 0.05). A positive interaction between EGF and progesterone was not observed. In addition, the presence of EGF, progesterone or both in culture medium did not influence the rate of follicle survival and antrum formation. However, the presence of only progesterone in cultured medium increased the expression of mRNAs for GDF9 and cyclin B1 in oocytes. EGF also significantly increased the levels of mRNAs for cMOS and GDF9 when compared to follicles cultured in control medium. Ultrastructural analyzes showed that cultured follicles in all treatments maintained the integrity of granulosa cells. In conclusion, the EGF promotes the development of secondary follicles cultured in vitro for 18 days and increases the expression of cMOS and GDF9, while progesterone alone or in association with EGF have not a positive effect on follicular growth. However, progesterone increases the expression of GDF9 and cyclin B1 in oocytes.

Therapeutic effects of human umbilical cord mesenchymal stem cell-derived microvesicles on premature ovarian insufficiency in mice

BACKGROUND

Premature ovarian insufficiency (POI) is one of the leading causes of female infertility, which is caused by an abnormal ovarian reserve. Currently, there is no effective treatment to restore the fertility of POI patients. Recent studies suggested that microvesicles (MVs) released from mesenchymal stem cells (MSCs) exert therapeutic effects in various degenerative diseases. In this study, the effect of human umbilical cord MSC-derived MVs (HUCMSC-MVs) on the restoration of ovarian function in a chemotherapy-induced POI mouse model is investigated.

METHODS

MVs were obtained from the supernatant of cultured HUCMSCs. The localization of PKH26-labeled HUCMSC-MVs in ovarian tissues was observed by confocal laser scanning microscopy. Histomorphometric analysis was performed to count the number of ovarian follicles and vessels. The ovarian sections were stained with anti-CD34 to evaluate angiogenesis. The levels of estradiol (E2) and follicle-stimulating hormone (FSH) were measured by enzyme-linked immunosorbent serologic assay. The mRNA expression of angiogenesis-related cytokines and the protein expression of AKT in mouse ovaries were measured by quantitative RT-PCR and western blot analysis. The parametric variables were compared by Student's t test and analysis of variance. The non-parametric variables were compared by the Mann-Whitney U test. Categorical variables were compared by χ² test. P < 0.05 was considered statistically significant.

RESULTS

PKH26-labeled HUCMSC-MVs were detectable within the ovaries and migrated to the ovarian follicles 24 h after transplantation. The transplantation of HUCMSC-MVs could increase the body weight and number of ovarian follicles (primordial, developing, and preovulatory follicles), induce ovarian angiogenesis, and recover the disturbed estrous cycle of POI mice. The expression levels of total AKT, p-AKT, and angiogenic cytokines (including VEGF, IGF, and angiogenin) in the ovaries of POI mice were markedly upregulated after HUCMSC-MVs transplantation, suggesting that HUCMSC-MVs transplantation might recover ovarian function by inducing angiogenesis via the PI3K/AKT signaling pathway.

CONCLUSIONS

This study provides valuable insight into the effects of HUCMSC-MVs on ovarian tissue angiogenesis and on the restoration of ovarian function in POI mice, which may be helpful to develop a treatment strategy for POI patients.

Prolactin induces lipid synthesis of organ-cultured pigeon crops

The objective of this research was to examine the effects of prolactin (PRL) on the lipid synthesis of organ-cultured pigeon crops in vitro. In experiment 1, the histology, activities of enzymes, and expression of genes involved in metabolism and apoptosis of organ-cultured pigeon crops were analyzed over a 7-d culture period. The results showed that cultured crops maintained their structural integrity for up to 3 d in vitro. Beyond 3 d, caspase-3 activity and Bak1 gene expression increased with day of culture, whereas the activities of succinate dehydrogenase, Na+-K+-ATPase, Ca2+-Mg2+-ATPase, total ATPase, and gene expression of Bcl-2 and CK-19 diminished (P < 0.05). In experiment 2, the crops were cultured for 24, 36, and 48 h in medium containing 0, 25, or 50 ng/mL PRL, respectively, and the accumulation of lipid droplets, lipid content, and expression of fatty acid transportation- and lipogenesis-related genes were analyzed. The results showed that the crops with PRL supplements showed higher amounts of lipid droplets than those of the controls, and the droplets were mainly located in the basal nutritive layer in response to PRL. The efficacy of inducing lipid accumulation increased as the concentration of PRL increased. Crops with 50 ng/mL PRL incubated for 36 h displayed the maximal lipid content. Increasing the concentration of PRL from 0 to 50 ng/mL resulted in a dose-dependent increase in the expression of acetyl-CoA carboxylase, fatty acid synthase, fatty acid translocase, fatty acid binding protein 5, acyl-CoA binding protein, and peroxisome proliferator-activated receptor γ genes after incubation for 36 h (P < 0.05). Therefore, our results indicated that the organ-cultured pigeon crops maintained good viability for up to 3 d in vitro. Furthermore, PRL induced the lipid synthesis of organ-cultured pigeon crops in a dose- and time-dependent manner, which was related to the increased expression of genes involved in fatty acid transportation and lipogenesis.

Human amnion-derived mesenchymal stem cell (hAD-MSC) transplantation improves ovarian function in rats with premature ovarian insufficiency (POI) at least partly through a paracrine mechanism

Background

Chemotherapy can induce premature ovarian insufficiency (POI) and reduce fertility in young female patients. Currently, there is no effective therapy for POI. Human amnion-derived mesenchymal stem cells (hAD-MSCs) may be a promising seed cell for regenerative medicine. This study investigated the effects and mechanisms of hAD-MSC transplantation on chemotherapy-induced POI in rats.

Methods

Chemotherapy-induced POI rat models were established by intraperitoneal injection of cyclophosphamide. Seventy-two female SD rats were randomly divided into control, POI, and hAD-MSC-treated groups. hAD-MSCs were labeled with PKH26 and injected into the tail veins of POI rats. To examine the underlying mechanisms, the differentiation of transplanted hAD-MSCs in the POI ovaries was analyzed by immunofluorescent staining. The in vitro expression of growth factors secreted by hAD-MSCs in hAD-MSC-conditioned media (hAD-MSC-CM) was analyzed by ELISA. Sixty female SD rats were divided into control, POI, and hAD-MSC-CM-treated groups, and hAD-MSC-CM was injected into the bilateral ovaries of POI rats. After hAD-MSC transplantation or hAD-MSC-CM injection, serum sex hormone levels, estrous cycles, ovarian pathological changes, follicle counts, granulosa cell (GC) apoptosis, and Bcl-2, Bax, and VEGF expression in ovaries were examined.

Results

PKH26-labeled hAD-MSCs mainly homed to ovaries after transplantation.

hAD-MSC transplantation reduced ovarian injury and improved ovarian function in rats with POI. Transplanted hAD-MSCs were only located in the interstitium of ovaries, rather than in follicles, and did not express the typical markers of oocytes and GCs, which are ZP3 and FSHR, respectively. hAD-MSCs secreted FGF2, IGF-1, HGF, and VEGF, and those growth factors were detected in the hAD-MSC-CM. hAD-MSC-CM injection improved the local microenvironment of POI ovaries, leading to a decrease in Bax expression and an increase in Bcl-2 and endogenous VEGF expression in ovarian cells, which inhibited chemotherapy-induced GC apoptosis, promoted angiogenesis and regulated follicular development, thus partly reducing ovarian injury and improving ovarian function in rats with POI.

Conclusions

hAD-MSC transplantation can improve ovarian function in rats with chemotherapy-induced POI at least partly through a paracrine mechanism. The presence of a paracrine mechanism accounting for hAD-MSC-mediated recovery of ovarian function might be attributed to the growth factors secreted by hAD-MSCs.

In vitro culture supplementation of EGF for improving the survival of equine preantral follicles

Folliculogenesis is a process of development and maturation of the ovarian follicles, being essential for the maintenance of fertility. In in vivo conditions, 99.9% of the follicles of an ovary do not ovulate and undergo atresia. In order to minimize this loss and to clarify the existing mechanisms, a technique was developed that allows for the in vitro follicular development. The objective of this study was to evaluate the effects of different epidermal growth factor (EGF) concentrations on the in vitro culturing of equine preantral follicles. Ovaries (n = 10) were collected from a local slaughterhouse of mares in seasonal anestrus, washed with 70% alcohol and PBS, and transported. The inner portion of the ovary was divided into 11 fragments of approximately 3 × 3 × 1 mm. A fragment of each ovary was immediately fixed in Bouin (control group). The remaining 10 fragments were individually cultured for 2 and 6 d. The medium was supplemented with different concentrations of EGF (0, 10, 50, 100, and 200 ng/mL). After cultivation, the fragments were processed and classified according to the developmental stage and morphology. In total, 1065 slides containing 6105 tissue sections were evaluated. Within 2 d of culture, there was a higher proportion of intact follicles at the EGF concentrations of 0 and 100 ng/mL (p > 0.05). After 6 d of culture, only the EGF concentration of 100 ng/mL demonstrated a difference when compared to the other treatments (0, 10, 50 and 200 ng/mL of EGF, p > 0.05). There was follicular development after 2 d at all EGF concentrations. Thus, we suggest that EGF promotes follicular survival in equines at a concentration of 100 ng/mL in in vitro cultures of ovarian fragments for 2 d. In addition, we suggest that EGF promotes follicular survival in equines at a concentration of 100 ng/mL in situ cultivation.

Programmed cell death in the human ovary

During a woman's reproductive life, only about 400 primordial follicles will develop into a preovulatory follicle and undergo ovulation, releasing an oocyte available for fertilization. The process of formation and selection of these follicles is complex and involves a multistep process characterized by a balance between survival and death of the oocytes and the surrounding follicular cells. Although the mechanisms underlying such process are not completely clarified yet, it is common idea that they can occur through various types of programmed cellular death (PCD). Since atresia is the principal destiny of the ovarian follicles, it is relevant to understand how this process takes place and how it is regulated. In this review, after a summary description of folliculogenesis in humans, the main mechanisms of atresia reported to occur during folliculogenesis from birth to adult age, in the human ovary and in other mammals when appropriate, are described.

Effects of low-intensity pulsed ultrasound (LIPUS)-pretreated human amnion-derived mesenchymal stem cell (hAD-MSC) transplantation on primary ovarian insufficiency in rats

Background

Human amnion-derived mesenchymal stem cells (hAD-MSCs) have the features of mesenchymal stem cells (MSCs). Low-intensity pulsed ultrasound (LIPUS) can promote the expression of various growth factors and anti-inflammatory molecules that are necessary to keep the follicle growing and to reduce granulosa cell (GC) apoptosis in the ovary. This study aims to explore the effects of LIPUS-pretreated hAD-MSC transplantation on chemotherapy-induced primary ovarian insufficiency (POI) in rats.

Methods

The animals were divided into control, POI, hAD-MSC treatment, and LIPUS-pretreated hAD-MSC treatment groups. POI rat models were established by intraperitoneal injection of cyclophosphamide (CTX). The hAD-MSCs isolated from the amnion were exposed to LIPUS or sham irradiation for 5 consecutive days and injected into the tail vein of POI rats. Expression and secretion of growth factors promoted by LIPUS in hAD-MSCs were detected by real-time quantitative polymerase chain reaction (RT-qPCR) and enzyme-linked immunosorbent assay (ELISA) in vitro. Estrous cycle, serum sex hormone levels, follicle counts, ovarian pathological changes, GC apoptosis, Bcl2 and Bax expression, and pro-inflammatory cytokine levels in ovaries were examined.

Results

Primary hAD-MSCs were successfully isolated from the amnion. LIPUS promoted the expression and secretion of growth factors in hAD-MSCs in vitro. Both hAD-MSC and LIPUS-pretreated hAD-MSC transplantation increased the body and reproductive organ weights, improved ovarian function, and reduced reproductive organ injuries in POI rats. Transplantation of hAD-MSCs increased the Bcl-2/Bax ratio and reduced GC apoptosis and ovarian inflammation induced by chemotherapy in ovaries. These effects could be improved by pretreatment with LIPUS on hAD-MSCs.

Conclusion

Both hAD-MSC transplantation and LIPUS-pretreated hAD-MSC transplantation can repair ovarian injury and improve ovarian function in rats with chemotherapy-induced POI. LIPUS-pretreated hAD-MSC transplantation is more advantageous for reducing inflammation, improving the local microenvironment, and inhibiting GC apoptosis induced by chemotherapy in ovarian tissue of POI rats.

Associations of IGF2 and DRD2 polymorphisms with laying traits in Muscovy duck

Insulin-like growth factor 2 (IGF2) and dopamine receptor 2 (DRD2) play important roles in ovarian follicular development. In this study, we analyzed tissue-specific expression of the Muscovy duck IGF2 and DRD2 genes and cloned those genes transcripts. Polymorphisms in these genes were tightly linked with egg production traits and both genes were highly expressed in the ovary. Moreover, we identified five single nucleotide polymorphisms (SNPs) for IGF1 and 28 for DRD2. Mutations A-1864G and C-1704G of IGF2 were positively correlated with increased egg laying at 59 weeks (E59W) (P < 0.05). The C+7T and C+364G mutations of DRD2 were highly and significantly associated with first-egg age (FEA) and egg numbers at 300 days (E300D) (P < 0.01). Moreover, C+3301G and C+3545G of DRD2 were highly significantly associated with FEA, E59W and E300D (P < 0.01). Other mutations were positively associated with FEA or E300D or E59W (P < 0.05). These data suggest specific roles for IGF1 and DRD2 polymorphisms in egg production in Muscovy ducks.

Mesenchymal Stem Cells in Restoration of Fertility at Experimental Pelvic Inflammatory Disease

Inflammatory disorders account for a significant percentage of gynecologic diseases, particularly in women of reproductive age. It is known that stem cells have anti-inflammatory and regenerative properties. Based on this, we investigated the effect of intravenous administration of cryopreserved mesenchymal stem cells (cMSCs) of bone marrow on experimental chronic inflammation of the ovaries. The paper shows that on the 21st day after cMSC therapy, leukocyte infiltration of ovaries was slightly relative to the control group without treatment, and the ratio of developing and atretic follicles in the animals with cMSC injection dramatically increased, while in the control, it still remained on the side of atretic forms. The number of apoptotic oocytes after stimulation of superovulation in the control group was significantly higher (85.3 ± 5.2%) than that in the animals with therapy (5.7 ± 0.8%). Relative number of fertilized eggs in the group with cMSC therapy was higher by 40% compare to that in the control. Pregnancy rate in natural estrous cycle after cell administration increased by 20%, and average number of litters in this group was two times significantly higher than that in the control. So the intravenous injection of cMSCs has the restorative effect on the fertility at experimental pelvic inflammatory disease.

EGF-FSH supplementation reduces apoptosis of pig granulosa cells in co-culture with cumulus-oocyte complexes

In cattle breeding, co-culture with granulosa cells (GCs) is one of the strategies to improve oocyte maturation and fertilization potential, but yields are still suboptimal due to GC apoptosis. We previously set up an in vitro co-culture system of cumulus-oocyte-complexes (COCs) anchored to GC multilayers adhering to the basal lamina (COCGs), in which GC apoptosis was inhibited by FSH supplementation. Here, we assessed the antiapoptotic effect of EGF (5 ng/ml-EGF5) alone or in synergism to FSH (50mU/ml-FSH50) on pig COCGs. COCG morphology, apoptotic rate, procaspase-8 and-9 expression levels and surface ultrastructure were determined. Results showed an increased % of apoptotic GCs in control and EGF5 (≈80%) respect to sampling (≈3%) and caspase-8 and -9 activation. In contrast, apoptotic cells were significantly reduced by FSH50 (≈35%) supplementation, with inactive Procaspase-8 and -9 highly expressed. The pro-survival effect of FSH was strengthened by EGF (EGF5+FSH50), as evidenced by a significant reduction of apoptosis (≈15%) and high expression levels of Procaspase-8 and -9. Ultrastructural analysis revealed that GC multilayers were characterized by round-to-ovoid cells connected each other and to the basal lamina by cytoplasmic projections. Microvilli shortening/thickening/reduction, cytoplasmic projection rarefaction, blebbing of apoptotic bodies and degenerating/atresic GCs were observed in control and EGF5 groups. FSH50 induced the formation of an abundant mucinous matrix, due to granulosa expansion. Blebs and atresic areas were rarely observed. In EGF5+FSH50 group, GCs were well-preserved, richly covered by microvilli and connected by numerous cytoplasmic projections. Degenerative phenomena were rarely observed. In conclusion, EGF in synergism with FSH seems to better counteract GC apoptosis in a co-culture of pig GC multilayers.

Lack of FSH support enhances LIF-STAT3 signaling in granulosa cells of atretic follicles in cattle

Subordinate follicles (SFs) of bovine follicular waves undergo atresia due to declining FSH concentrations; however, the signalling mechanisms have not been fully deciphered. We used an FSH-induced co-dominance model to determine the effect of FSH on signalling pathways in granulosa cells of the second-largest follicles (SF in control cows and co-dominant follicle (co-DF2) in FSH-treated cows). The SF was smaller than DF in control cows while diameters of co-DF1 and co-DF2 in FSH-treated cows were similar. The presence of cleaved CASP3 protein confirmed that granulosa cells of SFs, but not of DFs and co-DFs, were apoptotic. To determine the effect of FSH on molecular characteristics of the second-largest follicles, we generated relative variables for the second largest follicle in each cow. For this, variables of SF or co-DF2 were divided by the variables of the largest follicle DF or co-DF1 in each cow. There was higher transcript abundance of MAPK1/3 and AKT1/2/3 but lower abundance of phosphorylated MAPK3/1 in SF than co-DF2 granulosa cells. Abundance of mRNA and phosphorylated protein of STAT3 was higher in granulosa cells of control SF than FSH-treated co-DF2. SF granulosa cells had higher levels of LIFR and IL6ST transcripts, the two receptors involved in STAT3 activation. Further, lower transcript abundance of interleukin 6 receptor (IL6R), another receptor involved in STAT3 activation, indicated that STAT3 activation in SF granulosa cells could be mainly due to leukemia inhibitory factor (LIF) signalling. These results indicate that atresia due to lack of FSH is associated with activated LIF-STAT3 signalling in SF granulosa cells, as FSH treatment reversed such activation.

Ovarian follicle development in vitro and oocyte competence: advances and challenges for farm animals

During the last 2 decades, research on in vitro preantral follicle growth and oocyte maturation has delivered fascinating advances concerning the knowledge of processes regulating follicle growth and the developmental competence of oocytes. These advances include (1) information about the role of several hormones and growth factors on in vitro activation of primordial follicles; (2) increased understanding of the intracellular pathway involved in the initiation of primordial follicle growth; (3) the growth of primary and secondary follicles up to antral stages; and (4) production of embryos from oocytes from in vitro grown preantral follicles. This review article describes these advances, especially in regard farm animals, and discusses the reasons that limit embryo production from oocytes derived from preantral follicles cultured in vitro.

In vitro-growth and Gene Expression of Porcine Preantral Follicles Retrieved by Different Protocols

This study was conducted to determine how the isolation method of the porcine preantral follicles influenced the following follicular growth in vitro. Mechanical and enzymatical isolations were used for retrieving the follicles from prepubertal porcine ovaries, and in vitro-growth of the follicles and the expression of folliculogenesis-related genes were subsequently monitored. The enzymatic retrieval with collagenase treatment returned more follicles than the mechanical retrieval, while the percentage of morphologically normal follicles was higher with mechanical retrieval than with enzymatic retrieval. After 4 days of culture, mechanically retrieved, preantral follicles yielded more follicles with normal morphology than enzymatically retrieved follicles, which resulted in improved follicular growth. The mRNA expression of FSHR, LHR Cx43, DNMT1 and FGFR2 genes was significantly higher after culture of the follicles retrieved mechanically. These results suggest that mechanical isolation is a better method of isolating porcine preantral follicles that will develop into competent oocytes in in vitro culture.

Luteinizing hormone, insulin like growth factor-1, and epidermal growth factor stimulate vascular endothelial growth factor production in cultured bubaline granulosa cells

The objective of this study was to characterize in vitro expression and secretion of vascular endothelial growth factor (VEGF) in bubaline granulosa cells (GC), grown in serum containing media supplemented with luteinizing hormone (LH), insulin like growth factor-1 (IGF-1), and epidermal growth factor (EGF) at three different doses and time durations. GCs were collected from ovarian follicles of varying diameters [Gp-I (small), 4-6 mm; Gp-II (medium), 7-9 mm; Gp-III (large), 10-13 mm; Gp-IV (pre-ovulatory), >13 mm]. In general, each of the three treatments resulted in a dose as well as time dependent increase in the mRNA expression and secretion of VEGF in the cultured GCs of Gp-IV follicles. These results were well supported by our observations on immunocytochemistry in Gp IV granulosa cell culture (GCC). We also looked into the expression dynamics of an anti-apoptotic factor--proliferating cellular antigen (PCNA) and a pro-apoptotic factor--Bcl-2-associated X protein (BAX) in GCs of Gp IV follicles on treatments with LH, IGF-1, and EGF to evaluate their cytoprotective/anti-apoptotic property. Relative expressions of PCNA and BAX showed a mutually opposite trend with the PCNA expression increasing and BAX expression decreasing with increase in dose and time to reach the zenith (P<0.05) and nadir (P<0.05) at the highest dose(s) at the maximum time duration (72 h) for PCNA and BAX respectively on treatment with all the three factors. Thus, it can be concluded that LH, IGF-1, and EGF treatments have a cytoprotective/anti-apoptotic effect and stimulate VEGF production in granulosa cells of bubaline pre-ovulatory follicles.

In vitro changes in porcine ovarian granulosa cells induced by copper

Objective of this in vitro study was to examine the secretion activity (progesterone and insulin-like growth factor I) of porcine ovarian granulosa cells after copper (Cu) addition and to outline a potential intracellular mediator (cyclin B1) of its effects. It also aimed at investigating the apoptotic potential of Cu on porcine ovarian granulosa cells after addition in vitro. Ovarian granulosa cells were incubated with copper sulphate (CuSO4·5H2O) at the doses 0.33, 0.40, 0.50, 1.0 and 2.0 μL mL(-1) for 18 h and compared with control group without Cu addition. Release of progesterone (P4) and insulin-like growth factor I (IGF-I) by granulosa cells was assessed by RIA, expression of cyclin B1 by immunocytochemistry and apoptosis by TUNEL assay. Observations show that P4 release by granulosa cells was inhibited while the release of IGF-I and cyclin B1 was stimulated significantly (P < 0.05) by CuSO4·5H2O addition at the dose 2.0 μL mL(-1). Also, addition of CuSO4.5H2O at the lowest dose used in the study (0.33 μL mL(-1)) significantly (P < 0.05) decreased apoptosis in granulosa cells. In conclusion, results indicate dose dependent effect of Cu on (1) secretion of steroid hormone progesterone and growth factor IGF-I, (2) expression of cyclin B1 as marker of proliferation of porcine ovarian granulosa cells, (3) apoptosis of porcine ovarian granulosa cells and, (4) that the effect of Cu on ovarian cell proliferation could be mediated by IGF-I and cyclin B1. Obtained data suggest interference of Cu in the pathways of proliferation of porcine ovarian granulosa cells through hormonal and intracellular peptide cyclin B1.

Adipose-derived stem cells improved mouse ovary function after chemotherapy-induced ovary failure

Introduction

Young patients receiving chemotherapy occasionally face infertility and premature ovarian failure (POF). Numerous investigations reported that adipose-derived stem cells (ADSCs) transplantation could ameliorate the structure and function of injured tissues. The aim of this study was to explore the therapeutic efficacy of ADSC transplantation for chemotherapy-induced ovarian damage.

Methods

Female mice were injected intraperitoneally with 50 mg/kg cyclophosphamide (CTX). After 15 consecutive days of injection, ADSCs were transplanted either directly into bilateral ovaries or via intravenous injection, and the ovaries were excised after either 1 week or 1 month of treatment. The follicles were counted and categorized, and ovarian histologic sections were stained for TUNEL. Ovarian function was evaluated by monitoring ovulation. ADSC tracking, microarray analyses, and real-time polymerase chain reaction (PCR) were used to assess the inner mechanism of injury and repair.

Results

The ovarian function of mice exposed to CTX injection improved after ADSC transplantation. The population of follicles at different stages and ovulation significantly increased after the treatment. Immunofluorescence revealed reduced TUNEL staining. The tracking of ADSCs revealed that these cells did not directly differentiate into the follicle component. Microarray analyses indicated that changes in different groups of genes might affect follicle formation or ovulation.

Conclusions

ADSC transplantation improved ovarian function. Our results suggest a potential mechanism for ADSC therapy.

Role of insulin-like growth factor-I and follicular fluid from ovarian follicles with different diameters on porcine oocyte maturation and fertilization in vitro

The objective of this study was to determine the effects of insulin-like growth factor-I (IGF-I) (0, 60, 120, 180, and 240 ng/mL) and follicular fluid (FF) derived from 2 to 5 and 6 to 10 mm diameter follicles (SpFFs and LpFFs, respectively) added during in vitro maturation (IVM) of porcine oocytes on nuclear maturation and IVF. Cumulus-oocyte complexes (COCs) were matured in NCSU-37 medium supplemented with SpFFs or LpFFs and various IGF-I concentrations. The COCs were cultured for 44 hours, and then fertilized in vitro. Maturation and IVF results were recorded 18 hours after insemination. The IVM (%) was higher (P < 0.05) in the COCs matured in LpFFs than with SpFFs when 0 (90.0 ± 6.9 vs. 76.3 ± 10.7) or 60 ng/mL IGF-I (92.0 ± 8.1 vs. 81.8 ± 10.2) was added. In SpFFs media, there was a quadratic relationship (P < 0.01) between IGF-I concentration and IVM (peak results at IGF-I = 129 ng/mL). However, when the COCs were matured with LpFFs, there was a decreasing linear effect between IGF-I concentration and IVM. At all concentrations of IGF-I, the percentage of degenerated oocytes was higher in COCs matured in SpFFs than in LpFFs. Penetration (%) did not differ (P > 0.05) between COCs matured with SpFFs or LpFFs when 60 (66.8 ± 9.4 vs. 72.7 ± 11.3) or 180 ng/mL of IGF-I (75.7 ± 10.4 vs. 73.8 ± 13.2) were used. Monospermy (%) was similar between SpFFs and LpFFs only with addition of 120 ng/mL IGF-I. The IVF performance (%) did not differ between COCs matured with SpFFs or LpFFs when IGF-I concentrations of 120 (28.5 ± 8.8 vs. 38.5 ± 8.3) and 180 ng/mL (24.3 ± 10.2 vs. 30.12 ± 8.2) were used. There was no effect of IGF-I concentration or of FF type on the number of penetrated sperm per oocyte and on male pronuclear formation. For COCs matured with SpFFs, there was a quadratic relationship between IGF-I concentration and penetration, monospermy, and IVF performance (peak results at IGF-I = 179, 122, and 135 ng/mL, respectively). Thus, on the basis of the observed quadratic relationships, we inferred that when using SpFFs, the addition of IGF-I (122-179 ng/mL) to the IVM medium produced results similar to those obtained with LpFFs without adding IGF-I. In conclusion, the addition of IGF-I to the IVM medium supplemented with SpFFs increased maturation and improved IVF results. Alternatively, IGF-I had no effect on IVM or IVF when used with LpFFs.

The restorative effects of adipose-derived mesenchymal stem cells on damaged ovarian function

The clinical application of human adipose-derived mesenchymal stem cells (MSCs) as treatment for intractable diseases or traumatic tissue damage has attracted attention. To address the ability of reactivating injured ovaries, we prepared a rat model with damaged ovaries by using an anticancer agent, cyclophosphamide (CTX). We then investigated the restorative effects on ovarian function and the safety of adipose-derived MSCs (A-MSCs). MSCs were shown to be capable of inducing angiogenesis and restoring the number of ovarian follicles and corpus lutea in ovaries. No deformities, tumor formation or deaths were observed in F1 and F2 rats, indicating that the local injection of MSCs into the ovary did not have any obvious side effects. In addition, the localization of the Y chromosome was investigated using the fluorescent in situ hybridization method by injecting male A-MSCs into the ovaries; as a result, the Y chromosomes were localized not in the follicles, but in the thecal layers. ELISA revealed that A-MSCs secreted higher levels of vascular endothelial cell growth factor (VEGF), insulin-like growth factor-1 (IGF-1) and hepatocyte growth factor (HGF) than tail fibroblast cells. Quantitative real-time PCR and immunohistochemistry showed that higher expression levels of VEGF, IGF-1 and HGF were observed in CTX-treated ovaries after A-MSC transplantation. These findings suggest that MSCs may have a role in restoring damaged ovarian function and could be useful for regenerative medicine.

Insulin-like growth factor II (IGF-II) and follicle stimulating hormone (FSH) combinations can improve the in vitro development of grown oocytes enclosed in caprine preantral follicles

OBJECTIVE

Evaluate the possible role of IGF-II alone or in association with FSH on in vitro development of isolated caprine preantral follicles.

METHODS

Preantral follicles (≥150 μm) were isolated from goat ovaries and cultured for 18 days in basic αMEM medium (control) or supplemented with IGF-II alone at 20 or 50 ng/ml, named IGF20 and IGF50, respectively, or in combination with recombinant FSH (FSH, IGF20F or IGF50F). During in vitro culture, the follicles were analyzed by using morphology criteria, antrum formation and growth rate as parameters. After 18 days of follicular culture, oocytes equal to or larger than 110 μm were used for in vitro maturation (IVM). Oocyte viability and meiosis resumption were assessed by fluorescence microscopy after labeling with calcein-AM, ethidium homodimer and Hoechst 33342.

RESULTS

The IGF20 treatment was the only treatment capable of maintaining the percentage of morphologically normal follicles from D0 until D6 and from D12 to D18 (p>0.05), while in all other treatments the percentage of morphologically normal follicles decreased progressively during 18 days of in vitro culture (p<0.05). At D18, all treatments with IGF-II or FSH resulted in a significantly higher percentage of normal follicles when compared to αMEM alone. The IGF50F treatment provided a significantly higher early antrum formation rate when compared to αMEM and FSH alone. The addition of IGF-II alone (20 or 50 ng/ml) or in combination with FSH prevented oocyte degeneration after IVM. Moreover, the FSH treatment demonstrated a lower percentage of oocyte degeneration when compared to control (4.35% vs. 26.3%, respectively; p<0.05). Regarding meiosis resumption, the IGF20F treatment was the only treatment that significantly differed from αMEM alone. All treatments except the control (αMEM alone) presented oocytes at metaphase II.

CONCLUSION

IGF-II associated with FSH stimulated in vitro follicular development, oocyte viability and meiotic resumption of caprine oocytes after IVM.

The effects of epidermal growth factor (EGF) on the in vitro development of isolated goat secondary follicles and the relative mRNA expression of EGF, EGF-R, FSH-R and P450 aromatase in cultured follicles

The effects of varying concentrations of EGF were evaluated in terms of in vitro follicular development and the mRNA expression levels of EGF, EGF-R, FSH-R and P450 aromatase. After 6 days, the addition of 50 ng/mL of EGF to the culture medium increased the antrum formation rates in comparison to cultured control and after 18 days of culture produced oocytes with higher rates of meiosis resumption when compared to the other treatments (P<0.05). The daily follicular growth rates in presence of EGF (50 or 100) were increased in comparison to the cultured control (P<0.05). Treatment with EGF 50 stimulated the expression of EGF mRNA but reduced EGF-R mRNA expression and estradiol secretion as compared to the cultured control (P<0.05). After 18 days of culture, the mRNA levels for FSH-R and P450 aromatase were greater than those of the non-cultured controls (P<0.05). In conclusion, the effects of EGF treatment on the mRNA levels for EGF, EGF-R, FSH-R, and P450 aromatase varied according to the stage of follicle development.

Isolation of ovarian components essential for growth and development of mammalian oocytes in vitro

Mammalian ovaries contain a large number of oocytes, most of which degenerate either before or at various stages of growth. Dynamic and precise regulation in the ovary involves many factors, each with a unique role. Identifying the single most important factor is impossible; however, it may be possible to identify factors essential for oocyte growth. It is evident that oocytes can grow into competent ova in vitro; however, how faithfully the follicle should mimic the in vivo conditions remains unclear. In the culture system discussed in this review, bovine and mouse oocyte-granulosa cell complexes, at approximately the late mid-growth stage, spread on a substratum without the involvement of theca cells. The structural simplicity of this system is advantageous because it reduces the basic conditions essential for regulation of oocyte growth. Apart from biological factors, high concentrations of polyvinylpyrrolidone (molecular weight: 360000) improved oocyte growth. Among ovarian factors, androstenedione was used to compensate for the absence of theca cells, and it promoted both follicular growth and acquisition of oocyte meiotic competence. Most oocytes cultured in a group were viable after long-term culture, suggesting that unlike ovarian events, there was no exhaustive follicle selection. Collectively, oocytes and their associated granulosa cells can establish independent units capable of supporting oocyte growth in appropriately modified culture media.

Follicular growth and atresia in mammalian ovaries: regulation by survival and death of granulosa cells

The mammalian ovary is an extremely dynamic organ in which a large majority of follicles are effectively eliminated throughout their reproductive life. Due to the numerous efforts of researchers, mechanisms regulating follicular growth and atresia in mammalian ovaries have been clarified, not only their systemic regulation by hormones (gonadotropins) but also their intraovarian regulation by gonadal steroids, growth factors, cytokines and intracellular proteins. Granulosa cells in particular have been demonstrated to play a major role in deciding the fate of follicles, serving molecules that are essential for follicular growth and maintenance as well as killing themselves by an apoptotic process that results in follicular atresia. In this review, we discuss the factors that govern follicular growth and atresia, with a special focus on their regulation by granulosa cells. First, ovarian folliculogenesis in adult life is outlined. Then, we explain about the regulation of follicular growth and atresia by granulosa cells, in which hormones, growth factors and cytokines, death ligand-receptor system and B cell lymphoma/leukemia 2 (BCL2) family members (mitochondria-mediated apoptosis) are further discussed.

Co-culture of buffalo (Bubalus bubalis) preantral follicles with antral follicles: a comparative study of developmental competence of oocytes derived from in vivo developed and in vitro cultured antral follicles

The present study was undertaken to examine whether the presence of antral follicles (AFs) affects the survival, growth and steroidogenesis of preantral follicles (PFs) and compare the maturation and developmental competence of buffalo oocytes derived from in vivo developed and in vitro cultured AFs. Two experiments were carried out. In experiment I, PFs (200-250 μm) were isolated and cultured with or without AFs (3-5 mm) in TCM-199 medium that contained 10% fetal bovine serum (FBS), 1% insulin transferin selenium (ITS), 20 ng/ml epidermal growth factor (EGF), 0.5 μg/ml follicle-stimulating hormone (FSH) and 100 ng/ml insulin-like growth factor (IGF)-I. In experiment II, in vitro developmental competence was compared for the cumulus-oocyte complexes (COCs) recovered from in vivo developed and in vitro cultured AFs. Survival, growth, development of antrum, accumulation of estradiol and progesterone was (P < 0.05) higher when PFs were co-cultured with AFs. Developmental competence of both types of follicular oocytes did not differ significantly in terms of maturation and cleavage rate, but morula and blastocyst production rate were (P < 0.05) higher with in vivo developed AFs as compared with the in vitro cultured antral follicular oocytes. In conclusion, co-culture of PFs with AFs supports long-term survival and growth of buffalo PFs and this co-culture system plays a dual role for in vitro production of embryos as well as understanding the relationship between developing PFs and AFs.

Conditions affecting growth and developmental competence of mammalian oocytes in vitro

Mammalian ovaries contain a large number of oocytes at different stages of growth. To utilize potential female gametes, it is important to develop culture systems that permit oocytes to achieve full growth and competence in order to undergo maturation, fertilization and development. The desired culture systems should meet at least the following three conditions: (i) oocytes remain healthy and functional so that they can execute intrinsic programs that direct their growth and development; (ii) granulosa cells that are adjacent to oocytes proliferate efficiently to prevent oocytes from becoming denuded; and (iii) granulosa cells maintain (and develop) appropriate associations with oocytes during the culture period. For this reason, several systems have been developed, and they can be classified into four categories based on the structure and components of the follicle/oocyte-granulosa cell complex and the location of the oocyte in the physical organization of the complex. The resultant diverse morphologies are due to multiple factors, including the method for initial isolation of follicles, the culture substrate, and hormones and other factors added into the medium. It is important to find an optimal combination of such factors involved in the process to facilitate future research efforts.