RESUMO
During oocyte meiosis resumption, a coordinated program of transcript translation and decay machinery promotes a remodeling of mRNA stores, which determines the success of the acquisition of competence and early embryo development. We investigated levels of two genes related to mRNA translation (CPEB1 and CPEB4) and two related to mRNA degradation (CNOT7 and ZFP36L2) machinery and found ZFP36L2 downregulated in in vitro-matured bovine oocytes compared to in vivo counterparts. Thereafter, we tested the effects of a pre-IVM step with NPPC and a modified IVM with AREG on the modulation of members of mRNA translation and degradation pathways in cumulus cells and oocytes. Our data showed a massive upregulation of genes associated with translational and decay processes in cumulus cells, promoted by NPPC and AREG supplementation, up to 9h of IVM. The oocytes were less affected by NPPC and AREG, and even though ZFP36L2 transcript and protein levels were downregulated at 9 and 19h of IVM, only one (KDM4C) from the ten target genes evaluated was differently expressed in these treatments. These data suggest that cumulus cells are more prone to respond to NPPC and AREG supplementation in vitro, regarding translational and mRNA decay programs. Given the important nursing role of these cells, further studies could contribute to a better understanding of the impact of these modulators in maternal mRNA modulation and improve IVM outcomes.
RESUMO
BACKGROUND: It is well described that circulating progesterone (P4) plays a key role in several reproductive events such as oocyte maturation. However, during diestrus, when circulating P4 is at the highest concentrations, little is known about its local impact on the follicular cells such as intrafollicular P4 concentration due to corpus luteum (CL) presence within the same ovary. Based on that, our hypothesis is that the CL presence in the ovary during diestrus alters intrafollicular P4 concentrations, oocyte competence acquisition, follicular cells gene expression, and small extracellular vesicles (sEVs) miRNAs contents. RESULTS: P4 hormonal analysis revealed that ipsilateral to the CL follicular fluid (iFF) presented higher P4 concentration compared to contralateral follicular fluid (cFF). Furthermore, oocyte maturation and miRNA biogenesis pathways transcripts (ADAMTS-1 and AGO2, respectively) were increased in cumulus and granulosa cells of iFF, respectively. Nevertheless, a RT-PCR screening of 382 miRNAs showed that three miRNAs were upregulated and two exclusively expressed in sEVs from iFF and are predicted to regulate cell communication pathways. Similarly, seven miRNAs were higher and two exclusively expressed from cFF sEVs and are predicted to modulate proliferation signaling pathways. CONCLUSION: In conclusion, intrafollicular P4 concentration is influenced by the presence of the CL and modulates biological processes related to follicular cell development and oocyte competence, which may influence the oocyte quality. Altogether, these results are crucial to improve our knowledge about the follicular microenvironment involved in oocyte competence acquisition.
Assuntos
Vesículas Extracelulares , MicroRNAs , Feminino , Animais , Bovinos , Líquido Folicular/metabolismo , Progesterona/metabolismo , Folículo Ovariano/metabolismo , Ovário/metabolismo , MicroRNAs/genética , MicroRNAs/metabolismo , Oócitos/metabolismo , Corpo Lúteo/metabolismo , Vesículas Extracelulares/genética , Expressão GênicaRESUMO
OBJECTIVE: The use of animals as experimental models has been proposed to improve the techniques applied in human reproduction clinics. This prospective and observational study evaluates the effects of the use of cumulus cells and collagen membrane on the maturation process of bovine oocytes. METHODS: Design and Setting: Bovine oocytes with or without cumulus cells were cultured in maturation medium for 24 hours in the conventional system (2D), central well plates and in the three-dimensional (3D) system. Intervention: The oocytes were positioned in the collagen membrane and matured for the same period. The morphological evaluation was carried out with the parameters of maturation. Main Outcome Measure: Presence or absence of the first polar corpuscle, which were observed and classified as germinal vesicle (GV), meiosis I (MI) and meiosis II (MII). RESULTS: The percentage of oocytes in GV was higher (p<0.05) in treatments without cumulus cells than those with cells. The rates of MII were higher (p<0.05) in the treatments with cumulus cells, independent of the culture system. In general, oocytes with presence of cumulus cells have approximately 1.7 times more chances (p<0.001) of reaching MII after MIV than those matured without cells. CONCLUSIONS: The presence of the cells in the cumulus is essential for the maturation process of bovine oocytes; the three-dimensional collagen membrane culture system is favorable for the maturation process of bovine oocytes.
RESUMO
Abstract Objective Endometriosis causes a decrease in oocyte quality. However, this mechanism is not fully understood. The present study aimed to analyze the effect of endometriosis on cumulus cell adenosine triphosphate ATP level, the number of mitochondria, and the oocyte maturity level. Methods A true experimental study with a post-test only control group design on experimental animals. Thirty-two mice were divided into control and endometriosis groups. Cumulus oocyte complex (COC) was obtained from all groups. Adenosine triphosphate level on cumulus cells was examined using the Elisa technique, the number of mitochondria was evaluated with a confocal laser scanning microscope and the oocyte maturity level was evaluated with an inverted microscope. Results The ATP level of cumulus cells and the number of mitochondria in the endometriosis group increased significantly (p < 0.05; p < 0.05) while the oocyte maturity level was significantly lower (p < 0.05). There was a significant relationship between ATP level of cumulus cells and the number of mitochondrial oocyte (p < 0.01). There was no significant relationship between cumulus cell ATP level and the number of mitochondrial oocytes with oocyte maturity level (p > 0.01; p > 0.01). The ROC curve showed that the number of mitochondrial oocytes (AUC = 0.672) tended to be more accurate than cumulus cell ATP level (AUC = 0.656) in determining the oocyte maturity level. Conclusion In endometriosis model mice, the ATP level of cumulus cells and the number of mitochondrial oocytes increased while the oocyte maturity level decreased. There was a correlation between the increase in ATP level of cumulus cells and an increase in the number of mitochondrial oocytes.
Assuntos
Animais , Ratos , Oócitos , Trifosfato de Adenosina , Endometriose , Células do Cúmulo , Saúde Reprodutiva , MitocôndriasRESUMO
Multiple effects of stress on health have been reported; however, reproductive alterations in oocytes and cumulus cells have not been fully described. In females, chronic stress has been shown to produce alterations in the estrous cycle, to decrease oocyte in vivo maturation, and to increase the percentage of abnormal oocytes. The aim of this study was to evaluate whether the oocytes from chronically stressed female rats could recover and mature in vitro by providing them with all the necessary culture conditions, as well as to evaluate the functionality of the GAP junctions, and the viability and DNA integrity of the cumulus cells, which are crucial for the complete maturation and development of the oocyte. For this, rats were stressed daily by cold water immersion (15 °C) during 15 min for 30 consecutive days. Corticosterone serum levels in rats increased as an indicator of stress. Chronic stress decreased the percentage of in vitro matured oocytes because the cumulus cells presented irreparable damage to their DNA that led to their death, being unable to establish bidirectional communication with the oocyte for its meiotic resumption through the GAP junctions, which were also damaged. These findings could partially explain an association between stress and infertility.
Assuntos
Meiose , Oócitos , Ratos , Feminino , Animais , Oogênese , Células do Cúmulo , DNA , FertilidadeRESUMO
Cumulus cells from cumulus-oocyte complexes (COC) matured in vitro in serum-free medium show high incidence of apoptosis and DNA double-strand breaks (DSB). This study aimed to characterize the transcript expression profile of selected genes involved in DNA repair mechanisms in bovine cumulus cells cultured with bovine serum albumin (BSA) or fetal calf serum (FCS). Briefly, bovine cumulus-oocyte complexes were in vitro matured with either, 0.4% BSA or 10% FCS for 3, 6, 12 or 24 h. The total RNA of cumulus cells was used for real-time PCR analysis. Transcript abundance of XRCC6, XRCC5, DNAPK, GAAD45B, TP53BP1, RAD50, RAD52, ATM and BRCA2 target genes changed as the IVM proceeded (P < 0.05). However, an interaction between protein source (FCS or BSA) and time was not detected (P ≥ 0.05). Cumulus cells from COCs matured with BSA presented higher mRNA expression of two genes compared to FCS group: TP53BP1 at 6 h and BRCA1 at 3, 6, 12 and 24 h (P < 0.05). In summary, our results showed for the first time the expression profile of the key genes involved in DSB repair mechanisms in cumulus cells obtained from bovine COCs matured with FCS or BSA. The higher mRNA expression of BRCA1 and TP53BP1 and lower mRNA expression of TNFAIP6 suggests an increase in apoptosis rate and DNA damage in cumulus cells cultured in BSA-supplemented medium and may explain, at least to some extent, the reduced developmental potential of bovine oocytes matured in serum-free medium.
Assuntos
Células do Cúmulo , Soroalbumina Bovina , Feminino , Animais , Células do Cúmulo/metabolismo , Oócitos/metabolismo , Reparo do DNA , RNA Mensageiro/metabolismo , Células CultivadasRESUMO
Besides their canonical roles as energy sources, short-chain fatty acids act as metabolic regulators of gene expression through histone posttranslational modifications. Ketone body ß-hydroxybutyrate (BHB) causes a novel epigenetic modification, histone lysine ß-hydroxybutyrylation (Kbhb), which is associated with genes upregulated in starvation-responsive metabolic pathways. Dairy cows increase BHB in early lactation, and the effects of this increase on cellular epigenomes are unknown. We searched for and identified that Kbhb is present in bovine tissues in vivo and confirmed that this epigenetic mark is responsive to BHB in bovine and human fibroblasts cultured in vitro in a dose-dependent manner. Maturation of cumulus-oocyte complexes with high concentrations of BHB did not affect the competence to complete meiotic maturation or to develop until the blastocyst stage. BHB treatment strongly induced H3K9bhb in cumulus cells, but faintly in oocytes. RNA-seq analysis in cumulus cells indicated that BHB treatment altered the expression of 345 genes. The downregulated genes were mainly involved in glycolysis and ribosome assembly pathways, while the upregulated genes were involved in mitochondrial metabolism and oocyte development. The genes and pathways altered by BHB will provide entry points to carry out functional experiments aiming to mitigate metabolic disorders and improve fertility in cattle.
Assuntos
Ácido 3-Hidroxibutírico , Células do Cúmulo , Epigênese Genética , Histonas , Lisina , Oócitos , Ácido 3-Hidroxibutírico/metabolismo , Ácido 3-Hidroxibutírico/farmacologia , Animais , Bovinos , Células do Cúmulo/metabolismo , Feminino , Histonas/metabolismo , Humanos , Lisina/metabolismo , Oócitos/metabolismoRESUMO
Clomiphene citrate (CC) and letrozole are ovulatory stimulants that, despite high ovulation rates, achieve low pregnancy rates. This study aimed to investigate the in vitro effects of CC and letrozole, alone or in combination with estradiol, on apoptosis in human cumulus cells. We performed a controlled prospective study using primary cumulus cell cultures from patients undergoing in vitro fertilization (n=22). Alpha-inhibin immunocytochemistry was used to assess cell culture purity and morphology. Cell viability was evaluated by MTT assay, cell cycle status by flow cytometry, and Caspase-3, Bax and SOD-2, and S26 gene expression by qPCR. Cells were treated for 24 hours in 5 conditioned media: CC, CC + estradiol, letrozole, letrozole + estradiol and control. None of the treatments affected cell viability, but letrozole reduced the mean percentage of cells in the S phase compared to control (24.79 versus 21.70, p=0.0014). Clomiphene treatment increased mRNA expression of Bax (4 fold) and SOD-2 (2 fold), which was reversed by co-treatment with estradiol. SOD-2 expression increased in cells treated with letrozole compared to control (4 fold), which was also reversed by estradiol. These findings suggest that clomiphene citrate and letrozole do not significantly affect the viability of human cumulus cells. Still, the expression of genes involved in apoptosis was modulated by these drugs alone and in association with estradiol, suggesting that CC and letrozole may have direct effects on cumulus cells beyond their known mechanisms of action.
Assuntos
Fármacos para a Fertilidade Feminina , Infertilidade Feminina , Ciclo Celular , Clomifeno/farmacologia , Clomifeno/uso terapêutico , Células do Cúmulo , Estradiol/farmacologia , Estradiol/uso terapêutico , Feminino , Fármacos para a Fertilidade Feminina/farmacologia , Fármacos para a Fertilidade Feminina/uso terapêutico , Humanos , Infertilidade Feminina/tratamento farmacológico , Letrozol/farmacologia , Nitrilas/farmacologia , Nitrilas/uso terapêutico , Indução da Ovulação , Gravidez , Taxa de Gravidez , Estudos Prospectivos , Superóxido Dismutase , Triazóis/farmacologia , Triazóis/uso terapêutico , Proteína X Associada a bcl-2RESUMO
Perfluorooctanoic acid is a synthetic compound mostly used in a wide range of consumer products with several adverse effects on somatic cells and gametes. It has been linked to hepatotoxic and carcinogenic effects, alterations in the immune system, endocrine, and reproductive alterations. In vivo studies show an increase in reactive oxygen species and DNA damage. However, the mechanisms by which this compound affects fertility, remain contradictory. Therefore, the aim of the present study was to evaluate the effect of perfluorooctanoic acid on oocyte viability and maturation, as well as the viability, generation of oxidative stress, and genotoxic damage in the cumulus cells exposed during in vitro maturation. This compound had a negative effect on oocyte viability (lethal concentration, LC50 = 269 µM) and maturation (inhibition maturation concentration IM50 = 75 µM), while in cumulus cells the LC50 was 158 µM. The generation of reactive oxygen species evaluated in cumulus cells, protein carbonylation, and DNA damage, was significantly increased at 40 µM perfluorooctanoic acid. This study provides evidence that perfluorooctanoic acid causes reactive oxygen species generation, protein oxidation, and DNA damage in cumulus cells, compromising the maturation and viability of porcine oocyte, which may affect fertility.
Assuntos
Células do Cúmulo , Oócitos , Animais , Caprilatos , Células Cultivadas , Dano ao DNA , Feminino , Fluorocarbonos , Técnicas de Maturação in Vitro de Oócitos , Estresse Oxidativo , Espécies Reativas de Oxigênio/metabolismo , SuínosRESUMO
Citrato de clomifeno (CC) e letrozol (LE) são indutores de ovulação que, apesar das altas taxas de ovulação confirmada, atingem baixas taxas de gravidez. Este estudo teve como objetivo investigar os efeitos de CC e LE in vitro, isoladamente ou em combinação com estradiol (E), na apoptose de células do cumulus oophorus humano. Realizamos um estudo prospectivo controlado utilizando culturas primárias de células do cumulus de pacientes submetidas à fertilização in vitro (n=22). A coloração com Giemsa e a imunocitoquímica para alfa-inibina foram utilizadas para avaliar a pureza e a morfologia da cultura celular. A viabilidade celular foi avaliada pelo ensaio MTT, o ciclo celular por citometria de fluxo e a expressão gênica de Caspase-3, Bax e Superóxido dismutase 2 (SOD-2) e S26 por reação em cadeia de polimerase (PCR) em tempo real. As células foram tratadas por 24 horas em 5 grupos de tratamento: CC, CC + E, LE, LE + E e controle. Nenhum dos tratamentos afetou a viabilidade celular, mas o LE reduziu a porcentagem média de células na fase S em relação ao controle (24,79 versus 21,70, p=0,0014). O tratamento com CC aumentou a expressão gênica de Bax (4 vezes) e SOD-2 (2 vezes), que foi revertida quando adicionado E à cultura. A expressão de SOD-2 aumentou em células tratadas com LE quando comparado ao controle (4 vezes), que foi também revertida por adição de E. Estes achados sugerem que CC e LE não afetam significativamente a viabilidade das células do cumulus humana. Porém, houve modulação na expressão de genes envolvidos na apoptose por essas drogas isoladamente e em associação com E, sugerindo que CC e LE podem ter efeitos diretos nas células do cumulus além de seus mecanismos de ação conhecidos.
Clomiphene citrate (CC) and letrozole (LE) are ovulatory stimulants that, despite high ovulation rates, achieve low pregnancy rates. This study aimed to investigate the in vitro effects of CC and LE, alone or in combination with estradiol (E), on apoptosis in human cumulus cells. We performed a controlled prospective study using primary cumulus cell cultures from patients undergoing in vitro fertilization (n=22). Giemsa stain and alpha-inhibin immunocytochemistry was used to assess cell culture purity and morphology. Cell viability was evaluated by MTT assay, cell cycle status by flow cytometry, and Caspase-3, Bax and superoxide dismutase 2 (SOD-2), and S26 gene expression by real-time polymerase chain reaction (qPCR). Cells were treated for 24 hours in 5 conditioned media: CC, CC + E, LE, LE + E and control. None of the treatments affected cell viability, but LE reduced the mean percentage of cells in the S phase compared to control (24.79 versus 21.70, p=0.0014). CC treatment increased mRNA expression of Bax (4 fold) and SOD-2 (2 fold), which was reversed by co-treatment with E. SOD-2 expression increased in cells treated with LE compared to control (4 fold), which was also reversed by E. These findings suggest that CC and LE do not significantly affect the viability of human cumulus cells. Still, the expression of genes involved in apoptosis was modulated by these drugs alone and in association with E, suggesting that CC and LE may have direct effects on cumulus cells beyond their known mechanisms of action.
Assuntos
Clomifeno , Ácido Cítrico , Dissertação AcadêmicaRESUMO
BACKGROUND: The evaluation of the DNA damage generated in cumulus cells after mature cumulus-oocyte complexes vitrification can be considered as an indicator of oocyte quality since these cells play important roles in oocyte developmental competence. Therefore, the aim of this study was to determine if matured cumulus-oocyte complexes exposure to cryoprotectants (CPAs) or vitrification affects oocytes and cumulus cells viability, but also if DNA damage is generated in cumulus cells, affecting fertilization and embryo development. RESULTS: The DNA damage in cumulus cells was measured using the alkaline comet assay and expressed as Comet Tail Length (CTL) and Olive Tail Moment (OTM). Results demonstrate that oocyte exposure to CPAs or vitrification reduced oocyte (75.5 ± 3.69%, Toxicity; 66.7 ± 4.57%, Vitrification) and cumulus cells viability (32.7 ± 5.85%, Toxicity; 7.7 ± 2.21%, Vitrification) compared to control (95.5 ± 4.04%, oocytes; 89 ± 4.24%, cumulus cells). Also, significantly higher DNA damage expressed as OTM was generated in the cumulus cells after exposure to CPAs and vitrification (39 ± 17.41, 33.6 ± 16.69, respectively) compared to control (7.4 ± 4.22). In addition, fertilization and embryo development rates also decreased after exposure to CPAs (35.3 ± 16.65%, 22.6 ± 3.05%, respectively) and vitrification (32.3 ± 9.29%, 20 ± 1%, respectively). It was also found that fertilization and embryo development rates in granulose-intact oocytes were significantly higher compared to denuded oocytes in the control groups. However, a decline in embryo development to the blastocyst stage was observed after CPAs exposure (1.66 ± 0.57%) or vitrification (2 ± 1%) compared to control (22.3 ± 2.51%). This could be attributed to the reduction in both cell types viability, and the generation of DNA damage in the cumulus cells. CONCLUSION: This study demonstrates that oocyte exposure to CPAs or vitrification reduced viability in oocytes and cumulus cells, and generated DNA damage in the cumulus cells, affecting fertilization and embryo development rates. These findings will allow to understand some of the mechanisms of oocyte damage after vitrification that compromise their developmental capacity, as well as the search for new vitrification strategies to increase fertilization and embryo development rates by preserving the integrity of the cumulus cells.
RESUMO
INTRODUCTION: Oocyte competence and quality depend on communication between the oocyte and the cumulus and theca cells. In the preantral phase, the members of the transforming growth factor ß (TGF-ß) superfamily are responsible for this communication and play an important role in folliculogenesis. Members of the TGF-ß superfamily are related to endometriosis (overexpression in the ectopic endometrium); however, few studies have explored these proteins as influencing fertility in endometriosis. Considering endometriosis-related infertility and to better understand the role of the TGF-ß superfamily members in the antral phase in women with endometriosis, this research investigated the gene expression of the genes for ligands AMH, BMP-6, GDF-9, INHA, INHBB, and TGFß3; receptors AMHR2, BMPR2, and TGFßR3; and intracellular signalling: SMAD3 and SMAD4. MATERIAL AND METHODS: The gene expression of AMH, BMP-6, GDF-9, INHA, INHBB, TGFß3, AMHR2, BMPR2, TGFßR3, SMAD3, and SMAD4 in cumulus cells was investigated through quantitative real-time PCR in a case-control study including infertile women with and without peritoneal endometriosis undergoing in vitro fertilization. RESULTS: Age and outcomes of assisted reproduction were similar between the groups (P > .05). However, women with endometriosis showed reduced expression of BMP-6 and SMAD4 (P < .05) in cumulus cells compared with the control group, other genes did not present altered gene expression in women with endometriosis (P > .05). CONCLUSIONS: The reduced expression of BMP-6 and SMAD4 in women with peritoneal endometriosis compared with the control group indicates that granulosa (cumulus) cell function could be altered in these women.
Assuntos
Proteína Morfogenética Óssea 6/genética , Células do Cúmulo/metabolismo , Endometriose/complicações , Expressão Gênica , Infertilidade Feminina/complicações , Proteína Smad4/genética , Adulto , Hormônio Antimülleriano , Receptores de Proteínas Morfogenéticas Ósseas Tipo II , Estudos de Casos e Controles , Feminino , Fator 9 de Diferenciação de Crescimento , Humanos , Subunidades beta de Inibinas , Inibinas , Peptídeos e Proteínas de Sinalização Intracelular/genética , Peptídeos e Proteínas de Sinalização Intracelular/metabolismo , Ligantes , Proteoglicanas , Reação em Cadeia da Polimerase em Tempo Real , Receptores de Superfície Celular/genética , Receptores de Superfície Celular/metabolismo , Receptores de Peptídeos , Receptores de Fatores de Crescimento Transformadores beta , Proteína Smad3 , Fator de Crescimento Transformador beta/genética , Fator de Crescimento Transformador beta/metabolismo , Fator de Crescimento Transformador beta3RESUMO
RESEARCH QUESTION: Is the profile of microRNA (miRNA) altered in cumulus cells of infertile women with early (EI/II) and advanced (EIII/IV) endometriosis? DESIGN: In this prospective case-control study, a miRNA profile including 754 targets was evaluated in samples of cumulus cells from infertile women with endometriosis (5 EI/II, 5 EIII/IV) and infertile controls (5, male and/or tubal factor) undergoing ovarian stimulation for intracytoplasmic sperm injection, using TaqMan® Array Human MicroRNA Cards A and B. The groups were compared with Kruskal-Wallis test, followed by Benjamini-Hochberg correction and Dunn's post hoc test. An in silico enrichment analysis was performed to list the possibly altered pathways in which the altered miRNA target genes are involved. RESULTS: Only the miRNA miR-532-3p showed significant differences among the analysed groups, being down-regulated in the EIII/IV group compared with the infertile control group, as well as compared with the EI/II group. The enrichment analysis showed that some genes regulated by this miRNA are involved in important pathways for the acquisition of oocyte competence, such as the oxytocin, calcium, Wnt, FoxO, ErbB and Ras signalling pathways, as well as the oocyte meiosis pathway. CONCLUSION: The present findings bring new perspectives to understanding the follicular microenvironment of infertile women with different stages of endometriosis. It is suggested that the dysregulation of miR-532-3p may be a potential mechanism involved in the aetiopathogenesis of endometriosis-related infertility. Further studies are needed to evaluate these pathways in cumulus cells of infertile women with the disease, as well as their impact on the acquisition of oocyte competence.
Assuntos
Células do Cúmulo/metabolismo , Endometriose/metabolismo , Infertilidade Feminina/metabolismo , MicroRNAs/metabolismo , Adulto , Estudos de Casos e Controles , Endometriose/complicações , Feminino , Humanos , Infertilidade Feminina/etiologia , Estudos ProspectivosRESUMO
Addition effects of insulin-like growth factor-1 (IGF-1) and its synthetic analogue insulin-like growth factor-1 recombinant-3 (LongR3-IGF-1) after in vitro maturation (IVM) of cattle cumulus-oocyte complexes (COCs) were compared and evaluated on meiotic progression, apoptosis and profile genes of oocyte competence (GDF9, BMP15, BAX, BCL2, OOSP1, IGFBP2, IGBFP4 and IGFBP5), and their respective cumulus cells (AREG, EGFR, FSHR, COX2, BAX, BCL2, IGFBP2, IGFBP4 and IGFBP5). The 739 COCs (n = 10 pools) of bovine ovaries were collected, selected and matured with IGF-1 (100 ng/mL), LongR3-IGF-1 (100 ng/mL), and in two control groups with 0.1% polyvinyl alcohol (PVA) or 10% fetal bovine serum (FBS), for 22-24 h. The statistical analysis was performed by a linear mixed effects model, ANOVA and Tukey tests. There was no statistical difference between experimental groups taken into account the meiotic progression and apoptosis (P > 0.05). Nevertheless, there were statistical differences (P ≤ 0.05) among FBS, IGF-1 and LongR3-IGF-1 groups for IGFBP4 gene expression, and among PVA, IGF-1 and LongR3-IGF-1 for COX2 gene expression in cumulus cells. Moreover, statistical difference was found for BCL2 gene expression between IGF-1, FBS and PVA groups and for IGFBP4 gene expression between LongR3-IGF-1, PVA and FBS in oocytes. There was no statistical difference between experimental groups for other genes evaluated. These results showed a good performance of IVM of bovine oocytes in the presence of LongR3-IGF-1 and the possibility of replacement of IGF-1 and FBS.
Assuntos
Células do Cúmulo/efeitos dos fármacos , Técnicas de Maturação in Vitro de Oócitos/veterinária , Fator de Crescimento Insulin-Like I/farmacologia , Oócitos/efeitos dos fármacos , Proteínas Recombinantes/farmacologia , Animais , Bovinos , FemininoRESUMO
METHODS: This is a cohort study, conducted at a university-based reproductive medicine center and private reproductive medicine center that aimed to evaluate granulosa cumulus cell gene expression in the insulin signaling pathway in Polycystic Ovary Syndrome (PCOS) patients undergoing in vitro fertilization (IVF) treatment and to compare the cumulus gene expression between normal weight and obese women without clinical insulin resistance. Fifteen PCOS patients, nine normal weight patients and six obese patients presenting normal HOMA IR (Homeostasis Model Assessment-Insulin Resistance), participated. Patients underwent oocyte retrieval for IVF and after the procedure, granulosa cumulus cells were removed from the oocytes for RNA extraction. Quantitative polymerase chain reaction (PCR) array analysis of 84 genes from insulin signaling pathway was conducted. The results were expressed as fold up- or fold down-expression in obese patients compared with normal weight patients. Any fold change ⩾3 or ⩽3 and any p ⩽ 0.05 were considered statistically significant. RESULTS: There were 10 genes that were overexpressed in obese compared with normal weight women, BCL2L1, BRAF, CBL, DOK1, FBP1, FRS2, MTOR, PCK2, RPS6KA1, and SORBS1, that had a fold change ⩾3 and p ⩽ 0.05. DISCUSSION: In the obese group, the overexpressed genes are mainly responsible for the proliferation and differentiation of cumulus cells during oocyte maturation, insulin resistance, apoptosis regulation, and glucose metabolism during early embryogenesis, suggesting that in the follicular environment, insulin resistance is present even in the absence of clinical signs. CONCLUSION: Together, our findings and the related literature suggest that those alterations may be associated with the worse prognosis of follicular development and oocyte maturation observed in PCOS obese women.
RESUMO
This study aimed to assess the effects of the inhibition of nitric oxide synthase (NOS) on events that modulate bovine in vitro oocyte maturation. Cumulus-oocyte complexes (COCs) were cultured with hemisections (HSs) of the follicular walls in a maturation medium supplemented with different concentrations (0.1-10.0 mM) of Nω-nitro-l-arginine methyl ester hydrochloride (l-NAME). Controls consisted of COCs cultured in the presence (+HSs) or absence of HSs (-HSs) with no additional l-NAME supplementation. The following parameters were assessed: oocyte nuclear maturation stage; cumulus cell (CC) membrane integrity; nitrate/nitrite, progesterone, and estradiol concentrations in the culture medium at 22 h of cultivation; and the concentrations of cGMP and cAMP in COCs during the first hour of maturation. The addition of 1.0 mM l-NAME increased the percentage of oocytes that reached metaphase II (MII) and the percentage of intact CCs (P < 0.05). All l-NAME concentrations reduced the nitrate/nitrite concentrations (P < 0.05), but none affected steroid concentrations compared with control +HSs (P > 0.05). The addition of 1.0 mM l-NAME reduced cGMP concentrations at 3 h and increased cAMP concentrations in the first hour of culture (P < 0.05). Our findings suggest that the NOS/NO/cGMP pathway participates in meiosis progression (MI to MII) of the bovine oocytes matured in vitro in the presence of hemisections of the follicular walls. Lastly, the mechanisms that lead to the progression of meiosis after NOS inhibition do not involve changes in steroid production.
RESUMO
Metaphase II oocytes (MII) from polycystic ovary syndrome (PCOS) frequently have impaired oocyte competence. Since telomere maintenance is important for folliculogenesis, oocyte maturation, and early embryonic development, we sought to verify the implications of PCOS on telomere length and telomerase activity in immature oocytes and cumulus cells. 43 PCOS and 67 control women were included, and anthropometric, biochemical, and hormonal characteristics were evaluated. The telomere length in germinal vesicle stage (GV) and in metaphase I (MI) oocytes, as well as in the cumulus cells of immature (CCI) and mature oocytes (CCM), and in leukocytes was measured by qPCR. The telomerase activity in reproductive cells was evaluated by the TRAPeze® XL Kit. The body mass index (p = 0.001), LH (p = 0.015), estradiol (p = 0.004), insulin (p = 0.002), testosterone (p < 0.0001), androstenedione (p = 0.001), free androgen index (p < 0.0001), and c-reactive protein (p = 0.003) were greater, while the FSH (p = 0.0002) was lower in the PCOS group. The telomere length in the CCI (p = 0.649) and CCM (p = 0.378) did not differ between the PCOS and the control groups. On the other hand, telomerase activity in the CCI (p = 0.003) and CCM (p = 0.022) was higher in the PCOS group. In the leukocyte's cells, the telomere length was reduced in the PCOS group (p = 0.025). In the GV and MI oocytes, no differences were observed in telomere length and telomerase activity between the groups. We showed that telomere length is not altered in reproductive cells from PCOS. However, higher telomerase activity in the CCI and CCM may be required for telomere length maintenance.
Assuntos
Células do Cúmulo/metabolismo , Oócitos/metabolismo , Síndrome do Ovário Policístico/metabolismo , Telomerase/metabolismo , Telômero/metabolismo , Adulto , Androstenodiona/sangue , Índice de Massa Corporal , Estudos de Casos e Controles , Estradiol/sangue , Feminino , Hormônio Foliculoestimulante/sangue , Humanos , Insulina/sangue , Oogênese/fisiologia , Estudos Prospectivos , Testosterona/sangueRESUMO
Extracellular vesicles (EVs) are nanoparticles secreted by ovarian follicle cells. Extracellular vesicles are an important form of intercellular communication, since they carry bioactive contents, such as microRNAs (miRNAs), mRNAs, and proteins. MicroRNAs are small noncoding RNA capable of modulating mRNA translation. Thus, EVs can play a role in follicle and oocyte development. However, it is not clear if EV contents vary with the estrous cycle stage. The aim of this study was to investigate the bovine miRNA content in EVs obtained from follicles at different estrous cycle stages, which are associated with different progesterone (P4) levels in the follicular fluid (FF). We collected FF from 3 to 6 mm follicles and evaluated the miRNA profile of the EVs and their effects on cumulus-oocyte complexes during in vitro maturation. We observed that EVs from low P4 group have a higher abundance of miRNAs predicted to modulate pathways, such as MAPK, RNA transport, Hippo, Cell cycle, FoxO, oocyte meiosis, and TGF-beta. Additionally, EVs were taken up by cumulus cells and, thus, affected the RNA global profile 9 h after EV supplementation. Cumulus cells supplemented with EVs from low P4 presented upregulated genes that could modulate biological processes, such as oocyte development, immune responses, and Notch signaling compared with genes of cumulus cells in the EV free media or with EVs from high P4 follicles. In conclusion, our results demonstrate that EV miRNA contents are distinct in follicles exposed to different estrous cycle stage. Supplementation with EVs impacts gene expression and biological processes in cumulus cells.
Assuntos
Células do Cúmulo/metabolismo , Ciclo Estral/metabolismo , Vesículas Extracelulares/metabolismo , MicroRNAs/metabolismo , Oócitos/metabolismo , Animais , Bovinos , Ciclo Celular/fisiologia , Ciclo Estral/genética , Feminino , Líquido Folicular/metabolismo , Técnicas de Maturação in Vitro de Oócitos , Meiose/fisiologia , MicroRNAs/genética , Folículo Ovariano/metabolismoRESUMO
Significance: Four decades have passed since the first successful human embryo conceived from a fertilization in vitro. Despite all advances, success rates in assisted reproduction techniques still remain unsatisfactory and it is well established that oxidative stress can be one of the major factors causing failure in in vitro fertilization (IVF) techniques. Recent Advances: In the past years, researchers have been shown details of the supportive role CCs play along oocyte maturation, development, and fertilization processes. Regarding redox metabolism, it is now evident that the synergism between gamete and somatic CCs is fundamental to further support a healthy embryo, since the oocyte lacks several defense mechanisms that are provided by the CCs. Critical Issues: There are many sources of reactive oxygen species (ROS) in the female reproductive tract in vivo that can be exacerbated (or aggravated) by pathological features. While an imbalance between ROS and antioxidants can result in oxidative damage, physiological levels of ROS are essential for oocyte maturation, ovulation, and early embryonic growth where they act as signaling molecules. At the event of an assisted reproduction procedure, the cumulus/oophorus complex is exposed to additional sources of oxidative stress in vitro. The cumulus cells (CCs) play essential roles in protecting the oocytes from oxidative damage. Future Directions: More studies are needed to elucidate redox biology in human CCs and oocyte. Also, randomized controlled trials will identify possible benefits of in vivo or in vitro administration of antioxidants for patients seeking IVF procedure.
Assuntos
Células do Cúmulo/fisiologia , Oócitos/fisiologia , Animais , Antioxidantes/metabolismo , Biologia/métodos , Células do Cúmulo/metabolismo , Feminino , Fertilização in vitro/métodos , Humanos , Oócitos/metabolismo , Oxirredução , Estresse Oxidativo/fisiologia , Espécies Reativas de Oxigênio/metabolismoRESUMO
The effect of doramectin (DOR) was tested on two experimental somatic bovine cells in vitro: peripheral lymphocytes (PL) and cumulus cells (CC). The cytotoxicity and genotoxicity of DOR were assessed using 3-(4,5-dimethyl-2-thiazolyl)-2,5-diphenyl-2H-tetrazolium bromide (MTT) assay, single cell gel electrophoresis assay (SCGE) and cytokinesis-block micronucleus cytome (CBMN Cyt) assay. Both cells were treated with three concentrations of DOR (20, 40, 60 ng mL-1) for 24 h. The results obtained from PL demonstrated that DOR was able to induce cytotoxic effect and DNA damage with all concentrations tested. Additionally, DOR increased micronuclei (MNi) frequency and nuclear buds (NBuds) with 20, 40, 60 ng mL-1, and nucleoplasmic bridges (NPBs) only with 40 ng mL-1. On the other hand, the three concentrations of DOR were not able to induce cytotoxic effect and DNA damage using SCGE in the bovine CC. Nevertheless, the two higher concentrations of DOR (20, 40 µg mL-1) significantly increased the frequency of micronucleus formation in bovine CC. These results represent the first experimental evidence of genotoxic and cytotoxic effects exerted by DOR on bovine PL and CC.