Oxidative status in granulosa cells of infertile women undergoing IVF

Glutathione peroxidase (GPX1) - Selenocysteine metabolism preserves the follicular fluid's (FF) redox homeostasis via IGF-1- NMD cascade in follicular ovarian cysts (FOCs)

Follicular ovarian cysts (FOCs) are characterized by follicles in the ovaries that are >20 mm in diameter and persist for >10 days without the corpus luteum, leading to anovulation, dysregulation of folliculogenesis and subfertility in humans and livestock species. Despite their clinical significance, the precise impact of FOCs on oocyte reserve, maturation, and quality still needs to be explored. While FOCs are observed in both human and livestock populations, they are notably prevalent in livestock species. Consequently, livestock species serve as valuable models for investigating the molecular intricacies of FOCs. Thus, in this study, using goat FOCs, we performed integrated proteomic, metabolomic and functional analyses to demonstrate that oocyte maturation is hampered due to increased reactive oxygen species (ROS) in FOCs follicular fluid (FF) via downregulation of glutathione peroxidase (GPX1), a critical antioxidant seleno enzyme required to negate oxidative stress. Notably, GPX1 reduction was positively correlated with the FF's decline of free selenium and selenocysteine metabolic enzymes, O-phosphoryl-tRNA (Sec) selenium transferase (SEPSECS) and selenocysteine lyase (SCLY) levels. Adding GPX1, selenocysteine, or selenium to the culture media rescued the oocyte maturation abnormalities caused by FOCs FF by down-regulating the ROS. Additionally, we demonstrate that substituting GPX1 regulator, Insulin-like growth factor-I (IGF-1) in the in vitro maturation media improved the oocyte maturation in the cystic FF by down-regulating the ROS activity via suppressing Non-sense-mediated decay (NMD) of GPX1. In contrast, inhibition of IGF-1R and the target of rapamycin complex 1 (mTORC1) hampered the oocyte maturation via NMD up-regulation. These findings imply that the GPX1 regulation via selenocysteine metabolism and the IGF-1-mediated NMD may be critical for the redox homeostasis of FF. We propose that GPX1 enhancers hold promise as therapeutics for enhancing the competence of FOCs oocytes. However, further in vivo studies are necessary to validate these findings observed in vitro.

Impact of endometriosis on the ovarian follicles

A significant body of evidence has supported a negative impact of endometriosis on ovarian follicles; however, the origin and relevance of this ovarian impairment in endometriosis is still a matter of debate. The ovarian damage can be caused by endometriosis itself or by surgeries aiming to remove endometriotic lesions. In this review, we summarized the existing knowledge on the mechanisms by which endometriosis can impact the ovarian follicles, from molecular to clinical points of view. From a molecular standpoint, the presence of endometriosis or its consequences can induce oxidative stress, inflammation, aberrant mitochondrial energy metabolism and inappropriate steroid production in granulosa cells, phenomena that may impair the quality of oocytes to variable degrees. These alterations may have clinical relevance on the accelerated exhaustion of the ovarian reserve, on the ovarian response to gonadotrophin stimulation in IVF cycles and on the competence of the oocytes. Critical points to be considered in current clinical practices related to fertility issues in endometriosis are discussed.

Interleukin-22 promotes proliferation and reverses LPS-induced apoptosis and steroidogenesis attenuation in human ovarian granulosa cells: implications for polycystic ovary syndrome pathogenesis

OBJECTIVE

Interleukin 22 (IL-22) plays a role in inflammatory diseases. However, whether IL-22 affects the function of ovarian granulosa cells (GCs) and its relationship with Polycystic Ovary Syndrome (PCOS)remains unclear.

METHODS

We investigated the level of IL-22 in human follicular fluid using ELISA. The expression and localization of the IL-22 receptor 1 (IL-22R1) in GCs were investigated by RT-PCR and immunofluorescence staining, respectively. The proliferation of KGN cells (human GCs line) was assessed by CCK-8 assay and EdU assay after treatment with recombinant human IL-22 (rhIL-22) and lipopolysaccharide (LPS). Apoptosis was assessed using flow cytometry. Apoptotic proteins and steroidogenic genes were detected by western blotting.

RESULTS

ELISA's results showed that compared with the control group, PCOS patients showed lower expression of IL-22 in follicular fluid. Immunofluorescence showed that IL-22R1 is expressed and localized in human granulosa cell membranes. IL-22 promoted cell proliferation and reversed LPS-induced inhibition of cell proliferation. IL-22 alone did not affect apoptotic or steroidogenic protein expression, however, it reversed LPS-induced apoptosis via downregulation of Bcl-2, upregulation of Bax and cleaved caspase-3, and restoration of LPS-downregulated StAR, CYP11A1, and CYP19A1 expression. Western blotting confirmed that IL-22 activated the JAK2/STAT3 signaling.

CONCLUSION

IL-22 promotes cell proliferation, inhibits apoptosis, and regulates KGN cell steroidogenesis confronted with LPS, and decreased IL-22 may be involved in the development of PCOS.

Oxidative stress and mitochondrial dysfunction of granulosa cells in polycystic ovarian syndrome

Polycystic ovarian syndrome (PCOS) is one of the leading causes of anovulatory infertility in women, affecting 5%-15% of women of reproductive age worldwide. The clinical manifestations of patients include ovulation disorders, amenorrhea, hirsutism, and obesity. Life-threatening diseases, such as endometrial cancer, type 2 diabetes, hyperlipidaemia, hypertension, and cardiovascular disease, can be distant complications of PCOS. PCOS has diverse etiologies and oxidative stress (OS) plays an important role. Mitochondria, as the core organelles of energy production, are the main source of reactive oxygen species (ROS). The process of follicular growth and development is extremely complex, and the granulosa cells (GCs) are inextricably linked to follicular development. The abnormal function of GCs may directly affect follicular development and alter many symptoms of PCOS. Significantly higher levels of OS markers and abnormal mitochondrial function in GCs have been found in patients with PCOS compared to healthy subjects, suggesting that increased OS is associated with PCOS progression. Therefore, the aim of this review was to summarize and discuss the findings suggesting that OS and mitochondrial dysfunction in GCs impair ovarian function and induce PCOS.

Effects of myo-inositol plus folic acid on ovarian morphology and oocyte quality in PCOS mouse model

Although the role of myo-inositol (MYO) in promoting the oocyte quality of PCOS patients has been documented in human studies; the cellular effects of this supplement on oocytes have not been directly examined due to ethical limitations. In the first phase of this study, MYO dosimetry was carried out simultaneously with the PCOS model development. An effective dose was obtained following the assessment of fasting insulin and testosterone levels using ELISA and ovarian morphology appraisal by histopathology. In the second phase, following the continuous administration of the effective dose of MYO and dehydroepiandrosterone (DHEA), cellular evaluation was performed. The quality of oocytes from superovulation was analyzed by examining maturity and normal morphology percentage using a stereomicroscope, intracellular reactive oxygen species (ROS) and glutathione (GSH) levels using fluorometry, and ATP count evaluation using ELISA. The results revealed that, among the four different MYO concentrations, the 0.36 mg/g dose compared with the DHEA group reduced testosterone levels and large atretic antral follicles (LAtAnF) diameter. This dose also increased the corpus luteum count and the granulosa:theca (G/T)layer thickness ratio in antral follicles. Furthermore, this dose increased mature oocytes and normal morphology percentage, ATP count, and GSH levels; however, it decreased ROS levels in mature oocytes. Our findings provide the grounds for further cellular and molecular studies on the PCOS mouse model, suggesting that the improvement in mitochondrial function and its antioxidant properties is probably one of the mechanisms by which MYO increases oocyte quality.

Chromatin modifiers: A new class of pollutants with potential epigenetic effects revealed by in vitro assays and transcriptomic analyses

A great variety of endocrine-disrupting chemicals (EDCs) have been used extensively and become widespread in the environment nowadays. Limited mammalian studies have shown that certain EDCs may target chromosome and epigenome of the germline, leading to adverse effects in subsequent generations, despite these progenies having never been exposed to the EDC before. However, the underlying mechanisms of chromosomal changes induced by these pollutants remain poorly known. Using the human ovarian granulosa tumor cell line COV434 as a model, we investigated and compared the transcriptomic changes induced by nine EDCs with diverse chemical structures (i.e. BDE-47, BPA, BP-3, DEHP, DHP, EE2, TCS, TDCPP and NP), to inquire if there is any common epigenetic modification associated with reproductive functions induced by these EDCs. Our results showed that COV434 cells were more responsive to BP-3, NP, DEHP and EE2, and more importantly, these four EDCs altered the expression of gene clusters related to DNA damage response, cell cycle, proliferation, and chromatin remodeling, which can potentially lead to epigenetic modifications and transgenerational inheritance. Furthermore, dysregulation of similar gene clusters was common in DEHP and NP treatments. Bioinformatics analysis further revealed that BP-3 disturbed signaling pathways associated with reproductive functions, whereas alterations in telomere-related pathways were highlighted upon EE2 exposure. Overall, this study highlighted chromatin modifications caused by a class of chemicals which that may potentially lead to epigenetic changes and transgenerational reproductive impairments.

Repeated controlled ovarian stimulation-induced ovarian and uterine damage in mice through the PI3K/AKT signaling pathway

The effects of repeated controlled ovarian stimulation (COS) on the female reproductive system are still controversial. This study investigated the effects of repeated COS on the ovaries and uterus of mice and its possible mechanism. Female ICR (Institute of Cancer Research) mice were subjected to the COS using pregnant mare serum gonadotropin (PMSG) and human chorionic gonadotropin (hCG) for 1, 3, 5, and 7 cycles. Serum hormone levels, reactive oxidative stress (ROS), 8-hydroxy-2'-deoxyguanosine (8-OHdG), total antioxidant capacity (T-AOC), and superoxide dismutase (SOD) in the mouse ovary and uterus were analyzed by ELISA. The morphology of the ovary and endometrium, ovarian apoptosis, and expressions of the vascular endothelial growth factor (VEGF), leukemia inhibitory factor (LIF), PI3K, AKT, Bax, and Bcl-2 in the ovarian and uterine tissues were tested by hematoxylin-eosin (HE) staining, immunohistochemistry, and western blot. The results showed that repeated COS significantly decreased the hormone level (estradiol, progesterone and anti-Müllerian hormone), high-quality of the MII oocyte ratio, oocyte and embryo number, antioxidant capacity (T-AOC, SOD activity), and the protein level of Bcl-2, LIF, and VEGF, but increased the oxidative damage (ROS, 8-OHdG content), embryo fragment ratio, and expression of pro-apoptotic protein Bax. In addition, the expressions of p-PI3K and p-AKT also decreased with the increase of COS cycle. In conclusion, repeated COS causes ovarian and uterus damage possibly through the PI3K/AKT signaling pathway, and this finding may provide some experimental basis for guiding clinical treatment.

Distress response in granulosa cells of women affected by PCOS with or without insulin resistance

PURPOSE

In this study, we investigated whether metabolic dysfunction in women with Polycystic ovarian syndrome (PCOS) induces granulosa cell (GC) stress and activates in the endoplamatic reticulum and the mitochondria (UPRer and UPRmt, respectively).

METHODS

Women who were diagnosed with PCOS (based on the Rotterdam criteria), were divided into two groups, PCOS with insulin resistance (PCOS-IR; n = 20) and PCOS with no insulin resistance (PCOS-nIR; n = 20), and compared to healthy oocyte donors (CONT; n = 20). Insulin resistance (IR) was assessed on the results of homeostasis model assessment (HOMA) that determines IR using the concentration of fasting plasma glucose and fasting insuline. Expression of UPRer genes (i.e., IRE1, ATF4, ATF6, XBP1, BIP, and CHOP), and UPRmt genes (i.e., HSP60, HSP10, CLPP, and HSP40) was assessed in cumulus GCs by qRT-PCR.

RESULTS

We found that several genes involved in UPRer and UPRmt were overexpressed in the GCs of PCOS-IR and PCOS-nIR compared to CONT. IRE1, ATF4 and XBP1, that are activated by ER stress, were significantly overexpressed in PCOS-IR compared to CONT. BIP and CHOP were overexpressed in PCOS groups compared to CONT. HSP10 and HSP40 were upregulated in PCOS-IR and PCOS-nIR groups compared to the CONT. HSP60 and CLPP showed no statistical different expression in PCOS-IR and PCOS-nIR compared to CONT group.

CONCLUSION

Our findings suggest that the GCs of women with PCOS (with or without IR) are metabolically distressed and upregulate UPRer and UPRmt genes. Our study contributes to the understanding of the molecular mechanisms underlying the pathological changes that occur in the follicular microenvironment of women with PCOS.

OXIDATIVE STRESS AND REPRODUCTIVE FUNCTION: Oxidative stress in polycystic ovary syndrome

In brief

A genetic, epigenetic, and environmental association exists between oxidative stress (OS) and polycystic ovary syndrome (PCOS), expressed in a multifaceted clinical profile. This review summarizes and discusses the role of OS in the pathogenesis of PCOS syndrome, focusing on metabolic, reproductive, and cancer complications.

Abstract

Oxidative stress (OS), an imbalance between oxidants and antioxidants in cells, is one of many factors playing essential roles in the pathogenesis of polycystic ovary syndrome (PCOS). PCOS is described mainly as a disproportion of reproductive hormones, leading to chronic anovulation and infertility in women. Interestingly, OS in PCOS may be associated with many disorders and diseases. This review focuses on characteristic markers of OS in PCOS and the relationship between OS and PCOS related to insulin resistance (IR), hyperandrogenemia, obesity, chronic inflammation, cardiovascular diseases, and cancer. Interestingly, in patients with PCOS, an increase in oxidative status and insufficient compensation of the increase in antioxidant status before any cardiovascular complications are observed. Moreover, free radicals promote carcinogenesis in PCOS patients. However, despite these data, it has not been established whether oxygen stress influences PCOS development or a secondary disorder resulting from hyperglycemia, IR, and cardiovascular and cancer complications in women.

CXCL13 and CXCR5 are upregulated in PCOS mice ovaries but downregulated following metformin administration

Polycystic ovary syndrome (PCOS) is becoming a common pathology among women, yet its pathogenesis remains enigmatic. The chemokine C-X-C motif ligand 13 (CXCL13) and its receptor type 5 (CXCR5) regulate inflammatory responses but their roles in PCOS remain unknown. Metformin is commonly administered to PCOS patients but its mechanism of action remains unclear. Thus, we aimed to determine the expression of CXCL13 and CXCR5 in the ovaries of PCOS mice and to evaluate the therapeutic effect of metformin on them. The study comprised four groups of mice: control, PCOS, PCOS plus metformin, and PCOS plus vehicle. CXCL13 and CXCR5 were found to be elevated in the ovarian tissues of the PCOS mice. Metformin reduced ovarian CXCL13 and CXCR5 expressions in the PCOS mice. Hence, CXCL13 and CXCR5 are potentially involved in PCOS pathogenesis; and metformin may help alleviate the symptoms of PCOS by inhibiting CXCL13 expression and actions.

Pre-Treatment Physical Activity Could Positively Influence Pregnancy Rates in IVF despite the Induced Oxidative Stress: A Cohort Study on Salivary 8-Hydroxy-2'-deoxyguanosine

(1) Background: This study was designed to define whether pretreatment habitual physical activity (PA)-induced oxidative stress (OS) influences outcome measures by using 8-hydroxy-2′-deoxyguanosine (8-OHdG) in saliva samples of patients undergoing in vitro fertilization (IVF). (2) Method: In this cohort study, samples were obtained from 26 patients (age: 34.6 ± 5.5 years, BMI: 25.3 ± 5.1, infertility: 51.0 ± 28.7 months) before the treatment and a follow-up of outcome measures of IVF/ICSI. The 8-OHdG was evaluated by Abcam’s ELISA (ab201734), PA patterns by GPAQ-H and ActiGraph GT3X; (3) Results: The number of matured oocytes was positively influenced by the GPAQ-H recreation MET (R2 = 0.367, F = 10.994, p = 0.004; β = 0.005, p = 0.004, B Constant = 4.604) and a positive significant relationship (R2 = 0.757, F = 17.692, p < 0.001, B Constant = 1.342) was found with GPAQ-H recreational PA MET (β = 0.004, p < 0.001), and Grade 1 embryos and higher very vigorous activity (GT3X) were accompanied (R2 = 0.958, F = 408.479, p < 0.001) by higher ß-hCG levels (β = 63.703, p ≤ 0.001). Unanticipated positive correlation between 8-OHdG and ß-hCG level (R = 0.467, p = 0.028) was noticed, and there were significant differences in 8-OHdG in biochemical pregnancies (pregnant: 54.82 ± 35.56 ng/mL, non-pregnant: 30.06 ± 10.40 ng/mL, p = 0.022) as well. (4) Conclusions: Pretreatment PA could positively influence reproductive performance in IVF/ICSI despite the induced OS. However, a more sensitive biomarker and the recommended amount of activity should be further investigated.

Investigating the effect of Sulforaphane on AMPK/AKT/NRF2 pathway in human granulosa-lutein cells under H2O2-induced oxidative stress

Excessive production of reactive oxygen species (ROS) in granulosa cells (GCs) plays a role in pathogenesis of polycystic ovarian syndrome (PCOS) by developing oxidative stress (OS). It was shown that Sulforaphane (SFN), with known antioxidant properties, can have protective effects in different diseases through affecting the nuclear factor (erythroid-derived 2)-like 2 (NRF2) signaling pathway. Thus, the purpose of the current work was to examine the protective impact of SFN through the activation of the AMPK/AKT/NRF2 pathway against OS produced by H2O2 in granulosa-lutein cells (GLCs). Individuals' GLCs were obtained during ovum retrieval in intracytoplasmic sperm injection (ICSI) cycles. First, the induced OS model was created in GLCs using H₂O₂ exposure. To examine the protective effect of SFN against OS, the cells were cultured for 24 h in presence or absence of SFN. Eventually, the levels of intracellular ROS and apoptosis were measured by flow cytometry, and genes and proteins expression levels of AMPK, AKT, and NRF2 were evaluated using qRT-PCR and western blotting. Compared to the control group, the levels of intracellular ROS and apoptosis rose dramatically in GLCs with enhanced OS. SFN therapy decreased ROS and apoptosis levels and increased the overexpression of AMPK, AKT, and NRF2 genes and proteins. This study's results revealed that SFN exposure results in the alleviation of ROS and apoptosis levels possibly through activating the overexpression of genes and proteins of AMPK, AKT, and NRF2, and exerts its protective effects against OS in GLCs.

Elevated prohibitin 1 expression mitigates glucose metabolism defects in granulosa cells of infertile patients with endometriosis

Endometriosis is a common disease in women of childbearing age and is closely associated with female infertility. However, the pathogenesis of endometriosis-related infertility is still not fully understood. Prohibitin 1 (PHB1), a highly conserved protein related to mitochondrial function, is differentially expressed in the endometrium of patients with endometriosis. However, the role of PHB1 in glucose metabolism in granulosa cells remains unclear. In this study, we investigated whether PHB1 expression and glucose metabolism patterns differ in the granulosa cells of patients with endometriosis and those of patients serving as controls. We then evaluated these changes after PHB1 was upregulated or downregulated in the human granulosa cell line (KGN) using a lentivirus construct. In the granulosa cells of patients with endometriosis, significantly elevated PHB1 expression, increased glucose consumption and lactic acid production, as well as aberrant expression of glycolysis-related enzymes were found compared to those without endometriosis (P < 0.05). After PHB1 expression was upregulated in KGN cells, and the expression of enzymes related to glucose metabolism, glucose consumption and lactic acid production was strikingly increased compared to controls (P < 0.05). The opposite results were found when PHB1 expression was downregulated in KGN cells. Additionally, the cell proliferation and apoptosis rates, ATP synthesis, reactive oxygen species (ROS) levels, and mitochondrial membrane potential (MMP) were significantly altered after down-regulation of PHB1 expression in KGN cells (P < 0.05). This study suggested that PHB1 plays a pivotal role in mitigating the loss of energy caused by impaired mitochondrial function in granulosa cells of patients with endometriosis, which may explain, at least in part, why the quality of oocytes in these patients is compromised.

The Potential Role of MicroRNA‐124‐3p in Growth, Development, and Reproduction of Schistosoma japonicum

The microRNA‐124‐3p plays an important role in regulating development and neurogenesis. Previous microRNA sequencing analyses of Schistosoma japonicum revealed sja-miR-124-3p differential expression patterns in schistosomes from different hosts and at different developmental stages. This study explores the regulatory role of sja-miR-124-3p in S. japonicum development and reproduction. Quantitative reverse-transcription PCR (qRT-PCR) showed that the expression level of sja-miR-124-3p in S. japonicum from resistant hosts, such as Microtus fortis, and unsuitable hosts, such as rats and water buffalo, was significantly higher than that in mice and yellow cattle at the same developmental stage. Overexpressing sja-miR-124-3p in infected mice led to a hepatic egg reduction rate of 36.97%, smaller egg granulomas in the livers, increased liver weight, subsided hepatocyte necrosis, and diminished inflammatory cell infiltration. The width of female worms increased but decreased in males. The vitelline cells were irregular, swollen, or fused. The teguments and ventral sucker of males and females were swollen and broken, but the morphological changes were particularly notable in males. qRT-PCR and dual-luciferase reporter assay system were used to confirm the in-silico-predicted target genes, S. japonicum DEAD-box ATP-dependent RNA helicase 1 (sjDDX1) and DNA polymerase II subunit 2 (sjPOLE2). Our results showed that RNA interference (RNAi)-mediated sjDDX1 silencing in mice provided a 24.55% worm reduction rate and an 18.36% egg reduction rate, but the difference was not significant (p > 0.05). Thus, our findings suggest that sja-miR-124-3p has an important role in growth, development, and reproduction in S. japonicum. All these results will greatly contribute toward providing important clues for searching vaccine candidates and new drug targets against schistosomiasis.

Role of Granulosa Cells in the Aging Ovarian Landscape: A Focus on Mitochondrial and Metabolic Function

Mitochondria are at the intersection of aging and fertility, with research efforts centered largely on the role that these specialized organelles play in the relatively rapid decline in oocyte quality that occurs as females approach reproductive senescence. In addition to various roles in oocyte maturation, fertilization, and embryogenesis, mitochondria are critical to granulosa cell function. Herein, we provide a review of the literature pertaining to the role of mitochondria in granulosa cell function, with emphasis on how mitochondrial aging in granulosa cells may impact reproduction in female mammals.

The protective effect of sulforaphane against oxidative stress in granulosa cells of patients with polycystic ovary syndrome (PCOS) through activation of AMPK/AKT/NRF2 signaling pathway

Increased production of reactive oxygen species (ROS) in granulosa cells (GCs) causes oxidative stress (OS) and plays a role in pathogenesis of polycystic ovary syndrome (PCOS). Sulforaphane (SFN) has received a great deal of attention as potent antioxidant because of its ability to induce expression of antioxidant enzymes through nuclear factor (erythroid-derived 2)-like 2 (NRF2) signaling pathway. Therefore, the present study was done to investigate the protective effect of SFN against OS in granulosa-lutein cells (GLCs) of patients with PCOS through activation of AMP-activated protein kinase (AMPK)/AKT/NRF2 signaling pathway. GLCs were isolated from patients with PCOS and healthy fertile women, as control group, during egg retrieval procedure. Level of intracellular ROS and apoptosis was determined in the isolated cells. For investigating the protective effect of SFN against ROS production and apoptosis in GLCs, the cells were cultured for 24 h in the presence or absence of SFN. Finally, expression of AMPK, AKT, and NRF2 proteins and genes was evaluated by western blotting and quantitative real-time polymerase chain reaction (qRT-PCR), respectively. The results indicated the increased ROS and apoptosis levels in GLCs isolated from patients with PCOS compared to the control group. Addition of SFN to culture medium of GLCs of patients with PCOS reduced intracellular ROS and apoptosis levels, and increased expression of AMPK, AKT, and NRF2 proteins and genes. Our findings demonstrated the protective effect of SFN against OS by lowering level of ROS and apoptosis possibly through activation of AMPK, AKT, and NRF2 proteins and genes expression.

The effect of mitochondria-targeted antioxidant MitoQ10 on redox signaling pathway components in PCOS mouse model

PURPOSE

Considerable evidence suggests that mitochondrial dysfunction and oxidative stress contribute to the pathogenesis of Polycystic ovary syndrome (PCOS). We aimed to evaluate the effectiveness of mitochondria-targeted antioxidant, MitoQ10, on the redox signaling pathway's component in PCOS.

METHOD

We assessed TXNIP, TRX, and ASK1 expression in granulosa cells (GCs) of the DHEA-induced PCOS mouse model. Female BALB/c mice in five groups of Control, DHEA, and DHEA + MitoQ10 in three doses of 250, 500, and 750 μmol/L MitoQ10 were treated for 21 days.

RESULTS

Histological investigation showed a probable improvement in folliculogenesis; besides, ASK1 and TXNIP expression were significantly increased in GCs of the PCOS mouse F4Fmodel as compared to the control groups and decreased steadily in groups treated by MitoQ10. However, TRX expression showed a drop that was restored by MitoQ10 meaningfully (P ≤ 0.05).

CONCLUSION

The work presented herein suggests mitochondria-targeted antioxidant, MitoQ10, have modulating effects on folliculogenesis in the ovary and also on the redox signaling pathway in GCs of PCOS mouse model which may have potential to attenuate oxidative stress and its relative damages.

Effects of Bushen-Tiaojing-Fang on the pregnancy outcomes of infertile patients with repeated controlled ovarian stimulation

Bushen-Tiaojing-Fang (BSTJF) is commonly used to treat infertility. This study investigated the effects of BSTJF on the pregnancy outcomes of patients with repeated controlled ovarian stimulation (COS), on mitochondrial function, and on oxidative stress in ovarian granulosa cells (GCs) and follicular fluid (FF). The samples and clinical data of 97 patients, including 35 in the control group, 29 in the placebo group and 33 in the BSTJF group, were collected for this study. The mitochondrial ultrastructure, ATP content, mitochondrial DNA (mtDNA) number, 8-hydroxy-2-deoxyguanosine (8-OHdG), Mn-superoxide dismutase (Mn-SOD), glutathione peroxidase (GSH-Px) activity levels, and mRNA expression levels of Mn-SOD, GSH-Px, and nuclear factor erythroid-derived factor 2-related factor 2 (Nrf2) were analyzed. The high-grade embryo (P < 0.001), implantation (P = 0.033), and clinical pregnancy (P = 0.031) rates, as well as the ATP content (P = 0.014), mtDNA number (P = 0.035), GSH-Px activity (P = 0.004 in GCs and P = 0.008 in FF) and mRNA expression levels (P = 0.019), were significantly lower in the placebo group than in the control group, whereas the 8-OHdG content was significantly (P = 0.006 in FF) higher in the placebo group than in the control group. Compared with those in the placebo group, the high-grade embryo rate (P = 0.007), antioxidant enzyme activity (P = 0.037 and 0.036 in Mn-SOD; P = 0.047 and 0.030 in GSH-Px) and mRNA level (P < 0.001 in Nrf2, P = 0.039 in Mn-SOD and P = 0.002 in GSH-Px) were significantly higher in the BSTJF group, as were changes in mitochondrial ultrastructure, ATP (P = 0.040) and mtDNA number (P = 0.013). In conclusion, BSTJF can improve oxidative stress in patients with repeated COS and pregnancy outcomes.

Biological roles of l-carnitine in oocyte and early embryo development

Poor oocyte quality is responsible for female infertility. Multiple studies have been carried out to find supplements to enhance oocyte quality and mitigate infertility problems. l-carnitine and its derivatives have diverse roles in developing oocytes and early embryos. This review focuses on the in vitro and in vivo studies that using l-carnitine alone or in combination with other supplements for oocyte quality enhancement. The key roles of l-carnitine in oocyte quality and embryo growth were summarized, and the underlying mechanism was also elucidated. l-carnitine helps in the lipid metabolism process by controlling the transfer of fatty acids to mitochondria for β-oxidation. l-carnitine modulates glucose metabolism and enhances respiratory chain enzyme activity. Furthermore, it acts as an antioxidant to prevent oxidative damage and inhibit apoptosis, a signal in response to oxidative stress. Results show the potential of l-carnitine as a potential agent in assisted reproductive technology to improve oocyte quality and the subsequent embryonic development.

Effects of multicycle gonadotropin-releasing hormone antagonist protocols on oxidative stress of follicular fluid and ovarian granulosa cells

The effect of repeated multicycle gonadotropin-releasing hormone antagonist (GnRH-ant) protocols on oxidative stress (OS) in follicular fluid (FF) and ovarian granulosa cells (GCs) remains unclear. This study investigated the effects of repeated multicycle GnRH-ant protocols on OS markers of FF and ovarian GCs. A total of 145 patients were enrolled and divided into four groups: 1 cycle group (n = 42), 2 cycles group (n = 37), 3 cycles group (n = 45), and 4-5 cycles group (n = 21). The FF and ovarian GCs of the patients were collected on the day of last oocyte retrieval and the levels of 8-hydroxy-2-deoxyguanosine (8-OHdG), malondialdehyde (MDA), superoxide dismutase (SOD), catalase (CAT), and glutathione peroxidase (GSH-Px) were tested by ELISA. The results showed that the serum estradiol levels on hCG injection day in the 3 and 4-5 cycles were significantly (P < 0.05) lower than in the 1 and 2 cycles. The number of retrieved oocytes (12.1 ± 3.3 in cycle 1, 11.7 ± 3.1 in cycle 2, 10.4 ± 2.4 in cycle 3, and 9.4 ± 2.4 in cycles 4-5), embryos with two pronuclei (7.6 ± 3.0 in cycle 1, 7.0 ± 2.5 in cycle 2, 6.2 ± 2.6 in cycle 3, and 5.5 ± 2.1 in cycles 4-5), and the rates of high-quality embryos (52.2% in cycle 1, 47.9% in cycle 2, 38.6% in cycle 3, and 36.5% in cycles 4-5), implantation (35.4% in cycle 1, 32.4% in cycle 2, 23.8% in cycle 3, and 22.9% in cycles 4-5) and clinical pregnancy (50.0% in cycle 1, 43.2% in cycle 2, 33.3% in cycle 3, and 23.8% in cycles 4-5) in cycles 3 and 4-5 were significantly (P < 0.05) lower than those in cycles 1 and 2. Compared with 1 and 2 cycles, the 8-OHdG and SOD were significantly increased in the 3-5 cycles, while the CAT and GSH-Px levels were significantly decreased. Together, this study reveals repeated COS with the use of GnRH-ant protocols results in OS and changes the follicle microenvironment of FF and GCs, possibly leading to poor IVF outcomes in patients with 3-5 cycles of COS.

Astaxanthin Protects Human Granulosa Cells against Oxidative Stress through Activation of NRF2/ARE Pathway and Its Downstream Phase II Enzymes

Objective

Astaxanthin (AST) has been introduced as a radical scavenger and an anti-apoptotic factor that acts via regulating the nuclear factor-E2-related factor 2 (NRF2) and related factors. Here, we intended to examine the effect of AST on granulosa cells (GCs) against oxidative stress by examining NRF2 and downstream phase II antioxidant enzymes.

Materials and Methods

In this experimental study, we used cultured human primary GCs for the study. First, we performed the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) test to evaluate cells viability after treatment with hydrogen peroxide (H2O2) and AST. The apoptosis rate and ROS levels were measured by flow cytometry. To determine NRF2 and phase II enzymes expression, we performed real-time polymerase chain reaction (PCR). Finally, we used western blot to measure the protein levels of NRF2 and Kelch-like ECsH-associated protein 1 (KEAP1). Enzyme activity analysis was also performed to detect NRF2 activity.

Results

This study showed that AST suppressed ROS generation (P<0.01) and cell death (P<0.05) in GCs induced by oxidative stress. AST also elevated gene and protein expression and nuclear localization of NRF2 and had an inhibitory effect on the protein levels of KEAP1 (P<0.05). Furthermore, when we used trigonelline (Trig) as a known inhibitor of NRF2, it attenuated the protective effects of AST by decreasing NRF2 activity and gene expression of phase II enzymes (P<0.05).

Conclusion

Our results presented the protective role of AST against oxidative stress in GCs which was mediated through up-regulating the phase II enzymes as a result of NRF2 activation. Our study may help in improving in vitro fertilization (IVF) outcomes and treatment of infertility.

Novel therapeutic targets to improve IVF outcomes in endometriosis patients: a review and future prospects

BACKGROUND

Patients with endometriosis often experience infertility and have poor IVF outcomes, with low fertilization and pregnancy rates. Although many theories have tried to explain the mechanisms underlying infertility in these patients, none of them is conclusive.

OBJECTIVE AND RATIONALE

In this review, we discuss the pathologic mechanisms through which endometriosis likely leads to infertility along with the therapeutic options used to date to treat endometriosis-related infertility and, thereby, to improve IVF outcomes in patients with endometriosis.

SEARCH METHODS

We performed a comprehensive literature search of clinical outcomes in endometriosis and the molecular mechanisms contributing to oocyte quality using the PubMed database to identify human and animal studies published from 1992 until September 2020. In total, 123 manuscripts were included.

OUTCOMES

While some theories propose that endometriosis patients may have fertility problems as a result of decreased endometrial receptivity, others reinforce the idea that infertility could be associated with oocyte alterations and lower implantation rates. Single-cell RNA sequencing of oocytes from patients with endometriosis has identified dysregulated mechanisms involved in steroid metabolism and biosynthesis, response to oxidative stress and cell cycle regulation. Dysregulation of these mechanisms could result in the poor IVF outcomes observed in patients with endometriosis. Further, impaired steroidogenesis may directly affect oocyte and embryo quality. Increased oxidative stress in patients with endometriosis also has a detrimental effect on the follicular microenvironment, inducing cell cycle dysregulation in oocytes, poor oocyte quality, and infertility. Moreover, granulosa cells in the context of endometriosis undergo increased apoptosis and have an altered cell cycle that could adversely affect folliculogenesis, oocyte and embryo quality, and IVF outcomes. Endometriosis is also associated with inflammatory damage and impaired angiogenesis, which could be directly correlated with poor IVF outcomes. While therapeutic options using GnRH analogues, progestins and aromatase inhibitors do not improve endometriosis-related infertility, anti-inflammatory agents and antioxidant supplementation could improve oocyte quality as well as implantation and clinical pregnancy rates in patients with endometriosis.

WIDER IMPLICATIONS

Endometriosis is a heterogeneous disease whose pathogenesis is complex and could affect fertility by altering a collection of molecular mechanisms in oocytes. Thus, a single model is not sufficient to describe endometriosis-related infertility. Dysregulation of steroidogenesis, oxidative stress, cell cycle progression, inflammation and angiogenesis in the follicular environment and oocytes in individuals with endometriosis are all possible contributors to endometriosis-related infertility. Therefore, treatments targeting these mechanisms could be therapeutic alternatives to improve IVF outcomes for these patients.

The Effect of Astaxanthin and Metformin on Oxidative Stress in Granulosa Cells of BALB C Mouse Model of Polycystic Ovary Syndrome

Reactive oxygen species (ROS), involved in the pathogenesis of the polycystic ovary syndrome (PCOS), play a key role in the onset of apoptosis in follicles and granulosa cells (GCs). We aimed to investigate the antioxidant effects of AST and metformin separately and in combination on GCs using a PCOS mouse model. Forty-eight prepubertal female BALB C mice aged 25-30 days and weighing 12-14 g were studied. The PCOS model was created by subcutaneous injection of the dehydroepiandrosterone (DHEA) hormone in 8 mice of BALB C for 20 consecutive days. Apoptosis and the amount of ROS were evaluated in GCs of the ovaries via flow cytometry. The activity of AKT protein was measured by western blot, and the viability of GCs was investigated using spectrophotometry. Ovarian tissue sections were prepared, stained with H&E, and the morphology of the sections was examined. Statistical analysis was performed by SPSS v22.0 software using one-way ANOVA. We found that AST administration leads to a significant reduction in oxidative stress (P<0.01) and consequently a significant decrease in the rate of apoptosis (P<0.01). While the expression of AKT in the AST group revealed a significant increase (P<0.05), it decreased in the metformin group. However, it was still significantly higher than the control and PCOS groups. Ovulation was confirmed in both metformin and AST groups. Further studies are warranted to prove the efficacy of AST and to introduce it as a complementary therapeutic agent in PCOS.

Upsurge in autophagy, associated with mifepristone-treated polycystic ovarian condition, is reversed upon thymoquinone treatment

Polycystic ovarian syndrome (PCOS) is a multi-factorial gynecological endocrine disorder. It affects fertility in women and also predisposes to insulin resistance, type 2 diabetes mellitus, obesity etc. Earlier, significance of autophagy has been explored in PCOS-related metabolic disorders and during normal folliculogenesis. Increasing evidences reveal connection of autophagy with chronic inflammatory behaviour, an associated phenomena in polycystic ovaries. However, understanding of the association of autophagy with PCOS is still obscure. This study reveals that increased autophagy in mifepristone (RU486) treated KK-1 cells and in vivo PCO rat model is characterized by upregulated Androgen Receptor (AR) expression and downregulated PCO biomarker aromatase. The prevalence of autophagy has been observed to be concomitant with increased expression of two autophagic markers Beclin1 and MAP-LC3-II while the autophagy substrate p62/SQSTM1 was downregulated. Immunohistochemical staining revealed increased localization of MAP-LC3 in the compacted granulosa layers of the follicular cysts in the PCO model. The PCO rat models also demonstrated augmented levels of p65, the active subunit of NF-κB, which acts as a transcriptional regulator of several pro-inflammatory factors. NF-κB repressor and anti-inflammatory herbal drug thymoquinone, known to alleviate PCO condition, downregulated autophagy modules substantially. Pre-treatment with thymoquinone upregulated aromatase, reduced AR levels and decreased autophagic markers as well as p65 levels, simulating super-ovulated condition. In conclusion, the anti-inflammatory phytochemical thymoquinone alleviated PCO condition.

The impact of phthalate on reproductive function in women with endometriosis

BACKGROUND

Endometriosis is a common gynecological condition in which stromal or glandular epithelium is implanted in extrauterine locations. Endometriosis causes detrimental effects on the granulosa cells, and phthalate interferes with the biological and reproductive function of endometrial cells at a molecular level.

METHODS

This article retrospectively reviewed the studies on phthalate exposure and its relationship with endometriosis. A literature search was performed for scientific articles using the keywords "phthalate and endometriosis," "endometriosis and granulosa cells," "phthalate and granulosa cells," and "phthalates and endometrial cells."

RESULTS

Endometriosis can affect cytokine production, steroidogenesis, cell cycle progression, expression of estrogen receptor-α (ER-α)/progesterone receptor (PR), and cause endoplasmic reticulum stress, senescence, apoptosis, autophagy, and oxidative stress in the granulosa cells. Mono-n-butyl phthalate (MnBP) alters the expression of cytokines, cell cycle-associated genes, ovarian stimulation, steroidogenesis, and progesterone production. Several in vitro studies have demonstrated that phthalate caused inflammation, invasion, change in cytokines, increased oxidative stress, viability, resistance to hydrogen peroxide, and proliferation of endometrial cells.

CONCLUSION

This might provide new insights about the impact of phthalate on the pathogenesis of endometriosis and its consequences on the ovarian function.

The Ameliorating Effects of Bushen Huatan Granules and Kunling Wan on Polycystic Ovary Syndrome Induced by Dehydroepiandrosterone in Rats

Aim

To investigate the effects of Bushen Huatan Granules (BHG) and Kunling Wan (KW), the two Chinese medicines, on the regulation of polycystic ovary syndrome (PCOS) and their underlying mechanisms.

Materials and Methods

PCOS rat model was established by subcutaneous injection of dehydroepiandrosterone (DHEA) (6 mg/100 g/day) for 20 days, followed by treatment with BHG (0.75, 1.49, and 2.99 g/kg) or KW (0.46, 0.91, and 1.82 g/kg) by gavage for 4 weeks. Estrous cycle was detected by vaginal smears. Follicles development was assessed by histology. Levels of testosterone and insulin in serum were tested by ELISA. Apoptosis of Granulosa cells (GCs) was evaluated by terminal deoxynucleotidyl transferase-mediated dUTP-biotin nick end-labeling staining. Pathways associated with apoptosis were detected with western blot. Pregnancy outcome was also assessed. GCs were pre-treated with 10^–5 M testosterone in vitro for 24 h, then incubated with serum from rats receiving BHG (1.49 g/kg) or KW (1.82 g/kg). The parameters concerning apoptosis, mitochondrial function and endoplasmic reticulum stress were assessed.

Results

Post-treatment with either BHG or KW ameliorated DHEA-induced irregular estrous cycles, follicles development abnormalities, increase of testosterone and insulin in serum, and the apoptosis of GCs. Post-treatment with BHG decreased the expression of cleaved caspase-9/caspase 9, release of cytochrome C from mitochondria, and mitochondria reactive oxygen species production, increased activities of complex I, II, IV of ovarian tissue. Post-treatment with KW decreased the levels of caspase-12, GRP78, C/EBP homologous protein, phosphorylation of IRE-I, x-box-binding protein 1s, as well as phosphorylation of proline-rich receptor-like protein kinase, phosphorylation of eukaryotic translation initiation factor 2α and ATF4 of ovarian tissue and GCs. Both BHG and KW ameliorated pregnancy outcome.

Conclusion

This study demonstrated BHG or KW as a potential strategy for treatment of PCOS induced by DHEA, and suggested that the beneficial role of the two medicines were mediated by different pathway with the effect of BHG being correlated with the regulation of mitochondria, while the effect of KW being attributable to protection of endoplasmic reticulum stress.

Growth hormone activates PI3K/Akt signaling and inhibits ROS accumulation and apoptosis in granulosa cells of patients with polycystic ovary syndrome

BACKGROUND

It is reported that growth hormone (GH) can alleviate oxidative stress (OS) induced apoptosis in some types of cells by activating the PI3K/Akt signaling pathway. This study investigated the role and underlying mechanism of GH in OS and apoptosis in granulosa cells (GCs) of patients with polycystic ovary syndrome (PCOS).

METHODS

Primary GCs were collected from patients with and without PCOS (controls, n = 32) during oocyte retrieval. The patients with PCOS were randomly assigned to take GH treatment (PCOS-GH, n = 30) or without GH treatment (PCOS-C, n = 31). Reactive oxygen species (ROS) level was determined by spectrophotometry and fluorescence microscopy. GC apoptosis and mitochondrial membrane potential (MMP) were detected by Annexin V-FITC/PI double-staining and JC-1 staining, respectively (flow cytometry). The expression of apoptosis-related genes and proteins involved in PI3K/Akt signaling was determined by quantitative reverse-transcription polymerase chain reaction and western blotting, while active caspase-9 and caspase-3 levels of GCs were determined by enzyme-linked immunosorbent assay.

RESULTS

Our study found that in GCs of the PCOS-GH group, the ROS levels and apoptotic rates were significantly decreased, whereas MMP was significantly increased when compared to those in the PCOS-C group (P < 0.05). The mRNA levels of FOXO1, Bax, caspase-9, and caspase-3 were significantly decreased, whereas Bcl-2 was increased in GCs of the PCOS-GH group than those in the PCOS-C group (P < 0.05). The protein levels of FOXO1, Bax, cleaved caspase-9/caspase-9 and cleaved caspase-3/caspase-3 were decreased, whereas p-PI3K/PI3K, p-Akt/Akt, p-FOXO1 and Bcl-2 were increased in GCs of the PCOS-GH group, compared with those in the PCOS-C group (P < 0.05).

CONCLUSION

OS induced apoptosis and downregulated the PI3K/Akt signaling pathway in patients with PCOS. GH could alleviate apoptosis and activate the PI3K/Akt signaling pathway.

CLINICAL TRIAL REGISTRATION NUMBER

Chinese Clinical Trial Registry. ChiCTR1800019437 . Prospectively registered on October 20, 2018.

Salvia miltiorrhiza solution and its active compounds ameliorate human granulosa cell damage induced by H2O2

The dried roots or rhizomes of Salvia miltiorrhiza Bge are commonly used in Chinese medicine to promote blood circulation and regulate menstruation. Salvianic acid A and salvianolic acid B are the main active water-soluble compounds in Salvia miltiorrhiza solution. The present study investigated the protective effect of Salvia miltiorrhiza solution and its active compounds in H₂O₂-induced cell damage of the human ovarian granulosa tumor cell line (KGN) in vitro, as well as its underlying mechanism. Cell viability was detected using a Cell Counting Kit-8 assay. In addition, the levels of malondialdehyde (MDA), superoxide dismutase (SOD), glutathione (GSH) and tumor necrosis factor-α (TNF-α) were measured. Western blotting was performed to detect the protein expression of cleaved caspase-3 and caspase-9. Furthermore, immunocytochemistry was used to detect the expression of TNF-α. It was demonstrated that Salvia miltiorrhiza solution, salvianic acid A and salvianolic acid B did not affect the viability of KGN cells. Additionally, salvianic acid A and salvianolic acid B significantly reduced the H₂O₂-induced increased MDA levels, and reversed the H₂O₂-induced suppression of SOD and GSH activities in KGN cells (P<0.05). Treatment with Salvia miltiorrhiza solution, salvianic acid A and salvianolic acid B significantly reduced the overexpression of cleaved caspase-3, cleaved caspase-9 and TNF-α compared with the H₂O₂-treated group (P<0.05). Therefore, the present results indicated that Salvia miltiorrhiza solution and its main water-soluble compounds, salvianic acid A and salvianolic acid B, ameliorated KGN cell damage induced by H₂O₂.

miR-4463 regulates aromatase expression and activity for 17β-estradiol synthesis in response to follicle-stimulating hormone

Objective

The aim of this study was to investigate microRNAs (miRNAs) related to follicle-stimulating hormone (FSH) responsiveness using miRNA microarrays and to identify their target genes to determine the molecular regulatory pathways involved in FSH signaling in KGN cells.

Methods

To change the cellular responsiveness to FSH, KGN cells were treated with FSH receptor (FSHR)-specific small interfering RNA (siRNA) followed by FSH. miRNA expression profiles were determined through miRNA microarray analysis. Potential target genes of selected miRNAs were predicted using bioinformatics tools, and their regulatory function was confirmed in KGN cells.

Results

We found that six miRNAs (miR-1261, miR-130a-3p, miR-329-3p, miR-185-5p, miR-144-5p and miR-4463) were differentially expressed after FSHR siRNA treatment in KGN cells. Through a bioinformatics analysis, we showed that these miRNAs were predicted to regulate a large number of genes, which we narrowed down to cytochrome P450 family 19 subfamily A member 1 (CYP19A1) and estrogen receptor alpha (ESR1) as the main targets for miR-4463. Functional analysis revealed that miR-4463 is a regulatory factor for aromatase expression and function in KGN cells.

Conclusion

In this study, we identified differentially expressed miRNAs related to FSH responsiveness. In particular, upregulation of miR-4463 expression by FSHR deficiency in human granulosa cells impaired 17β-estradiol synthesis by targeting CYP19A1 and ESR1. Therefore, our data might provide novel candidates for molecular biomarkers for use in research into poor responders.

Mitochondrial Function in Modulating Human Granulosa Cell Steroidogenesis and Female Fertility

Ovarian follicle steroidogenesis associated with embryo quality results in a successful pregnancy. Each follicle consists of an oocyte surrounded by granulosa cells, which secrete several steroid and peptide hormones. Follicles harvested from women who conceived after assisted reproductive therapy (ART) had significantly higher estradiol levels in follicular fluids than the follicles from women who failed to conceive after ART. The higher follicular estradiol levels correlate well with successful fertilization following ART. Mitochondria are the central sites for steroid hormone biosynthesis. The first and rate-limiting step in the biosynthesis of steroid hormones occurs in the mitochondria of granulosa cells. In the present study, we hypothesized that the mitochondria in granulosa cells are critical for maintaining oocyte quality and fertility capacity. This study aims to clarify the relationship between mitochondrial function and granulosa cell steroidogenesis, and the relationship between hormone levels and fertility capacity. Sera, follicular fluids and granulosa cells were obtained from individuals undergoing IVF-ET treatment. The oocyte numbers, oocyte quality, fertilization rate, and pregnancy rate were also recorded. The patients who provided the granulosa cells were further classified into four groups: endometriosis, ovarian endometrioma, endometriosis without ovarian endometrioma, and polycystic ovary syndrome (PCOS); patients with other female factor infertility and male factor infertility were used as controls. We measured the levels of estradiol (E2) by radioimmunoassay. Concurrently, we analyzed the mitochondrial mass and membrane potential, and apoptosis by flow cytometry using nonyl acridine orange, TMRE, Annexin V-FITC and PI. Mitochondrial morphology was visualized by transfection with pLV-mitoDsRed. In addition, we assessed the protein levels of steroidogenic enzymes, steroidogenic acute regulatory protein (StAR) and 3β-hydroxysteroid dehydrogenase (3β-HSD) by Western blot. The results showed significantly decreased serum E2 and follicular E2 levels, and decreased IVF outcomes, in the patients with endometriosis. Reduced mitochondrial mass and decreased mitochondrial membrane potential were correlated with lower E2. Furthermore, a significant decrease in StAR and 3β-HSD was found in patients with ovarian endometrioma. The enzyme levels of StAR and 3β-HSD were highly correlated with E2 levels. Finally, elevated cumulus cell apoptosis was found in the patient group with ovarian endometrioma and PCOS. In conclusion, mitochondrial dysfunction of human granulosa cells may contribute to the decline of steroidogenesis, decreased fertilization rate, oocyte maturation rate, and oocyte quality, and it can ultimately jeopardize fertility.

Reactive oxygen species in reproduction: harmful, essential or both?

The process of embryonic development is crucial and radically influences preimplantation embryo competence. It involves oocyte maturation, fertilization, cell division and blastulation and is characterized by different key phases that have major influences on embryo quality. Each stage of the process of preimplantation embryonic development is led by important signalling pathways that include very many regulatory molecules, such as primary and secondary messengers. Many studies, both in vivo and in vitro, have shown the importance of the contribution of reactive oxygen species (ROS) as important second messengers in embryo development. ROS may originate from embryo metabolism and/or oocyte/embryo surroundings, and their effect on embryonic development is highly variable, depending on the needs of the embryo at each stage of development and on their environment (in vivo or under in vitro culture conditions). Other studies have also shown the deleterious effects of ROS in embryo development, when cellular tissue production overwhelms antioxidant production, leading to oxidative stress. This stress is known to be the cause of many cellular alterations, such as protein, lipid, and DNA damage. Considering that the same ROS level can have a deleterious effect on the fertilizing oocyte or embryo at certain stages, and a positive effect at another stage of the development process, further studies need to be carried out to determine the rate of ROS that benefits the embryo and from what rate it starts to be harmful, this measured at each key phase of embryonic development.

Vitamin D3 affects mitochondrial biogenesis through mitogen-activated protein kinase in polycystic ovary syndrome mouse model

Polycystic ovarian syndrome (PCOS) is a disorder characterized by oligomenorrhea, anovulation, and hyperandrogenism. Altered mitochondrial biogenesis can result in hyperandrogenism. The goal of this study was to examine the effect of vitamin D3 on mitochondrial biogenesis of the granulosa cells in the PCOS-induced mouse model. Vitamin D3 applies its effect via the mitogen-activated pathway kinase-extracellular signal-regulated kinases (MAPK-ERK1/2) pathway. The PCOS mouse model was induced by the injection of dehydroepiandrosterone (DHEA). Isolated granulosa cells were subsequently treated with vitamin D3, MAPK activator, and MAPK inhibitor. Gene expression levels were measured using real-time polymerase chain reaction. MAPK proteins were investigated by western blot analysis. We also determined reactive oxygen species (ROS) levels with 2', 7'-dichlorofluorescein diacetate. Mitochondrial membrane potential (mtMP) was also measured by TMJC1. Mitochondrial biogenesis (peroxisome proliferator-activated receptor gamma coactivator 1-α and nuclear respiratory factor), antioxidant (superoxide dismutase, glutathione peroxidase, and catalase), and antiapoptotic (B-cell lymphoma-2) genes were upregulated in the PCOS mice that treated with vitamin D3 compared with the PCOS mice without any treatment. Vitamin D3 and MAPK activator-treated groups also reduced ROS levels compared with the nontreated PCOS group. In summary, vitamin D3 and MAPK activator increased the levels of mitochondrial biogenesis, MAPK pathway, and mtMP markers, while concomitantly decreased ROS levels in granulosa cells of the PCOS-induced mice. This study suggests that vitamin D3 may improve mitochondrial biogenesis through stimulation of the MAPK pathway in cultured granulosa cells of DHEA-induced PCOS mice which yet to be investigated.

Optimization of The Cell Aggregates Method for Isolation and Purification of Human Granulosa Cells from Follicular Fluid

BACKGROUND

Aspirated ovarian follicular fluids (FF) contain luteal granulosa cells (LGCs) and other contaminating cell types. Several strategies, such as the antibody binding methods, the flask method, the cell strainer and positive selection of granulosa aggregates after density gradient (DG) centrifugation, were tested as LGC purification methods. Each of these strategies has its own advantages and disadvantages. Positive selection of granulosa aggregates after DG centrifugation is simple, rapid and efficient in terms of LGC recovery. However, it results in a low purity. Here, we aimed to test whether modifying the traditional protocol by collecting the aggregates from the FF, before the DG centrifugation could decrease the percentage of contaminating cells.

MATERIALS AND METHODS

In the present prospective study, 32 FF, from 32 women,were randomly assigned into one of the two purification techniques: positive selection of granulosa aggregates from the FF, after DG centrifugation (DG/ Agg, n=16) or positive selection of granulosa aggregates from the FF, before DG centrifugation (Agg/DG, n=16). At the end of each procedure cell count, vitality, morphology and purity of the cell suspension were evaluated.

RESULTS

No significant difference was detected in the total number of GCs between DG/Agg and Agg/DG (P>0.05). However, higher percentage of GCs with normal morphology was detected in Agg/DG compared to DG/Agg (P<0.001). Moreover, lower percentages of white blood cells (P<0.01), red blood cells (P<0.001) and epithelial cells (P<0.01) were identified in Agg/DG compared to DG/Agg.

CONCLUSION

Here we showed that positive selection of granulosa aggregates from the FF prior to DG technique had a higher purity compared to the traditional protocol. Thus, it could be a method of choice to prepare GCs for research purposes in clinical in vitro fertilization settings.

Quercetin protects human granulosa cells against oxidative stress via thioredoxin system

Granulosa Cells (GCs) are sensitive to excessive production of reactive oxygen species (ROS). Quercetin (QUR) is a free radical scavenger which can alleviate oxidative stress through nuclear factor (erythroid-derived 2)-like 2 (Nrf2)/antioxidant response element (ARE) pathway and thioredoxin (Trx) system. We aimed to explore the probable protective role of QUR on cultured human GCs treated with hydrogen peroxide (H₂O₂) as an inducer of oxidative stress. MTT assay was applied for evaluating the cell cytotoxicity of QUR and H₂O₂. The rate of apoptotic cells and intracellular ROS generation were determined by Annexin V-FITC/PI staining and 2'-7'-dichlorodihydrofluorescein diacetate fluorescent probes (DCFH-DA), respectively. Quantitative real-time polymerase chain reaction (qRT-PCR) analysis and western blot analysis were used to evaluate the gene and protein expression of Nrf2 and kelch-like ech-associated protein 1 (Keap1)1. The Nrf2 and Trx activities were measured by Enzyme-linked Immunosorbent Assay (ELISA). The results indicated that QUR pretreatment can decrease ROS production and apoptosis induced by H₂O₂. In addition, QUR increased Nrf2 gene and protein expression, as well as its nuclear translocation. Moreover, in QUR-treated group, a lower level of Keap1 protein was observed, which was not reported as significant. The results also indicated a significant correlation between the expression of Nrf2 and Keap1 in QUR-treated group. Further, QUR protected GCs from oxidative stress by increasing Trx gene expression and activity. This study suggests that QUR as a supplementary factor may protect GCs from oxidative stress in diseases related to this condition.

The myo-inositol effect on the oocyte quality and fertilization rate among women with polycystic ovary syndrome undergoing assisted reproductive technology cycles: a randomized clinical trial

PURPOSE

The aim of the present study was to evaluate the effect of myo-Inositol administration on oocyte quality, fertilization rate and embryo quality in patients with PCOS during assisted reproductive technology (ART) cycles.

METHODS

Fifty infertile PCOS patients were randomly designated in two groups. In the study group, patients received daily doses of 4 g myo-Inositol combined with 400 mg folic acid and in the control group patients received only 400 mg folic acid from 1 month before starting the antagonist cycle until the day of ovum pick up. Oocyte and embryo qualities were assessed according to European Society of Human Reproduction and Embryology (ESHRE) guidelines. The gene expression of PGK1, RGS2 and CDC42 as a factor of oocyte quality in granulosa cells was analyzed using real-time RT-PCR. Levels of total antioxidant capacity (TAC) and reactive oxygen species (ROS) were evaluated by chemiluminescence assay in follicular fluid.

RESULTS

The percentage of metaphase II oocyte, fertilization rate and embryo quality significantly improved in the study group (p < 0.05), but the number of retrieved oocytes and follicle count were not statistically different between groups. Furthermore, the gene expression of PGK1, RGS2 and CDC42 was significantly higher in the study group (p < 0.05) but no differences were found between two groups in terms of TAC and ROS levels.

CONCLUSIONS

The present study findings suggest that myo-Inositol alters the gene expression in granulosa cells and improves oocyte and embryo quality among PCOS patients undergoing ART.

Implications and Future Perspectives of AGEs in PCOS Pathophysiology

Human, animal, and in vitro studies provide evidence that advanced glycation end-products (AGEs) may contribute to the pathogenesis of polycystic ovary syndrome (PCOS) and its metabolic and reproductive consequences. AGEs are able to induce, via activation of key intracellular signaling pathways, the generation of oxidative stress and proinflammatory cytokines, thus contributing to the adverse health impact of PCOS. This review presents the implications of AGEs in several disease pathophysiologies, including PCOS, as well as the cellular and systemic effects of AGEs on insulin resistance (IR), hyperandrogenemia, endoplasmic reticulum (ER) stress, hypoxia, and ovarian function. The gaps in our knowledge will serve as launching pad for future developments ranging from dietary and lifestyle changes to pharmaceutical interventions aiming at potential applications in women with PCOS.

Crosstalk between advanced glycation end products and vitamin D: A compelling paradigm for the treatment of ovarian dysfunction in PCOS

Women with PCOS have elevated levels of the harmful advanced glycation end products (AGEs) and low serum levels of vitamin D. AGEs and their receptors may contribute to the pathogenesis of PCOS and its metabolic and reproductive consequences. On the other hand, vitamin D might improve PCOS phenotype and could alleviate the detrimental effects of AGEs. A literature review using PubMed was performed. Critical analysis was carried out for articles pertaining to: 1) the role of AGEs and their receptors in the pathophysiology of PCOS, in particular ovarian dysfunction, and 2) the action of vitamin D in attenuating the adverse effects of AGEs in women with PCOS at both the serum and the cellular levels. Data from in vitro experiments, animal models, and human studies provide compelling evidence that AGEs and their receptors may contribute to the pathogenesis of ovarian dysfunction in PCOS. The actions of AGEs in PCOS might be attenuated and/or reversed by the presence or supplementation of vitamin D. Once a mechanistic understanding of the relationship between AGEs and vitamin D is established, this knowledge might contribute to the subsequent development of new-targeted pharmacological therapies for improving ovarian health in women with PCOS.

Levels of total antioxidant capacity and 8-hydroxy-2'-deoxyguanosine of serum and follicular fluid in women undergoing in vitro fertilization: focusing on endometriosis

This study was designed to evaluate the levels of oxidative stress (OS) markers, total non-enzymatic antioxidant capacity (TAC) and 8-hydroxy-2'-deoxyguanosine (8-OHdG) in the serum and follicular fluid (FF) of patients undergoing in vitro fertilization (IVF). The impact of these biomarkers on IVF outcome was also analysed. Samples were obtained from 61 patients (age: 36.40 ± 4.99 years; BMI: 22.54 ± 2.46; infertility: 3.7 ± 2.5 years [mean ± SD]) before and after controlled ovarian hyperstimulation (COH). Patients with and without endometriosis were also evaluated separately. TAC was quantified by enhanced chemiluminescence assay and 8-OHdG was measured by enzyme-linked immunosorbent assay. It was demonstrated that these biomarkers responded to COH differently. No relationship could be detected in their FF levels, although their cumulative serum levels were inversely related. Both FF TAC and FF 8-OHdG had a negative impact on the number of good quality embryos, but an effect of Serum TAC and 8-OHdG could not be observed. When women with and without endometriosis were evaluated separately, inconsistent results were obtained. However, women without endometriosis had higher levels of serum and FF TAC when they progressed to clinical pregnancy. Our findings support the notion that OS has an important contribution to the reproductive potential in IVF patients, the ideal biomarkers of outcome measures, however, need to be further explored.

Effects of vitamin C on the outcome of in vitro fertilization-embryo transfer in endometriosis: A randomized controlled study

OBJECTIVE

This study was performed to investigate the effect of vitamin C (VitC) supplementation on the outcomes of in vitro fertilization-embryo transfer (IVF-ET) in patients with endometriosis (EMs).

METHODS

A total of 280 patients with EMs underwent IVF-ET (VitC treatment group, n=160; VitC non-treatment group, n=120). An additional 150 patients who did not have EMs but underwent IVF-ET (control group) were also enrolled in this study. Superoxide dismutase (SOD), total antioxidant capacity (TAC), malondialdehyde (MDA) and reactive oxygen species (ROS) were measured to determine the role of VitC on oxidative stress markers in serum and follicular fluid (FF).

RESULTS

In total, 245 patients with EMs and 132 patients without EMs underwent successful IVF-ET and follow-up. The serum or FF levels of VitC, SOD, and TAC were lower in the EMs than control group; however, the MDA and ROS levels in serum or FF were higher in the EMs than control group. After 2 months of VitC treatment, the serum VitC levels in serum and FF were significantly increased, while oxidative stress markers were unaffected.

CONCLUSION

Treatment with VitC oral formulation improved the serum and FF levels of VitC but did not affect oxidative stress markers in patients with EMs.

Acrolein, a commonly found environmental toxin, causes oocyte mitochondrial dysfunction and negatively affects embryo development

Recent studies have revealed that acrolein, a commonly found toxin and a potent metabolite of cyclophosphamide (CTX), can cause deterioration of mouse oocyte quality through a mechanism involving the generation of reactive oxygen species (ROS). We extend these studies to evaluate the effects of acrolein, in varying concentrations, on the oocyte mitochondrial membrane and oocyte apoptosis and its effect on embryo development in vitro. Metaphase II mouse oocytes were exposed for 45 minutes to acrolein and CTX (10 & 25 µM) and mitochondrial dysfunction, a major source of ROS overproduction, was evaluated by the 5,5,6,6-tetrachloro-1,1,3,3-tetraethyl-β-benzimidazolylcarbocyanine iodide (JC-10) mitochondrial membrane potential assay. Treatment with acrolein led to mitochondrial membrane damage as well as induction of apoptosis compared to untreated control (p < 0.05). Similar results were obtained when oocytes were exposed to CTX (p < .05). Subsequently, the effect of acrolein exposure was evaluated by observing in vitro development of embryos after exposure. Acrolein treatment caused higher proportions of arrested and poor-quality embryos, evidenced by irregular cleavage, severe asymmetry of blastomeres, presence of large percentage of anuclear fragments, and dark granularity of the cytoplasm. Development at various durations in culture revealed that optimal embryo growth was significantly inhibited in a dose dependent manner, when compared to control (p < .05). A global model that links acrolein accumulation, generation of ROS, and mitochondrial dysfunction and their effect on oocyte and embryo quality is discussed further. Collectively, understanding the mechanism by which CTX and acrolein impact fertility is helpful in finding potential alternative or supplemental treatment options.

The capacity of oocytes for DNA repair

Female fertility and offspring health are critically dependent on the maintenance of an adequate supply of high-quality oocytes. Like somatic cells, oocytes are subject to a variety of different types of DNA damage arising from endogenous cellular processes and exposure to exogenous genotoxic stressors. While the repair of intentionally induced DNA double strand breaks in gametes during meiotic recombination is well characterised, less is known about the ability of oocytes to repair pathological DNA damage and the relative contribution of DNA repair to oocyte quality is not well defined. This review will discuss emerging data suggesting that oocytes are in fact capable of efficient DNA repair and that DNA repair may be an important mechanism for ensuring female fertility, as well as the transmission of high-quality genetic material to subsequent generations.

Activation of Nrf2 might reduce oxidative stress in human granulosa cells

Nuclear factor-E2-related factor 2 (Nrf2)/Kelch-like ECH-associated protein 1 (Keap1)-antioxidant response element (ARE) signaling pathway is one of the most important defense mechanisms against oxidative stress (OS). It is well documented that equilibration status of OS plays fundamental roles in human reproductive medicine, and the physiological role of Nrf2 in ovarian granulosa cells (GCs) has not been determined yet. Herein we aimed to study the function of Nrf2 in GCs. Human ovarian tissues were subjected to immunohistochemistry to localize Nrf2 and Keap1 and we detected the expression of Nrf2 and Keap1 in the human GCs. Human luteinized GCs were isolated and cultured, and hydrogen peroxide (H₂O₂) or Dimethylfumarates (DMF), an activator of Nrf2, were added to GCs to analyze the relationship between Nrf2 and antioxidants by quantitative RT-PCR. The mRNA levels of Nrf2, catalase, superoxide dismutase 1 (SOD1), and 8-Oxoguanine DNA glycosylase (OGG1) were elevated by H₂O₂, and DMF treatment showed similar but pronounced effects through activation of Nrf2. To determine the relationship of Nrf2 and the generation of antioxidants, siRNAs were used and quantitative RT-PCR were conducted. Decreased expression of Nrf2 resulted in a decreased level of these antioxidant mRNA. Intracellular levels of ROS were investigated by fluorescence of 8-hydroxy-2'-deoxyguanosine and fluorescent dye, 2',7'-dichlorodihydrofluorescein diacetate after H₂O₂ and/or DMF treatment, and DMF treatment quenched intracellular ROS generation by H₂O₂. These results show that activation of Nrf2 might lead to alleviate OS in human GCs, and this could provide novel insight to conquer the age-related fertility decline that is mainly attributed to the accumulation of aberrant OS.

Transcripts encoding free radical scavengers in human granulosa cells from primordial and primary ovarian follicles

PURPOSE

To study the presence and distribution of genes encoding free radical scavengers in human granulosa cells from primordial and primary ovarian follicles.

METHODS

A class comparison study on existing granulosa cell transcriptome from primordial (n = 539 follicles) and primary (n = 261) follicles donated by three women having ovarian tissue cryopreserved before chemotherapy was performed and interrogated.

RESULTS

In granulosa cells from primordial follicles, 30 genes were annotated 'mitochondrial dysfunction' including transcripts (PRDX5, TXN2) encoding enzymatic free radical scavengers peroxiredoxin 5 and thioredoxin 2. Several apoptosis regulation genes were noted (BCL2, CAS8, CAS9, AIFM1). In granulosa cells from primary follicles, mitochondrial dysfunction signalling pathway was annotated. High expression of transcripts encoding the free radical scavenger peroxiredoxin 3, as well as anti-apoptotic enzyme BCL2, was found. Interestingly, PARK7 encoding the deglycase (DJ-1) protein was expressed in granulosa cells from primary follicles. DJ-1 is implicated in oxidative defence and functions as a positive regulator of the androgen receptor and as a negative regulator of the phosphatidylinositol 3-kinase (PI3K)/phosphatase and tensin homolog (PTEN)/serine-threonine protein kinase (AKT) signalling pathway suppressor PTEN.

CONCLUSIONS

The results indicate extensive energy production and free radical scavenging in the granulosa cells of primordial follicles with potential implications for ovarian ageing, cigarette smoking, premature ovarian failure and polycystic ovarian syndrome. Furthermore, DJ-1 may be involved in androgen responsiveness and the regulation of follicle growth via PI3K/PTEN/AKT signalling pathway regulation in the granulosa cells of primary follicles. The involvement of mitochondrial free radical production in the age-related decline of competent oocytes is becoming apparent.

Dysregulated genes and their functional pathways in luteinized granulosa cells from PCOS patients after cabergoline treatment

Polycystic ovarian syndrome (PCOS) is a common reproductive disorder frequently associated with a substantial risk factor for ovarian hyperstimulation syndrome (OHSS). Dopamine receptor 2 (D2) agonists, like cabergoline (Cb2), have been used to reduce the OHSS risk. However, lutein granulosa cells (LGCs) from PCOS patients treated with Cb2 still show a deregulated dopaminergic tone (decreased D2 expression and low dopamine production) and increased vascularization compared to non-PCOS LGCs. Therefore, to understand the PCOS ovarian physiology, it is important to explore the mechanisms that underlie syndrome based on the therapeutic effects of Cb2. Here, LGCs from non-PCOS and PCOS patients were cultured with hCG in the absence/presence of Cb2 (n = 12). Subsequently, a transcriptomic-paired design that compared untreated vs treated LGCs within each patient was performed. After transcriptomic analysis, functions and genes were prioritized by systems biology approaches and validated by RT-qPCR. We identified that similar functions were altered in both PCOS and non-PCOS LGCs treated with Cb2; however, PCOS-treated LGCs exhibited more significant changes than non-PCOS. Among the prioritized functions, dopaminergic synapse, vascular endothelial growth factor (VEGF) signaling, apoptosis and ovarian steroidogenesis were highlighted. Finally, network modeling showed CASP9, VEGFA, AKT1, CREB, AIF, MAOA, MAPK14 and BMAL1 as key genes implicated in these pathways in Cb2 response, which might be potential biomarkers for further studies in PCOS.

The Potential of Nanotechnology in Medically Assisted Reproduction

Reproductive medicine is a field of science which searches for new alternatives not only to help couples achieve pregnancy and preserve fertility, but also to diagnose and treat diseases which can impair the normal operation of the reproductive tract. Assisted reproductive technology (ART) is a set of methodologies applied to cases related to infertility. Despite being highly practiced worldwide, ART presents some challenges, which still require special attention. Nanotechnology, as a tool for reproductive medicine, has been considered to help overcome some of those impairments. Over recent years, nanotechnology approaches applied to reproductive medicine have provided strategies to improve diagnosis and increase specificity and sensitivity. For in vitro embryo production, studies in non-human models have been used to deliver molecules to gametes and embryos. The exploration of nanotechnology for ART would bring great advances. In this way, experiments in non-human models to test the development and safety of new protocols using nanomaterials are very important for informing potential future employment in humans. This paper presents recent developments in nanotechnology regarding impairments still faced by ART: ovary stimulation, multiple pregnancy, and genetic disorders. New perspectives for further use of nanotechnology in reproductive medicine studies are also discussed.

Endometriosis Is a Cause of Infertility. Does Reactive Oxygen Damage to Gametes and Embryos Play a Key Role in the Pathogenesis of Infertility Caused by Endometriosis?

Approximately, 10-15% of women of reproductive age are affected by endometriosis, which often leads to infertility. Endometriosis often has an inherited component, and several causative predisposing factors are hypothesized to underlie the pathogenesis of endometriosis. One working hypothesis is the theory of retrograde menstruation. According to the theory of retrograde menstruation, components of refluxed blood, including apoptotic endometrial tissue, desquamated menstrual cells, lysed erythrocytes, and released iron, induce inflammation in the peritoneal cavity. This in turn activates macrophage release of reactive oxygen species (ROS), leading to oxidative stress via the respiratory burst. Refluxed blood promotes the Fenton reaction, terminating in the production of hydroxyl radical, the most potently destructive ROS. In this article, we review the papers that demonstrate decreased quantity and quality of oocytes and embryos retrieved from IVF/ICSI patients with endometriosis. We discuss literature data demonstrating that ROS are generated in endometriotic tissues that have physical proximity to gametes and embryos, and demonstrating adverse impacts on oocyte, sperm and embryo microtubule apparatus, chromosomes, and DNA. Data that addresses the notions that endometriosis causes oocyte and fetal aneuploidy and that these events are mediated by ROS species are also discussed. Literature data are also discussed that employ use of anti-oxidant molecules to evaluate the importance of ROS-mediated oxidative damage in the pathogenesis of endometriosis. Studies are discussed that have employed anti-oxidants compounds as therapeutics to improve oocyte and embryo quality in infertile subjects, and improve fertility in patients with endometriosis.

Association of CYP19A1 gene polymorphisms with anoestrus in water buffaloes

Cytochrome P450 aromatase (encoded by the CYP19A1 gene) regulates oestrogen biosynthesis and so plays an essential role in female fertility. We investigated the genetic association of CYP19A1 with the risk of anoestrus in Egyptian water buffaloes. A total of 651 animals (326 anoestrous and 325 cycling) were used in this case-control study. Using single-strand conformation polymorphisms and sequencing, four single nucleotide polymorphisms (SNPs) were detected; c.−135T > C SNP in the 5′UTR and three non-synonymous SNPs: c.559G > A (p. V187M) in Exon 5, c.1285C > T (p. P429S) and c.1394A > G (p. D465G) in Exon 10. Individual SNP-anoestrus association analyses revealed that genotypes (CC, AA and GG) and alleles (C, A and G) of the −135T > C, c.559G > A and c.1394A > G SNPs respectively were high risk for anoestrus. A further analysis confirmed that these three SNPs were in linkage disequilibrium. Additionally, haplotypes with two (TAG/122 and CAA/221) or three (CAG/222) risk alleles were significantly associated with susceptibility to anoestrus, lower blood levels of both oestradiol and antioxidant enzymes (superoxide dismutase, glutathione peroxidase (GPX) and catalase) and downregulated expression levels of CYP19A1, oestrogen receptor α and Gpx3 in the ovary, as well as increased serum level of malondialdehyde. This suggests the occurrence of a high incidence of oxidative ovarian damage and subsequently ovarian inactivity in buffaloes carrying risk alleles. Therefore, with this study we suggest the selection of buffaloes with protective alleles at these SNPs to improve the reproductive efficiency of the herd.

Oxidative Stress in Granulosa-Lutein Cells From In Vitro Fertilization Patients

Ovarian aging is associated with gradual follicular loss by atresia/apoptosis. Increased production of toxic metabolites such as reactive oxygen species (ROS) and reactive nitrogen species as well as external oxidant agents plays an important role in the process of ovarian senescence and in the pathogenesis of ovarian pathologies such as endometriosis and polycystic ovary syndrome (PCOS). This review provides a synthesis of available studies of oxidative stress (OS) in the ovary, focusing on the most recent evidence obtained in mural granulosa-lutein (GL) cells of in vitro fertilization patients. Synthesis of antioxidant enzymes such as peroxiredoxin 4, superoxide dismutase, and catalase and OS damage response proteins such as aldehyde dehydrogenase 3, member A2 decreases with aging in human GL cells, favoring an unbalance in ROS/antioxidants that mediates molecular damage and altered cellular function. The increase in OS in the granulosa cell correlates with diminished expression of follicle-stimulating hormone receptor (FSHR) and a dysregulation of the FSHR signaling pathway and may be implicated in disrupted steroidogenic function and poor response to FSH in women with aging. Women with endometriosis and PCOS have lower antioxidant production capacity that may contribute to abnormal follicular development and infertility. Further investigation of the signaling pathways involved in cellular response to OS could shed light into molecular characterization of these diseases and development of new treatment strategies to improve reproductive potential in these women.