Effects of Alginic Acid on the Porcine Granulosa Cells and Maturation of Porcine Oocytes

SCOPE

Alginic acid (AA) from brown algae is a marine organic compound. There is extensive use of AA in the food industry and healthcare, suggesting a high probability of AA exposure. The present study investigates the effects of AA on porcine ovarian granulosa cells (GCs) and oocytes to explore its mechanism in female reproduction because of its adverse effects on reproduction.

METHODS AND RESULTS

The study adds 20 µM AA to the porcine primary ovarian GCs medium and porcine oocyte in vitro maturation (IVM) medium. Estrogen and progesterone levels are downregulated in GCs. Reactive oxygen species are excessive, and the antioxidant capacity declines. Then mitochondria-mediated apoptosis pathway is involved in GCs apoptosis. In addition, scores of autophagosomes are found in the experimental cells. Furthermore, AA significantly inhibits the proliferation of GCs around cumulus-oocyte complexes (COCs) accompanied by abnormal spindle assembly, chromosome arrangement disorder, and aberrant cortical granules distribution in oocytes, leading to a decreased oocyte maturation rate.

CONCLUSION

These findings suggest that 20 µM AA is toxic to sow reproduction by interfering with estrogen production, oxidative stress, mitochondria-mediated apoptosis, autophagy in GCs of sows, and oocyte maturation.

Perfluorooctanoic acid (PFOA) affects steroidogenesis and antioxidant defence in granulosa cells from swine ovary

PFOA is mainly employed in products with water and oil repellent properties. Due to its persistence, bioaccumulation and critical effects on health, its use has been restricted in several countries. This research was intended to explore PFOA action on the main functions of swine ovarian granulosa cells, a valuable model for translational medicine. Moreover, since we previously demonstrated a disruptive effect on free radical generation we sought to explore PFOA effects on the main antioxidant enzymes. PFOA inhibited cell proliferation (p < 0.001), assessed by BrdU uptake. Steroidogenesis was disrupted: PFOA also stimulated 17β-estradiol production (p < 0.05), increased progesterone production (p < 0.05) at the lowest dose while it displayed an inhibitory effect at higher concentrations (p < 0.05). SOD (p < 0.001), catalase (p < 0.05) and peroxidase (p < 0.01) activities were stimulated. Therefore, our study supports a disruptive effect of PFOA in cultured swine granulosa cells.

Melatonin Protects the Apoptosis of Sheep Granulosa Cells by Suppressing Oxidative Stress via MAP3K8 and FOS Pathway

Melatonin is not only a highly effective active oxygen scavenger but also an important reproductive hormone. Melatonin has a regulatory effect on animal reproduction, especially on the ovaries. It can affect the proliferation and apoptosis of cells in follicles. However, the mechanisms of the dual antioxidation and anti-apoptosis effects of melatonin on granulosa cells are still not clear, especially in sheep. Therefore, we investigated the mechanisms of the protective effect of melatonin against oxidative damage in granulosa cells. At a concentration of 250 µmol/L, H₂O₂ promoted granulosa cell apoptosis; however, 10 ng/mL melatonin effectively alleviated the pro-apoptotic effect of H₂O₂. Furthermore, through the application of high-throughput sequencing technology, we identified 109 significantly differentially expressed genes (35 upregulated and 74 downregulated genes) involved in the protective effect of melatonin against apoptosis. The expression levels of nine related genes, i.e., ATF3, FIBIN, FOS, HSPA6, MAP3K8, FOSB, PET117, DLX2, and TRIB1, changed significantly. MAP3K8 and FOS gene overexpression impacted the protective effect of melatonin in granulosa cells; the two genes exhibited an upstream and downstream regulatory relationship. Our findings indicated that melatonin alleviated H₂O₂-induced apoptosis in sheep granulosa cells through the MAP3K8-FOS pathway.

Redox Status, Estrogen and Progesterone Production by Swine Granulosa Cells Are Impaired by Triclosan

Triclosan is a chlorinated biphenolic with a broad spectrum of antiseptic activities used in cosmetics and hygiene products. Continuous exposure can lead to absorption and bioaccumulation of this substance with harmful health effects. In fact, previous studies have shown that Triclosan acts as an endocrine-disrupting chemical on reproductive organs, with consequent negative effects on reproductive physiology. Therefore, to assess potential adverse impacts on fertility, we tested Triclosan on swine granulosa cells, a model of endocrine reproductive cells. We examined its effects on the main features of granulosa cell functions such as cell growth (BrdU incorporation and ATP production) and steroidogenesis (17-β estradiol and progesterone secretion). Moreover, since oxidant−antioxidant balance plays a pivotal role in follicular function, redox status markers (superoxide, hydrogen peroxide and nitric oxide production, enzymatic and non-enzymatic scavenging activity) were studied. Our results show that Triclosan significantly inhibits cell growth (p < 0.001), steroidogenesis (p < 0.001), superoxide and nitric oxide production (p < 0.001), while it increases (p < 0.05) enzymatic defense systems. Collectively, these data suggest a disruption of the main granulosa cell functions, i.e., proliferation and hormone production, as well as an imbalance in redox status. On these bases, we can speculate that Triclosan would impair granulosa cell functions, thus exerting negative effects on reproductive function. Further studies are needed to explore lower Triclosan concentrations and to unravel its mechanisms of action at gene level.

The effects of nanoplastics on adipose stromal cells from swine tissues

Plastic is one of the main sources of marine and terrestrial pollution. This material can fragment into micro- (<-5 mm) and nanoplastics (NPs) (<100 nm) following degradation. Animals are exposed to these particles by ingesting contaminated food, respiration or filtration, and transdermally. In organisms, NPs can cross biological membranes, and cause oxidative stress, cell damage, apoptosis, and endocrine interference. We previously demonstrated that polystyrene - NPs interfered with ovarian cell functions. Since reproduction involves a high energy expenditure and a crucial role is played by adipose tissue, the aim of the present study was to evaluate the effects of NPs on primary adipose stromal cells (ASCs) isolated from swine adipose tissues. In particular, the effects on cell viability, proliferation, metabolic activity, inflammatory process mediators and oxidative stress markers were assessed. The obtained results did not reveal a significant variation in cell proliferation, metabolic activity was increased (P < 0.01) but only at the lowest concentration, while viability showed a significant decrease after prolonged exposure to NPs (P < 0.01). TNF-α was increased (P < 0.05), while PAI-1 was inhibited (P < 0.001). Redox status was significantly modified; in particular, the production of O₂^-_, H₂O₂ and NO was stimulated (P < 0.05), the non-enzymatic antioxidant power was reduced (P < 0.05) while catalase activity was significantly (P < 0.01) increased.

Aquaporin-8 transports hydrogen peroxide to regulate granulosa cell autophagy

Aquaporin-8 (AQP8), a member of the aquaporin family, is strongly expressed in follicular granulosa cells, which could affect the hormone secretion level in females. AQP8, as a membrane protein, could mediate H₂O₂ into cells, thereby triggering various biological events. The deficiency of Aqp8 increases female fertility, resulting from the decrease in follicular atresia. The low cell death rate is related to the apoptosis of granulosa cells. However, the mechanism by which AQP8 regulates the autophagy of granulosa cells remains unclear. Thus, this study aimed to explore the effect of AQP8 on autophagy in follicular atresia. We found that the expression of the autophagy marker light-chain protein 3 was significantly downregulated in the granulosa cells of Aqp8-knockout (Aqp8^−/−) mice, compared with wild-type (Aqp8^+/+) mice. Immunofluorescence staining and transmission electron microscopic examination indicated that the number of autophagosomes in the granulosa cells of Aqp8^−/− mice decreased. Using a follicular granulosa cell autophagy model, namely a follicular atresia model, we verified that the concentration of H₂O₂ significantly increased during the autophagy of granulosa cells, consistent with the Aqp8 mRNA level. Intracellular H₂O₂ accumulation was modulated by endogenous AQP8 expression level, indicating that AQP8-mediated H₂O₂ was involved in the autophagy of granulosa cells. AQP8 deficiency impaired the elevation of H₂O₂ concentration through phosphorylated tyrosine activation. In addition, we carried out the analysis of transcriptome sequencing datasets in the ovary and found there were obvious differences in principal components, differentially expressed genes (DEGs) and KEGG pathways, which might be involved in AQP8-regulated follicular atresia. Taken together, these findings indicated that AQP8-mediated H₂O₂ transport could mediate the autophagy of granulosa cells. AQP8 might be a potential target for diseases related to ovarian insufficiency.

Downregulation of miR-192 Alleviates Oxidative Stress-Induced Porcine Granulosa Cell Injury by Directly Targeting Acvr2a

Follicular atresia is primarily caused by breakdown to granulosa cells (GCs) due to oxidative stress (OS). MicroRNAs (miRNAs) elicit a defense response against environmental stresses, such as OS, by acting as gene-expression regulators. However, the association between miRNA expression and OS in porcine GCs (PGCs) is unclear. Here, we examined the impact of H₂O₂-mediated OS in PGCs through miRNA-Seq. We identified 22 (14 upregulated and 8 downregulated) and 33 (19 upregulated and 14 downregulated) differentially expressed miRNAs (DEmiRNAs) at 100 μM and 300 μM H₂O₂, respectively, compared with the control group. Among the DEmiRNAs, mi-192 was most induced by H₂O₂-mediated OS, and the downregulation of miR-192 alleviated PGC oxidative injury. The dual-luciferase reporter assay results revealed that miR-192 directly targeted Acvr2a. The Acvr2a level was found to be remarkably decreased after OS. Furthermore, grape seed procyanidin B2 (GSPB2) treatment significantly reduced the H₂O₂-induced upregulation of miR-192, and decreased PGC apoptosis and oxidative damage. Meanwhile, GSPB2 prevented an H₂O₂-induced increase in caspase-3 activity, which was enhanced by the application of the miR-192 inhibitor. These results indicate that GSPB2 protects against PGC oxidative injury via the downregulation of miR-192, the upregulation of Acvr2a expression, and the suppression of the caspase-3 apoptotic signaling pathway.

Use of giant unilamellar lipid vesicles as antioxidant carriers in in vitro culture medium of bovine embryos

Giant unilamellar vesicles (GUVs) are composed of lipophilic layers and are sensitive to the action of reactive oxygen species (ROS). The use of GUVs as microcarriers of biological macromolecules is particularly interesting since ROS produced by gametes or embryos during in vitro culture can induce the opening of pores in the membrane of these vesicles and cause the release of their content. This study investigated the behavior of GUVs [composed of 2-dioleoyl-sn-glycero-3-phosphocholine and 1,2-dioleoyl-sn-glycero-3-phosphoethanolamine-N-(lissamine rhodamine B sulfonyl)] in co-culture with in vitro produced bovine embryos, as well as their embryotoxicity and effectiveness as cysteine carriers in culture medium. Embryonic developmental rates were unaffected, demonstrating the absence of toxicity of GUVs co-cultured with the embryos. No increase of intracellular ROS levels was observed in the embryos co-cultured with GUVs, indicating that the higher lipid content of the culture environment resulting from the lipid composition of the GUV membrane itself did not increase oxidative stress. Variations in the diameter and number of GUVs demonstrated their sensitivity to ROS produced by embryos cultured under conditions that generate oxidative stress. Encapsulation of cysteine in GUVs was found to be more effective in controlling the production of ROS in embryonic cells than direct dilution of this antioxidant in the medium. In conclusion, the use of GUVs in in vitro culture was found to be safe since these vesicles did not promote toxic effects nor did they increase intracellular ROS concentrations in the embryos. GUVs were sensitive to oxidative stress, which resulted in structural changes in response to the action of ROS. The possible slow release of cysteine into the culture medium by GUV rupture would therefore favor the gradual supply of cysteine, prolonging its presence in the medium. Thus, the main implication of the use of GUVs as cysteine microcarriers is the greater effectiveness in preventing the intracytoplasmic increase of ROS in in vitro produced bovine embryos.

Perfluorooctanoic Acid (PFOA) Induces Redox Status Disruption in Swine Granulosa Cells

Perfluorooctanoic acid (PFOA) is employed in the production and processing of several plastic materials, mainly during the production of waterproof fabrics or nonstick cookware. PFOA is identified as a substance of very high concern, as it is classified as a persistent, bioaccumulative, and toxic (PBT) substance because of its persistence in the environment and its potential accumulation in organisms. Thus, safe levels of exposure cannot be established, and PFOA emissions should be minimized. PFOA has recently been linked to several health concerns in humans. In particular, a disruptive effect on redox status homeostasis has been documented, with a potential impairment of normal reproductive function that requires adequate oxidative balance. Therefore, the aim of the present study was to evaluate the effects of PFOA (2, 20, and 200 ng/mL) on ovarian granulosa cells, a model of reproductive cells. The obtained results reveal that PFOA stimulated cell viability (p < 0.05). Regarding the effects on free radical production, O2−, NO, and H2O2 were significantly inhibited (p < 0.05), while the nonenzymatic antioxidant power was not significantly modified. Collectively, the present results deserve attention since free radical molecules play a crucial role in ovarian follicle development leading to a successful ovulation.

Oxidative stress and DNA damage status in couples undergoing in vitro fertilization treatment

This study examined the status of oxidative stress in 599 couples undertaking in vitro fertilization (IVF) treatment and its association with reproductive hormones, smoking, and outcomes. Oxidative stress biomarkers such as malondialdehyde, 8-hydroxy-2-deoxyguanosine, hydrogen peroxide (H₂O₂), catalase (CAT), and total antioxidant capacity (TAC) were determined in follicular fluid and seminal plasma. Tail moment (TM) was used to evaluate DNA damage in the sperm and granulosa cells. Reproductive hormones in serum and cotinine (COT) in urine, follicular fluid, and seminal plasma samples were determined. Separate multivariate linear regression was used to assess associations between levels of each oxidative stress biomarker and each hormone and smoking parameter (modeled as natural log-transformed). The findings indicate that some oxidative stress and DNA damage biomarkers played a role in disrupting certain reproductive hormones in women and their male partners either by overproducing reactive oxygen species or reducing antioxidant defense capacity. Although women were nonsmokers, COT levels > 50 and 10 µg/L in urine and follicular were observed in 5.7 and 1.7%, respectively. Levels of follicular fluid COT were positively associated with H₂O₂ and TM. We used log-binomial multivariate regression to estimate relative risks for the association between oxidative stress/DNA damage and IVF binary outcomes (fertilization rate > 50%, biochemical pregnancy, clinical pregnancy, and live birth). An increase in the CAT levels of follicular fluid was associated with a 48 and 41% decrease in the risk of poor fertilization rate (≤50%) and unsuccessful live birth, respectively. After the models were adjusted for hormonal factors, the associations remained the same, except that the elevated TAC in follicular fluid became significantly associated with a decrease of 42% in the risk of poor fertilization rate (≤50%). The higher antioxidant activity (CAT and TAC) in follicular fluid might positively impact specific IVF outcomes.

The Key Role of Peroxisomes in Follicular Growth, Oocyte Maturation, Ovulation, and Steroid Biosynthesis

The absence of peroxisomes can cause disease in the human reproductive system, including the ovaries. The available peroxisomal gene-knockout female mouse models, which exhibit pathological changes in the ovary and reduced fertility, are listed in this review. Our review article provides the first systematic presentation of peroxisomal regulation and its possible functions in the ovary. Our immunofluorescence results reveal that peroxisomes are present in all cell types in the ovary; however, peroxisomes exhibit different numerical abundances and strong heterogeneity in their protein composition among distinct ovarian cell types. The peroxisomal compartment is strongly altered during follicular development and during oocyte maturation, which suggests that peroxisomes play protective roles in oocytes against oxidative stress and lipotoxicity during ovulation and in the survival of oocytes before conception. In addition, the peroxisomal compartment is involved in steroid synthesis, and peroxisomal dysfunction leads to disorder in the sexual hormone production process. However, an understanding of the cellular and molecular mechanisms underlying these physiological and pathological processes is lacking. To date, no effective treatment for peroxisome-related disease has been developed, and only supportive methods are available. Thus, further investigation is needed to resolve peroxisome deficiency in the ovary and eventually promote female fertility.

Resveratrol protects human luteinised granulosa cells against hydrogen peroxide-induced oxidative injury through the Sirt1

Granulosa cells (GCs) control follicular development and are important for female reproduction. Resveratrol (Res) was considered as an antioxidant and Sirt1 inducer. Hydrogen peroxide (H2O2) is the classical reagent to study oxidative stress. The study was conducted to investigate the role of Res against H2O2 in human luteinised granulosa cells (LGCs). The LGCs in the H2O2 group were treated with 100μmol/L H2O2 for 24h. The LGCs in the Res group were treated with 50μmol/L Res for 2h, followed by H2O2. The LGCs in the Sirt1 blockage group were treated with 2.5μmol/L EX527+50μmol/L Res for 2h, followed by H2O2. Results showed that Res significantly increased LGCs viability in H2O2-induced LGCs. The apoptotic rate and ROS in the H2O2 group was higher and the antioxidant enzyme activity was lower compared with other groups. Following the Res, the apoptotic rate and ROS level were reduced and the antioxidant enzyme activity were increased. In the Res blockage group, no significant alterations in the cell apoptosis, ROS and antioxidant enzyme activity were observed compared with the H2O2 group. The Res group had a Caspase-3 downregulation and Sirt1 upregulation compared with the other groups. In conclusion, Res had a protective effect against the H2O2-induced LGCs, and the mechanism may be associated with Sirt1.

Stanniocalcin-1 in the female reproductive system and pregnancy

BACKGROUND

Stanniocalcin-1 (STC-1) is a widely expressed glycoprotein hormone involved in a diverse spectrum of physiological and pathophysiological processes including angiogenesis, mineral homeostasis, cell proliferation, inflammation and apoptosis. Over the last 20 years, numerous studies have reported STC-1 expression within female reproductive tissues including the uterus, ovaries and placenta and implicated STC-1 in processes such as ovarian follicular development, blastocyst implantation, vascular remodelling in early pregnancy and placental development. Notably, dysregulation of STC-1 within reproductive tissues has been linked to the onset of severe reproductive disorders including endometriosis, polycystic ovary syndrome, poor trophoblast invasion and placental perfusion in early pregnancy. Furthermore, significant changes in tissue expression and in maternal systemic concentration take place throughout pregnancy and further substantiate the vital role of this protein in reproductive health and disease.

OBJECTIVE AND RATIONALE

Our aim is to provide a comprehensive overview of the existing literature, to summarise the expression profile and roles of STC-1 within the female reproductive system and its associated pathologies. We highlight the gaps in the current knowledge and suggest potential avenues for future research.

SEARCH METHODS

Relevant studies were identified through searching the PubMed database using the following search terms: ‘stanniocalcin-1’, ‘placenta’, ‘ovary’, ‘endometrium’, ‘pregnancy’, ‘reproduction’, ‘early gestation’. Only English language papers published between 1995 and 2020 were included.

OUTCOMES

This review provides compelling evidence of the vital function that STC-1 plays within the female reproductive system. The literature presented summarise the wide expression profile of STC-1 within female reproductive organs, as well as highlighting the putative roles of STC-1 in various functions in the reproductive system. Moreover, the observed link between altered STC-1 expression and the onset of various reproductive pathologies is presented, including those in pregnancy whose aetiology occurs in the first trimester. This summary emphasises the requirement for further studies on the mechanisms underlying the regulation of STC-1 expression and function.

WIDER IMPLICATIONS

STC-1 is a pleiotropic hormone involved in the regulation of a number of important biological functions needed to maintain female reproductive health. There is also growing evidence that dysregulation of STC-1 is implicated in common reproductive and obstetric disorders. Greater understanding of the physiology and biochemistry of STC-1 within the field may therefore identify possible targets for therapeutic intervention and/or diagnosis.

Effect of Embryo Aggregation on In Vitro Development of Adipose-Derived Mesenchymal Stem Cell-Derived Bovine Clones

Somatic cell nuclear transfer (SCNT) is a method with unique ability to reprogram the epigenome of a fully differentiated cell. However, its efficiency remains extremely low. In this work, we assessed and combined two simple strategies to improve the SCNT efficiency in the bovine. These are the use of less-differentiated donor cells to facilitate nuclear reprogramming and the embryo aggregation (EA) strategy that is thought to compensate for aberrant epigenome reprogramming. We carefully assessed the optimal time of EA by using in vitro-fertilized (IVF) embryos and evaluated whether the use of adipose-derived mesenchymal stem cells (ASCs) as donor for SCNT together with EA improves the blastocyst rates and quality. Based on our results, we determined that the EA improves the preimplantation embryo development per well of IVF and SCNT embryos. We also demonstrated that day 0 (D0) is the optimal aggregation time that leads to a single blastocyst with uniform distribution of the original blastomeres. This was confirmed in bovine IVF embryos and then, the optimal condition was translated to SCNT embryos. Notably, the relative expression of the trophectoderm (TE) marker KRT18 was significantly different between aggregated and nonaggregated ASC-derived embryos. In the bovine, no effect of the donor cell is observed on the developmental rate, or the embryo quality. Therefore, no synergistic effect of the use of both strategies is observed. Our results suggest that EA at D0 is a simple and accessible strategy that improves the blastocyst rate per well in bovine SCNT and IVF embryos and influence the expression of a TE-related marker. The aggregation of two ASC-derived embryos seems to positively affect the embryo quality, which may improve the postimplantation development.

Nanoplastics impair in vitro swine granulosa cell functions

Soil, water, and air pollution by plastic represents an issue of great concern since the particles produced by degradation of plastic materials can be ingested by animals and humans, with still uncertain health consequences. As a contribution on this crucial subject, the present work reports an investigation on the in vitro effects of different concentrations of polystyrene nanoplastics (5, 25, and 75 µg/mL) on swine granulosa cells, a model of endocrine reproductive cells. In particular, cell growth (BrDU incorporation and ATP production), steroidogenesis (17-β estradiol and progesterone secretion) and redox status (superoxide and nitric oxide production, enzymatic and non-enzymatic scavenging activity) were studied. Nanoplastics, at the highest concentration, stimulated cell proliferation (P < 0.05), while cell viability resulted unaffected. Steroidogenesis was disrupted (P < 0.05). Both enzymatic and non-enzymatic scavenging activity were increased after exposure at the highest nanoplastic dose (P < 0.05, P < 0.001). Nitric oxide secretion was increased by 25 and 75 µg/mL (P < 0.05) while superoxide generation was stimulated (P < 0.001) only by the highest concentration tested. Taken together, main features of cultured swine granulosa cells resulted affected by exposure to nanoplastics. These results raise concerns since environment nanoplastic contamination can represents a serious threat to animal and human health.

Susceptibility of Oocytes from Gilts and Sows to Beauvericin and Deoxynivalenol and Its Relationship with Oxidative Stress

Beauvericin (BEA) and deoxynivalenol are toxins produced by Fusarium species that can contaminate food and feed. The aim of this study was to assess the effects of these mycotoxins on the maturation of oocytes from gilts and sows. Furthermore, the antioxidant profiles in the oocytes' environment were assessed. Cumulus-oocyte-complexes (COCs) from gilts and sows were exposed to beauvericin (BEA) or deoxynivalenol (DON) and matured in vitro. As an extra control, these COCs were also exposed to reactive oxygen species (ROS). The maturation was mostly impaired when oocytes from gilts were exposed to 0.02 μmol/L DON. Oocytes from sows were able to mature even in the presence of 5 μmol/L BEA. However, the maturation rate of gilt oocytes was already impaired by 0.5 μmol/L BEA. It was observed that superoxide dismutase (SOD) and glutathione (GSH) levels in the follicular fluid (FF) of gilt oocytes was higher than that from sows. However, the expression of SOD1 and glutathione synthetase (GSS) was higher in the oocytes from sows than in those from gilts. Although DON and BEA impair cell development by diverse mechanisms, this redox imbalance may partially explain the vulnerability of gilt oocytes to these mycotoxins.

Heavy Metal Assessment in Feathers of Eurasian Magpies (Pica pica): A Possible Strategy for Monitoring Environmental Contamination?

In the present study, the Eurasian magpie (Pica pica), was evaluated as a possible bioindicator of environmental pollution by heavy metals (HMs). Levels of Ni, Pb, Cd, and Hg in feathers of 64 magpies (31 males and 33 females) were measured by ICP-MS technique. Plasmatic biomarkers of oxidative stress (OS) were also assessed. The birds were captured in the province of Parma (Italy), in different capture sites within 1 km from urban area (UZ), and farther than 5 km from urban area (RZ). Median HM levels were 0.68 mg/kg (0.18–2.27), 2.80 mg/kg (0.41–17.7), <limit of detection (LOD) mg/kg (<LOD–0.25), 3.90 mg/kg (1.35–85.9) for Ni, Pb, Cd and Hg, respectively. No significant differences in HM levels were found according to sex, while Ni and Pb were significantly higher in adult compared to young birds (p = 0.047, p = 0.004). Conversely, Cd and Hg levels in young magpies resulted higher than those of adults (p = 0.001 and p = 0.004). No correlation was found between OS biomarkers and HM levels. No differences were found in HM levels according to capture area, except for Hg level, which resulted higher in magpies of RZ (4.05 mg/kg (1.35–12.7)) compared to UZ (2.99 mg/kg (1.54–85.9)). Further experiments are needed to establish whether magpie feathers could represent a suitable non-invasive tool for biomonitoring HMs in the environment.

Redox Status in Canine Leishmaniasis

Simple Summary

Leishmaniasis is under strict observation by World Health Organization but its pathogenesis has not been completely clarified yet. Our aim was to compare healthy and affected dogs measuring parameters related to oxidative stress, namely reactive oxygen species, reactive nitrogen species and scavenger activities, using colorimetric assays. Our results demonstrate that several of the examined parameters are modified in canine Leishmaniasis. Therefore, it is essential to further investigate this topic to shed light on the pathogenesis of the disease.

Abstract

The World Health Organization defined leishmaniasis as one of the priority attention diseases. Aiming to clarify some aspects of its pathogenetic mechanisms, our study focused on the assessment of redox status in dogs, the main reservoir for Leishmania infantum. Forty-five dogs from an endemic area in southern Italy were divided into four different groups (from mild disease with negative to low positive antibody levels to very severe disease with medium to high positive antibody levels) according to the LeishVet group guidelines. Their plasma and/or sera were tested for reactive oxygen species (ROS), namely the superoxide anion (O₂⁻), reactive nitrogen species (RNS), such as nitric oxide (NO) and hydroperoxides (ROOH), as well as activity of the detoxifying enzyme superoxide dismutase (SOD), and total nonenzymatic antioxidant capacity, as determined by the ferric reducing-antioxidant power (FRAP) assay. O₂⁻ generation was significantly (p < 0.05) reduced in leishmaniasis-affected dogs independently of the clinical stage, while NO production was stimulated (p < 0.05) only in II and III stage patients. No difference could be found for the levels of hydroperoxides and SOD activity between healthy and pathological subjects. FRAP values were lower in affected dogs but only in stage II. Taken together, although we demonstrated that several redox status parameters are altered in the plasma of dog affected by leishmaniasis, the oxidative stress changes that are observed in this disease, are possibly mainly due to cellular blood components i.e., neutrophils responsible for the elimination of the parasite. Further studies are required to assess the clinical values of the collected data.

Evaluation of Oxidative Stress Parameters in Healthy Saddle Horses in Relation to Housing Conditions, Presence of Stereotypies, Age, Sex and Breed

Oxidative stress plays an important role in the development of many horse diseases and it has been shown that housing has important implications for the psychophysical well-being of horses. The aim of this study is to determine if there are any differences between the redox status in horses in relation to housing conditions. The four housing conditions analyzed were: single box, without external access and without contact (Cat A), single box with external access and possibility of partial contact (Cat B), group housing with box and large paddock (Cat C), pasture with more than 7 horses and the possibility of green forage for the whole year (Cat D). A group of 117 healthy horses were selected in several private stables in Northern Italy. All subjects treated with any type of drug were excluded. At the end of the enrollment, the 117 selected horses were divided into the four housing categories. Stereotypies were highest in the group of horses in single box, without external access and without contact (Cat A). Oxidative stress was evaluated by testing plasma or serum samples for the following parameters: superoxide anion (WST), nitric oxide (NO), reactive oxygen species (d-ROMs), ferric reducing ability of plasma (FRAP), and the activity of superoxide dismutase (SOD). Simultaneously with the blood sampling, the owners completed a questionnaire with all the management aspects of the horse (signaling, feeding, equestrian activity, vaccinations, foot management etc.). The statistical evaluation was carried out based on the categories previously described, on the presence and absence of stereotypies and on some signaling data obtained from the questionnaire. There were no significant differences in the parameters analyzed between the categories. No significant redox status differences were detected based on the presence or absence of stereotypies. Interestingly, when the age was introduced as selection (<14 and >14 years old) parameter inside the categories, statistical significance was observed for some of the stress markers considered. Finally, independently of the housing conditions, the horses of the most two represented breeds exhibited different values of FRAP. All these aspects are commented in the discussion.

Porcine follicular fluid derived from > 8 mm sized follicles improves oocyte maturation and embryo development during in vitro maturation of pigs

The aim of the present study was to investigate the effects of porcine follicular fluid (pFF) from large-sized (LFF; >8 mm in diameter) and medium-sized (MFF; 3-6 mm in diameter) follicles on the maturation and developmental competence of porcine oocytes. Cumulus-oocyte complexes (COCs) were collected from follicles 3-6 mm in diameter. The collected COCs were incubated for 22 h with LFF or MFF (in vitro maturation (IVM)-I stage) and were incubated subsequently for 22 h with LFF or MFF (IVM-II stage). Cumulus expansion was confirmed after the IVM-I stage and nuclear maturation was evaluated after the IVM-II stage. Intracellular glutathione (GSH) and reactive oxygen species (ROS) levels were measured and embryonic development was evaluated. Relative cumulus expansion and GSH levels were higher in the LFF group compared with in the MFF group after the IVM-I stage (P < 0.05). After the IVM-II stage, the numbers of oocytes in metaphase-II were increased in the LFF group and GSH content was higher in all of the LFF treatment groups compared with in the MFF treatment groups during both IVM stages (P < 0.05). ROS levels were reduced by LFF treatment regardless of IVM stage (P < 0.05). Blastocyst formation and the total numbers of cells in blastocysts were increased in all LFF treatment groups compared with the control group (P < 0.05). These results suggested that pFF from large follicles at the IVM stage could improve nucleic and cytoplasmic maturation status and further embryonic development through reducing ROS levels and enhancing responsiveness to gonadotropins.

Oxidant–Antioxidant Status in Canine Multicentric Lymphoma and Primary Cutaneous Mastocytoma

Oxidative stress is a prominent event in several acute and chronic diseases including neoplasia. Although its direct involvement in carcinogenesis still remains to be clearly defined, a deeper knowledge of oxidative stress in oncologic patients could help to monitor their clinical outcome and to develop new therapeutic approaches. Therefore, the present study was undertaken to explore redox status in blood of neoplastic dogs affected either by multicentric lymphoma or by primary cutaneous mastocytoma. Superoxide anion (O2 •−), nitric oxide (NO) and hydroperoxides (ROOH) were measured. Detoxifying enzyme superoxide dismutase (SOD) and total non-enzymatic antioxidant capacity (ferric reducing-antioxidant power (FRAP)) were assessed. The oxidative stress index (OSi) both for enzymatic (OSiE) and non-enzymatic (OSiNE) scavengers were evaluated. Both pathologies, showed a reduced NO generation, while O2 •− levels were decreased only in mastocytoma. The oxidative stress indexes showed a significant decrease in mastocytoma patients, only for OSiE.

Proteomics Analysis Reveals that Warburg Effect along with Modification in Lipid Metabolism Improves In Vitro Embryo Development under Low Oxygen

The molecular mechanism regulating embryo development under reduced oxygen tension remains elusive. This study aimed to identify the molecular mechanism impacting embryo development under low oxygen conditions. Buffalo embryos were cultured under 5% or 20% oxygen and were evaluated according to their morphological parameters related to embryo development. The protein profiles of these embryos were compared using iTRAQ-based quantitative proteomics. Physiological O2 (5%) significantly promoted blastocyst yield, hatching rate, embryo quality and cell count as compared to atmospheric O2 (20%). The embryos in the 5% O2 group had an improved hatching rate of cryopreserved blastocysts post-warming (p < 0.05). Comparative proteome profiles of hatched blastocysts cultured under 5% vs. 20% O2 levels identified 43 differentially expressed proteins (DEPs). Functional analysis indicated that DEPs were mainly associated with glycolysis, fatty acid degradation, inositol phosphate metabolism and terpenoid backbone synthesis. Our results suggest that embryos under physiological oxygen had greater developmental potential due to the pronounced Warburg Effect (aerobic glycolysis). Moreover, our proteomic data suggested that higher lipid degradation, an elevated cholesterol level and a higher unsaturated to saturated fatty acid ratio might be involved in the better cryo-survival ability reported in embryos cultured under low oxygen. These data provide new information on the early embryo protein repertoire and general molecular mechanisms of embryo development under varying oxygen levels.

Potential physiological involvement of nesfatin-1 in regulating swine granulosa cell functions

Nesfatin-1 has recently been indicated as a pleiotropic molecule that is primarily involved in the metabolic regulation of reproductive functions acting at hypothalamic level. The aim of this study was to explore the local action of nesfatin-1 in swine ovarian follicles. Nucleobindin 2 (NUCB2) was verified using real-time quantitative polymerase chain reaction in swine granulosa cells from different sized follicles and nesfatin-1 was localised by immunohistochemistry in sections of the whole porcine ovary. The effects of different concentrations of nesfatin-1 on cell growth, steroidogenesis and the redox status of granulosa cells were determined invitro. In addition, the effects of nesfatin-1 were evaluated in an angiogenesis bioassay because vessel growth is essential for ovarian follicle function. Immunohistochemistry revealed intense positivity for nesfatin-1 in swine granulosa cells in follicles at all developmental stages. Expression of the gene encoding the precursor protein NUCB2 was higher in granulosa cells from large rather than from medium and small follicles. Further, nesfatin-1 stimulated cell proliferation and progesterone production and interfered with redox status by modifying nitric oxide production and non-enzyme scavenging activity in granulosa cells from large follicles. Moreover, nesfatin-1 exhibited a stimulatory effect on angiogenesis. This study demonstrates, for the first time, that nesfatin-1 is physiologically present in the swine ovarian follicle, where it may impair granulosa cell functions.

Plasma Metabolic Characterisation of Dairy Cows with Inactive Ovaries and Oestrus During the Peak of Lactation

Introduction

Differential metabolites (DMs) between cows with inactive ovaries (IO) and oestrous (E) cows were screened and metabolic pathways of DMs associated with IO were determined.

Material and Methods

Cows at 50 to 60 days (d) postpartum from an intensive dairy farm were randomly selected and allocated into an E group (n = 16) or an IO group (n = 16) according to a pedometer and rectal examinations. Their plasma samples were analysed by liquid chromatography–mass spectrometry (LC–MS) to compare plasma metabolic changes between the E and IO groups. Multivariate pattern recognition was used to screen the DMs in the plasma of IO cows.

Results

Compared with normal E cows, there were abnormalities in 20 metabolites in IO cows, including a significantly decreased content (VIP > 1, P < 0.05) of cholic acid, p-chlorophenylalanine, and arachidonic acid, and a significantly increased content (VIP > 1, P < 0.05) of tyramine, betaine, L-phenylalanine, L-glutamate, D-proline, L-alanine, and L-pyrophosphate. Five DMs (cholic acid, D-proline, L-glutamate, L-alanine, and L-pyroglutamic acid) with higher variable importance in projection (VIP) values between groups were validated by ELISA with blind samples of re-selected cows (IO, 50 to 60 d postpartum) and the validated results were consistent with the LC–MS results.

Conclusion

The 20 DMs in IO cows during the peak of lactation indicated that the pathogenesis of IO was involved in complex metabolic networks and signal transduction pathways. This study provides a basis for further exploration of the pathogenesis and prevention of IO in cows in the future.

Acute nutrient treatment causes alterations in intra-follicular antioxidation and AKT signaling

This study aimed to determine if short-term nutrient alteration affects (1) ovarian morphology, (2) plasma and ovarian antioxidant capability and (3) cell apoptosis and AKT signaling within the ovary. After estrus synchronization, 24 Hu sheep were assigned to three groups based on the nutrient requirement recommended for maintenance (M): 1 × M (Control), 1.5 × M (S) and 0.5 × M (R) during days 7–14 of their estrous cycle. The results indicated that undernourishment significantly increased the counts and volume of follicles <2.5 mm and decreased the counts and volume of follicles ≥2.5 mm (P < 0.05). Feed restriction altered the plasma and follicular redox balance within follicles ≥2.5 mm by inhibiting total antioxidant capacity, increasing malondialdehyde concentration (P < 0.05) and reducing the mRNA expression levels of superoxide dismutase 2 (SOD2) and glutathione peroxidase (GSH-PX), as well as the activities of total SOD and GSH-PX. Feed restriction also attenuated B-cell lymphoma-2 (BCL2) but enhanced Bcl-2-associated X protein (BAX) andBAX/BCL2transcription and translation levels in granulosa cells (P < 0.05). Uniform staining intensities of AKT and P-AKT-Ser473 were observed in each follicle stage, whereas weaker P-AKT-Thr308 staining in the antral follicle than in the pre-antral follicle suggested possible involvement of P-AKT-Thr308 during the beginning of follicle development. P-AKT-Ser473 levels in follicles ≥2.5 mm was significantly reduced in the R group (P < 0.05). The results presented in this study demonstrate that suppressed folliculogenesis caused by feed restriction might be associated with attenuated AKT signaling, reduced follicular antioxidant capacity and enhanced granulosa cells apoptosis.

The Role of Antioxidant Enzymes in the Ovaries

Proper physiological function of the ovaries is very important for the entire female reproductive system and overall health. Reactive oxygen species (ROS) are generated as by-products during ovarian physiological metabolism, and antioxidants are indicated as factors that can maintain the balance between ROS production and clearance. A disturbance in this balance can induce pathological consequences in oocyte maturation, ovulation, fertilization, implantation, and embryo development, which can ultimately influence pregnancy outcomes. However, our understanding of the molecular and cellular mechanisms underlying these physiological and pathological processes is lacking. This article presents up-to-date findings regarding the effects of antioxidants on the ovaries. An abundance of evidence has confirmed the various significant roles of these antioxidants in the ovaries. Some animal models are discussed in this review to demonstrate the harmful consequences that result from mutation or depletion of antioxidant genes or genes related to antioxidant synthesis. Disruption of antioxidant systems may lead to pathological consequences in women. Antioxidant supplementation is indicated as a possible strategy for treating reproductive disease and infertility by controlling oxidative stress (OS). To confirm this, further investigations are required and more antioxidant therapy in humans has to been performed.

Melatonin potentially acts directly on swine ovary by modulating granulosa cell function and angiogenesis

Melatonin exerts well-known reproductive effects, mainly acting on hypothalamic gonadotrophin-releasing hormone release. More recent data suggest that melatonin acts directly at the ovarian level, even if, at present, these aspects have been only partly investigated. Swine follicular fluid contains melatonin and its concentration is significantly reduced during follicular growth. Therefore, the present study was undertaken to examine the effects of melatonin, used at physiological concentrations, on cultured swine granulosa cells collected from small (<3 mm) and large (>5 mm) follicles on the main parameters of granulosa cell function such as proliferation and steroidogenesis, namely oestradiol 17β and progesterone (P4) production. Moreover, the effects of melatonin on superoxide anion and nitric oxide (NO) generation by swine granulosa cells were also investigated. Finally, since angiogenesis is crucial for follicle growth, the effects of melatonin on new vessel growth were studied. Collected data indicate that melatonin interferes with cultured granulosa cell proliferation and steroidogenesis, specifically in terms of P4 production and NO output. In addition, the events of physiological follicular angiogenesis were stimulated by melatonin as evidenced by angiogenesis bioassay. Therefore, we suggest that physiological melatonin concentrations could potentially be involved in local modulation of swine ovarian follicle function.

Impact of stress on oocyte quality and reproductive outcome

Stress is an important factor that affects physical and mental status of a healthy person disturbing homeostasis of the body. Changes in the lifestyle are one of the major causes that lead to psychological stress. Psychological stress could impact the biology of female reproduction by targeting at the level of ovary, follicle and oocyte. The increased level of stress hormone such as cortisol reduces estradiol production possibly by affecting the granulosa cell functions within the follicle, which results deterioration in oocyte quality. Adaptation of lifestyle behaviours may generate reactive oxygen species (ROS) in the ovary, which further affects female reproduction. Balance between level of ROS and antioxidants within the ovary are important for maintenance of female reproductive health. Physiological level of ROS modulates oocyte functions, while its accumulation leads to oxidative stress (OS). OS triggers apoptosis in majority of germ cells within the ovary and even in ovulated oocytes. Although both mitochondria- as well as death-receptor pathways are involved in oocyte apoptosis, OS-induced mitochondria-mediated pathway plays a major role in the elimination of majority of germ cells from ovary. OS in the follicular fluid deteriorates oocyte quality and reduces reproductive outcome. On the other hand, antioxidants reduce ROS levels and protect against OS-mediated germ cell apoptosis and thereby depletion of germ cells from the ovary. Indeed, OS is one of the major factors that has a direct negative impact on oocyte quality and limits female reproductive outcome in several mammalian species including human.

Swine Granulosa Cells Show Typical Endothelial Cell Characteristics

Granulosa cells, which belong to the somatic compartment of the ovarian follicle, are actively involved as endocrine cells in follicle growth. Recently, it has been proposed that these cells are not terminally differentiated and possess multipotency. Therefore, we cultured swine granulosa cells in specific endothelial cell culture medium (EBM-2), and phenotypic and functional characteristics of endothelial cells were assessed. The collected data suggest that these endocrine cells can also behave as endothelial cells, therefore potentially contributing to follicular angiogenesis, a crucial process in follicle growth and selection.

Changes in signal molecules and maturation promoting factor levels associate with spontaneous resumption of meiosis in rat oocytes

The present study was aimed to find out changes in signal molecules and maturation promoting factor (MPF) levels during meiotic cell cycle progression from diplotene and metaphase-II (M-II) arrest, a period during which oocyte achieves meiotic competency. Data suggest that high levels of adenosine 3'-5'-cyclic monophosphate (cAMP), guanosine 3'-5'-cyclic monophosphate (cGMP), and nitric oxide (NO) are associated with diplotene arrest, while reduction in their levels correlates with reduced MPF level and meiotic resumption from diplotene arrest. On the other hand, increased intracellular NO, calcium (Ca(2+) ) as well as hydrogen peroxide (H2 O2 ) levels correlate with decreased cAMP, Thr-161 phosphorylated cyclin-dependent kinase-1 (Cdk1) as well as cyclin B1 levels. The decreased Thr-161 phosphorylated Cdk1 and cyclin B1 level reduce MPF level leading to exit from M-II arrest in oocytes cultured in vitro. These data suggest that the decrease of cAMP level and increase of cytosolic free Ca(2+) as well as H2 O2 levels associate with the reduced MPF level and meiotic resumption from diplotene arrest. On the other hand, increase of NO, cGMP, Ca(2+) as well as H2 O2 levels are associated with reduced MPF and spontaneous exit from M-II arrest in rat oocytes cultured in vitro.

Seasonal changes in some oxidant and antioxidant parameters during folliculogenesis in Egyptian buffalo

Knowledge regarding oxidant and antioxidant status in follicular fluid remains limited and its studying in vivo should enhance our understanding of the impact of them on fertility and contribute to optimization of in vitro maturation conditions. The present study was conducted on follicular fluid and serum samples obtained from 708 buffaloes. They were examined for Malondialdehyde (MDA) as indicator of lipid peroxidation as well as superoxide dismutase (SOD) and total antioxidant capacity (TAC) as antioxidant markers. The obtained results revealed that MDA levels and SOD activity in follicular fluid decreased significantly as follicle size increased, while TAC increased significantly with the increase in follicular size. Whereas MDA level was significantly higher in summer, the TAC was significantly higher in spring. Moreover, MDA levels and SOD activities were significantly higher in the follicular fluid from different size follicles during the luteal phase than follicular phase. MDA levels in medium follicles in luteal phase and small follicles in follicular and luteal phases were significantly higher in summer than other seasons. Serum MDA levels were significantly increased in summer. In addition, MDA levels, SOD activities and TAC in serum were significantly higher during luteal phase than follicular phase in summer. TAC levels were significantly higher in follicular fluid than serum, while MDA was significantly lower in follicular fluid than serum. In conclusion, the present study revealed that oxidants/antioxidants balance may play a role in normal follicular development and oxidative stress that occur in summer could be related to reproductive seasonality in buffalo.

Effects of a Ferulate-Derived Dihydrobenzofuran Neolignan on Angiogenesis, Steroidogenesis, and Redox Status in a Swine Cell Model

In the ongoing search for new therapeutic compounds, lignans and neolignans, which are widely distributed in plants, deserve special attention because of their interactions with several biological targets. Searching for potential antiangiogenic agents related to natural lignans/neolignans, we were attracted by a previously studied synthetic dihydrobenzofuran neolignan. We synthesized the compound by means of an eco-friendly, enzyme-mediated biomimetic coupling of the methyl ester of ferulic acid, and the present study was aimed to deeply investigate its effect in angiogenesis bioassays validated in our laboratory. In addition, a previously well-defined granulosa cell model was employed to evaluate the effect of dihydrobenzofuran neolignan on cell viability, steroidogenesis, and redox status. Present data support the antiangiogenic effect of this neolignan. Moreover, we demonstrate that, at least at the highest concentrations tested, dihydrobenzofuran neolignan affects granulosa cell viability and steroidogenesis. In addition, the compound inhibits generation of free radicals and stimulates scavenger enzyme activities. The present data, which are a further deepening of the evaluation of the biological activities of the dihydrobenzofuran lignan in well-defined cell models, are of interest and worthy of special attention.

Effect of bovine follicular fluid on reactive oxygen species and glutathione in oocytes, apoptosis and apoptosis-related gene expression of in vitro-produced blastocysts

The reactive oxygen species (ROS) generated during the in vitro maturation of oocytes affect oocyte maturation and subsequent embryonic development. Bovine follicular fluid (bFF) has an effective antioxidant capacity. This study was conducted to investigate the effects of supplementing oocyte maturation media with bFF from different size classes (3-8 and 9-13 mm) on the glutathione (GSH) and ROS levels of oocytes. Embryonic development and apoptosis, as well as the relative abundance of INFτ, BAX, BCL2 and HSP70 transcripts in blastocysts, were also monitored. Oocytes collected from ovaries were matured in TCM-199 with FBS (control) and 10% 3-8 mm (M), 9-13 mm (L) or a mixture of 3-8 mm and 9-13 mm (M + L) bFF. Glutathione and ROS levels in oocytes after 24 h were assessed by Cell Tracker Blue CMF2HC and DCHFDA staining, respectively. Apoptosis in day-8 blastocysts was assessed by TUNEL staining. The relative abundance of BAX, BCL2, HSP70 and INFτ transcripts was assessed using quantitative real-time polymerase chain reaction (PCR). The GSH level was significantly higher in the L group compared to the other groups (p < 0.05), while the ROS levels in the M group were significantly higher than in the other groups (p < 0.05). The apoptosis levels of blastocysts in the FBS group were significantly higher than those in the M + L group (p < 0.05), although the embryonic development did not differ between the groups. The HSP70 and INFτ expression levels in group M were significantly greater than in the controls (p < 0.05). There was no significant difference in BAX expression between the groups. Supplementation with bFF from various sizes of follicles into the maturation medium was capable of supporting oocyte cytoplasmic maturation by decreasing the ROS. Moreover, bFF subsequently affected antioxidative gene expression, increasing HSP70 and INFτ expressions.

Follicular fluid hydrogen peroxide and lipid hydroperoxide in bovine antral follicles of various size, atresia, and dominance status

PURPOSE

To avoid inducing a state of oxidative stress (OS), assisted reproductive technologies (ART) must maintain a balance of reactive oxygen species (ROS) and antioxidants during the in vitro culture of oocytes. However, oocyte requirements and tolerance thresholds for ROS during in vivo development are still unclear. Previous studies have examined ROS levels in follicular fluid (FF) using pooled samples or according to follicle size. This study sought to examine two OS markers, lipid hydroperoxides (LPO) and hydrogen peroxide (H2O2), in FF of individually sampled follicles from bovine ovary pairs according to follicle size, atresia, and dominance status.

METHODS

TUNEL and cleaved Caspase-3 labeling were used to identify apoptotic granulosa cells and determine follicle atresia status. LPO were measured directly for the first time in FF.

RESULTS

Non-atretic follicles and dominant follicles contained more FF H2O2 than atretic follicles and corresponding subordinate follicles, respectively. FF LPO did not vary in relation to atretic status, and no difference existed between dominant and subordinate follicles. However, FF LPO was significantly lower in first subordinate follicles than in the second subordinate follicles from each ovary pair. Neither H2O2 nor LPO levels correlated with follicle size.

CONCLUSIONS

These data provide clear evidence that the events of antral folliculogenesis are relevant to ROS dynamics in vivo. Furthermore, such studies will help to optimize in vitro conditions for oocyte culture protocols, particularly when combined with a comparison of oocyte quality with respect to source follicle characteristics.

Disrupted redox homeostasis and aberrant redox gene expression in porcine oocytes contribute to decreased developmental competence

The objective of this study was to identify specific redox-related genes whose function contributes to oocyte quality and to characterize the role of redox homeostasis in oocyte development. We determined the redox genes glutaredoxin 2 (GLRX2), protein disulfide isomerase family A, members 4 and 6 (PDIA4, PDIA6), and thioredoxin reductase 1 (TXNRD1) were differentially expressed between adult (more competent) and prepubertal (less competent) porcine in vitro-matured (IVM) oocytes. The association between these genes and oocyte quality was further validated by comparing transcript abundance in IVM with that in in vivo-matured (VVM) prepubertal and adult oocytes. By maturing oocytes in variable redox environments, we demonstrated that a balanced redox environment is important for oocyte quality, and over-reduction of the environment is as detrimental as excess oxidation. Critical levels of reactive oxygen species (ROS) and glutathione (GSH) are required for oocyte competence. Elevated GSH and lower ROS in prepubertal oocytes suggest disrupted redox homeostasis exists in these cells. By further comparing GLRX2, PDIA4, PDIA6, and TXNRD1 expression levels in oocytes matured under these different redox environments, we found aberrant expression patterns in prepubertal oocytes but not in adult oocytes when the maturation medium contained high concentrations of antioxidants. These results suggest that prepubertal oocytes are less competent in regulating redox balance than adult oocytes, contributing to lower oocyte quality. In conclusion, aberrant redox gene expression patterns and disrupted redox homeostasis contribute to decreased developmental competence in prepubertal and IVM porcine oocytes. The balance between ROS and GSH plays an important role in oocyte quality.

Reduced oxidative tissue damage during endotoxemia in IRAK-1 deficient mice

The generation of reactive oxygen species (ROS) triggered by bacterial endotoxin lipopolysaccharide (LPS) plays a key role during the pathogenesis of sepsis. Given the key role that the interleukin-1 receptor associated kinase-1 (IRAK-1) plays in LPS-mediated Toll-like-receptor 4 (TLR4) pathway, we herein tested whether deletion of IRAK-1 gene in mice may render protection from LPS-induced oxidative tissue damage. In this report, we studied the levels of oxidative stress in vital organs including liver, kidney, and brain from wild type (WT) and IRAK-1 deficient mice injected with a lethal dose of LPS (25mg/kg), a TLR4-specific agonist. We demonstrated that LPS challenge induced marked elevation of lipid peroxidation and nitrite levels in the plasma and tissues of WT mice, as well as elevated pro-inflammatory mediators. In contrast, IRAK-1 deficient mice had significantly lower lipid peroxidation and nitrite levels, as well as lower levels of pro-inflammatory mediators. Mechanistically, LPS triggered higher levels of iNOS activity and elevated membrane translocation of p47(phox), a key component of NADPH oxidase in immune cell derived from WT mice compared to IRAK-1 deficient mice. Additionally, tissues harvested from WT mice injected with LPS exhibited reduced activities of anti-oxidant enzymes including glutathione peroxidase (GPx), catalase, and superoxide dismutase (SOD). In contrast, LPS challenge failed to reduce the activities of GPx and SOD in IRAK-1 deficient tissues. As a consequence, LPS caused significantly pronounced damage to liver and kidney tissues in WT mice as compared to IRAK-1 deficient mice.

Hypoxia stimulates the production of the angiogenesis inhibitor 2-methoxyestradiol by swine granulosa cells

We previously demonstrated the presence of 2-methoxyestradiol (2-ME) in swine follicular fluid. Present study was aimed first of all to investigate if swine granulosa cell produce 2-ME; in addition, we tried to assess a potential effect of hypoxia in modulating 2-ME output. Finally, we explored the effect of 2-ME in an angiogenesis bioassay set up in our lab. Our data show that cultured granulosa cells are able to produce 2-ME; interestingly, the secretion of the hormone appeared to be stimulated by hypoxia. Angiogenesis bioassay points out that 2-ME displays an inhibitory effect on neovascularisation. Therefore our data suggest that 2-ME could be a local effector in determining the fine tuning responsible for follicle angiogenesis. These data deserve special attention since the ovary is a valuable experimental model in angiogenesis research.

Fluctuations in total antioxidant capacity, catalase activity and hydrogen peroxide levels of follicular fluid during bovine folliculogenesis

Follicular fluid is an important environment for oocyte development, yet current knowledge regarding its in vivo oxidant and antioxidant levels remains limited. Examining follicular fluid oxidants and antioxidants will improve understanding of their changes in vivo and contribute to optimisation of in vitro maturation conditions. The aim of the present study was to consider selected markers, namely catalase (CAT) enzyme activity, total antioxidant capacity (TAC) and hydrogen peroxide (H(2)O(2)) in follicular fluid samples (n = 503) originating from bovine antral follicles. The dynamic changes in two relevant antioxidant measures and one reactive oxygen species (ROS) were measured through stages of bovine follicular development and the oestrous cycle. CAT activity and H(2)O(2) levels decreased significantly as follicle size increased, whereas TAC increased significantly as follicle size increased. Lower TAC and higher H(2)O(2) in small follicles suggest increased ROS in the initial stages of folliculogenesis. Because CAT levels are highest in the follicular fluid of small follicles in the setting of an overall low TAC, CAT may represent a dominant antioxidant defence in the initial stages of folliculogenesis. Future studies must focus on other reactive oxygen species and their various scavenger types during antral folliculogenesis.

Melatonin protects against clomiphene citrate-induced generation of hydrogen peroxide and morphological apoptotic changes in rat eggs

The present study was aimed to determine whether clomiphene citrate-induces generation of hydrogen peroxide in ovary, if so, whether melatonin could scavenge hydrogen peroxide and protect against clomiphene citrate-induced morphological apoptotic changes in rat eggs. For this purpose, forty five sexually immature female rats were given single intramuscular injection of 10 IU pregnant mare's serum gonadotropin for 48 h followed by single injections of 10 IU human chorionic gonadotropin and clomiphene citrate (10 mg/kg bw) with or without melatonin (20 mg/kg bw) for 16 h. The histology of ovary, ovulation rate, hydrogen peroxide concentration and catalase activity in ovary and morphological changes in ovulated eggs were analyzed. Co-administration of clomiphene citrate along with human chorionic gonadotropin significantly increased hydrogen peroxide concentration and inhibited catalase activity in ovary, inhibited ovulation rate and induced egg apoptosis. Supplementation of melatonin reduced hydrogen peroxide concentration and increased catalase activity in the ovary, delayed meiotic cell cycle progression in follicular oocytes as well as in ovulated eggs since extrusion of first polar body was still in progress even after ovulation and protected against clomiphene citrate-induced egg apoptosis. These results clearly suggest that the melatonin reduces oxidative stress by scavenging hydrogen peroxide produced in the ovary after clomiphene citrate treatment, slows down meiotic cell cycle progression in eggs and protects against clomiphene citrate-induced apoptosis in rat eggs.

The impact of the phyto-oestrogen genistein on swine granulosa cell function

Soya and soybean products used in swine feeding contain genistein, a non-steroidal phyto-oestrogen which has been demonstrated to influence endocrine functions. This observation leads us to design this study to evaluate the effect of genistein on swine granulosa cell steroidogenesis and proliferation. In the attempt to unravel the genistein signal transduction mechanisms, we verified the effect of lavendustin, a Tyrosine Kinase (TK) inhibitor, and the potential involvement of NO/cGMP pathway. Finally, as angiogenesis is essential for follicle development, we tested the effect of the phyto-oestrogen on vascular endothelial growth factor production and on granulosa cell redox status, because free-radical species modulate neovascularization. Our data provide evidence that genistein interferes with granulosa cell steroidogenesis while it does not modulate cell growth: this effect could be at least partially produced by inhibiting TK-dependent signalling systems. On the contrary, NO/cGMP pathway or vascular endothelial growth factor production can be excluded as signalling mechanism involved in phyto-oestrogen effects. Remarkably, genistein stimulates hydrogen peroxide production thus potentially inhibiting follicular angiogenesis. Collectively, these results suggest that genistein consumption could potentially negatively impact swine reproductive function.

Stanniocalcin 1 affects redox status of swine granulosa cells

Stanniocalcin 1 (STC1) is a glycoprotein hormone expressed in different mammalian tissues. In previous studies, we showed STC1 expression in swine ovarian follicles and we demonstrated that STC1 may be a physiological regulator of follicular function. Since reactive oxygen species (ROS) are important signal transducers in the ovary, the present study was undertaken to investigate STC1 action on ROS generation and on the activity of the major enzymatic and non-enzymatic scavengers in swine granulosa cells. O(2)- generation, catalase activity and FRAP levels were increased by STC1, whereas H(2)O(2) generation and peroxidase activity were decreased by STC1. Taken together, our data show that STC1 modulates redox status in swine granulosa cells.

Gelatinases (MMP2 and MMP9) in swine antral follicle

Follicular growth is allowed by extracellular matrix remodeling and vascular network development. Since matrix metalloproteinases (MMPs) play a crucial role in both of these processes, the aim of the present study was to evaluate the expression of gelatinases MMP2 and MMP9 in swine ovarian follicle (theca and granulosa compartments) during its development. Moreover, we measured gelatinase activities into follicular fluids (FF). Our data demonstrate for the first time that MMP2 and MMP9 are expressed in swine ovarian follicle both in theca and granulosa layers; moreover we show that the expression of both gelatinases increases in theca while decreases in granulosa during follicle growth. Additionally, MMP2 activity has been detected in FF. The spatial pattern of expression of gelatinases in swine follicle suggests a differential role during physiological ovarian events.

Reactive oxygen and nitrogen species during meiotic resumption from diplotene arrest in mammalian oocytes

Mammalian ovary is metabolically active organ and generates by-products such as reactive oxygen species (ROS) and reactive nitrogen species (RNS) on an extraordinary scale. Both follicular somatic cells as well as oocyte generate ROS and RNS synchronously and their effects are neutralized by intricate array of antioxidants. ROS such as hydrogen peroxide (H(2)O(2)) and RNS such as nitric oxide (NO) act as signaling molecules and modulate various aspects of oocyte physiology including meiotic cell cycle arrest and resumption. Generation of intraoocyte H(2)O(2) can induce meiotic resumption from diplotene arrest probably by the activation of adenosine monophosphate (AMP)-activated protein kinase A (PRKA)-or Ca(2+)-mediated pathway. However, reduced intraoocyte NO level may inactivate guanylyl cyclase-mediated pathway that results in the reduced production of cyclic 3',5'-guanosine monophosphate (cGMP). The reduced level of cGMP results in the activation of cyclic 3',5'-adenosine monophosphate (cAMP)-phosphodiesterase 3A (PDE3A), which hydrolyses cAMP. The reduced intraoocyte cAMP results in the activation of maturation promoting factor (MPF) that finally induces meiotic resumption. Thus, a transient increase of intraoocyte H(2)O(2) level and decrease of NO level may signal meiotic resumption from diplotene arrest in mammalian oocytes.