Mogroside V improves porcine oocyte in vitro maturation and subsequent embryonic development

Recent Advances in the Distribution, Chemical Composition, Health Benefits, and Application of the Fruit of Siraitia grosvenorii

The fruits of Siraitia grosvenorii (S. grosvenorii) have attracted a lot of scientific interest as part of the current healthy diet. S. grosvenorii has diverse health-promoting effects, including antioxidant, anti-inflammatory, antimicrobial, respiratory modulation, metabolic modulation, antitumor, and neuroprotective effects, as well as gastrointestinal function modulation. As a plant resource, S. grosvenorii has broad application prospects, which promotes the development of the horticultural industry. Moreover, Mogroside has attracted much attention as an important active ingredient of S. grosvenorii. This review provides an in-depth exploration of the distribution, chemical composition, health benefits, and application of S. grosvenorii, particularly Mogroside. This comprehensive exploration highlights the important therapeutic potential of S. grosvenorii, prompting further research into its applications. As value-added functional ingredients, S. grosvenorii and its constituents have significant potential for disease prevention and are widely used in the development of food and health supplements.

Ovarian aging: energy metabolism of oocytes

In women who are getting older, the quantity and quality of their follicles or oocytes and decline. This is characterized by decreased ovarian reserve function (DOR), fewer remaining oocytes, and lower quality oocytes. As more women choose to delay childbirth, the decline in fertility associated with age has become a significant concern for modern women. The decline in oocyte quality is a key indicator of ovarian aging. Many studies suggest that age-related changes in oocyte energy metabolism may impact oocyte quality. Changes in oocyte energy metabolism affect adenosine 5'-triphosphate (ATP) production, but how related products and proteins influence oocyte quality remains largely unknown. This review focuses on oocyte metabolism in age-related ovarian aging and its potential impact on oocyte quality, as well as therapeutic strategies that may partially influence oocyte metabolism. This research aims to enhance our understanding of age-related changes in oocyte energy metabolism, and the identification of biomarkers and treatment methods.

Gonadotropin elevation is ootoxic to ovulatory oocytes and inhibits oocyte maturation, and activin decoy receptor ActRIIB:Fc therapeutically restores maturation

BACKGROUND

Elevated FSH often occurs in women of advanced maternal age (AMA, age ≥ 35) and in infertility patients undergoing controlled ovarian stimulation (COS). There is controversy on whether high endogenous FSH contributes to infertility and whether high exogenous FSH adversely impacts patient pregnancy rates.

METHODS

The senescence-accelerated mouse-prone-8 (SAMP8) model of female reproductive aging was employed to assess the separate impacts of age and high FSH activity on the percentages (%) of viable and mature ovulated oocytes recovered after gonadotropin treatment. Young and midlife mice were treated with the FSH analog equine chorionic gonadotropin (eCG) to model both endogenous FSH elevation and exogenous FSH elevation. Previously we showed the activin inhibitor ActRIIB:Fc increases oocyte quality by preventing chromosome and spindle misalignments. Therefore, ActRIIB:Fc treatment was performed in an effort to increase % oocyte viability and % oocyte maturation.

RESULTS

The high FSH activity of eCG is ootoxic to ovulatory oocytes, with greater decreases in % viable oocytes in midlife than young mice. High FSH activity of eCG potently inhibits oocyte maturation, decreasing the % of mature oocytes to similar degrees in young and midlife mice. ActRIIB:Fc treatment does not prevent eCG ootoxicity, but it restores most oocyte maturation impeded by eCG.

CONCLUSIONS

FSH ootoxicity to ovulatory oocytes and FSH maturation inhibition pose a paradox given the well-known pro-growth and pro-maturation activities of FSH in the earlier stages of oocyte growth. We propose the FOOT Hypothesis ("FSH OoToxicity Hypothesis), that FSH ootoxicity to ovulatory oocytes comprises a new driver of infertility and low pregnancy success rates in DOR women attempting spontaneous pregnancy and in COS/IUI patients, especially AMA women. We speculate that endogenous FSH elevation also contributes to reduced fecundity in these DOR and COS/IUI patients. Restoration of oocyte maturation by ActRIB:Fc suggests that activin suppresses oocyte maturation in vivo. This contrasts with prior studies showing activin A promotes oocyte maturation in vitro. Improved oocyte maturation with agents that decrease endogenous activin activity with high specificity may have therapeutic benefit for COS/IVF patients, COS/IUI patients, and DOR patients attempting spontaneous pregnancies.

Smart seq2 revealed distinct molecular responses during in vitro porcine oocyte maturation before or after the addition of mogroside V

Oocyte maturation involves both nuclear and cytoplasmic maturation. Mogroside V (MV) has been shown to enhance nuclear maturation, mitochondrial content, and developmental potential of porcine oocyte during in vitro maturation (IVM). However, the impact of MV on cytoplasmic maturation and its underlying mechanisms are not understood. This study aimed to assess the effect of MV on cytoplasmic maturation. Germinal vesicle (GV) oocytes treated with MV exhibited a noticeable increase in cortical granules (CGs) formation. Additionally, MV enhanced the expression of NNAT and improved glucose uptake in mature oocytes. Further insights were gained through Smart-seq2 analysis of RNA isolated from 100 oocytes. A total of 11,274 and 11,185 transcripts were identified in oocytes treated with and without MV, respectively. Among quantified genes, 438 differentially expressed genes (DEGs) were identified for further analysis. Gene Ontology (GO) enrichment analysis indicated that these DEGs were primarily involved in DNA repair regulation, cellular response to DNA damage, intracellular components, and organelles. Furthermore, the DEGs were significantly enriched in three KEGG pathways: fatty acid synthesis, pyruvate metabolism, and WNT signalling. To validate the results, lipid droplets (LD) and triglyceride (TG) were examined. MV led to an increase in the accumulation of LD and TG production in mature oocytes. These findings suggest that MV enhances cytoplasmic maturation by promoting lipid droplet synthesis. Overall, this study provides valuable insights into the mechanisms through which MV improves oocyte quality during IVM. The results have significant implications for research in livestock reproduction and offer guidance for future studies in this field.

A comprehensive review of Siraitia grosvenorii (Swingle) C. Jeffrey: chemical composition, pharmacology, toxicology, status of resources development, and applications

Siraitia grosvenorii (Swingle) C. Jeffrey (S. grosvenorii), a perennial indigenous liana from the Cucurbitaceae family, has historically played a significant role in southern China's traditional remedies for various ailments. Its dual classification by the Chinese Ministry of Health for both medicinal and food utility underscores its has the potential of versatile applications. Recent research has shed light on the chemical composition, pharmacological effects, and toxicity of S. grosvenorii. Its active ingredients include triterpenoids, flavonoids, amino acids, volatile oils, polysaccharides, minerals, vitamins, and other microconstituents. Apart from being a natural sweetener, S. grosvenorii has been found to have numerous pharmacological effects, including alleviating cough and phlegm, preventing dental caries, exerting anti-inflammatory and anti-allergic effects, anti-aging and anti-oxidative, hypoglycemic, lipid-lowering, anti-depression, anti-fatigue, anti-schizophrenic, anti-Parkinson, anti-fibrotic, and anti-tumor activities. Despite its versatile potential, there is still a lack of systematic research on S. grosvenorii to date. This paper aims to address this gap by providing an overview of the main active components, pharmacological efficacy, toxicity, current status of development and application, development dilemmas, and strategies for intensive exploitation and utilization of S. grosvenorii. This paper aims to serve as a guide for researchers and practitioners committed to exploiting the biological resources of S. grosvenorii and further exploring its interdisciplinary potential.

Siraitia grosvenorii As a Homologue of Food and Medicine: A Review of Biological Activity, Mechanisms of Action, Synthetic Biology, and Applications in Future Food

Siraitia grosvenorii (SG), also known as Luo Han Guo or Monk fruit, boasts a significant history in food and medicine. This review delves into SG's historical role and varied applications in traditional Chinese culture, examining its phytochemical composition and the health benefits of its bioactive compounds. It further explores SG's biological activities, including antioxidant, anti-inflammatory, and antidiabetic properties and elucidates the mechanisms behind these effects. The review also highlights recent synthetic biology advances in enhancing the production of SG's bioactive compounds, presenting new opportunities for broadening their availability. Ultimately, this review emphasizes SG's value in food and medicine, showcasing its historical and cultural importance, phytochemistry, biological functions, action mechanisms, and the role of synthetic biology in its sustainable use.

Ursolic acid alleviates meiotic abnormalities induced by 3-nitropropionic acid in mouse oocytes

3-nitropropionic acid (3-NPA), a toxic metabolite produced by mold, is mainly found in moldy sugarcane. 3-NPA inhibits the activity of succinate dehydrogenase that can induce oxidative stress injury in cells, reduce ATP production and induce oxidative stress in mouse ovaries to cause reproductive disorders. Ursolic acid (UA) has a variety of biological activities and is a pentacyclic triterpene compound found in many plants. This experiment aimed to investigate the cytotoxicity of 3-NPA during mouse oocyte in vitro maturation and the protective effects of UA on oocytes challenged with 3-NPA. The results showed that UA could alleviate 3-NPA-induced oocyte meiotic maturation failure. Specifically, 3-NPA induced a decrease in the first polar body extrusion rate of oocytes, abnormal distribution of cortical granules, and an increase in the proportion of spindle abnormalities. In addition, 3-NPA caused mitochondrial dysfunction and induced oxidative stress, including decreases in the GSH, mitochondrial membrane potential and ATP levels, and increases in the ROS levels, and these effects led to apoptosis and autophagy. The addition of UA could significantly improve the adverse effects caused by 3-NPA. In general, our data show that 3-NPA affects the normal development of oocytes during the in vitro culture, and the addition of UA can effectively repair the damage caused by 3-NPA to oocytes.

Effects of limonin on oxidative stress and early apoptosis in oocytes during in vitro maturation

To investigate the effects of limonin (Lim) on oxidative stress and early apoptosis in bovine oocytes during in vitro maturation (IVM), different concentrations of Lim (0, 10, 20, 50 μmol/L) were added to bovine IVM medium. Oocyte maturation rates and development 24 h after in vitro fertilization (IVF) were examined to determine the optimal Lim concentration. The optimal Lim concentration was added to the IVM medium, and 0 μmol/L Lim was used as the control. Immunofluorescence staining was used to detect the abnormal rate of spindle assembly, reactive oxygen species (ROS), glutathione (GSH), mitochondrial membrane potential (MMP) levels, mitochondrial distribution, and the fluorescence intensity of cathepsin B (CB)-active LC3 protein. RT‒qPCR was used to detect the mRNA expression levels of antioxidant-, apoptosis- and autophagy-related genes in oocytes. The total number of blastocysts and the proportion of apoptotic cells among blastocysts were detected. The results showed that the PBI ejection rate, cleavage rate and blastocyst rate of bovine oocytes in the 20 μmol/L Lim group were significantly higher than those in the control group (P < 0.05). Compared with those in the control group, ROS levels, abnormal mitochondrial distribution, the proportion of abnormal spindle assembly, CB activity and LC3 protein fluorescence intensity of oocytes in the 20 μmol/L Lim group were significantly decreased (P < 0.05), and GSH and MMP levels were significantly increased (P < 0.05). The expression of antioxidant genes (Prdx3, Prdx6, Sirt1) and antiapoptotic genes (Bcl-xl, Survivin) were significantly upregulated (P < 0.05), and the expression levels of proapoptotic genes (Caspase-4, BAX) and autophagy-related genes (LC3) were significantly downregulated (P < 0.05). The total number of cells among in vitro fertilized embryos was significantly increased (P < 0.05), and the apoptosis rate of blastocysts was significantly decreased (P < 0.05). Here, we show that Lim exerts positive effects on bovine oocyte IVM by regulating REDOX homeostasis, reducing spindle damage and enhancing mitochondrial function during IVM, thereby inhibiting oocyte apoptosis and autophagy.

Mogroside V alleviates the heat stress-induced disruption of the porcine oocyte in vitro maturation

Heat stress (HS) is a stressor that negatively affect female reproduction. Specially, oocytes are very sensitive to HS. It has been demonstrated that some active compounds can protect oocyte from HS. We previously found that Mogroside V (MV), extracted from Siraitia grosvenorii (Luo Han Guo), can protect oocyte from many kinds of stresses. However, how MV alleviates HS-induced disruption of oocyte maturation remains unknown. In this study, we treated the HS-induced porcine oocytes with MV to examine their maturation and quality. Our findings demonstrate that MV can effectively alleviate HS-induced porcine oocyte abnormal cumulus cell expansion, decrease of first polar body extrusion rate, spindle assembly and chromosome separation abnormalities, indicating MV attenuates oocyte mature defects. We further observed that MV can effectively alleviate HS-induced cortical granule distribution abnormality and decrease of blastocyst formation rate after parthenogenesis activation. In addition, MV treatment reversed mitochondrial dysfunction and lipid droplet content decrease, reduced reactive oxygen species levels, early apoptosis and DNA damage in porcine oocytes after HS. Collectively, this study suggests that MV can effectively protect porcine oocytes from HS.

O-GlcNAcylation orchestrates porcine oocyte maturation through maintaining mitochondrial dynamics and function

O-linked β-N-acetylglucosamine (O-GlcNAc) modification exists widely in cells, playing a crucial role in the regulation of important biological processes such as transcription, translation, metabolism, and the cell cycle. O-GlcNAc modification is an inducible reversible dynamic protein post-translational modification, which regulates complex cellular activities through transient glycosylation and deglycosylation. O-GlcNAc glycosylation is specifically regulated by O-GlcNAc glycosyltransferase (O-GlcNAc transferase, OGT) and O-GlcNAc glycoside hydrolase (O-GlcNAcase). However, the mechanisms underlying the effects of O-GlcNAc modification on the female reproductive system, especially oocyte quality, remain unclear. Here, we found that after OGT was inhibited, porcine oocytes failed to extrude the first polar body and exhibited abnormal actin and microtubule assembly. Meanwhile, the mitochondrial dynamics and function were also disrupted after inhibition of OGT function, resulting in the occurrence of oxidative stress and autophagy. Collectively, these results inform our understanding of the importance of the glycosylation process for oocyte maturation, especially for the maturation quality of porcine oocytes, and the alteration of O-GlcNAc in oocytes to regulate cellular events deserves further investigation.

Promising anti-ovarian aging herbal formulation He's Yangchao promotes in vitro maturation of oocytes from advanced maternal age mice

ETHNOPHARMACOLOGICAL RELEVANCE

Marveled at the discovery of artemisinin, the world's expectations for traditional Chinese medicine are rising. He's Yangchao formula (HSYC) is a traditional Chinese herbal formula with the effects of tonifying kidney and essence, and reconciling yin and yang. It has been clinically proven to have anti-ovarian aging effects. Age is the primary cause of diminished ovarian reserve and assisted reproductive failure in women, whether HSYC has the potential to improve in vitro maturation of oocytes from advanced maternal age (AMA) mice has yet to be determined.

AIM OF THE STUDY

This study aims to evaluate the efficacy and possible mechanism of HSYC in promoting in vitro maturation of oocytes from AMA mice.

MATERIALS AND METHODS

The GV oocytes were obtained from young and aged mice. The GV oocytes from young mice were cultured in drops of M16 medium, and the GV oocytes from AMA mice were randomly divided four groups: Vehicle group (cultured in 90% M16 medium +10% blank serum), Low HSYC group (cultured in 90% M16 medium + 10% Low HSYC-medicated serum), High-HSYC group (cultured in 90% M16 medium +10% High HSYC-medicated serum), and Quercetin group (cultured in M16 medium supplemented with 10 μM quercetin). The rates of first polar body extrusion, reactive oxygen species (ROS), intracellular calcium, and mitochondrial membrane potential levels in each groups were observed. In addition, expression levels of mitochondrial function, autophagy, DNA damage, and antioxidant-related proteins were assessed.

RESULTS

Supplementation of HSYC in vitro alleviated age-associated meiotic progression defects in maternally aged oocytes. Importantly, HSYC supplementation eliminated the age-related ROS accumulation to suppress DNA damage and autophagy during the in vitro maturation of maternally aged oocytes. Meanwhile, the mitochondrial function was improved after HSYC treatment, as manifested by higher mitochondrial membrane potential and lower Ca2+ levels. Furthermore, we found that HSYC supplementation during in vitro maturation of maternally aged oocytes upregulated the expression level of SIRT3, a crucial protein in regulating mitochondrial function. Consistently, the expression levels of the SOD2, PCG1α, and TFAM were increased, while the SOD2 acetylation level was decreased, which further proved its antioxidant function.

CONCLUSIONS

HSYC supplementation promotes in vitro maturation of oocytes from AMA mice mainly via improving mitochondrial function and alleviating oxidative stress. The mechanism may be related to the regulation of SIRT3-dependent deacetylation of the SOD2 pathway.

Role of the NLRP3 inflammasome in gynecological disease

The NLR family pyrin domain containing 3 (NLRP3) inflammasome is involved in the innate immune system and is a three-part macromolecular complex comprising the NLRP3 protein, apoptosis-associated speck-like protein containing a CARD (ASC) and the cysteine protease pro-caspase-1. When the NLRP3 inflammasome is activated, it can produce interleukin (IL)- 1β and IL-18 and eventually lead to inflammatory cell pyroptosis. Related studies have demonstrated that the NLRP3 inflammasome can induce an immune response and is related to the occurrence and development of gynecological diseases, such as endometriosis, polycystic ovary syndrome and breast cancer. NLRP3 inflammasome inhibitors are beneficial for maintaining cellular homeostasis and tissue health and have been found effective in targeting some gynecological diseases. However, excessive inhibitor concentrations have been found to cause adverse effects. Therefore, proper control of NLRP3 inflammasome activity is critical. This paper summarizes the structure and function of the NLRP3 inflammasome and highlights the therapeutic potential of targeting it in gynecological diseases, such as endometriosis, polycystic ovary syndrome and breast cancer The application of NLRP3 inflammasome inhibitors is also discussed.

The role of mtDNA in oocyte quality and embryo development

The mitochondrial genome resides in the mitochondria present in nearly all cell types. The porcine (Sus scrofa) mitochondrial genome is circa 16.7 kb in size and exists in the multimeric format in cells. Individual cell types have different numbers of mitochondrial DNA (mtDNA) copy number based on their requirements for ATP produced by oxidative phosphorylation. The oocyte has the largest number of mtDNA of any cell type. During oogenesis, the oocyte sets mtDNA copy number in order that sufficient copies are available to support subsequent developmental events. It also initiates a program of epigenetic patterning that regulates, for example, DNA methylation levels of the nuclear genome. Once fertilized, the nuclear and mitochondrial genomes establish synchrony to ensure that the embryo and fetus can complete each developmental milestone. However, altering the oocyte's mtDNA copy number by mitochondrial supplementation can affect the programming and gene expression profiles of the developing embryo and, in oocytes deficient of mtDNA, it appears to have a positive impact on the embryo development rates and gene expression profiles. Furthermore, mtDNA haplotypes, which define common maternal origins, appear to affect developmental outcomes and certain reproductive traits. Nevertheless, the manipulation of the mitochondrial content of an oocyte might have a developmental advantage.

Beneficial Effects of Catalpol Supplementation during In Vitro Maturation of Porcine Cumulus-Oocyte Complexes

Oxidative stress degrades oocytes during in vitro maturation (IVM). Catalpol, a well-known iridoid glycoside, exhibits antioxidant, anti-inflammatory, and antihyperglycemic effects. In this study, catalpol supplementation was tested on porcine oocyte IVM and its mechanisms. Corticalgranule (GC) distribution, mitochondrial function, antioxidant capacity, DNA damage degree, and real-time quantitative polymerase chain reaction were used to confirm the effects of 10 μmol/L catalpol in the maturation medium during IVM. Catalpol treatment significantly increased the first-pole rate and cytoplasmic maturation in mature oocytes. It also increased oocyte glutathione (GSH), mitochondrial membrane potential and blastocyst cell number. However, DNA damage as well as reactive oxygen species (ROS) and malondialdehyde (MDA) levels. Mitochondrial membrane potential and blastocyst cell number were also increased. Thus, the supplementation of 10 μmol/L catalpol in the IVM medium improves porcine oocyte maturation and embryonic development.

Effects of n-3 PUFA supplementation on oocyte in vitro maturation in mice with polycystic ovary syndrome

n-3 PUFAs are classic antioxidant that can be used to treat follicular dysplasia and hyperinsulinemia caused by excessive oxidative stress in PCOS women. To investigate the effect of n-3 PUFA supplementation on the oocyte quality of polycystic ovary syndrome (PCOS) mice during in vitro maturation, a PCOS mouse model was established by dehydroepiandrosterone (DHEA). The GV oocytes of the control and PCOS groups were collected and cultured in vitro with or without n-3 PUFAs. After 14 h, the oocytes were collected. Our data demonstrated that the oocyte maturation rate of PCOS mice significantly increased after the addition of 50 µM n-3 PUFAs. The results of immunofluorescence showed that the abnormal rates of spindles and chromosomes in the PCOS + n-3 PUFA group were lower than those in the PCOS group. The mRNA expression of an antioxidant-related gene (Sirt1) and DNA damage repair genes (Brca1/Msh2) was found to be significantly rescued after n-3 treatment. Additionally, the results of living cell staining showed that the addition of n-3 PUFAs could reduce the levels of reactive oxygen species and mitochondrial superoxide in PCOS oocytes. In conclusion, the addition of 50 µM n-3 PUFAs during the in vitro maturation of PCOS mouse oocytes can improve the maturation rate by reducing the level of oxidative stress and the rate of spindle/chromosome abnormalities, providing valuable support during the IVM process.

Silibinin supplementation ameliorates the toxic effects of butyl benzyl phthalate on porcine oocytes by eliminating oxidative stress and autophagy

Butyl benzyl phthalate (BBP) is a common environmental pollutant, it is high in paints, adhesives and other decorative materials, food packaging bags, cleaning agents, is a plasticizer is very widely used in daily life. However, it remains unknown whether BBP causes damage to oocytes cultured in vitro and whether there is an effective rescue strategy. Here, we evaluated the effects of exposure to different concentrations of BBP (10, 50, and 100 μM) on the meiosis of porcine oocytes. The results showed that exposure to BBP (100 μM) severely impaired expansion of cumulus-oocyte complex (COCs) and PBE (control:71.6% vs 100 μM: 48.8%). Spindle conformation and chromosome alignment were also significantly abnormal (34.8% and 46.0%, respectively) compared to the control (11.1% and 17.5%, respectively), and BBP caused damage to microfilaments and cortical granules (CGs). In addition, oocyte exposure to BBP induced impaired mitochondrial function and disrupted mitochondrial integrity. Silibinin is a natural active substance isolated from the seeds of Silybum marianum (L.) Gaertneri with strong antioxidant and anti-inflammatory effects. Noteworthy, we added different concentrations of silibinin (10, 20, and 50 μM) to BBP-exposed oocytes for rescue experiments, where 50 μM effectively rescued BBP-induced meiotic failure (70.6%). It also prevented the generation of excessive autophagy and apoptosis in oocytes by inhibiting the production of ROS. In a word, our results suggest that supplementation of silibinin attenuates the impaired oocyte development caused by BBP exposure，which provides a potential strategy to protect oocytes from environmental pollutants.

Oxr1a prevents the premature ovarian failure by regulating oxidative stress and mitochondrial function in zebrafish

Premature ovarian failure (POF) is characterized as the ovarian dysfunction and defective oocyte development. In POF patients, ROS level is reported to be significantly higher than normal individuals. However, the involvement of oxidative stress in POF and the regulatory mechanisms underlying the antioxidative process in oocyte development remain largely unknown. Here, we discover that oxidation resistance 1a (Oxr1a), the ortholog of mammalian Oxr1, protects the oocytes of female zebrafish against oxidative stress and thus represses the POF phenotype. Oxr1a was widely expressed in oocytes at different developmental stages, of which the mRNA expression levels were significantly upregulated upon follicle activation and oocyte maturation. Oxr1a knockout exacerbated the POF phenotype, as evidenced by the decreased number and quality of oocytes. Moreover, the oocytes of oxr1a knockout zebrafish exhibited excessive ROS, increased mitochondrial DNA damage, reduced mitochondria, and abnormal morphology. Mechanistically, instead of decomposing ROS directly, Oxr1a participated in the process of oxidative stress through regulating the mRNA expression levels of the key antioxidant enzymes Cat and Sod1. Moreover, treatment with antioxidant N-Acetyl-l-cysteine attenuated the mitochondrial oxidative damage and improved the fertility of mutant females, indicating that Oxr1a may mediates the Sod1/Cat pathway to metabolize the intracellular ROS and avoid the mitochondrial oxidative damage, thus ensuring the normal development and maturation of oocytes. Taken together, these findings are useful for the elucidation of molecular mechanisms underlying the oxidative damage in oocytes and beneficial to the clinical therapeutics of POF.

Schisandrin B protects boar spermatozoa against oxidative damage and increases their fertilization ability during in vitro storage

Oxidative stress due to low temperatures during in vitro preservation reduces boar spermatozoa quality. It has been proven that Schisandrin B (Sch-B) can act against oxidative stress in cells. Therefore, the purpose of this study was to investigate whether the treatment with Sch-B could improve the quality of boar sperm during storage at 17 °C. Semen samples were randomly divided into four groups and added to the Beltsville Thawing Solution containing different concentrations of Sch-B (0, 0.1, 0.5, and 1 mg/L) after collection. Each group was then preserved at 17 °C and the sperm motility, membrane integrity, and acrosome integrity were detected to determine the maximum available concentration of Sch-B for sperm. The optimal concentration was set at 0.1 mg/L and was used in subsequent experiments. Sperms treated with 0 and 0.1 mg/L Sch-B were evaluated for lipid peroxidation (MDA) and fertilization ability through in vitro fertilization. Finally, the quality of blastocysts which were formed by 0 and 0.1 mg/L Sch-B-treated sperm was determined. The results showed that compared with the control, the addition of 0.1 mg/L Sch-B improved boar sperm motility, and the addition of 0.1 and 0.5 mg/L Sch-B improved sperm membrane integrity and acrosome integrity. Treatment with 0.1 mg/L Sch-B reduced the level of MDA and increased the cleavage rate, blastocyst rate, and total cell number of blastocysts compared to the rate and number in the control group. However, no significant difference was observed in the ROS levels of blastocysts between the treatment and the control groups. The expression levels of CAT, SOD2, and Bcl-2 in IVF-blastocysts formed using sperm stored for one day at 17 °C were significantly higher than those in the control blastocysts. On day 4 of storage, CAT and Bcl-2 expression were significantly higher in IVF-blastocysts formed from sperm treated with 0.1 mg/L Sch-B than that in the control blastocysts. The ratio of Bax/Bcl-2 was also significantly higher in IVF-blastocysts formed using Sch-B-treated sperm. Our findings demonstrate that treatment with Sch-B can protect boar sperm from oxidative stress during liquid preservation and can increase the fertilization ability of the sperm.

Mitochondrial DNA Deficiency and Supplementation in Sus scrofa Oocytes Influence Transcriptome Profiles in Oocytes and Blastocysts

Mitochondrial DNA (mtDNA) deficiency correlates with poor oocyte quality and fertilisation failure. However, the supplementation of mtDNA deficient oocytes with extra copies of mtDNA improves fertilisation rates and embryo development. The molecular mechanisms associated with oocyte developmental incompetence, and the effects of mtDNA supplementation on embryo development are largely unknown. We investigated the association between the developmental competence of Sus scrofa oocytes, assessed with Brilliant Cresyl Blue, and transcriptome profiles. We also analysed the effects of mtDNA supplementation on the developmental transition from the oocyte to the blastocyst by longitudinal transcriptome analysis. mtDNA deficient oocytes revealed downregulation of genes associated with RNA metabolism and oxidative phosphorylation, including 56 small nucleolar RNA genes and 13 mtDNA protein coding genes. We also identified the downregulation of a large subset of genes for meiotic and mitotic cell cycle process, suggesting that developmental competence affects the completion of meiosis II and first embryonic cell division. The supplementation of oocytes with mtDNA in combination with fertilisation improves the maintenance of the expression of several key developmental genes and the patterns of parental allele-specific imprinting gene expression in blastocysts. These results suggest associations between mtDNA deficiency and meiotic cell cycle and the developmental effects of mtDNA supplementation on Sus scrofa blastocysts.

Mechanisms of action of non-enzymatic antioxidants to control oxidative stress during in vitro follicle growth, oocyte maturation, and embryo development

In vitro follicle growth and oocyte maturation still has a series of limitations, since not all oocytes matured in vitro have the potential to develop in viable embryos. One of the factors associated with low oocyte quality is the generation of reactive oxygen species (ROS) during in vitro culture. Therefore, this review aims to discuss the role of non-enzymatic antioxidants in the control of oxidative stress during in vitro follicular growth, oocyte maturation and embryonic development. A wide variety of non-enzymatic antioxidants (melatonin, resveratrol, L-ascorbic acid, L-carnitine, N-acetyl-cysteine, cysteamine, quercetin, nobiletin, lycopene, acteoside, mogroside V, phycocyanin and laminarin) have been used to supplement culture media. Some of them, like N-acetyl-cysteine, cysteamine, nobiletin and quercetin act by increasing the levels of glutathione (GSH), while melatonin and resveratrol increase the expression of antioxidant enzymes and minimize oocyte oxidative stress. L-ascorbic acid reduces free radicals and reactive oxygen species. Lycopene positively regulates the expression of many antioxidant genes. Additionally, L-carnitine protects DNA against ROS-induced damage, while acteoside and laminarin reduces the expression of proapoptotic genes. Mogrosides increases mitochondrial function and reduces intracellular ROS levels, phycocyanin reduces lipid peroxidation, and lycopene neutralizes the adverse effects of ROS. Thus, it is very important to know their mechanisms of actions, because the combination of two or more antioxidants with different activities has great potential to improve in vitro culture systems.

Resveratrol ameliorates the defects of meiotic maturation in lipopolysaccharide exposed porcine oocytes

Lipopolysaccharide (LPS), a significant virulence factor of gram-negative bacteria, adversely affects female reproduction, especially the maturation and early embryonic development of oocytes, through inducing of inflammatory and oxidative stress-associated toxic responses. Resveratrol (Res), a potent antioxidant, exhibits many beneficial effects on the maturation and developmental competence of oocytes. However, it is unclear whether Res can restore LPS-induced defects in the maturation of oocytes during meiosis. In this study, we used porcine oocytes to explore the protective effects of Res and its underlying mechanism against the toxic impacts of LPS exposure on meiotic maturation and developmental competence of oocytes during meiosis. The oocytes were randomly assigned to a control, LPS-exposed or Res-supplemented group. Nuclear and cytoplasmic maturation was assessed after 26 h (MI) or 44 h (MII) of in vitro maturation (IVM). Our results showed that 10 µM Res significantly improved the rates of oocyte maturation and blastocyst formation after exposure to 15 µg/mL LPS. In addition, Res preserved the normal spindle/chromosome structure and maintained acetylated tubulin levels, actin polymerization and cortical granules (CGs) distribution. Additionally, Res protected mitochondrial content and function, scavenges reactive oxygen species (ROS), and reduced DNA damage and apoptosis in LPS-exposed oocytes. Furthermore, inhibition of SIRT1 by its specific inhibitor EX527 suppressed the recovery of ROS levels, mitochondrial content, and spindle/chromosome structure by Res supplementation. In summary, this study shows that Res can alleviate the impacts of LPS-induced toxicity on meiosis in porcine oocytes by upregulating SIRT1, which ameliorates oxidative stress and increasing mitochondrial content.

Quercetin protects porcine oocytes from in vitro aging by reducing oxidative stress and maintaining the mitochondrial functions

Quercetin (QUE) is a component of the flavonoid family that shows various therapeutic properties, such as antioxidant effects. However, whether QUE affects porcine oocyte in vitro aging has not yet been investigated. Therefore, in this study, we applied various doses of QUE to freshly isolated porcine oocytes and found that 10 µM QUE improved the oocyte maturation rate in vitro, as reflected by the increased degree of cumulus cell expansion and first polar body extrusion. More importantly, we found that QUE reduced in vitro aging and improved the maturity level of porcine oocytes after another 24 h of culturing, accompanied by the upregulated expression levels of bone morphogenetic protein 15, growth differentiation factor 9, Moloney sarcoma oncogene, and cyclin-dependent kinase 2. In addition, we found that QUE treatment significantly reduced the intracellular reactive oxygen species levels, apoptosis, and autophagy and upregulated the expression levels of superoxide dismutase 2 and catalase in aged porcine oocytes. In addition, QUE restored impaired mitochondrial membrane potential and spindle assembly in aged porcine oocytes. Our findings demonstrate that QUE can protect porcine oocytes from in vitro aging by reducing oxidative stress and maintaining mitochondrial function.

A Review of the Phytochemistry and Pharmacology of the Fruit of Siraitia grosvenorii (Swingle): A Traditional Chinese Medicinal Food

Siraitia grosvenorii (Swingle) C. Jeffrey ex Lu et Z. Y. Zhang is a unique economic and medicinal plant of Cucurbitaceae in Southern China. For hundreds of years, Chinese people have used the fruit of S. grosvenorii as an excellent natural sweetener and traditional medicine for lung congestion, sore throat, and constipation. It is one of the first species in China to be classified as a medicinal food homology, which has received considerable attention as a natural product with high development potential. Various natural products, such as triterpenoids, flavonoids, amino acids, and lignans, have been released from this plant by previous phytochemical studies. Phar- macological research of the fruits of S. grosvenorii has attracted extensive attention, and an increasing number of extracts and compounds have been demonstrated to have antitussive, expectorant, antiasthmatic, antioxidant, hypoglycemic, immunologic, hepatoprotective, antibacte- rial, and other activities. In this review, based on a large number of previous studies, we summarized the related research progress of the chemical components and pharmacological effects of S. grosvenorii, which provides theoretical support for further investigation of its biological functions and potential clinical applications.

Glyphosate decreases bovine oocyte quality by inducing oxidative stress and apoptosis

Glyphosate is a universal herbicide with genital toxicity, but the effect of glyphosate on oocytes has not been reported. This study aimed to evaluate the effect of glyphosate (0, 10, 20, 50 and 100 mM) on bovine oocyte in vitro maturation. We showed that 50 mM glyphosate adversely affects the development of bovine oocytes. Exposure of oocytes to 50 mM glyphosate caused an abnormal reduction in oxidative (redox) levels compared with that in the control group, with a significantly higher reactive oxide species level (P < 0.05) and significantly lower glutathione (GSH) expression (P < 0.05). Additionally, the mRNA levels of antioxidant genes (SOD1, SOD2, SIRT2, SIRT3) and the mitochondrial membrane potential (MMP) were significantly reduced (P < 0.05). Furthermore, treatment with 50 mM glyphosate-induced apoptosis, and the mRNA levels of the apoptotic genes Caspase-3 and Caspase-4 were significantly higher than those in the control group (P < 0.05); however, the mRNA level of BAX was significantly higher than that in the control group (P < 0.01). Additionally, the mRNA levels of the anti-apoptotic genes Survivin and BCL-XL were significantly lower than those in the control group (P < 0.05), and oocyte quality was adversely affected. Together, our results confirmed that glyphosate impairs the quality of oocytes by promoting abnormal oocyte redox levels and apoptosis.

Therapeutic effects of aqueous extract of bioactive active component of Ageratum conyzoides on the ovarian-uterine and hypophysis-gonadal axis in rat with polycystic ovary syndrome: Histomorphometric evaluation and biochemical assessment

Background

Polycystic ovary syndrome (PCOS) is an endocrine disorder, affecting women of reproductive age. Ageratum conyzoïdes (AGC) is used traditionally in the treatment of fever, rheumatism, and ulcer. This study investigates the effects of AGC on ovarian-uterine in PCOS rats.

Methods

Female rats were randomized into four groups (n = 6). Group A control received 2 ml distilled water. Group B received a single dose of 4 mg/kg body weight (bwt) i.p estradiol valerate (EV). Group C received 500 mg/kg bwt AGC and group D received a single dose of 4 mg/kg bwt i.p EV followed by 500 mg/kg bwt AGC orally for 30 days. Parameters tested include follicle-stimulating hormone (FSH), luteinizing hormone (LH), testosterone (T), estradiol (E2), progesterone (P), C-reactive protein (CRP), interleukin (IL)-6, IL-18 and tumor necrosis factor (TNF)- α, malondialdehyde (MDA), superoxide dismutase (SOD), Catalase (CAT), total protein (TP), total cholesterol (TC), triglycerides (TG), low-density lipoprotein cholesterol (LDL), high-density lipoprotein cholesterol (HDL), and ovary and uterus histomorphometric.

Results

Ageratum conyzoides decrease insulin resistance, obesity indices, TC, TG, LDL, MDA, T, LH, FSH, CRP, IL-6, IL-18, and TNF- α in PCOS rats. And increase HDL, E2, P, TP, CAT, and SOD in PCOS rats. AGC improved ovary and uterus histo-architecture, tertiary, and Graafian follicles, corpus luteum and endometrial thickness increased,and cystic and atretic follicles decreased.

Conclusion

Ageratum conyzoides improved insulin sensitivity, antioxidant activities, hormonal imbalance, inflammatory makers, and histological changes in PCOS rats. Therefore AGC can be used as a potential adjuvant agent in the treatment of PCOS.

Mito-Q promotes porcine oocytes maturation by maintaining mitochondrial thermogenesis via UCP2 downregulation

Mitochondrial thermogenesis is an adaptive response of cells to their surrounding stress. Oxidative stress is one of the common stresses during in vitro maturation (IVM) of oocytes, which leads to mitochondrial dysfunction. This study aimed to probe the effects of the mitochondria-targeted antioxidant Mito-Q on oocyte development and unravel the role of Mito-Q in mitochondrial ATP production and thermogenesis regulation. Our results showed that Mito-Q had a positive effect on porcine oocytes maturation and subsequent embryo development. During oocytes IVM, Mito-Q could reduce ATP levels and ROS, increase lipid droplets accumulation, induce autophagy, and maintain mitochondrial temperature stability. Moreover, in metaphase II (MII) oocytes, Mito-Q would induce mitochondrial uncoupling manifested by decreased ATP, attenuated mitochondrial membrane potential (MMP), and increased mitochondrial thermogenesis. Notably, the expression of mitochondrial uncoupling protein (UCP2) was significantly reduced in oocytes treated with Mito-Q. Further study indicated that specific depletion of UCP2 in oocytes also resulted in increased thermogenesis, decreased ATP and declined MMP, suggesting that UCP2 downregulation may participate in Mito-Q-induced mitochondrial uncoupling. In summary, our data demonstrate that Mito-Q promotes oocyte maturation in vitro and maintains the stability of mitochondrial thermogenesis by inhibiting UCP2 expression.

Mogroside-Rich Extract From Siraitia grosvenorii Fruits Ameliorates High-Fat Diet-Induced Obesity Associated With the Modulation of Gut Microbiota in Mice

Siraitia grosvenorii is a kind of medicinal food plant. The mogroside-rich extract (MGE) of its fruits can effectively ameliorate obesity, but the underlying mechanisms remain underexplored. In this study, we aimed to determine whether MGE can ameliorate obesity by protecting against the divergences of gut microbiota. Mice were challenged with a high-fat diet (HFD) and treated with MGE by oral gavage. Then, the characteristics of the gut microbiota were determined by 16S rDNA analysis. Our findings showed that MGE could significantly reduce body weight gain and fat tissue weight of the mice fed with HFD. Moreover, MGE markedly attenuated fatty liver, and improved glucose tolerance and insulin sensitivity. We further found that the gut microbiota structures were disturbed by HFD feeding. In particular, the abundance of Firmicutes was increased and the abundance of Bacteroidetes was decreased, resulting in an increased proportion of Firmicutes to Bacteroidetes (F/B), which contributes to obesity. Interestingly, the abnormal proportion of F/B of HFD feeding mice was restored to the level of control mice by MGE treatment. Additionally, the abundances of obesogenic microbiota, such as Ruminiclostridium and Oscillibacter were also decreased after MGE treatment. In summary, our findings demonstrate that MGE can modulate gut microbiota in obese mice and shed new light on how it alleviates obesity.

Supplementation with kaempferol relieves oxidative stress and enhances development of early bovine embryos in vitro

Oxidative stress (OS) has been considered the principle cause of developmental failure of early embryos cultured in vitro; therefore, the addition of antioxidants is very important for improving in vitro culture (IVC) systems. Various antioxidants have been tested for IVC systems, but most have exhibited some side effects. Kaempferol (3,5,7-trihydroxy-2-(4-hydroxyphenyl)-4h-1-benzopyran-4-one, KAE) is a flavonoid with strong antioxidant activity and no obvious side effects. This study explored the effect of KAE on antioxidant capacity and developmental competence of bovine embryos after fertilization. KAE was added to bovine IVC medium and significantly reduced reactive oxygen species (ROS) in 2-, 4- and 8-cell stage embryos and increased blastocyst formation. In addition, the level of H3K9ac was increased, the apoptotic index was reduced, and total cell numbers and trophectoderm cell numbers in day 7 blastocysts were increased significantly in KAE-treated embryos compared to control. Expression of the apoptotic gene, Bcl-2, was higher in blastocysts after KAE treatment, while expression of the endoplasmic reticulum (ER) stress genes, Bip and HDAC1, and the pro-apoptotic gene, Bax, were significantly lower in the KAE group. Thus, KAE significantly reduced ROS damage and improved development of IVC bovine embryos.

Mogroside V ameliorates the oxidative stress-induced meiotic defects in porcine oocytes in vitro

It has been reported that environmental factors, such as industrial pollution, environmental toxins, environmental hormones, and global warming contribute to the oxidative stress-induced deterioration of oocyte quality and female fertility. However, the prevention or improvement approaches have not been fully elucidated. Here, we explored the mechanism regarding how Mogroside V (MV), a main extract of Siraitia grosvenorii, improves the oxidative stress-induced meiotic defects in porcine oocytes. Our results showed that MV supplementation restores the defective oocyte maturation and cumulus cell expansion caused by H₂O₂ treatment. We further found that MV supplementation promoted the oocyte cytoplasmic maturation through preventing cortical granules from the aberrant distribution, and drove the nuclear maturation by maintaining the cytoskeleton structure. Notably, our single-cell RNA sequencing data indicated that H₂O₂-treated oocytes led to the oxidative stress primarily through two pathways 'meiosis' and 'oxidative phosphorylation'. Lastly, we evaluated the effects of MV supplementation on the mitochondrial distribution pattern and membrane potential in H₂O₂-treated oocytes, revealing that MV supplementation eliminated the excessive ROS induced by the mitochondrial abnormalities and consequently suppressed the apoptosis. In conclusion, our study demonstrates that MV supplementation is an effective approach to ameliorate the oxidative stress-induced meiotic defects via recovering the mitochondrial integrity in porcine oocytes.

Genome-scale transcriptomic insights into the gene co-expression network of seed abortion in triploid Siraitia grosvenorii

BACKGROUND

Siraitia grosvenorii (Swingle) C. Jeffrey, also known as Luohanguo or monk fruit, is a famous traditional Chinese medicine ingredient with important medicinal value and broad development prospects. Diploid S. grosvenorii has too many seeds, which will increase the utilization cost of active ingredients. Thus, studying the molecular mechanism of seed abortion in triploid S. grosvenorii, identifying the abortion-related genes, and regulating their expression will be a new direction to obtain seedless S. grosvenorii. Herein, we examined the submicroscopic structure of triploid S. grosvenorii seeds during abortion.

RESULTS

Upon measuring the endogenous hormone content, we found that abscisic acid (ABA) and trans-zeatin (ZR) levels were significantly downregulated after days 15 and 20 of flowering. RNA sequencing of triploid seeds at different developmental stages was performed to identify key genes regulating abortion in triploid S. grosvenorii seeds. Multiple genes with differential expression between adjacent stages were identified; seven genes were differentially expressed across all stages. Weight gene co-expression network analysis revealed that the enhancement of monoterpene and terpene metabolic processes might lead to seed abortion by reducing the substrate flow to ABA and ZR.

CONCLUSIONS

These findings provide insights into the gene-regulatory network of seed abortion in triploid S. grosvenorii from different perspectives, thereby facilitating the innovation of the breeding technology of S. grosvenorii.

α-Ketoglutarate Improves Meiotic Maturation of Porcine Oocytes and Promotes the Development of PA Embryos, Potentially by Reducing Oxidative Stress through the Nrf2 Pathway

α-Ketoglutarate (α-KG) is a metabolite in the tricarboxylic acid cycle. It has a strong antioxidant function and can effectively prevent oxidative damage. Previous studies have shown that α-KG exists in porcine follicles, and its content gradually increases as the follicles grow and mature. However, the potential mechanism of supplementation of α-KG on porcine oocytes during in vitro maturation (IVM) has not yet been reported. The purpose of this study was to explore the effect of α-KG on the early embryonic development of pigs and the mechanisms underlying these effects. We found that α-KG can enhance the development of early pig embryos. Adding 20 μM α-KG to the in vitro culture medium significantly increased the rate of blastocyst formation and the total cell number. Compared with to that of the control group, apoptosis in blastocysts of the supplement group was significantly reduced. α-KG reduced the production of reactive oxygen species and glutathione levels in cells. α-KG not only improved the activity of mitochondria but also inhibited the occurrence of apoptosis. After supplementation with α-KG, pig embryo pluripotency-related genes (OCT4, NANOG, and SOX2) and antiapoptotic genes (Bcl2) were upregulated. In terms of mechanism, α-KG activates the Nrf2/ARE signaling pathway to regulate the expression of antioxidant-related targets, thus combating oxidative stress during the in vitro culture of oocytes. Activated Nrf2 promotes the transcription of Bcl2 genes and inhibits cell apoptosis. These results indicate that α-KG supplements have a beneficial effect on IVM by regulating oxidative stress during the IVM of porcine oocytes and can be used as a potential antioxidant for IVM of porcine oocytes.

Insufficient pyruvate in culture medium arrests mouse embryos at the first cleavage stage associated with abnormal epigenetic modifications

Energy is essential for early embryogenesis, and fertilized eggs can successfully develop to blastocyst in in vitro culture medium with an appropriate energy supply. Conversely, embryonic development is negatively affected by a suboptimal energy supply. We previously observed that a low level of pyruvate greatly arrests mouse embryos at the 2-cell stage. However, how methylation modifications are affected at this specific stage remains unknown. In this study, we found that mouse embryos could timely develop to the 4-cell stage in K⁺simplex optimized medium (KSOM) with control level of pyruvate, but embryos were significantly arrested at the 2-cell stage when pyruvate was reduced to 0.2-fold of the control level. Moreover, the fluorescence intensities of 5 mC, H3K4me2, H3K9me2 and H3K27me2 in the 2-cell stage embryos of the 0.2-fold pyruvate group were notedly lower than those of the control group, but N6-methyladenosine (m⁶A) fluorescence intensity was higher, suggesting that global genomic DNA, histone and m⁶A methylation modifications are disrupted with low levels of pyruvate. Consistently, the mRNA levels of genes related to DNA methylation, histone methylation and m⁶A modifications were also disturbed in the 2-cell stage embryos cultured with low levels of pyruvate. In summary, our findings demonstrate that insufficient pyruvate in culture medium results in mouse embryonic developmental arrest, at least in part due to defects in methylation modifications.

Simazine perturbs the maturational competency of mouse oocyte through inducing oxidative stress and DNA damage

Simazine is a triazine pesticides that typically detected in ground water and soil, and can reportedly affect reproductive health in humans and animals. However, the effect of simazine on female germ cell development remains unclear. In the present study, we observed that simazine exposure decreased oocyte maturation competence and embryonic developmental capacity. Importantly, simazine exposure disrupted microtubule stability and actin polymerization, resulting in failure of spindle assembly and migration. In addition, simazine exposure impaired mitochondrial function and cytosolic Ca2+ homeostasis in both oocyte and 2-cell embryos, thus increasing the levels of reactive oxygen species (ROS). Moreover, simazine exposure induced DNA damage and early apoptosis during oocyte maturation. Collectively, our results demonstrate that simazine exposure-induced mitochondrial dysfunction and apoptosis are major causes of poor oocytes quality.

Mogroside-rich extract from Siraitia grosvenorii fruits protects against the depletion of ovarian reserves in aging mice by ameliorating inflammatory stress

Mogroside-rich extract (MGE), the main bioactive component of dried Siraitia grosvenorii fruit, has long been used as a natural sweetener and traditional Chinese medicine. This extract possesses various types of pharmacological activities, such as anti-inflammatory, antioxidative, hypoglycemic and hypolipemic activities. Moreover, we recently revealed that MGE has beneficial effects on female reproduction. Increasing maternal age leads to a rapid reduction in female fertility; in particular, it dramatically decreases ovarian function. Nevertheless, whether MGE can alleviate ovarian aging and the underlying mechanisms have not yet been explored. In this study, mice were treated with MGE by supplementation in drinking water from 10 to 44 weeks of age. Then, ovarian function and molecular changes were determined. Our findings showed that MGE treatment protected aged mice from estrous cycle disorder. Moreover, MGE treatment significantly increased the ovarian reserves of aged mice. RNA-seq data showed that MGE upregulated the expression of genes related to gonad development, follicular development, and hormone secretion in ovarian tissue. Additionally, inflammatory stress was induced, as indicated by upregulation of inflammation-related gene expression and elevated TNF-α levels in the ovarian tissues of aged mice; however, MGE treatment attenuated inflammatory stress. In summary, our findings demonstrate that MGE can ameliorate age-related estrous cycle disorder and ovarian reserve decline in mice, possibly by alleviating ovarian inflammatory stress.

Effects of different concentrations of eugenol in maturation medium on bovine oocytes, oxidative status and preimplantation embryos

ContextEugenol is a bioactive compound with defined attributes, including a role in reducing oxidative stress. Therefore, it is an interesting candidate for in vitro embryo production that has an environment that favours the formation of reactive oxygen species.AimThe objective of the study was to evaluate different concentrations of eugenol in bovine oocytes during in vitro maturation to observe the oxidative status and embryonic development.MethodsOocytes were allocated into five groups: control (without antioxidant), 100μM cysteamine, 83μM eugenol (E83), 100μM eugenol and 120μM eugenol. Three experiments were performed with 23 replicates. Oocytes were evaluated for metaphase II, first polar body, cytoplasmic maturation, cumulus cell expansion and viability. Oxidative status was measured by mitochondrial membrane potential, reactive oxygen species and glutathione. Oocytes were artificially activated and cultured in vitro.Key resultsThe presence of eugenol at 83μM improved the metaphase II rate compared with all treatments (P&lt;0.05). E83 and 100μM cysteamine improved first polar body extrusion, cumulus cell expansion, viability and mitochondrial aggregation rates (P&lt;0.05). All antioxidant treatments resulted in increased cytoplasmic maturation and decreased mitochondrial membrane potential (P&lt;0.05). Reactive oxygen species levels decreased, and glutathione levels increased with E83 and 100μM cysteamine treatments (P&lt;0.05). Finally, the E83 group increased the cleavage rates, embryo development, number of expanded blastocysts and number of blastomeres (P&lt;0.05).ConclusionsA low concentration of eugenol (83μM) is sufficient to generate a significant effect, attenuating the oxidative status and optimising in vitro maturation and embryo development.ImplicationsThis study provides information of a new natural antioxidant with defined concentration, 83μM eugenol, representing a lower cost alternative capable of improving the efficiency of in vitro embryo production in cattle.

Mogroside V Improves Follicular Development and Ovulation in Young-Adult PCOS Rats Induced by Letrozole and High-Fat Diet Through Promoting Glycolysis

Polycystic ovary syndrome (PCOS) is a heterogeneous endocrine disorder characterized by hyperandrogenism, ovulatory dysfunction, and polycystic ovaries. In this study, we induced a young-adult PCOS rat model by oral administration of letrozole combined with a high-fat diet and then treated with mogroside V (MV) to evaluate the protective effects of MV on endocrine and follicle development in young-adult PCOS rats. MV (600 mg/kg/day) administration not only significantly reduced the body weight and ovary weight, but also attenuated the disrupted estrous cycle and decreased the level of testosterone. MV restored the follicular development, especially by increasing the number of corpus luteum and the thickness of the granular layer in young-adult POCS rats. Moreover, metabolomics showed that MV markedly increased the levels of D-Glucose 6-phosphate, lactate and GTP, while decreased the level of pyruvate. Bioinformatic analysis revealed that MV recovered multiple metabolism-related processes including gluconeogenesis, glycolysis and glucose metabolic process. Further real-time quantitative PCR analysis showed that MV upregulated the expression of lactate dehydrogenase A (Ldha), hexokinase 2 (Hk2) and pyruvate kinase M2 (Pkm2). Western blotting and immunohistochemistry analysis showed that MV restored the expression of lactate dehydrogenase A (Ldha), hexokinase 2 (Hk2) and pyruvate kinase M2 (Pkm2). Collectively, these findings indicated that MV could effectively improve the ovarian microenvironment by upregulating the expression of LDHA, HK2 and PKM2 in granulosa cells and enhancing lactate and energy production, which may contribute to follicle development and ovulation of young-adult PCOS rats.

Sorbitol accumulation decreases oocyte quality in aged mice by altering the intracellular redox balance

Sorbitol is a product of glucose metabolism through the polyol pathway. Many studies have demonstrated that excessive sorbitol can disrupt the intracellular redox balance. However, we still know very little about the impact of excessive intracellular sorbitol on oocyte quality, oocyte maturation, and embryo developmental potential. This study explored whether intracellular sorbitol accumulates in the oocytes of aged mice during in vitro maturation (IVM) and what roles sorbitol plays in oocyte development and maturation. Our results showed that sorbitol levels were significantly higher in in vitro-matured oocytes from aged mice than in oocytes from young mice (14.08 ± 3.78 vs. 0.23 ± 0.04 ng/oocyte). The expression of aldose reductase (AR) mRNA was significantly higher in the in vitro-cultured oocytes from 9-month-old mice than prior to culture. To decrease the excessive intracellular sorbitol in oocytes from aged mice, sorbinil, a specific inhibitor of aldose reductase, was supplemented in IVM medium, and the sorbitol level was significantly decreased (14.08 ± 3.78 vs. 0.48 ± 0.19 ng/oocyte). Our results indicated that the percentage of oocytes with first polar body extrusion (PBE) was significantly higher in the sorbinil group than in the aged group (82.4% ± 7.2% vs. 66.1% ± 6.9%), and the content of sorbitol was drastically increased in the aged group. The ROS fluorescence intensity in the sorbinil group was drastically lower than that in the aged group, while the GSH fluorescence intensity was significantly higher. Interestingly, SOD1 was upregulated in the sorbinil group. The present study suggests that excessive sorbitol accumulation is induced during IVM in aged mouse oocytes, which negatively influences oocyte quality by altering the intracellular redox balance. Inhibition of sorbitol accumulation may be a potential method to improve the nuclear maturation of aged oocytes.

Protective Effects of Mogroside V on Oxidative Stress Induced by H2O2 in Skin Fibroblasts

Purpose

Damage caused by oxidative stress leads to the premature aging of cells. Mogrosides, the main active components of Siraitia grosvenorii, have strong antioxidant activity; however, it is unclear whether mogroside V (MV) exerts these effects in skin cells. This was investigated in the present study by evaluating the protective effects of MV against oxidative damage induced by hydrogen peroxide (H₂O₂) in skin fibroblasts.

Methods

Mouse skin fibroblasts (MSFs) were treated with H₂O₂ and cell viability, total antioxidant capacity, reactive oxygen species (ROS) production, malondialdehyde (MDA) content, and antioxidant enzyme activity were assessed.

Results

Treatment with MV reduced the ROS level and MDA content in MSFs treated with H₂O₂. This was accompanied by increased superoxide dismutase (SOD), glutathione peroxidase (GSH-Px), and catalase (CAT) activities.

Conclusion

MV reduces H₂O₂-induced oxidative stress and enhances endogenous antioxidant activity in skin fibroblasts. Thus, MV can potentially be used as an ingredient in anti-aging cosmetic products.

Melatonin reverses mitochondria dysfunction and oxidative stress-induced apoptosis of Sudan I-exposed mouse oocytes

Sudan I is one of the industry dyes and widely used in cosmetics, wax agent, solvent and textile. Sudan I has multiple toxicity such as carcinogenicity, mutagenicity, genotoxicity and oxidative damage. However, Sudan I has been illegally used as colorant in food products, triggering worldwide attention about food safety. Nevertheless, the toxicity of Sudan I on reproduction, particularly on oocyte maturation is still unclear. In the present study, using mouse in vivo models, we report the toxicity effects of Sudan I on mouse oocyte. The results reflect that Sudan I exposure disrupts spindle organization and chromosomes alignment as well as cortical actin distribution, thus leading to the failure of polar body extrusion. Based on the transcriptome results, it is found that the exposure of Sudan I leads to the change in expression of 764 genes. Moreover, it's further reflected that the damaging effects of Sudan I are mediated by the destruction of mitochondrial functions, which induces the accumulated ROS to stimulate oxidative stress-induced apoptosis. As an endogenous hormone, melatonin within the ovarian follicle plays function on improving oocyte quality and female reproduction by efficiently suppressing oxidative stress. Moreover, melatonin supplementation also improves oocyte quality and increases fertilization rate during in vitro culture. Consistent with these, we find that in vivo supplementation of melatonin efficaciously suppresses mitochondrial dysfunction and the accompanying apoptosis, thus reverses oocyte meiotic deteriorations. Collectively, our results prove the reproduction toxicity of Sudan I for the exposure of Sudan I reduces the oocyte quality, and demonstrate the protective effects of melatonin against Sudan I-induced meiotic deteriorations.

Research progress of pharmacological effects of Siraitia grosvenorii extract

OBJECTIVES

To summarise the ingredients of Luo Han Guo extract and the different pharmacological activity of the different ingredients. Find and evaluate the research value of Luo Han Guo extract as a therapeutic drug.

KEY FINDINGS

Siraitia grosvenorii is a fruit native to China and has many years of medicinal history. Because of its low-calorie and sugar-free properties, it is approved as a sweetener substitute in foods for obese and diabetic patients. Experiments have shown that this sweetener is non-toxic. This article summarises much literature on S. grosvenorii extracts, briefly introduces their chemical composition and metabolic distribution and summarises the possible pharmacological effects of each S. grosvenorii extract. Siraitia grosvenorii extract has anti-diabetic, anti-tumour, anti-inflammatory, antioxidant, neuroprotective and lipogenic inhibitory effects. These pharmacological activities suggest the medicinal value of S. grosvenorii.

SUMMARY

Luo Han Guo extract is a low-calorie, non-toxic substance, and its pharmacological activity and its potential medicinal properties support its further utilisation and research.

The Role of Mitochondria in Oocyte Maturation

With the nucleus as an exception, mitochondria are the only animal cell organelles containing their own genetic information, called mitochondrial DNA (mtDNA). During oocyte maturation, the mtDNA copy number dramatically increases and the distribution of mitochondria changes significantly. As oocyte maturation requires a large amount of ATP for continuous transcription and translation, the availability of the right number of functional mitochondria is crucial. There is a correlation between the quality of oocytes and both the amount of mtDNA and the amount of ATP. Suboptimal conditions of in vitro maturation (IVM) might lead to changes in the mitochondrial morphology as well as alternations in the expression of genes encoding proteins associated with mitochondrial function. Dysfunctional mitochondria have a lower ability to counteract reactive oxygen species (ROS) production which leads to oxidative stress. The mitochondrial function might be improved with the application of antioxidants and significant expectations are laid on the development of new IVM systems supplemented with mitochondria-targeted reagents. Different types of antioxidants have been tested already on animal models and human rescue IVM oocytes, showing promising results. This review focuses on the recent observations on oocytes’ intracellular mitochondrial distribution and on mitochondrial genomes during their maturation, both in vivo and in vitro. Recent mitochondrial supplementation studies, aiming to improve oocyte developmental potential, are summarized.

Mogroside V Alleviates Oocyte Meiotic Defects and Quality Deterioration in Benzo(a)pyrene-Exposed Mice

Accumulating evidence has demonstrated that benzo(a)pyrene (BaP) exposure adversely affects female reproduction, especially oocyte meiotic maturation and subsequent embryo development. Although we previously found that mogroside V (MV), a major bioactive component of S. grosvenorii, can protect oocytes from quality deterioration caused by certain stresses, whether MV can alleviate BaP exposure-mediated oocyte meiotic defects remains unknown. In this study, female mice were exposed to BaP and treated concomitantly with MV by gavage. We found that BaP exposure reduced the oocyte maturation rate and blastocyst formation rate, which was associated with increased abnormalities in spindle formation and chromosome alignment, reduced acetylated tubulin levels, damaged actin polymerization and reduced Juno levels, indicating that BaP exposure results in oocyte nucleic and cytoplasmic damage. Interestingly, MV treatment significantly alleviated all the BaP exposure-mediated defects mentioned above, indicating that MV can protect oocytes from BaP exposure-mediated nucleic and cytoplasmic damage. Additionally, BaP exposure increased intracellular ROS levels, meanwhile induced DNA damage and early apoptosis in oocytes, but MV treatment ameliorated these defective parameters, therefore it is possible that MV restored BaP-mediated oocyte defects by reducing oxidative stress. In summary, our findings demonstrate that MV might alleviate oocyte meiotic defects and quality deterioration in BaP-exposed mice.

Exposure to chlorpyrifos leads to spindle disorganization and mitochondrial dysfunction of porcine oocytes during in vitro maturation

Chlorpyrifos (CPF), as one of the most extensively applied organophosphorus pesticides (OPs) in agricultural and domestic settings, causes a potential threat to human and animal health. Various reproductive toxicities of CPF have been reported, however, little information is available on whether CPF exposure could exert toxic effects on mammalian oocytes. Herein, the effects of CPF on the meiotic maturation and developmental capability of porcine oocytes were investigated, and the possible toxic mechanisms of CPF were also explored. Porcine cumulus-oocyte complexes (COCs) were treated with 0, 5, 10, or 20 μM CPF for 44 h during in vitro maturation (IVM), and the results showed that the first polar body (PB1) extrusion rate was significantly decreased, and the subsequent developmental competence of the resulting metaphase II (MII) oocytes was also impaired when the concentration of CPF reached 10 μM. In addition, a higher percentage of CPF-exposed oocytes were arrested at the anaphase-telophase I (ATI) stage, accompanied by misaligned chromosomes and aberrant spindles. Furthermore, higher levels of ROS and upregulated antioxidant-related genes (CAT, SOD1, SOD2, GPX) were detected in CPF-treated oocytes. Additionally, CPF treatment led to the depolarization of mitochondrial membrane potential (MMP) and the release of cytochrome c (Cyt c). Simultaneously, the apoptotic rate of the oocytes was significantly increased, and the expression levels of Bax and CASPASE3 were significantly upregulated after CFP exposure. Together, exposure to 10 μM CPF can disrupt the meiotic cycle progression, lead to aberrant spindles and mitochondrial dysfunction, which eventually induce oxidative stress and apoptosis in porcine oocytes.

Tributyltin Oxide Exposure During in vitro Maturation Disrupts Oocyte Maturation and Subsequent Embryonic Developmental Competence in Pigs

Tributyltin oxide (TBTO), an organotin compound, has been demonstrated to have toxic effects on several cell types. Previous research has shown that TBTO impairs mouse denuded oocyte maturation. However, limited information is available on the effects of TBTO exposure on livestock reproductive systems, especially on porcine oocytes in the presence of dense cumulus cells. In the present research, we evaluated the effects of TBTO exposure on porcine oocyte maturation and the possible underlying mechanisms. Porcine cumulus-oocyte complexes were cultured in maturation medium with or without TBTO for 42 h. We found that TBTO exposure during oocyte maturation prevented polar body extrusion, inhibited cumulus expansion and impaired subsequent blastocyst formation after parthenogenetic activation. Further analysis revealed that TBTO exposure not only induced intracellular reactive oxygen species (ROS) accumulation but also caused a loss of mitochondrial membrane potential and reduced intracellular ATP generation. In addition, TBTO exposure impaired porcine oocyte quality by disrupting cellular iron homeostasis. Taken together, these results demonstrate that TBTO exposure impairs the porcine oocyte maturation process by inducing intracellular ROS accumulation, causing mitochondrial dysfunction, and disrupting cellular iron homeostasis, thus decreasing the quality and impairing the subsequent embryonic developmental competence of porcine oocytes.

Supplementation with asiatic acid during in vitro maturation improves porcine oocyte developmental competence by regulating oxidative stress

Asiatic acid is a natural triterpene found in Centella asiatica that acts as an effective free radical scavenger. Our previous research showed that asiatic acid delayed porcine oocyte ageing in vitro and improved preimplantation embryo development competence in vitro; however, the protective effects of asiatic acid against oxidative stress in porcine oocyte maturation are still unclear. Here, we investigated the effects of asiatic acid on porcine oocyte in vitro maturation (IVM) and subsequent embryonic development competence after parthenogenetic activation (PA) and in vitro fertilization (IVF). The results of the present research showed that 10 μM asiatic acid supplementation did not affect the expansion of cumulus cells or polar body extrusion of porcine oocytes, while asiatic acid application significantly increased the subsequent blastocyst formation rate and quality of porcine PA and IVF embryos. Hydrogen peroxide (H₂O₂) is a reactive oxygen species (ROS) that induces oxidative stress in porcine oocytes. As expected, asiatic acid supplementation not only decreased intracellular ROS levels but also attenuated H₂O₂-induced intracellular ROS generation. Further analysis revealed that asiatic acid supplementation enhanced intracellular glutathione production, mitochondrial membrane potential, and ATP generation at the end of IVM. In summary, our results reveal that asiatic acid supplementation exerts beneficial effects on porcine oocytes by regulating oxidative stress during the IVM process and could act as a potential antioxidant in porcine oocytes matured in vitro production systems.

Granulosa cells affect in vitro maturation and subsequent parthenogenetic development of buffalo (Bubalus bubalis) oocytes

Granulosa cells (GCs) play a crucial role in follicular development and atresia. Previous studies have showed that GCs in the form of monolayer influenced in vitro maturation (IVM) of oocytes. However, the effects of GCs in the form of conditioned medium and monolayer on IVM and development competence of buffalo oocytes remain unclear. In the present study, we examined the impacts of GC-conditioned medium (GCCM) and monolayer GC on maturation efficiency and embryo development of buffalo oocytes after parthenogenetic activation (PA). Our results showed that GCCM that was collected on day 2 and added to IVM medium at a 20% proportional level (2 days and 20%) exerted significant negative effects on IVM rate (41.6% vs. 44.5%), but significantly enhanced embryo development (oocyte cleavage, 81.3% vs. 69.3%; blastocyst formation, 36.3% vs. 29.3%) of buffalo oocytes after PA compared with the control group. Furthermore, monolayer GC significantly reduced both maturation efficiency (40.2% vs. 44.5%) and embryo development (oocyte cleavage, 60.6% vs. 69.3%; blastocyst formation, 20.6% vs. 29.3%) of buffalo oocytes after PA compared to the control group. Our study indicated that GCs in the form of GCCM (2 days and 20%) and monolayer GC had different effects on IVM and subsequent parthenogenetic development of buffalo oocytes.

Iron Overload-Induced Ferroptosis Impairs Porcine Oocyte Maturation and Subsequent Embryonic Developmental Competence in vitro

Accumulating evidence indicates that ferroptosis is an iron-dependent form of regulated cell death. This type of iron-dependent programmed cell death is different from traditional forms of regulated cell death, such as apoptosis and autophagy. However, the role of ferroptosis in porcine oocyte maturation and the associated mechanism remain unclear. In the present research, we investigated the effects of ferric ammonium citrate (FAC), a specific ferroptosis inducer, on porcine oocyte meiotic maturation and quality and subsequent embryonic developmental competence. FAC treatment caused obvious accumulation of intracellular ferrous ions in porcine oocytes. At the end of the in vitro maturation (IVM) period, there was a significant decrease in the polar body (PB) extrusion rate and an increase in the percentage of abnormal oocytes in the FAC treatment groups, indicating that iron overload-induced ferroptosis may suppress the meiotic process during porcine oocyte maturation. We also found that after FAC treatment, the subsequent two-cell rate, four-cell rate and blastocyst formation rate were significantly decreased in porcine parthenogenetic activation (PA) embryos, indicating that iron overload-induced ferroptosis decreased porcine oocyte quality. Further analysis revealed that FAC treatment not only enhanced intracellular reactive oxygen species (ROS) generation, decreased intracellular free thiol levels and induced mitochondrial dysfunction but also triggered autophagy in porcine oocytes. Taken together, these findings suggest that iron overload-induced ferroptosis impairs porcine oocyte meiosis and decreases porcine oocyte quality, possibly by increasing oxidative stress, inducing mitochondrial dysfunction and triggering autophagy.

The Effect of Sodium Selenite on Expression of Mitochondrial Transcription Factor A during In Vitro Maturation of Mouse Oocyte

BACKGROUND

The aim of the present study was to investigate the effect of Sodium Selenite (SS) supplemented media on oocyte maturation, expression of mitochondrial transcription factor A (TFAM) and embryo quality.

METHODS

Mouse Germinal Vesicle (GV) oocytes were collected after administration of Pregnant Mare Serum Gonadotropin (PMSG); in experimental group 1, oocytes were cultured and then subjected for in vitro maturation in the absence of SS, and in experimental group 2, they were matured in vitro in the presence of 10 ng/ml of SS up to 16 hr. The control group included MII oocytes obtained from the fallopian tubes after ovarian stimulation with PMSG, followed by human chorionic gonadotropin. Then, the expression of TFAM in MII oocytes in all three groups was investigated using real-time RT-PCR. The fertilization and embryo developmental rates were assessed, and finally the quality of the blastocysts was evaluated using propidium iodide staining.

RESULTS

The oocyte maturation rate to MII stage in SS treated group was significantly higher than non-treated oocytes (75.65 vs. 68.17%, p<0.05). Also, the rates of fertilization, embryo development to blastocyst stage as well as the cell number of blastocyst in SS supplemented group were higher than other experimental group (p<0.05). There was a significant decrease in TFAM gene expression in both in vitro groups compared to the group with in vivo obtained oocytes (p<0.05). Moreover, there was a significant increase in TFAM gene expression in oocytes that matured in the presence of SS compared to that of the group without SS (p<0.05).

CONCLUSION

Supplementation of oocyte maturation culture media with SS improved the development rate of oocytes and embryo and also enhanced TFAM expression in MII oocytes which can affect the mitochondrial biogenesis of oocytes.