The Usefulness of Retinoic Acid Supplementation during In Vitro Oocyte Maturation for the In Vitro Embryo Production of Livestock: A Review

The beneficial effects of quinoa seed extract supplementation on ram sperm quality following cryopreservation

Although cryopreservation is a reliable method used in assisted reproduction to preserve genetic materials, it can stimulate the occurrence of oxidative stress, which affects sperm structure and function. This research was conducted to explore the effects of quinoa seed extracts (QSE) on ram sperm quality, oxidative biomarkers, and the gene expression of frozen-thawed ram sperm. Semen samples were diluted in extenders supplemented with 0 (QSE0), 250 (QSE1), 500 (QSE2), 750 (QSE3), and 1000 (QSE4) µg of QSE /mL, and then frozen according to the typical procedure. The findings indicate that the QSE3 and QSE4 groups provided the optimal results in terms of sperm viability and progressive motility. Sperm kinematics were considerably enhanced in the QSE3 group compared to the other groups (P<0.01). QSE (500-1000 µg/mL) significantly decreased the apoptosis-like changes (higher viable and lower apoptotic sperm) in ram sperm (P<0.001). The percentage of live sperm with intact acrosomes was significantly increased, while the percentage of detached and intact acrosomes in live and dead sperm were significantly decreased respectively by the QSE addition (P<0.001). All QSE groups had higher TAC and lower MDA and H2O2 levels than the control group (P<0.001). The expressions of SOD1, CAT, GABPB1, and GPX1 genes in sperm samples were significantly increased, while the CASP3 gene was significantly decreased in all QSE-supplemented samples. Our data suggest that QSE has beneficial effects on sperm quality of cryopreserved ram semen, which are achieved by promoting sperm antioxidant-related genes and reducing apoptosis-related gene.

Effects of supplemental vitamin A on reproduction and antioxidative status of aged laying hens, and growth, blood indices and immunity of their offspring

The purpose of this investigation was to evaluate the impacts of vitamin A (VA) supplementation in feed at levels of 0 (control), 2,000, 4,000, 6,000, and 8,000 IU VA/kg diet on the reproductive efficiency and antioxidative properties of aged Sinai laying hens at 52 wk of age (n = 300 females and 30 males) in 6 replicates (10 females + 1 male/replicate). As well as blood biochemical indicators, carcass characteristics, growth performance, immunity, and the antioxidative status of their chicks. Results showed that diets supplemented with 2,000 or 6,000 IU/kg of VA increased fertility rate and decreased early embryonic mortality (P < 0.05). Increasing VA from 4,000 to 6,000 IU/kg significantly boosted hatchability rates. All VA levels significantly enhanced glutathione peroxidase (GPx) and reduced malondialdehyde (MDA) and late embryonic mortality. In the shell gland, dietary supplementation of 6,000 or 8,000 IU/kg of VA enhanced actions of GPx actions, catalase (CAT), and superoxide dismutase (SOD). In hatched chicks, all VA levels boosted (P < 0.05) hemoglobin, red blood cell count, and serum concentration of total proteins and IgA while decreasing eosinophils percentage and aspartate aminotransferase activity (AST) concentration. Dietary VA supplementations from 4,000 to 8,000 IU/kg improved lymphocytes, serum total antioxidant capacity (TAC), SOD, and IgM, while decreasing heterophils, heterophils/lymphocytes ratio, and creatinine in hatched chicks. Serum triglyceride concentration was reduced by adding 6,000 or 8,000 IU/kg of VA, while globulin and high-density lipoprotein concentrations were heightened only by 8,000 IU/kg of VA. It could be concluded that the dietary supplementation of VA (6,000 IU/kg) improved reproductive efficiency and antioxidative status in the liver and the shell gland of aged laying hens and improved hemato-biochemicals parameters, antioxidative status, and immunity of their offspring.

Isoliquiritin can cause mitochondrial dysfunction and regulate Nrf2 to affect the development of mouse oocytes

IsoliQuirtigenin (ILG) has been widely studied in somatic cells and tissues, but less in reproductive development. It is a kind of widely used food additive. In this study, it was found that ILG could significantly increase the levels of ROS,GSH and MMP in mouse oocytes (P < 0.01). In order to explore the cause of this phenomenon, it was found that the abnormal distribution of mitochondria and ATP synthesis levels were significantly increased (P < 0.05). At this time, we made a reasonable hypothesis that ILG affected mitochondrial function. In subsequent studies, it was found that the endogenous ROS accumulation level in mitochondria was significantly increased. After continuous RT-PCR screening, it was found that the expression of Nrf2 was significantly inhibited (P < 0.01). Its upstream and downstream FOXO3 GPX1, CAT, SOD2, SIRT1 gene also appear different degree of significant change (P < 0.05), in which the lower expression of NADP + (P < 0.05) illustrates the mitochondrial ATP synthesis electronic chain were suppressed, it also has the reason, By inhibiting electron chain and ATP synthesis, ILG leads to oocyte apoptosis and initiation of autophagy, reducing oocyte and its subsequent developmental potential.

Integrated metabolomics and transcriptomics to reveal biomarkers and mitochondrial metabolic dysregulation of premature ovarian insufficiency

Background

The metabolic characteristics of premature ovarian insufficiency (POI), a reproductive endocrine disease characterized by abnormal sex hormone metabolism and follicle depletion, remain unclear. Metabolomics is a powerful tool for exploring disease phenotypes and biomarkers. This study aims to identify metabolic markers and construct diagnostic models, and elucidate the underlying pathological mechanisms for POI.

Methods

Non-targeted metabolomics was utilized to characterize the plasma metabolic profile of 40 patients. The metabolic markers were identified through bioinformatics and machine learning, and constructed an optimal diagnostic model by classified multi-model analysis. Enzyme-linked immunosorbent assay (ELISA) was used to verify antioxidant indexes, mitochondrial enzyme complexes, and ATP levels. Finally, integrated transcriptomics and metabolomics were used to reveal the dysregulated pathways and molecular regulatory mechanisms of POI.

Results

The study identified eight metabolic markers significantly correlated with ovarian reserve function. The XGBoost diagnostic model was developed based on six machine learning models, demonstrating its robust diagnostic performance and clinical applicability through the evaluation of receiver operating characteristic (ROC) curve, decision curve analysis (DCA), calibration curve, and precise recall (PR) curve. Multi-omics analysis showed that mitochondrial respiratory chain electron carrier (CoQ10) and enzyme complex subunits were down-regulated in POI. ELISA validation revealed an elevation in oxidative stress markers and a reduction in the activities of antioxidant enzymes, CoQ10, and mitochondrial enzyme complexes in POI.

Conclusion

Our findings highlight that mitochondrial dysfunction and energy metabolism disorders are closely related to the pathogenesis of POI. The identification of metabolic markers and predictive models holds significant implications for the diagnosis, treatment, and monitoring of POI.

Thermoprotective molecules: Effect of insulin-like growth factor type I (IGF-1) in cattle oocytes exposed to high temperatures

The adverse effects of heat stress (HS) on the welfare and productivity of cattle are the result of the associated hyperthermia and the physiological and behavioral mechanisms performed by the animal to regulate body temperature. The negative effects of HS on in vitro oocyte maturation and in vitro bovine embryo production have been reported; being one of the major concerns due to economic and productive losses, and several mechanisms have been implemented to reduce its impact. These mechanisms include supplementation of the medium with hormones, adjuvants, identification of protective genes, among others. This review aims to explore the cellular and molecular mechanisms of insulin-like growth factor-1 (IGF-1) during in vitro and in vivo maturation of bovine oocytes and its thermoprotective effect under HS. Although the supplementation of the culture medium during oocyte maturation with IGF-1 has been implemented during the last years, there are still controversial results, however, supplementation with low concentration showed a positive effect on maturation and thermoprotection of oocytes exposed to higher temperatures. Additionally, IGF-1 is involved in multiple cellular pathways, and it may regulate cell apoptosis in cases of HS and protect oocyte competence under in vitro conditions.

L-arginine and lisinopril supplementation protects against sodium fluoride-induced nephrotoxicity and hypertension by suppressing mineralocorticoid receptor and angiotensin-converting enzyme 3 activity

Sodium fluoride (NaF) is one of the neglected environmental toxicants that has continued to silently cause toxicity to both humans and animals. NaF is universally present in water, soil, and atmosphere. The persistent and alarming rate of increase in cardiovascular and renal diseases caused by chemicals such as NaF in mammalian tissues has led to the use of various drugs for the treatment of these diseases. The present study aimed at evaluating the renoprotective and antihypertensive effects of L-arginine against NaF-induced nephrotoxicity. Thirty male Wistar rats (150-180 g) were used in this study. The rats were randomly divided into five groups of six rats each as follows: Control, NaF (300 ppm), NaF + L-arginine (100 mg/kg), NaF + L-arginine (200 mg/kg), and NaF + lisinopril (10 mg/kg). Histopathological examination and immunohistochemistry of renal angiotensin-converting enzyme (ACE) and mineralocorticoid receptor (MCR) were performed. Markers of renal damage, oxidative stress, antioxidant defense system, and blood pressure parameters were determined. L-arginine and lisinopril significantly (P < 0.05) ameliorated the hypertensive effects of NaF. The systolic, diastolic, and mean arterial blood pressure of the treated groups were significantly (P < 0.05) reduced compared with the hypertensive group. This finding was concurrent with significantly increased serum bioavailability of nitric oxide in the hypertensive rats treated with L-arginine and lisinopril. Also, there was a significant reduction in the level of blood urea nitrogen and creatinine of hypertensive rats treated with L-arginine and lisinopril. There was a significant (P < 0.05) reduction in markers of oxidative stress such as malondialdehyde and protein carbonyl and concurrent increase in the levels of antioxidant enzymes in the kidney of hypertensive rats treated with L-arginine and lisinopril. The results of this study suggest that L-arginine and lisinopril normalized blood pressure, reduced oxidative stress, and the expression of renal ACE and mineralocorticoid receptor, and improved nitric oxide production. Thus, L-arginine holds promise as a potential therapy against hypertension and renal damage.

Carotenoids in female and male reproduction

Carotenoids are among the best-known pigments in nature, confer color to plants and animals, and are mainly derived from photosynthetic bacteria, fungi, algae, plants. Mammals cannot synthesize carotenoids. Carotenoids' source is only alimentary and after their assumption, they are mainly converted in retinal, retinol and retinoic acid, collectively known also as pro-vitamins and vitamin A, which play an essential role in tissue growth and regulate different aspects of the reproductive functions. However, their mechanisms of action and potential therapeutic effects are still unclear. This review aims to clarify the role of carotenoids in the male and female reproductive functions in species of veterinary interest. In female, carotenoids and their derivatives regulate not only folliculogenesis and oogenesis but also steroidogenesis. Moreover, they improve fertility by decreasing the risk of embryonic mortality. In male, retinol and retinoic acids activate molecular pathways related to spermatogenesis. Deficiencies of these vitamins have been correlated with degeneration of testis parenchyma with consequent absence of the mature sperm. Carotenoids have also been considered anti-antioxidants as they ameliorate the effect of free radicals. The mechanisms of action seem to be exerted by activating Kit and Stra8 pathways in both female and male. In conclusion, carotenoids have potentially beneficial effects for ameliorating ovarian and testes function.

Retinoic acid (all-trans) presents antioxidant properties within human ovary and reduces progesterone production by human granulosa cells

Both vitamin A and E support female reproduction and embryonic development. These vitamins have been associated with decreased fertility or failure to end the pregnancy in animals. An observational study was conducted on follicular fluid (FF) samples to determine the concentrations of fat-soluble vitamins of women undergoing in vitro fertilization and its correlation with assisted reproductive technology characteristics and pregnancy outcomes. Moreover, the effects of all-trans-retinoic acid (atRA) and alpha-tocopherol on granulosa cell viability, apoptosis, autophagy and hormonal production were evaluated. No association was identified between fat-soluble vitamin concentrations in FF and infertility aetiology, body mass index or woman's age. There were differences in follicular antioxidant profiles and ovarian response stimulation. In vitro evaluation of atRA and alpha-tocopherol reveals that, at physiological concentrations, both compounds may affect the viability of granulosa cells. In addition, these compounds are able to protect granulosa cells from oxidative stress, as well as to affect estradiol and progesterone production. Our data suggest that atRA and alpha-tocopherol levels should be well controlled as they may have implications in the function and viability of granulosa cells and highlights retinol as a marker of the oxidative defenses within ovary environment.

How in vitro maturation changes the proteome of ovine cumulus-oocyte complexes?

The present study evaluated the effects of in vitro maturation (IVM) on the proteome of cumulus-oocyte complexes (COCs) from ewes. Extracted COC proteins were analyzed by LC-MS/MS. Differences in protein abundances (p < 0.05) and functional enrichments in immature versus in vitro-matured COCs were evaluated using bioinformatics tools. There were 2550 proteins identified in the COCs, with 89 and 87 proteins exclusive to immature and mature COCs, respectively. IVM caused downregulation of 84 and upregulation of 34 proteins. Major upregulated proteins in mature COCs were dopey_N domain-containing protein, structural maintenance of chromosomes protein, ubiquitin-like modifier-activating enzyme 2. Main downregulated proteins in mature COCs were immunoglobulin heavy constant mu, inter-alpha-trypsin inhibitor heavy chain 2, alpha-2-macroglobulin. Proteins exclusive to mature COCs and upregulated after IVM related to immune response, complement cascade, vesicle-mediated transport, cell cycle, and extracellular matrix organization. Proteins of immature COCs and downregulated after IVM were linked to metabolic processes, immune response, and complement cascade. KEGG pathways and miRNA-regulated genes attributed to downregulated and mature COC proteins related to complement and coagulation cascades, metabolism, humoral response, and B cell-mediated immunity. Thus, IVM influenced the ovine COC proteome. This knowledge supports the future development of efficient IVM protocols for Ovis aries.

Association between serum vitamin A levels and premature ovarian insufficiency: a case-control, cross-sectional survey study

BACKGROUND

Although vitamin A is known to play an important role in ovarian function, its association with ovarian insufficiency has not been reported yet. Therefore, the aim of the study was to explore the association between serum vitamin A levels and premature ovarian insufficiency (POI).

METHODS

This cross-sectional survey included women with POI (n = 47) and normo-ovulatory controls (n = 67) who were enrolled between December 2016 and May 2018 in Zhejiang, China. The serum levels of follicle-stimulating hormone (FSH), luteinizing hormone (LH), estradiol (E₂), anti-Müllerian hormone (AMH), vitamin A, and total cholesterol (TC) were measured for each participant. The association of TC-adjusted vitamin A levels with the risk of POI was assessed using binary logistic regression analysis.

RESULTS

Serum vitamin A levels appeared to be slightly higher in the POI group than in the control group, but there was no evidence of a statistically significant difference (728.00 ± 176.00 µg/L vs. 503.93 ± 145.64 µg/L, p = 0.13). After adjustment for serum lipid levels, the serum vitamin A/TC ratio was significantly lower in the POI group than in the control group (143.14 ± 35.86 vs. 157.56 ± 35.21 µg/mmol, p = 0.04). Further, the serum vitamin A/TC ratio was significantly and inversely associated with POI risk (unadjusted odds ratio [OR] = 0.988, 95% confidence interval [CI]: 0.977-0.999, p = 0.04). The association remained after adjusting for confounding factors (age, BMI, annual household income, and education) (OR = 0.986, 95% CI: 0.972-0.999, p = 0.04).

CONCLUSIONS

Serum vitamin A/TC ratio was inversely associated with POI risk. Therefore, the serum vitamin A/TC ratio may serve as a predictive factor for POI, and vitamin A supplementation may play help prevent or treat POI.

The role of forskolin as a lipolytic stimulator during in vitro oocyte maturation and the in vitro embryo production of livestock

Cryopreservation is a modern technique which assists in the preservation of genetic material from oocytes and embryos for a long time. However, elevated vulnerability to cryopreservation due to the large accumulation of intracellular lipids within oocytes or embryos avoids success of this method. These lipids remain the main crucial factor limiting survival rates of oocytes and embryos after thawing. Lipid ingathering in the oocyte cytoplasm augments lipid peroxidation (LPO) and oxidative stress increases the apoptosis process, declines the viability after thawing, declines cytoskeleton actin filament injuries, lowers the blastocyst rates and reduces cryotolerance in the early stages of embryo development. There have been several attempts to reduce the ingathering of intracellular lipids in oocytes or embryos during the cryopreservation process, in that way enhancing the competence of cryopreserved oocytes or embryos and increasing their viability. One of the most applied agents for chemical delipidation is forskolin. Forskolin exhibited a possible part in improving the oocytes cryopreservation through stimulating cyclic adenosine monophosphate (cAMP) production. The main purpose of cAMP modulation is to provide energy to sustain the mammalian oocytes´ meiotic arrest. The purpose of the existing article is to assess and offer more evidence concerning the forskolin utilization as a modulator of cAMP during the cryopreservation of oocytes and its influence on meiosis completion and the reorganization of cytoplasm, which are prerequisites for the development of oocytes in addition to the contribution to fertilization and subsequently, the development of embryos.

Enhancing in vitro oocyte maturation competence and embryo development in farm animals: roles of vitamin-based antioxidants – a review

Oocyte/embryo in vitro culture is one of the most important assisted reproductive technologies used as a tool for maintaining genetic resources biodiversity and the inheritance of valuable genetic resources through generations. The success of such processes affects the final goal of the in vitro culture, getting viable and healthy offspring. In common in vitro oocyte maturation and/or embryo development techniques, the development of oocytes/embryos is carried out at 5% carbon dioxide and roughly 20% atmosphere-borne oxygen ratios in cell culture incubators due to their reduced cost in comparison with low atmospheric oxygen-tension incubators. These conditions are usually accompanying by the emergence of reactive oxygen species (ROS), which can extremely damage cell membrane integrity and other vital cellular organelles, as well as genetic material. The present review mainly focuses on the antioxidant roles of different vitamins on in vitro oocyte maturation competence and embryo development in farm animals. Because, the conditions of in vitro embryo production (IVEP) are usually accompanying by the emergence of reactive oxygen species (ROS), which can extremely damage cell membrane integrity and other vital cellular organelles as well as genetic material. The use of antioxidant agents may prevent the extreme augmentation of ROS generation and enhance in vitro matured oocyte competence and embryo development. Therefore, this review aimed to provide an updated outline of the impact of antioxidant vitamin (Vit) supplementations during in vitro maturation (IVM) and in vitro fertilization (IVF) on oocyte maturation and consequent embryo development, in various domestic animal species. Thus, the enrichment of the culture media with antioxidant agents may prevent and neutralize the extreme augmentation of ROS generation and enhance the in vitro embryo production (IVEP) outcomes.

Enhanced Synergistic-Antioxidant Activity of Melatonin and Tretinoin by Co-encapsulation into Amphiphilic Chitosan Nanocarriers: During Mice In Vitro Matured Oocyte/Morula-Compact Stage Embryo Culture Model

The use of exogenous antioxidants or the combination of them during in vitro oocyte/embryo culture media is reasonable. Co-delivery by nanocarrier has been designed to overcome the limitations of combining them traditionally. In this work, amphiphilic chitosan nanocarrier (ACN) was applied to co-encapsulate melatonin (Mel) and tretinoin (TTN) by the self-assembled method and evaluate their synergistic antioxidant efficacy in mice oocytes/embryos. The formation of single/dual-ACN was confirmed by Fourier-transformed infrared spectroscopy (FT-IR). The average particle diameter, size distribution, polydispersity index (PDI), and zeta potential of them were measured by dynamic light scattering (DLS), and the morphology was evaluated by TEM and SEM technologies. Also, the encapsulation efficiency (EE%) and drug loading content (DL%) of the nanocapsules were determined by UV-vis spectrophotometry. Studies of the in vitro release showed a continued drug release without any bursting effect of Mel+TTN-ACNs compared with single Mel/TTN-ACNs. Then, in both experiments, nuclear staining (Aceto-orcein and Hoechst 33342), fluorescent staining of H2DCFDA, chemiluminescence test, and qRT-PCR technique were performed as in vitro toxicity studies. The results of all these evaluations demonstrated that the dual delivery of Mel and TTN could accumulate a safety (without high-dose toxicity) synergistic anti-oxidative effect in oocyte/embryo by passive controlled, and inhibit intra/extracellular ROS levels by an enhanced intracellular penetration.

Beneficial effects and health benefits of Astaxanthin molecules on animal production: A review

Astaxanthin (AST) is a red pigment of carotenoid and is considered a high-quality keto-carotenoid pigment with food, livestock, cosmetic, therapeutic and nutraceutical proposes. Astaxanthin exists naturally in fish, crustacean, algae, and birds that naturally exists, principally as fatty acid esters. Many investigations have exhibited the beneficial impacts of astaxanthin when utilized as a pharmaceutical agent in animal nutrition. Astaxanthin has a variety of considerable biological actions, such as being antihypertensive, an antioxidant, anti-obesity properties, and anti-carcinogenic. Astaxanthin has recently acquired popularity as a powerful immunomodulator to maintain the health status and well-being of both animals and humans. The use of astaxanthin is broadly utilized in medical sciences and the nutrition pf aquatic species; however, it presently has limited applications in broader animal nutrition. Understanding astaxanthin's structure, source, and mode of action in the body provides a conceptual base for its clinical application and could enhance the screening of compounds associated with the treatment of many diseases. This review article aims to clarify the important aspects of astaxanthin such as its synthesis, bioavailability, and therapeutics actions, with special interest in practical applications. Awareness of this benefits and production is expected to aid the livestock industry to develop nutritional strategies that ensure the protection of animal health.

Co-encapsulation of tertinoin and resveratrol by solid lipid nanocarrier (SLN) improves mice in vitro matured oocyte/ morula-compact stage embryo development

As a promising strategy in overcoming drug resistance, the nano drug co-delivery system (NDCDS) can transport two or more drugs into the cell. In this study, we sought to compare the dual and single drug-delivery system, to deliver the optimal dose of Resveratrol (RES) and Tretinoin (TTN) into the in vitro matured oocyte and morula-compact stage embryonic cells. The formation of single (RES/TTN) and dual-drug (RES + TTN)-SLN were confirmed by Uv-vis spectrophotometery, dynamic light scattering (DLS), transmission electron microscopy (TEM), and scanning electron microscopy (SEM) technologies. In two experiments, the oocytes/presumptive zygotes were cultured under various concentrations of the single (RES/TTN) and dual-drug (RES + TTN)-SLN. In vitro toxicity studies, including nuclear staining (Aceto-orcein and Hoechst 33342), H2DCFDA fluorescent staining, chemiluminescence assay, and quantitative reverse transcription-PCR (qRT-PCR) techniques, indicated an excellent oocyte/embryo internalization of RES and TTN. Moreover, when oocytes/embryos were treated with the lowest concentration of RES + TTN-SLN, antioxidants-related genes were upregulated, apoptotic-related genes were downregulated, and intra/extracellular ROS production was reduced. In vitro cytotoxicity studies also demonstrated that single/dual-encapsulation of RES or TTN were safe even at the highest concentration (10 and 5 μM) compared to the control group. To sum it up, both delivery systems of RES and TTN by SLN (dual or single encapsulation) can deliver the optimal dose of RES and TTN into the oocyte/embryo. Where the dual-delivery of RES and TTN even at the lowest concentration (0.25 μM + 0.1 μm) showed a synergistic anti-oxidative effect in oocyte/embryo with a better inhibition of intra/extra-cellular ROS production by an enhanced/controlled intracellular penetration.

Cryoprotective Effect of Tretinoin-Loaded Solid Lipid-Core Nanocapsules During Fresh and Freeze/Thaw Media on NMRI Mouse Sperm Parameters, DNA Damage, and Reactive Oxygen Species Production

Due to the induced oxidative stress that exists in sperm freezing/thawing procedures and handling media, the use of exogenous antioxidant agents seems necessary. Drug delivery by nanocarriers has been designed to overcome the limitations of antioxidants, such as high-dose toxicity and short biological half-life. In this study, we tried to investigate the effects of tretinoin-loaded solid lipid core nanocapsules (TTN-SLN) added to freezing/thawing and handling media (in three experimental groups) on sperm motility (total/progressive), viability, DNA fragmentation, and extracellular reactive oxygen species (ROS) levels. Sperm samples from at least 30 adult male NMRI mice were evaluated in this study. The results of experiments 1 and 2 showed that the addition of 0.5 μM TTN-SLN in freezing and thawing medium significantly increased sperm viability and total/progressive motility and decreased DNA fragmentation and extracellular ROS levels (p < 0.05). Adding 0.25 and 0.5 μM of TTN-SLN to the handling medium (experiment 3), increased sperm parameters and decreased DNA fragmentation and extracellular ROS levels significantly (p < 0.05) compared with the control group. Briefly, our results indicate that SLN can deliver the lowest concentrations of tretinoin in a controlled release mechanism into the intracellular space of sperm. Also, high-dose TTN-SLN is safe during freezing/thawing and handling processes of mouse sperm.

Epigallocatechin-3-Gallate Promotes the in vitro Maturation and Embryo Development Following IVF of Porcine Oocytes

Purpose

Epigallocatechin-3-gallate (EGCG) is a major ingredient of catechin polyphenols and exerts protective effects because of its strong antioxidant properties. As far as we know, there is still a lack of systematic research on the effects of EGCG on the in vitro maturation (IVM) and in vitro fertilization (IVF) of porcine oocytes. The present study aimed to determine the effects of EGCG on the IVM and IVF of porcine oocytes.

Methods

Porcine oocytes were treated with different concentrations of EGCG (5, 10 and 20 µM), and the cumulus cell expansion, oocyte maturation rate, reactive oxygen species (ROS), glutathione (GSH) and malondialdehyde (MDA) levels, total antioxidant capacity were determined. The mRNA expression levels of oxidative stress- and apoptosis-associated genes were determined by quantitative real-time PCR. The cleavage rate and blastocyst rate of oocytes after 10 μM EGCG treatment during IVM and IVF were also evaluated.

Results

EGCG at 5, 10 and 20 μM significantly promoted cumulus cell expansion, and EGCG at 10 μM increased the oocyte maturation rate. EGCG (10 μM) treatment reduced the ROS and MDA levels, while increased the antioxidant capacity and GSH concentrations in the mature oocytes. The qRT-PCR results showed that EGCG treatment up-regulated the mRNA expression of catalase, glutathione peroxidase and superoxide dismutase in the mature oocytes. In addition, EGCG treatment also decreased the mRNA expression levels of Bax and caspase-3 and increased the Bcl-2 mRNA expression level in the mature oocytes. In addition, the cleavage rate and blastocyst rate of oocytes treated with 10 μM EGCG during IVM and IVF were significantly higher than those of the control group.

Conclusion

Our results suggest that EGCG promotes the in vitro maturation and embryo development following IVF of porcine oocytes. The protective effects of EGCG on the oocytes may be associated with its antioxidant and anti-apoptosis properties.

Clinical Application of Antioxidants to Improve Human Oocyte Mitochondrial Function: A Review

Mitochondria produce adenosine triphosphate (ATP) while also generating high amounts of reactive oxygen species (ROS) derived from oxygen metabolism. ROS are small but highly reactive molecules that can be detrimental if unregulated. While normally functioning mitochondria produce molecules that counteract ROS production, an imbalance between the amount of ROS produced in the mitochondria and the capacity of the cell to counteract them leads to oxidative stress and ultimately to mitochondrial dysfunction. This dysfunction impairs cellular functions through reduced ATP output and/or increased oxidative stress. Mitochondrial dysfunction may also lead to poor oocyte quality and embryo development, ultimately affecting pregnancy outcomes. Improving mitochondrial function through antioxidant supplementation may enhance reproductive performance. Recent studies suggest that antioxidants may treat infertility by restoring mitochondrial function and promoting mitochondrial biogenesis. However, further randomized, controlled trials are needed to determine their clinical efficacy. In this review, we discuss the use of resveratrol, coenzyme-Q10, melatonin, folic acid, and several vitamins as antioxidant treatments to improve human oocyte and embryo quality, focusing on the mitochondria as their main hypothetical target. However, this mechanism of action has not yet been demonstrated in the human oocyte, which highlights the need for further studies in this field.

Molecular, functional, and cellular alterations of oocytes and cumulus cells induced by heat stress and shock in animals

Global warming is considered as the main environmental stress affecting ecosystems as well as physiological and biochemical characteristics, and survivability of living organisms. High temperature induces various stresses and causes reduction of fertility through reducing the oocyte developmental competence and alteration in surrounding cells' functions. This causes major economic loss to livestock creating a selective pressure on animals to the advantage of better adapted genotypes and to the detriment of others. In this review, a search in Science Direct, Google Scholar, PubMed, Web of Science, Scopus, and SID databases until 2020 was conducted. Keywords which include heat stress, shock, high temperature, oocyte, cumulus, and animals were investigated. Studies have exhibited that heat stress can disturb the development and function of oocyte and cumulus cells (CCs) concerning reproductive efficiency. Heat stress has deleterious consequences on oocyte maturation and development via reduced number of polar body extrusion, adenosine monophosphate, and guanosine monophosphate synthesis. Heat stress caused the alteration of cytoplasmic and nuclear features as well as trans-zonal projections and gap junctions. In addition, heat stress is accompanied with reduced mitochondrial activity (copy mDNA number, distribution, and membrane potential) in cumulus-oocyte complexes. This review targets the description of results in the most recent studies that aimed to call attention to the influences of heat stress on molecular, functional, and cellular changes in oocytes and CCs in animals to design evidence on the acting mechanisms as the core of this problem from a comparative review.

Carnosic acid improves porcine early embryonic development by inhibiting the accumulation of reactive oxygen species

Carnosic acid (CA), a natural catechol rosin diterpene, is used as an additive in animal feeds and human foods. However, the effects of CA on mammalian reproductive processes, especially early embryonic development, are unclear. In this study, we added CA to parthenogenetically activated porcine embryos in an in vitro culture medium to explore the influence of CA on apoptosis, proliferation, blastocyst formation, reactive oxygen species (ROS) levels, glutathione (GSH) levels, mitochondrial membrane potential, and embryonic development-related gene expression. The results showed that supplementation with 10 μM CA during in vitro culture significantly improved the cleavage rates, blastocyst formation rates, hatching rates, and total numbers of cells of parthenogenetically activated porcine embryos compared with no supplementation. More importantly, supplementation with CA also improved GSH levels and mitochondrial membrane potential, reduced natural ROS levels in blastomeres, upregulated Nanog, Sox2, Gata4, Cox2, Itga5, and Rictor expression, and downregulated Birc5 and Caspase3 expression. These results suggest that CA can improve early porcine embryonic development by regulating oxidative stress. This study elucidates the effects of CA on early embryonic development and their potential mechanisms, and provides new applications for improving the quality of in vitro-developed embryos.

Thermoprotective molecules to improve oocyte competence under elevated temperature

Heat stress is an environmental factor that challenges livestock by disturbing animal homeostasis. Despite the broad detrimental effects of heat stress on reproductive function, the germline and the early preimplantation embryo are particularly prone. There is extensive evidence that elevated temperature reduces oocyte developmental competence through a series of cellular and molecular damages. Further research revealed that the oocyte respond to stress by activating cellular mechanisms such as heat shock response, unfolded protein response and autophagy to improve survival under heat shock. Such knowledge paved the way for the identification of thermoprotective molecules that alleviate heat-induced oocyte oxidative stress, organelle damage, and apoptosis. Therefore, this review depicts the deleterious effects of heat shock on oocyte developmental competence, heat-induced cellular and molecular changes, outlines pro-survival cellular mechanisms and explores thermoprotective molecules to improve oocyte competence.

Effect of season on the in-vitro maturation and developmental competence of buffalo oocytes after somatic cell nuclear transfer

Somatic cell nuclear transfer (SCNT) is a valuable technology tool with various uses in transgenic animals, regenerative medicine, and stem cell research. However, the efficiency of SCNT embryos appears to have poor developmental competency. Environmental issues may adversely affect SCNT embryos in buffalo. Thereafter, the present study aimed to explore the effect of season on the maturation of buffalo oocytes and subsequent developmental capability after parthenogenetic activation and SCNT in buffalo. Buffalo oocytes (n = 6353) were collected from local slaughterhouse at various seasons; spring (March-April), summer (May-August), autumn (September-November), and winter (December-January). A significant increase (p < 0.05) was recorded in the maturation rate (57.07%) at autumn compared with spring, summer, and winter (50.46, 50.93, and 50.66%, respectively). No significant differences were recorded in the fusion and the cleavage rates among all seasons. Blastocyst development rate was higher (p < 0.05) in autumn and winter (16.52 ± 8.45% and 15.98 ± 7.17%, respectively) than in spring and summer (9.47 ± 6.71% and 10.84 ± 6.58%, respectively) seasons. It could be concluded that the season had a significant effect on oocyte development competence which can be used for SCNT in buffalo.