Mito-Q supplementation of in vitro maturation or in vitro culture medium improves maturation of buffalo oocytes and developmental competence of cloned embryos by reducing ROS production

Impact of Curcumin on Frozen Bovine Sperm Quality and In Vitro Bovine Oocyte Maturation

This study aimed to analyze the effect of curcumin on the antioxidant properties and fertility of freeze-thawed bovine spermatozoa and bovine oocytes. In this study, curcumin concentrations of 0, 5, 10, 25, and 50 µM were added bovine sperm cryopreservation solution and oocyte IVM medium to assess sperm quality, antioxidant properties, oocyte maturation, IVF rate, and embryonic development. The results demonstrated that adding curcumin to the cryopreservation solution significantly improved the viability, motility, and acrosome integrity of bull sperm after freezing and thawing (p < 0.05). The addition of 25 µM curcumin resulted in the best sperm quality. Analysis of antioxidant capacity showed that 25 µM curcumin significantly increased the activities of MMP and antioxidant enzymes, such as CAT, SOD, and GSH-PX, and lowered the levels of MDA and ROS (p < 0.05). Adding curcumin to the in vitro maturation medium notably enhanced the maturation rate and decreased DNA fragmented nuclei of bovine oocytes (p < 0.05), with optimal outcomes observed at 25 and 50 µM curcumin. Totals of 25 and 50 µM curcumin markedly elevated GSH and MMP (p < 0.05), reduced ROS and malondialdehyde concentrations (p < 0.05), and significantly enhanced fertilization rates and blastocyst formation (p < 0.05). In conclusion, incorporating curcumin into both the bovine semen cryopreservation solution and the oocyte IVM medium significantly improved the quality of frozen-thawed sperm, antioxidant activity, oocyte maturation, IVF rate, and embryonic development.

Supplementation with L-kynurenine during in vitro maturation improves bovine oocytes developmental competence through its antioxidative action

Oxidative stress impairs the developmental potential of oocytes during in vitro maturation (IVM). L-kynurenine (L-KYN), an endogenous metabolite, exhibits antioxidant, anti-inflammatory and neuroprotective effects. This work aimed to evaluate the potential effects of L-KYN on bovine oocyte IVM and its mechanisms. Different concentrations of L-KYN (0, 10, 50, 100, and 200 μmol/L) were supplemented to bovine oocyte IVM medium. Results shown a notable enhancement in the oocyte maturation rate and the subsequent zygote cleavage and blastocyst formation rate when the L-KYN concentration reached 100 μmol/L. Further analysis revealed that this treatment effectively down-regulated expression levels of genes to cumulus cell apoptosis (Bax and Caspase3), up-regulated expression levels of genes to cumulus cell expansion (HAS2, PTX3, and PTGS2) and oocyte antioxidant (GPX4 and CAT). L-KYN supplementation also effectively increased glutathione (GSH) levels, promoted oocytes mitochondrial activity, enhanced DNA repairability, deceased reactive oxygen species (ROS) levels, and reduced apoptosis. In conclusion, adding 100 μmol/L of L-KYN to IVM medium could enhance bovine oocyte quality and the subsequent embryonic development. L-KYN could be a potential antioxidant supplement for bovine oocyte maturation in vitro.

Mitoquinone improves porcine embryo development through modulating oxidative stress and mitochondrial function

Oxidative stress caused by excess reactive oxygen species (ROS) is one of the main causes of low efficiency in in vitro production of embryos. These ROS can cause mitochondrial dysfunction and apoptosis, resulting in poor embryo development. Therefore, to prevent mitochondrial damage and apoptosis caused by ROS, we investigated the effects of mitoquinone (MitoQ), a mitochondrial-targeted antioxidant, on the in vitro culture (IVC) of porcine embryos. Various concentrations of MitoQ (0, 0.01, 0.1, or 1 nM) were supplemented during the entire period of IVC. The results showed that supplementation with 0.1 nM MitoQ significantly increased the blastocyst formation rate, with a higher total cell number including trophectoderm cell number and higher transcript expression of lineage-specific transcription factors in blastocysts. In addition, the 0.1 nM MitoQ-treated group showed a significantly lower percentage and number of apoptotic cells in blastocysts with positively regulated transcript expression of apoptosis-related genes. Therefore, 0.1 nM MitoQ was suggested as optimal concentration for porcine IVC and used for further investigations. MitoQ treatment significantly reduced intracellular ROS levels and increased glutathione levels in Day 2 embryos, with upregulated the transcript expression of antioxidant enzymes-related genes. Furthermore, the MitoQ group exhibited a significantly higher mitochondrial quantity, mitochondrial membrane potential, and ATP content in Day 2 embryos, with increased transcript expression of mitochondrial biogenesis-related genes. Taken together, these findings reveal that MitoQ supplementation can enhance the developmental competence of porcine embryos by decreasing oxidative stress and improving mitochondrial function.

Establishment of CRISPR-Cas9 ribonucleoprotein mediated MSTN gene edited pregnancy in buffalo: Compare cells transfection and zygotes electroporation

Genome editing is recognized as a powerful tool in agriculture and research, enhancing our understanding of genetic function, diseases, and productivity. However, its progress in buffaloes has lagged behind other mammals due to several challenges, including long gestational periods, single pregnancies, and high raising costs. In this study, we aimed to generate MSTN-edited buffaloes, known for their distinctive double-muscling phenotype, as a proof of concept. To meet our goal, we used somatic cell nuclear transfer (SCNT) and zygotic electroporation (CRISPR-EP) technique. For this, we firstly identified the best transfection method for introduction of RNP complex into fibroblast which was further used for SCNT. For this, we compared the transfection, cleavage efficiency and cell viability of nucleofection and lipofection in adult fibroblasts. The cleavage, transfection efficiency and cell viability of nucleofection group was found to be significantly (P ≤ 0.05) higher than lipofection group. Four MSTN edited colony were generated using nucleofection, out of which three colonies was found to be biallelic and one was monoallelic. Further, we compared the efficacy, embryonic developmental potential and subsequent pregnancy outcome of SCNT and zygotic electroporation. The blastocyst rate of electroporated group was found to be significantly (P ≤ 0.05) higher than SCNT group. However, the zygotic electroporation group resulted into two pregnancies which were confirmed to be MSTN edited. Since, the zygotic electroporation does not require complex micromanipulation techniques associated with SCNT, it has potential for facilitating the genetic modification in large livestock such as buffaloes. The present study lays the basis for inducing genetic alternation with practical or biological significance.

Mitochondria as therapeutic targets in assisted reproduction

Mitochondria are essential organelles with specialized functions, which play crucial roles in energy production, calcium homeostasis, and programmed cell death. In oocytes, mitochondrial populations are inherited maternally and are vital for developmental competence. Dysfunction in mitochondrial quality control mechanisms can lead to reproductive failure. Due to their central role in oocyte and embryo development, mitochondria have been investigated as potential diagnostic and therapeutic targets in assisted reproduction. Pharmacological agents that target mitochondrial function and show promise in improving assisted reproduction outcomes include antioxidant coenzyme Q10 and mitoquinone, mammalian target of rapamycin signaling pathway inhibitor rapamycin, and nicotinamide mononucleotide. Mitochondrial replacement therapies (MRTs) offer solutions for infertility and mitochondrial disorders. Autologous germline mitochondrial energy transfer initially showed promise but failed to demonstrate significant benefits in clinical trials. Maternal spindle transfer (MST) and pronuclear transfer hold potential for preventing mitochondrial disease transmission and improving oocyte quality. Clinical trials of MST have shown promising outcomes, but larger studies are needed to confirm safety and efficacy. However, ethical and legislative challenges complicate the widespread implementation of MRTs.

Oocyte maturation, blastocyst and embryonic development are mediated and enhanced via hormesis

The present paper provides the first integrative assessment of the capacity of dietary, endogenous and other agents to induce hormetic dose responses in oocytes, their supportive cells such as granulosa cells, blastocyst formation and early stage embryo development with the goal of improving fertility and reproductive success. The analysis showed that numerous agents enhance oocyte maturation and blastocyst/embryonic development in an hormetic fashion. These findings indicate that numerous agents improve oocyte-related biological functioning under normal conditions as well as enhancing its capacity to prevent damage from numerous chemical toxins and related stressor agents, including heat and age-related processes in pre-post conditioning and concurrent exposures. The present assessment suggests that hormetic-based lifestyles and dietary interventions may offer the potential to enhance healthy reproductive performance with applications to animal husbandry and human biology. The present findings also significantly extend the generality of the hormesis dose response concept to multiple fundamental biological processes (i.e., oocyte maturation, fertilization and blastocyst/embryo development).

Enhancing the quality of inferior oocytes of buffalo for in vitro embryo production: The impact of melatonin on maturation, SCNT, and epigenetic modifications

Success of animal cloning is limited by oocyte quality, which is closely linked to reprogramming ability. The number of layers of cumulus cells is typically used to assess the quality of oocyte; a minimum of one-third of collected cumulus-oocyte complexes (COCs) are discarded as inferior oocytes because they have less cumulus cells. Melatonin, which has been recognised for its ability to sequester free radicals and perform multiple functions, has emerged as a potentially effective candidate for enhancing inferior oocytes quality and, consequently, embryo development competency. The current study investigates to improve the quality of inferior oocytes by supplementation of melatonin (10-9 M) during in vitro maturation (IVM) and subsequent cloned embryo production and its mechanism. The results indicate that melatonin supplementation significantly (p<0.05) enhances inferior oocytes maturation, reduces oxidative stress by reducing ROS levels, and improves mitochondrial function by boosting GSH levels. The melatonin treatment (10-9 M) enhances the expression of SOD, GPx1, GDF 9, BMP 15, ATPase 6, and ATPase 8 in inferior oocytes. Furthermore, melatonin treatment increases the total cell number in the treated groups, promoting cloned blastocyst formation rates derived from inferior oocytes. Furthermore, compared to the control, 10-9 M melatonin supplementation enhances H3K9ac acetylation and lowers H3K27me3 methylation in cloned blastocysts derived from inferior oocytes. In conclusion, 10-9 M melatonin supplementation during IVM increased inferior oocyte maturation and promoted cloned buffalo embryo development by lowering oxidative stress and promoting epigenetic alterations. These studies show that melatonin may improve the quality of poor oocytes and buffalo cloning.

LPS-Induced Mitochondrial Dysfunction Reduces Oocyte Maturation and Developmental Competence of Buffalo Embryos via ROS Mediated TLR4 Signalling

PROBLEM

Lipopolysaccharide (LPS) from gram-negative bacteria has reportedly been associated with infectious diseases like metritis, which has a substantial adverse effect on animal reproductive performance and causes serious financial losses for the dairy sector. The current work aimed to establish the impact of LPS on in vitro oocyte maturation and subsequent in vitro developmental competence of oocytes, as well as to investigate the explanatory molecular mechanism underlying this effect.

METHOD OF STUDY

Buffalo cumulus-oocyte complexes (COCs) were challenged with 0, 5, 10 and 20 µg/mL LPS during IVM followed by IVF and IVC. Cytoplasmic and nuclear maturation, cleavage and blastocyst rate, intracellular reactive oxygen species (ROS), mitochondrial membrane potential (MMP, ΔΨm) and transcript abundance of genes related to inflammation, antioxidation and apoptosis were evaluated.

RESULTS

The maturation and subsequent embryonic development competency were found to be significantly (p ≤ 0.05) reduced with the addition of 10 and 20 µg/mL LPS to IVM media. ROS production accompanied by a decreased ΔΨm was recorded in LPS-treated oocytes in comparison to the control group (p ≤ 0.05). Our results were further supported by the transcriptional expression of proinflammatory (TLR4, CD14 and RPS27A) and apoptotic gene (Caspase 3) which were found to be significantly increased while antioxidant genes (SOD2 and GPX1) were decreased significantly in matured oocytes and blastocyst after LPS exposure.

CONCLUSIONS

The deleterious effects of LPS are mediated through ROS generation, which triggers inflammatory processes via the TLR4 pathway and impairs oocyte maturation and subsequent embryonic development.