Podophyllotoxin affects porcine oocyte maturation by inducing oxidative stress-mediated early apoptosis

Antileishmanial effect of podophyllotoxin and podophyllin on Leishmania major in vitro and in vivo

Therapeutic research is very important in the prevention and treatment of leishmaniasis due to problems such as drug resistance, scarring and disease recurrence. The aim of this study was to determine how Leishmania major responds to the anti-leishmaniasis properties of podophyllotoxin and podophyllin. Cultured Leishmania promastigotes were exposed to different concentrations of podophyllotoxin and podophyllin for 24 and 48 h. Then, during the animal phase, Balb/c mice were experimentally injected with Leishmania promastigotes. After wounding, the effects of 0.5% podophyllotoxin and 25% podophyllin on reducing wound diameter and the number of amastigotes in the wound were evaluated. Podophyllotoxin and podophyllin were 83% and 59% lethal to Leishmania major promastigotes at the highest concentrations (200 µg/ml) and time (48 h). In the in vivo study, the mean lesion diameter at the end of treatment in the negative control group was 15.10 mm compared to 14.21 mm and 11.55 mm in the 25% podophyllin and 0.5% podophyllotoxin groups, respectively. Although both agents reduced the size of mice wounds and the number of amastigotes in the wounds, podophyllotoxin was more effective in this regard. Based on the results, podophyllotoxin and podophyllin can be used as leishmaniasis drugs after further research.

Graphical abstract

Unravelling the epigenetic impact: Oxidative stress and its role in male infertility-associated sperm dysfunction

Male infertility is a multifactorial condition influenced by epigenetic regulation, oxidative stress, and mitochondrial dysfunction. Oxidative stress-induced damage leads to epigenetic modifications, disrupting gene expression crucial for spermatogenesis and fertilization. Paternal exposure to oxidative stress induces transgenerational epigenetic alterations, potentially impacting male fertility in offspring. Mitochondrial dysfunction impairs sperm function, while leukocytospermia exacerbates oxidative stress-related sperm dysfunction. Therefore, this review focuses on understanding these mechanisms as vital for developing preventive strategies, including targeting oxidative stress-induced epigenetic changes and implementing lifestyle modifications to prevent male infertility. This study investigates how oxidative stress affects the epigenome and sperm production, function, and fertilization. Unravelling the molecular pathways provides valuable insights that can advance our scientific understanding. Additionally, these findings have clinical implications and can help to address the significant global health issue of male infertility.

Disturbed Follicular Microenvironment in Polycystic Ovary Syndrome: Relationship to Oocyte Quality and Infertility

Polycystic ovary syndrome (PCOS) is a common endocrine disorder associated with infertility and poor reproductive outcomes. The follicular fluid (FF) microenvironment plays a crucial role in oocyte development. This review summarizes evidence elucidating the alterations in FF composition in PCOS. Various studies demonstrated a pronounced proinflammatory milieu in PCOS FF, characterized by increased levels of cytokines, including but not limited to interleukin-6 (IL-6), tumor necrosis factor α, C-reactive protein, and IL-1β, concomitant with a reduction in anti-inflammatory IL-10. T lymphocytes and antigen-presenting cells are dysregulated in PCOS FF. PCOS FF exhibit heightened reactive oxygen species production and the accumulation of lipid peroxidation byproducts, and impaired antioxidant defenses. Multiple microRNAs are dysregulated in PCOS FF, disrupting signaling critical to granulosa cell function. Proteomic analysis reveals changes in pathways related to immune responses, metabolic perturbations, angiogenesis, and hormone regulation. Metabolomics identify disturbances in glucose metabolism, amino acids, lipid profiles, and steroid levels with PCOS FF. Collectively, these pathological alterations may adversely affect oocyte quality, embryo development, and fertility outcomes. Further research on larger cohorts is needed to validate these findings and to forge the development of prognostic biomarkers of oocyte developmental competence within FF. Characterizing the follicular environment in PCOS is key to elucidating the mechanisms underlying subfertility in this challenging disorder.

Supplementation with Eupatilin during In Vitro Maturation Improves Porcine Oocyte Developmental Competence by Regulating Oxidative Stress and Endoplasmic Reticulum Stress

Eupatilin (5,7-dihydroxy-3',4',6-trimethoxyflavone) is a flavonoid derived from Artemisia plants that has beneficial biological activities, such as anti-apoptotic, anti-oxidant, and anti-inflammatory activities. However, the protective effects of eupatilin against oxidative stress and endoplasmic reticulum stress in porcine oocyte maturation are still unclear. To investigate the effect of eupatilin on the development of porcine oocytes after in vitro maturation and parthenogenetic activation, we added different concentrations of eupatilin in the process of porcine oocyte maturation in vitro, and finally selected the optimal concentration following multiple comparisons and analysis of test results using SPSS (version 17.0; IBM, Chicago, IL, USA) software. The results showed that 0.1 μM eupatilin supplementation did not affect the expansion of porcine cumulus cells, but significantly increased the extrusion rate of porcine oocyte polar bodies, the subsequent blastocyst formation rate, and the quality of parthenogenetically activated porcine embryos. Additionally, it reduced the level of reactive oxygen species in cells and increased glutathione production. Further analysis revealed that eupatilin supplementation could reduce apoptosis, DNA double-strand breaks, and endoplasmic reticulum stress. In conclusion, supplementation with 0.1 μM eupatilin during in vitro maturation improved oocyte maturation and subsequent embryo development by reducing oxidative stress and endoplasmic reticulum stress.

Glutathione Mitigates Meiotic Defects in Porcine Oocytes Exposed to Beta-cypermethrin by Regulating ROS Levels

Beta-cypermethrin (β-CYP) is a commonly used insecticide that is potentially toxic and has adverse effects on the health of both animals and humans. Studies have indicated that β-CYP damages organs like the liver, thyroid, intestinal tract, and uterus. However, the underlying mechanisms that β-CYP affects oocyte quality are poorly understood. According to our research, β-CYP exposure led to the aberrant assembly of spindles and alignment of chromosomes, resulting in porcine oocytes' defective nuclear maturation. Concurrently, β-CYP exposure perturbed the cytoplasmic maturation by disturbing the cortical granules (CGs), endoplasmic reticulum (ER), and mitochondrial integrity. It also led to accumulating reactive oxygen species (ROS) and apoptosis. We found that supplementation with glutathione (GSH) mitigated the meiotic defects induced by β-CYP exposure via regulating ROS levels. Our observations illustrate that β-CYP exposure adversely impacts oocyte meiotic maturation, and taking GSH supplementation is an effective strategy.

Natural Ghee Enhances the Biochemical and Immunohistochemical Reproductive Performance of Female Rabbits

The reproductive effects of several dietary fats (margarine, ghee, and olive oil) on female rabbits were studied. For that purpose, 40 mature female rabbits were designed into four groups of ten rabbits each. Group I was given a control diet, Group II received 10% margarine, Group III received 10% ghee, and Group IV received 10% olive oil; after two months, all rabbits were sacrificed. Lipid profile and reproductive hormones levels were assayed in serum besides ovarian antioxidant enzyme and lipid peroxidation. Furthermore, ovarian tissue was examined using hematoxylin−eosin staining and immunohistochemistry of estrogen, follicle-stimulating hormone (FSH), luteinizing hormone (LH) receptor, and caspase 3. Our data revealed that the margarine significantly (p < 0.05) increased lipid profile and malondialdehyde (MDA) level, which decreased in olive oil and ghee compared to the control. In addition, serum FSH and estrogen (estradiol (E2)) were significantly (p < 0.05) decreased in the group treated with margarine. Furthermore, there was a significant decrease in ovarian superoxide dismutase (SOD) and catalase activity in the margarine-treated group. In contrast, SOD and MDA showed a significant (p > 0.05) increase in the olive oil and ghee- treated group compared to the control group. At the same time, there was a significant increase in serum FSH and (estradiol (E2)) in the ghee and olive oil groups, respectively, compared to the control. The margarine feed group showed moderate immunoreaction of estrogen, FSH, LH receptor, and strong caspase 3, while ghee and olive oil showed strong immunoreaction of estrogen, FSH, LH receptor, and mild immunoreaction of caspase 3 in ovarian tissue. Photomicrograph of rabbit ovarian tissue showed vacuolation in small and growing follicles in the margarine group but appeared normal in ghee and the olive oil-treated group. In conclusion, based on these results, olive oil and ghee have a strong capability of enhancing lipid profile, antioxidant status, and female hormonal functions.

Effects of 2,2',4,4'-tetrabromodiphenyl ether (BDE-47) on reproductive and endocrine function in female zebrafish (Danio rerio)

BACKGROUND

Polybrominated diphenyl ethers (PBDEs), a group of brominated flame retardants (BFRs), were reported exist extensively in various ecological environmental. Studies have indicated that PBDEs induce reproductive toxic effects on human health, but the mechanisms remain poorly understood. In this study, the adult female zebrafish were used to investigate the effects of 2, 2', 4, 4'-tetrabromodiphenyl ether (BDE-47) on the reproductive endocrine system and its mechanism.

METHODS

Female zebrafish (AB strains) were continuously exposed to BDE-47 at the concentrations of 0, 10, 50, 100 and 500 µg/L till 21 days. The morphology of ovary were stained and evaluated with hematoxylin-eosin (H&E), and levels of sex hormones including follicle-stimulating hormone (FSH), luteinizing hormone (LH), testosterone (T) and 17β-estradiol (E₂) and the biomarkers of oxidative stress such as superoxide dismutase (SOD) and malondialdehyde (MDA), were measured via ELISA. Subsequently, the expression of genes along the hypothalamic pituitary-gonad (HPG) and oxidative stress were determined using quantitative real-time PCR (qRT-PCR).

RESULT

The results showed that exposure to high level of BDE-47 reduced the index of condition factor (CF) and gonadosomatic index (GSI). Treatment with BDE-47 impaired the normal development and structure of oocytes in zebrafish ovary. Moreover, the steroid hormone of FSH, LH, T and E₂ were significantly decreased in BDE-47 exposure group. A dose-dependent elevation in SOD activity and MDA levels were recorded. Meanwhile, the transcription level of cyp19a, cyp19b, fshβ, lhβ were up-regulated while the transcription of fshr, lhr, cyp17a, 17βhsd were down-regulated in the gonad of female adult zebrafish.

CONCLUSION

Exposure to BDE-47 have detrimental impact on the development of ovary, decreasing sex hormone levels, inducing oxidative damage as well as altering HPG axis-related genes.

Supplementation of SDF1 during Pig Oocyte In Vitro Maturation Improves Subsequent Embryo Development

The quality of in vitro matured oocytes is inferior to that of in vivo matured oocytes, which translates to low developmental capacity of embryos derived from in vitro matured oocytes. The developmental potential of in vitro matured oocytes is usually impaired due to oxidative stress. Stromal cell-derived factor-l (SDF1) can reduce oxidative stress and inhibit apoptosis. The aim of this study was to investigate the effects of SDF1 supplementation during pig oocyte in vitro maturation (IVM) on subsequent embryo development, and to explore the acting mechanisms of SDF1 in pig oocytes. We found that the IVM medium containing 20 ng/mL SDF1 improved the maturation rate of pig oocytes, as well as the cleavage rate and blastocyst rate of embryos generated by somatic cell nuclear transfer, in vitro fertilization, and parthenogenesis. Supplementation of 20 ng/mL SDF1 during IVM decreased the ROS level, increased the mitochondrial membrane potential, and altered the expression of apoptosis-related genes in the pig oocytes. The porcine oocyte transcriptomic data showed that SDF1 addition during IVM altered the expression of genes enriched in the purine metabolism and TNF signaling pathways. SDF1 supplementation during pig oocyte IVM also upregulated the mRNA and protein levels of YY1 and TET1, two critical factors for oocyte development. In conclusion, supplementation of SDF1 during pig oocyte IVM reduces oxidative stress, changes expression of genes involved in regulating apoptosis and oocyte growth, and enhances the ability of in vitro matured pig oocytes to support subsequent embryo development. Our findings provide a theoretical basis and a new method for improving the developmental potential of pig in vitro matured oocytes.

Citrinin impairs pig oocyte maturation by inducing oxidative stress and apoptosis

Citrinin (CTN) is a polyketide mycotoxin produced by several strains of Penicillium, Monascus, and Aspergillus. While CTN poses various toxic effects on the female reproductive system in animals, its direct effects on germ cell development are unclear. This study aimed to evaluate the effects of increasing concentrations of CTN (0,20,40,80,100 μM) on porcine oocyte in vitro maturation. Our results indicate that CTN supplementation inhibited polar body extrusion in a dose-dependent manner. Actin and spindle assembly were also disrupted after treatment, indicating that CTN affects the cytoskeleton of porcine oocytes. Oxidative stress and apoptosis were observed under CTN treatment to explore the cause of meiotic maturation failure in porcine oocytes. The results showed that reactive oxygen species levels, cathepsin B activity, and caspase-3 activity were increased in the treated group, indicating that CTN induced oxidative stress and apoptosis. In conclusion, CTN exposure could reduce porcine oocyte maturation by affecting cytoskeletal dynamics, oxidative stress, and apoptosis.

Evidence-based hormonal, mutational, and endocrine-disrupting chemical-induced zebrafish as an alternative model to study PCOS condition similar to mammalian PCOS model

Polycystic ovarian syndrome (PCOS) causes swollen ovaries in women at reproductive age due to hormonal disorder with small cysts on the outer edges. The cause of the disorder is still yet to be found. Multiple factors have increased PCOS prevalence, hyperandrogenism, oxidative stress, inflammation, and insulin resistance. Various animal PCOS models have been developed to imitate the pathophysiology of PCOS in humans. Zebrafish is one of the most versatile animal experimental models because of the transparency of the embryos, small size, and rapid growth. The zebrafish similarity to higher vertebrates made it a useful non-mammalian model for PCOS drug testing and screening. This review provides an insight into the usage of zebrafish, a non-mammalian model for PCOS, as an opportunity for evaluating future initiatives in such a research domain.

Podophyllotoxin-combined 5-aminolevulinic acid photodynamic therapy significantly promotes HR-HPV-infected cell death

BACKGROUND

Human papillomavirus (HPV) infection and related diseases are difficult clinical challenges. The efficacy of 5-aminolevulinic acid photodynamic therapy (ALA-PDT) in treating condyloma acuminata is remarkable, with high virus clearance and low recurrence rates. Podophyllotoxin (POD) is the first-line drug with a significant therapeutic effect on condyloma acuminata. However, no studies have determined whether POD-combined ALA-PDT improves high-risk (HR)-HPV-infected cell killing. We aimed to investigate whether POD-combined ALA-PDT could promote HPV-infected cell death more effectively than the single treatment and explore the underlying mechanism.

METHODS

In HeLa and SiHa cells, flow cytometry, EdU assay and LDH release test were used to detect apoptosis, cell proliferation change and necrosis, respectively. To investigate whether the combined therapy might activate apoptosis and induce endoplasmic reticulum (ER) stress, flow cytometry was used to determine intracellular levels of ROS and calcium, and Western blotting was used to determine the expression of related proteins. Mitochondrial membrane depolarization was detected by JC-1 assay. Immunofluorescence staining and Western blotting were used to detect the activation of autophagy.

RESULTS

Podophyllotoxin -combined ALA-PDT inhibited the proliferation and promoted apoptosis and necrosis more effectively than the single treatment at the same intensity and concentration. The activation of the caspase-dependent apoptosis pathway, ER stress and autophagy was more substantial in POD-combined ALA-PDT than with single treatments.

CONCLUSION

Podophyllotoxin -combined ALA-PDT effectively promoted cell death through several pathways in HeLa and SiHa cells. This combination might be a promising therapeutic strategy for the HR-HPV infection.

Synthesis and Evaluation of Chiral Rhodanine Derivatives Bearing Quinoxalinyl Imidazole Moiety as ALK5 Inhibitors

BACKGROUND

TGF-β signaling pathway inhibition is considered an effective way to prevent the development of several diseases. In the design and synthesis of TGF-β inhibitors, a rhodanine compound containing a quinoxalinyl imidazole moiety was found to have strong antimicrobial activity.

OBJECTIVE

The purpose of this work was to investigate the antimicrobial activity of other chiral rhodanine TGF-β inhibitors synthesized.

METHODS

Two series of 3-substituted-5-((5-(6-methylpyridin-2-yl)-4-(quinoxalinyl-6-yl)- 1H-imidazol-2-yl)methylene)-2-thioxothiazolin-4-ones (12a-h and 13a-e) were synthesized and evaluated for their ALK5 inhibitory and antimicrobial activity. The structures were confirmed by their 1H NMR, 13C NMR, and HRMS spectra. All the synthesized compounds were screened against Gram-positive strains, Gram-negative strains, and fungi.

RESULTS

Among the synthesized compounds, compound 12h showed the highest activity (IC50 = 0.416 μM) against ALK5 kinase. Compound 12h exhibited a good selectivity index of > 24 against p38α MAP kinase and was 6.0-fold more selective than the clinical candidate, compound 2 (LY-2157299). Nearly all the compounds displayed high selectivity toward both Gram-positive and Gram-negative bacteria. They also showed similar or 2.0-fold greater antifungal activity (minimum inhibitory concentration [MIC] = 0.5 µg/mL) compared with the positive control compounds Gatifloxacin (MIC = 0.5 µg/mL) and fluconazole (MIC = 1 µg/mL).

CONCLUSION

The findings suggest that the synthesized rhodanine compounds have good ALK5 inhibitory activity and can be used for further research and development as potential antifungal drugs.

Oxidative stress in oocyte aging and female reproduction

In a healthy body, reactive oxygen species (ROS) and antioxidants remain balanced. When the balance is broken toward an overabundance of ROS, oxidative stress appears and may lead to oocyte aging. Oocyte aging is mainly reflected as the gradual decrease of oocyte quantity and quality. Here, we aim to review the relationship between oxidative stress and oocyte aging. First, we introduced that the defective mitochondria, the age-related ovarian aging, the repeated ovulation, and the high-oxygen environment were the ovarian sources of ROS in vivo and in vitro. And we also introduced other sources of ROS accumulation in ovaries, such as overweight and unhealthy lifestyles. Then, we figured that oxidative stress may act as the "initiator" for oocyte aging and reproductive pathology, which specifically causes follicular abnormally atresia, abnormal meiosis, lower fertilization rate, delayed embryonic development, and reproductive disease, including polycystic ovary syndrome and ovary endometriosis cyst. Finally, we discussed current strategies for delaying oocyte aging. We introduced three autophagy antioxidant pathways like Beclin-VPS34-Atg14, adenosine 5'-monophosphate (AMP)-activated protein kinase/mammalian target of rapamycin (AMPK/mTOR), and p62-Keap1-Nrf2. And we also describe the different antioxidants used to combat oocyte aging. In addition, the hypoxic (5% O₂ ) culture environment for oocytes avoiding oxidative stress in vitro. So, this review not only contribute to our general understanding of oxidative stress and oocyte aging but also lay the foundations for the therapies to treat premature ovarian failure and oocyte aging in women.

Podophyllotoxin Exposure Affects Organelle Distribution and Functions in Mouse Oocyte Meiosis

Podophyllotoxin (POD) is one of the most characterized lignans that is commonly found in podophyllum, and its preparations and derivatives are widely used in clinical treatment due to strong antitumor and antivirus activities. POD has been reported for its neurotoxicity, liver toxicity, and potential reproductive toxicity. In the present study, we investigated the effects of POD on the organelles of mouse oocytes during meiosis. Our results showed that exposure to POD significantly reduced the developmental competence of mouse oocytes. Further analysis revealed that the endoplasmic reticulum (ER) failed to accumulate to the spindle periphery, suggesting that POD exposure might affect protein synthesis during oocyte meiotic maturation. Similarly, abnormal Golgi apparatus distribution was found after POD exposure, which could be confirmed by the aberrant localization of Rab11a-related vesicles, indicating that POD induced vesicle-based protein transport disorder. We also found the aberrant accumulation of lysosomes in the cytoplasm of POD-exposed oocytes, which implied that POD might lead to aberrant protein degradation. Moreover, the perinuclear distribution of mitochondria was also significantly disturbed, indicating the mitochondrial dysfunction after POD exposure. In all, our study illustrated that exposure to POD might disrupt protein synthesis, transport, degradation, and ATP production by its effects on the distribution and functions of organelles during mouse oocyte meiotic maturation.

CD44 enhances adriamycin resistance in chronic myelogenous leukaemia cells K562

INTRODUCTION

To investigate CD44 effects on the adriamycin-resistant in chronic myelogenous leukaemia cells K562, we explored the role of CD44 in the K562 cells migration and apoptosis.

METHODS

GeneChip^® screening is used for elucidating various chemoresistance-related gene expression in the adriamycin-resistant leukaemia cells K562/ADR. We constructed K562/CD44 cells by transfection of an EGFP-SV40-CD44 plasmid, and adriamycin-resistant ability was confirmed by detecting migration and apoptosis-related proteins and mRNA expression using Western blotting and Real-time PCR respectively.

RESULTS

K562/CD44 cells were generated by the transfection of an EGFP-SV40-CD44 plasmid with high CD44 expression. mRNA expression levels of CD44 and P-glycoprotein (P-gp), along with the proliferation rate, were increased, while the apoptosis rate of K562/CD44 cells was decreased. Migration-associated proteins such as MMP-2 and MMP-9 were upregulated, whereas apoptosis-related protein Bax was downregulated and Bcl-2 protein was not significantly altered in the K562/CD44 cells.

CONCLUSIONS

CD44 might be involved in adriamycin resistance via regulation of P-gp, MMP-2, MMP-9, and Bcl-2/Bax.

Induction of Oxidative Stress and Mitochondrial Dysfunction by Juglone Affects the Development of Bovine Oocytes

Juglone, a major naphthalenedione component of walnut trees, has long been used in traditional medicine as an antimicrobial and antitumor agent. Nonetheless, its impact on oocyte and preimplantation embryo development has not been entirely clarified. Using the bovine model, we sought to elucidate the impact of juglone treatment during the in vitro maturation (IVM) of oocytes on their maturation and development of embryos. Results showed a severe reduction in oocyte nuclear maturation and cumulus expansion and a significant increase in mitochondrial dysfunction and reactive oxygen species (ROS) levels in cumulus-oocyte complexes (COCs) treated with juglone (12.5, 25.0, and 50.0 µM). In addition, RT-qPCR showed downregulation of the expansion-related (HAS2, TNFAIP6, PTX3, and PTGS2) and mitochondrial (ATPase6 and ATP5F1E) genes in juglone-treated COCs. Moreover, the development rates of day 4 total cleavage and 8-16 cell stage embryos, as well as day 8 blastocysts, were significantly reduced following exposure to juglone. Using immunofluorescence, the apoptotic marker caspase-9 was overexpressed in oocytes exposed to juglone (25.0 µM) compared to the untreated control. In conclusion, our study reports that exposing bovine oocytes to 12.5-50.0 µM of juglone can reduce their development through the direct induction of ROS accumulation, apoptosis, and mitochondrial dysfunction.

Podophyllotoxin Exposure Causes Spindle Defects and DNA Damage-Induced Apoptosis in Mouse Fertilized Oocytes and Early Embryos

Podophyllotoxin (PPT) is a kind of lignans extracted from the roots and stems of the genus Podophyllum from the tiller family, and it has been widely used in the treatment of condyloma acuminatum, multiple superficial epithelioma in the clinics. However, PPT has been reported to be toxic and can cause liver defects and other organ poisoning. In addition, emerging evidences also indicate that PPT has reproductive toxicity and causes female reproduction disorders. In this study, we used fertilized oocytes and tried to explore the effects of PPT on the early embryonic development with the mouse model. The results showed that exposure to PPT had negative effects on the cleavage of zygotes. Further analysis indicated that PPT could disrupt the organization of spindle and chromosome arrangement at the metaphase of first cleavage. We also found that PPT exposure to the zygotes induced excessive reactive oxygen species (ROS), suggesting the occurrence of oxidative stress. Moreover, in the PPT-exposed embryos, there was positive γH2A.X and Annexin-V signals, indicating that PPT induced embryonic DNA damage and early apoptosis. In conclusion, our results suggested that PPT could affect spindle formation and chromosome alignment during the first cleavage of mouse embryos, and its exposure induced DNA damage-mediated oxidative stress which eventually led to embryonic apoptosis, indicating the toxic effects of PPT on the early embryo development.

Fluoride impairs ovary development by affecting oogenesis and inducing oxidative stress and apoptosis in female zebrafish (Danio rerio)

Previous studies have shown that waterborne fluoride exposure has adverse effects on the reproductive system of zebrafish. However, the underlying toxic mechanisms were still not clear. In the present study, female zebrafish were exposed to different concentrations of 0.787 (Control), 18.599, 36.832 mg/L of fluoride for 30 d and 60 d, and the effects of different doses of fluoride on ovary development, reproductive hormones, oogenesis, ROS content, antioxidant levels, and the expression of apoptosis-related genes and proteins in the ovaries of female zebrafish were analyzed. The results showed that ovarian weight and GSI were significantly decreased, FSH, LH and VTG levels were significantly reduced, the transcriptional profiles of oogenesis-related genes (tgfβ1, bmp15, gdf9, mprα, mprβ, ptg2β) were remarkably altered, ROS levels was notably increased, the SOD, CAT, GPx activities and GSH content as well as their mRNA expressions were significantly decreased, MDA content was remarkably increased, the expressions of apoptosis-related genes and proteins (caspase3, caspase8, caspase9, Fas-L, Cytochrome C, Bax and Bcl-2) were significantly changed, the ratio of Bax/Bcl-2 protein levels were notably increased. Taken together, this study demonstrated that fluoride exposure significantly affected ovarian development, decreased the reproductive hormones, affected oogenesis, induced oxidative stress, caused apoptosis through both extrinsic and intrinsic pathways in ovary of zebrafish. Indicating that oogenesis, oxidative stress, and apoptosis were responsible for the impairment of ovarian development.

Nicotinamide Supplementation during the In Vitro Maturation of Oocytes Improves the Developmental Competence of Preimplantation Embryos: Potential Link to SIRT1/AKT Signaling

Nicotinamide (NAM), the amide form of vitamin B3, plays pivotal roles in regulating various cellular processes including energy production and maintenance of genomic stability. The current study aimed at deciphering the effect of NAM, when administered during in vitro maturation (IVM), on the developmental competence of bovine preimplantation embryos. Our results showed that low NAM concentrations reduced the oxidative stress and improved mitochondrial profile, total cleavage and 8–16 cell stage embryo development whereas the opposite profile was observed upon exposure to high NAM concentrations (10 mM onward). Remarkably, the hatching rates of day-7 and day-8 blastocysts were significantly improved under 0.1 mM NAM treatment. Using RT-qPCR and immunofluorescence, the autophagy-related (Beclin-1 (BECN1), LC3B, and ATG5) and the apoptotic (Caspases; CASP3 and 9) markers were upregulated in oocytes exposed to high NAM concentration (40 mM), whereas only CASP3 was affected, downregulated, following 0.1 mM treatment. Additionally, the number of cells per blastocyst and the levels of SIRT1, PI3K, AKT, and mTOR were higher, while the inner cell mass-specific transcription factors GATA6, SOX2, and OCT4 were more abundant, in day-8 embryos of NAM-treated group. Taken together, to our knowledge, this is the first study reporting that administration of low NAM concentrations during IVM can ameliorate the developmental competence of embryos through the potential regulation of oxidative stress, apoptosis, and SIRT1/AKT signaling.