The Antioxidant Role of Selenium via GPx1 and GPx4 in LPS-Induced Oxidative Stress in Bovine Endometrial Cells

Bioactive Compounds Protect Mammalian Reproductive Cells from Xenobiotics and Heat Stress-Induced Oxidative Distress via Nrf2 Signaling Activation: A Narrative Review

Oxidative stress occurs when there is an imbalance between the production of reactive oxygen species (ROS) and the body's antioxidant defenses. It poses a significant threat to the physiological function of reproductive cells. Factors such as xenobiotics and heat can worsen this stress, leading to cellular damage and apoptosis, ultimately decreasing reproductive efficiency. The nuclear factor erythroid 2-related factor 2 (Nrf2) signaling pathway plays a crucial role in defending against oxidative stress and protecting reproductive cells via enhancing antioxidant responses. Dysregulation of Nrf2 signaling has been associated with infertility and suboptimal reproductive performance in mammals. Recent advancements in therapeutic interventions have underscored the critical role of Nrf2 in mitigating oxidative damage and restoring the functional integrity of reproductive cells. In this narrative review, we delineate the harmful effects of heat and xenobiotic-induced oxidative stress on reproductive cells and explain how Nrf2 signaling provides protection against these challenges. Recent studies have shown that activating the Nrf2 signaling pathway using various bioactive compounds can ameliorate heat stress and xenobiotic-induced oxidative distress and apoptosis in mammalian reproductive cells. By comprehensively analyzing the existing literature, we propose Nrf2 as a key therapeutic target for mitigating oxidative damage and apoptosis in reproductive cells caused by exposure to xenobiotic exposure and heat stress. Additionally, based on the synthesis of these findings, we discuss the potential of therapies focused on the Nrf2 signaling pathway to improve mammalian reproductive efficiency.

Minerals and the Menstrual Cycle: Impacts on Ovulation and Endometrial Health

The role of minerals in female fertility, particularly in relation to the menstrual cycle, presents a complex area of study that underscores the interplay between nutrition and reproductive health. This narrative review aims to elucidate the impacts of minerals on key aspects of the reproductive system: hormonal regulation, ovarian function and ovulation, endometrial health, and oxidative stress. Despite the attention given to specific micronutrients in relation to reproductive disorders, there is a noticeable absence of a comprehensive review focusing on the impact of minerals throughout the menstrual cycle on female fertility. This narrative review aims to address this gap by examining the influence of minerals on reproductive health. Each mineral's contribution is explored in detail to provide a clearer picture of its importance in supporting female fertility. This comprehensive analysis not only enhances our knowledge of reproductive health but also offers clinicians valuable insights into potential therapeutic strategies and the recommended intake of minerals to promote female reproductive well-being, considering the menstrual cycle. This review stands as the first to offer such a detailed examination of minerals in the context of the menstrual cycle, aiming to elevate the understanding of their critical role in female fertility and reproductive health.

The effect of selenium on the proliferation of bovine endometrial epithelial cells in a lipopolysaccharide-induced damage model

BACKGROUND

Endometritis is a common bovine postpartum disease. Rapid endometrial repair is beneficial for forming natural defense barriers and lets cows enter the next breeding cycle as soon as possible. Selenium (Se) is an essential trace element closely related to growth and development in animals. This study aims to observe the effect of Se on the proliferation of bovine endometrial epithelial cells (BEECs) induced by lipopolysaccharide (LPS) and to elucidate the possible underlying mechanism.

RESULTS

In this study, we developed a BEECs damage model using LPS. Flow cytometry, cell scratch test and EdU proliferation assay were used to evaluate the cell cycle, migration and proliferation. The mRNA transcriptions of growth factors were detected by quantitative reverse transcription-polymerase chain reaction. The activation of the phosphatidylinositol 3-kinase (PI3K)/protein kinase B (AKT) and Wnt/β-catenin pathways were detected by Western blotting and immunofluorescence. The results showed that the cell viability and BCL-2/BAX protein ratio were significantly decreased, and the cell apoptosis rate was significantly increased in the LPS group. Compared with the LPS group, Se promoted cell cycle progression, increased cell migration and proliferation, and significantly increased the gene expressions of TGFB1, TGFB3 and VEGFA. Se decreased the BCL-2/BAX protein ratio, promoted β-catenin translocation from the cytoplasm to the nucleus and activated the Wnt/β-catenin and PI3K/AKT signaling pathways inhibited by LPS.

CONCLUSIONS

In conclusion, Se can attenuate LPS-induced damage to BEECs and promote cell proliferation and migration in vitro by enhancing growth factors gene expression and activating the PI3K/AKT and Wnt/β-catenin signaling pathways.

SeMet alleviates LPS-induced eggshell gland necroptosis mediated inflammation by regulating the Keap1/Nrf2/HO-1 pathway

Exposure to lipopolysaccharide (LPS) can lead to inflammation in a variety of tissues and organs. Selenium (Se) plays a crucial role in mitigating inflammatory damage. Compared with inorganic selenium, organic selenium, such as selenomethionine (SeMet), has the advantages of a higher absorption rate and lower toxicity in animals. This study examined the protective effects of SeMet on eggshell gland tissue damage caused by LPS. Hy-Line Brown laying hens were chosen as the experimental animals and were randomly assigned to four groups: control group (C), lipopolysaccharide group (LPS), SeMet group (Se), and SeMet + lipopolysaccharide group (Se + LPS). H&E staining and transmission electron microscope were performed to observe the pathological changes of eggshell glands, oxidative stress related indicators were measured using relevant kits, qRT‒PCR and western blotting were used to evaluate the mRNA and protein levels of the Nrf2 pathway, necroptosis, and inflammation related indicators. The results showed that LPS treatment increased the content of malondialdehyde (MDA), decreased the activities of superoxide dismutase (SOD), catalase (CAT), and glutathione peroxidase (GPX), and decreased the content of glutathione (GSH). LPS increased the levels of Keap1, RIPK1, RIPK3, MLKL, TNF-α, COX-2, and NF-κB, while decreasing the levels of HO-1, NQO1, Nrf2, and Caspase-8. However, SeMet treatment effectively reversed the changes of the above indicators, indicating that SeMet alleviates eggshell gland cell necroptosis-mediated inflammation induced by LPS via regulating the Keap1/Nrf2/HO-1 pathway. This study elucidated the mechanism by which SeMet alleviates LPS-induced eggshell gland tissue damage in Hy-Line Brown laying hens and provided a new direction for expanding the application of SeMet in the feeding and production of laying hens.

Transcription Factor Nrf2 Modulates Lipopolysaccharide-Induced Injury in Bovine Endometrial Epithelial Cells

Endometritis in high-yield dairy cows adversely affects lactation length, milk quality, and the economics of dairy products. Endoplasmic reticulum stress (ERS) in bovine endometrial epithelial cells (BEECs) occurs as a consequence of diverse post-natal stressors, and plays a key role in a variety of inflammatory diseases. Nuclear-factor-erythroid-2-related factor 2 (Nrf2) is an important protective regulatory factor in numerous inflammatory responses. However, the mechanism by which Nrf2 modulates inflammation by participating in ERS remains unclear. The objective of the present study was to explore the role of Nrf2 in lipopolysaccharide (LPS)-induced injury to BEECs and to decipher the underlying molecular mechanisms of this injury. The expression of Nrf2- and ERS-related genes increased significantly in bovine uteri with endometritis. Isolated BEECs were treated with LPS to stimulate the inflammatory response. The expression of Nrf2 was significantly higher in cells exposed to LPS, which also induced ERS in BEECs. Activation of Nrf2 led to enhanced expression of the genes for the inflammation markers TNF-α, p65, IL-6, and IL-8 in BEECs. Moreover, stimulation of Nrf2 was accompanied by activation of ERS. In contrast, Nrf2 knockdown reduced the expression of TNF-α, p65, IL-6, and IL-8. Additionally, Nrf2 knockdown decreased expression of ERS-related genes for the GRP78, PERK, eIF2α, ATF4, and CHOP proteins. Collectively, our findings demonstrate that Nrf2 and ERS are activated during inflammation in BEECs. Furthermore, Nrf2 promotes the inflammatory response by activating the PERK pathway in ERS and inducing apoptosis in BEECs.

Methionine alleviates heat stress-induced ferroptosis in bovine mammary epithelial cells through the Nrf2 pathway

Heat stress (HS) triggers mammary gland degradation, accompanied by apoptosis and autophagy in bovine mammary epithelial cells, negatively affecting milk performance and mammary gland health. Ferroptosis is iron-mediated regulated cell death caused by over production of lipid peroxides, however, the relationship between ferroptosis and HS in bovine mammary epithelial cells has not been clarified. Methionine (Met) plays a notable role in alleviating HS affecting the mammary glands in dairy cows, but the underlying mechanisms require further exploration. Therefore, we evaluated the regulatory effect and mechanism of Met in alleviating HS-induced ferroptosis by using bovine mammary epithelial cell line (MAC-T) as an in vitro model. The results showed that Met improved cell vitality, restored mitochondrial function; reduced the content of various reactive oxygen species (ROS), especially hydrogen peroxide (H₂O₂) and superoxide anion (O_2·-); had positive effects on antioxidant enzyme activity, namely glutathione peroxidase (GSH-Px) and superoxide dismutase (SOD). More importantly, Met reduced labile iron protein (LIP) levels; increased iron storage and simultaneously decreased the levels of lipid reactive oxygen species (lipid ROS) and malondialdehyde (MDA), which all caused by HS in MAC-T. Mechanistically, Met increased the protein expression levels of glutathione peroxidase 4 (GPX4), solute carrier family 7, member 11 (SLC7A11) and ferritin heavy chain 1 (FTH1) by activating nuclear factor E2-related factor 2 (Nrf2) expression. Additionally, the protection effect of Met was cut off in MAC-T cells after interference with Nrf2, manifesting in decresing the protein expression levels of GPX4, SLC7A11 and FTH1,and increasing the levels of LIP and lipid ROS. Our findings indicate that Met eases HS-induced ferroptosis in MAC-T through the Nrf2 pathway, revealing that Met produces a marked effect on easing HS-induced bovine mammary gland injury in dairy cows.

Serum Essential Trace Element Status in Women and the Risk of Endometrial Diseases: a Case-Control Study : Serum Essential Trace Element Status in Women and the Risk of Endometrial Diseases: a Case-Control Study

Endometrial diseases, including uterine fibroids, polyps, intrauterine adhesion, endometritis, etc., are the major causes of infertility among women. However, the association between essential trace element status in women and the risk of endometrial disease is limited and unclear. This study aimed to investigate this association using a case-control study design; a total of 302 women patients with endometrial diseases and 302 healthy women were included. Compared to women in the control group, serum selenium (Se) (p = 0.024) and zinc (Zn) (p = 0.017) levels were significantly lower, while copper (Cu) (p = 0.004) and molybdenum (Mo) (p = 0.005) levels were significantly higher among women with endometrial diseases. In addition, compared to women in the first quartile of the copper/zinc (Cu/Zn) ratio value group, the adjusted ORs (95% CIs) of endometrial diseases were 1.50 (1.05, 2.14), 1.68 (1.18, 2.39), and 1.47 (1.02, 2.10), respectively, in the second, third, and fourth quartile of the Cu/Zn ratio value group (p trend = 0.047). In addition, the results from restricted cubic splines showed that the dose-response relationships of serum levels of these essential elements with the risk of endometrial diseases were nonlinear for Se, Cu, and Zn and relatively linear for Mo and Cu/Zn ratio. The present study showed serum levels of Zn and Se among women with endometrial diseases were significantly lower compared to that among healthy women, while serum levels of Cu and Mo were significantly higher, in addition, the serum Cu/Zn ratio value was also significantly and positively associated with the risk of endometrial diseases.

Effects of dietary pretreated Chinese herbal medicine supplementation on production performance, egg quality, uterine histopathological changes, and antioxidant capacity in late-phase laying hens

Aims: The study aimed to evaluate the effects of pretreated Chinese herbal medicine (PCHM) on egg quality, production performance, histopathological changes in the uterus, antiox idant capacity, and antioxidant gene expression in late-phase layers. Methods: Jinghong No.1 layers (n = 360, 68 weeks old) were assigned randomly to one of f our dietary interventions. Each treatment was replicated six times. Repeat 15 chickens per g roup. All birds were fed a diet composed of a corn-soybean meal-based diet supplemented with 0, 0.2, 0.4, or 0.8% PCHM for 6 weeks. Results: Dietary PCHM supplementation had no significant effects on laying rate, feed con sumption, yolk color, and shape index. With increasing PCHM level the Haugh unit linearly increased (P < 0.05). Supplementation of 0.8% PCHM increased egg weight, compared with the control (P < 0.05). PCHM can effectively alleviated the pathological changes caused by aging in the uterus including hemorrhage, and many inflammatory cell infiltrations. Supplementation of 0.4% PCHM increased glutathione peroxidase (GSHPx) in liver, magnum, and plasm considerably, compared with the control (P < 0.05). Supplementation of PCHM decr ease in the liver, magnum, and uterus on malondialdehyde (MDA) content, compared with the control (P < 0.05). Compared with the control group, mRNA expressions of glutathione peroxidase 1 (GPX1), peroxidase 4 (GPX4), catalase (CAT), and nuclear factor E2-related factor 2 (Nrf2) in the magnum, liver, and uterus were dramatically rose in the 0.4% PCHM supplementation group (P < 0.05). In summary, dietary supplementation after PCHM increased egg weight and quality in late-phase laying hens. Conclusion: Dietary PCHM increased the antioxidative capacity of late-phase laying hens, which could be associated with increased mRNA expression of antioxidant enzymes and Nrf2. These findings provide potential for using PCHM to increase the production performance in late-phase laying hens.

Selenomethionine Alleviates DON-Induced Oxidative Stress via Modulating Keap1/Nrf2 Signaling in the Small Intestinal Epithelium

The small intestinal epithelium is regulated in response to various beneficial or harmful environmental information. Deoxynivalenol (DON), a mycotoxin widely distributed in cereal-based feeds, induces oxidative stress damage in the intestine due to the mitochondrial stress. As a functional nutrient, selenomethionine (Se-Met) is involved in synthesizing several antioxidant enzymes, yet whether it can replenish the intestinal epithelium upon DON exposure remains unknown. Therefore, the in vivo model C57BL/6 mice and the in vitro model MODE-K cells were treated with l-Se-Met and DON alone or in combination to confirm the status of intestinal stem cell (ISC)-driven epithelial regeneration. The results showed that 0.1 mg/kg body weight (BW) Se-Met reinstated the growth performance and integrity of jejunal structure and barrier function in DON-challenged mice. Moreover, Lgr5⁺ ISCs and PCNA⁺ mitotic cells in crypts were prominently increased by Se-Met in the presence of DON, concomitant with a significant increase in absorptive cells, goblet cells, and Paneth cells. Simultaneously, crypt-derived jejunal organoids from the Se-Met + DON group exhibited more significant growth advantages ex vivo. Furthermore, Se-Met-stimulated Keap1/Nrf2-dependent antioxidant system (T-AOC and GSH-Px) to inhibit the accumulation of ROS and MDA in the jejunum and serum. Moreover, Se-Met failed to rescue the DON-triggered impairment of cell antioxidant function after Nrf2 perturbation using its specific inhibitor ML385 in MODE-K cells. In conclusion, Se-Met protects ISC-driven intestinal epithelial integrity against DON-induced oxidative stress damage by modulating Keap1/Nrf2 signaling.

Selenium supplementation and pregnancy outcomes

In vertebrates and invertebrates, selenium (Se) is an essential micronutrient, and Se deficiency or excess is associated with gonadal insufficiency and gamete dysfunction in both males and females, leading to implantation failure, altered embryonic development and, ultimately, infertility. During pregnancy, Se excess or deficiency is associated with miscarriage, pre-eclampsia (hypertension of pregnancy), gestational diabetes, fetal growth restriction and preterm birth. None of this is surprising, as Se is present in high concentrations in the ovary and testes, and work in animal models has shown that addition of Se to culture media improves embryo development and survival in vitro in association with reduced reactive oxygen species and less DNA damage. Selenium also affects uterine function and conceptus growth and gene expression, again in association with its antioxidant properties. Similarly, Se improves testicular function including sperm count, morphology and motility, and fertility. In animal models, supplementation of Se in the maternal diet during early pregnancy improves fetal substrate supply and alters fetal somatic and organ growth. Supplementation of Se throughout pregnancy in cows and sheep that are receiving an inadequate or excess dietary intake affected maternal whole-body and organ growth and vascular development, and also affected expression of angiogenic factors in maternal and fetal organs. Supplemental Se throughout pregnancy also affected placental growth, which may partly explain its effects on fetal growth and development, and also affected mammary gland development, colostrum yield and composition as well as postnatal development of the offspring. In conclusion, Se supplementation in nutritionally compromised pregnancies can potentially improve fertility and pregnancy outcomes, and thereby improve postnatal growth and development. Future research efforts should examine in more detail and more species the potential benefits of Se supplementation to reproductive processes in mammals.

Serum Selenium, Vitamin A, and Vitamin E Levels of Healthy Individuals in High- and Low-Risk Areas of Esophageal Cancer

Background: Esophageal cancer is one of the main causes of cancer mortality in the world. Golestan province, in the northern part of Iran, has the highest esophageal cancer rate in the world. The north and south districts of Golestan province can be classified as low and high-risk areas for esophageal cancer. One of the potential risk factors for esophageal cancer in this population is a nutrient-deficient diet. Dietary antioxidant compounds such as selenium, vitamin E, vitamin A, and β-carotene are reactive oxygen species (ROC) scavengers that play a key role in cellular responses to oxidative stress and preventing DNA damage. This study aims to compare the serum levels of selenium, vitamin E, and vitamin A in healthy individuals in high and low-risk areas of esophageal cancer. Methods: This study is a population of 242 healthy individuals. Serum selenium levels were assessed by atomic absorption spectroscopy. Vitamin E and A were assessed by reversed-phase high-performance liquid chromatography. Results: Vitamin E levels of healthy individuals in high-risk areas were significantly lower than in low-risk areas, while there was no significant difference between the selenium and vitamin A levels of healthy individuals in high-risk areas and low-risk areas. Also, there was no significant difference between selenium, vitamin E, and vitamin A levels in urban and rural areas and men and women in Golestan province. Conclusion: High levels of selenium with lower levels of vitamin E, along with other risk factors, may be associated with esophageal squamous cell carcinoma in high-risk areas of Golestan province.

microRNA-196b alleviates lipopolysaccharide-induced inflammatory injury by targeting NRAS

Bovine endometritis is a serious hazard to husbandry, so it is necessary to know the mechanism of endometritis. In past research, we found microRNAs (miRNAs) might be regulators in inflammation, including miR-196b, but the mechanism of miR-196b in bovine endometritis was unknown. Therefore, we tended to find out what role miR-196b would play in bovine endometritis. As a result, we found miR-196b up-regulated in the endometritis tissue and the high concentration lipopolysaccharide (LPS)-stimulated bovine endometrial epithelial (BEND) cell line, but down-regulated in the low concentration. And, over-expression of miR-196b inhibited the expressions of some inflammatory factors, such as tumor necrosis factor-alpha (TNF-α), interleukin-1β (IL-1β), interleukin-6 (IL-6), and neuroblastoma RAS (NRAS)/nuclear factor (NF)-κB pathway proteins. Furthermore, the dual-luciferase reporter assay and NRAS knockdown confirmed that miR-196b inhibited activation of the downstream pathway by directly targeting NRAS. In conclusion, we provide evidence that miR-196b alleviates LPS-induced inflammatory injury by targeting NRAS.

Immune infiltration and a ferroptosis-associated gene signature for predicting the prognosis of patients with endometrial cancer

Ferroptosis, a form of programmed cell death induced by excess iron-dependent lipid peroxidation product accumulation, plays a critical role in cancer. However, there are few reports about ferroptosis in endometrial cancer (EC). This article explores the relationship between ferroptosis-related gene (FRG) expression and prognosis in EC patients. One hundred thirty-five FRGs were obtained by mining the literature, retrieving GeneCards and analyzing 552 malignant uterine corpus endometrial carcinoma (UCEC) samples, which were randomly assigned to training and testing groups (1:1 ratio), and 23 normal samples from The Cancer Genome Atlas (TCGA). We established a signature using eight screened FRGs (MDM2, GPX4, PRKAA2, PRNP, SLC11A2, ATP5MC3, PHKG2 and ACO1) related to overall survival using LASSO regression analysis. The samples were divided into low- and high-risk subgroups according to the median risk score. Kaplan-Meier survival curves showed that the low-risk group had better OS. ROC curves showed that this signature performed well in predicting OS (1-, 2-, 3-, and 5-year AUCs of 0.676, 0.775, 0.797, and 0.826, respectively). We systematically analyzed the immune infiltrating profile in UCEC samples from TCGA. Overall, our study identified a novel prognostic signature of 8 FRGs that can potentially predict the prognosis of EC.