Redox events in interleukin-1 signaling

MicroRNAs and their Modulatory Effect on the Hallmarks of Osteosarcopenia

PURPOSE OF THE REVIEW

Osteosarcopenia is a geriatric syndrome associated with disability and mortality. This review summarizes the key microRNAs that regulate the hallmarks of sarcopenia and osteoporosis. Our objective was to identify components similarly regulated in the pathology and have therapeutic potential by influencing crucial cellular processes in both bone and skeletal muscle.

RECENT FINDINGS

The simultaneous decline in bone and muscle in osteosarcopenia involves a complex crosstalk between these tissues. Recent studies have uncovered several key mechanisms underlying this condition, including the disruption of cellular signaling pathways that regulate bone remodeling and muscle function and regeneration. Accordingly, emerging evidence reveals that dysregulation of microRNAs plays a significant role in the development of each of these hallmarks of osteosarcopenia. Although the recent recognition of osteosarcopenia as a single diagnosis of bone and muscle deterioration has provided new insights into the mechanisms of these underlying age-related diseases, several knowledge gaps have emerged, and a deeper understanding of the role of common microRNAs is still required. In this study, we summarize current evidence on the roles of microRNAs in the pathogenesis of osteosarcopenia and identify potential microRNA targets for treating this condition. Among these, microRNAs-29b and -128 are upregulated in the disease and exert adverse effects by inhibiting IGF-1 and SIRT1, making them potential targets for developing inhibitors of their activity. MicroRNA-21 is closely associated with the occurrence of muscle and bone loss. Conversely, microRNA-199b is downregulated in the disease, and its reduced activity may be related to increased myostatin and GSK3β activity, presenting it as a target for developing analogues that restore its function. Finally, microRNA-672 stands out for its ability to protect skeletal muscle and bone when expressed in the disease, highlighting its potential as a possible therapy for osteosarcopenia.

Selenium supplementation effect on glycemic control: A GRADE-assessed systematic review and dose-response meta-analysis of randomized controlled trials

Results from different studies on the effects of selenium supplementation on glycemic control are still debated. To fill this knowledge gap, we investigated the overall effects of selenium supplementation on some glycemic parameters such as fasting blood sugar (FBS), hemoglobinA1c (HbA1c), fasting insulin, quantitative insulin sensitivity check index (QUICKI), and homeostatic model assessment of insulin resistance (HOMA-IR). A comprehensive literature search was conducted from inception to April 2023 on Scopus, Web of Science, PubMed, Google Scholar, and Cochrane databases. All randomized controlled trials (RCTs) which reported an effect of selenium supplementation on glycemic parameters were included. A random-effects model was used to estimate the weighted mean difference (WMD) and 95% CI for each outcome. Between-studies heterogeneity was assessed by the I2 and Cochran's Q test. 20 trials were included in the meta-analysis. Pooled analysis showed that selenium intake significantly reduced fasting insulin (WMD: -3.02 µIu/mL, 95% CI; -5.13, -0.90, P = 0.005) and increased QUICKI levels (WMD: 0.01, 95% CI: 0.01, 0.02, P = 0.005). However, selenium supplementation did not change FBS (WMD: -1.32 mg/dL, 95% CI; -4.02, 1.37, P = 0.332), HbA1c (WMD = 0.05%, 95% CI: -0.19, 0.28, p = 0.701), and HOMA-IR (WMD: -0.82, 95% CI; -2.14, 0.50, P = 0.223). Moreover, we found that there is a non-linear association between selenium supplementation dosage and FBS (P-nonlinearity = 0.008). In conclusion, our study findings indicate some benefits of selenium on fasting insulin, and QUICKI compared with placebo, but elicits no effect on HbA1c, HOMA-IR, and FBS. Further well-designed RCTs with larger samples are necessary to ascertain the effects of selenium supplementation on glycemic control.

Fat and Protein Combat Triggers Immunological Weapons of Innate and Adaptive Immune Systems to Launch Neuroinflammation in Parkinson's Disease

Parkinson's disease (PD) is the second-most common neurodegenerative disease in the world, affecting up to 10 million people. This disease mainly happens due to the loss of dopaminergic neurons accountable for memory and motor function. Partial glucocerebrosidase enzyme deficiency and the resultant excess accumulation of glycosphingolipids and alpha-synuclein (α-syn) aggregation have been linked to predominant risk factors that lead to neurodegeneration and memory and motor defects in PD, with known and unknown causes. An increasing body of evidence uncovers the role of several other lipids and their association with α-syn aggregation, which activates the innate and adaptive immune system and sparks brain inflammation in PD. Here, we review the emerging role of a number of lipids, i.e., triglyceride (TG), diglycerides (DG), glycerophosphoethanolamines (GPE), polyunsaturated fatty acids (PUFA), sphingolipids, gangliosides, glycerophospholipids (GPL), and cholesterols, and their connection with α-syn aggregation as well as the induction of innate and adaptive immune reactions that trigger neuroinflammation in PD.

Out of Control: The Role of the Ubiquitin Proteasome System in Skeletal Muscle during Inflammation

The majority of critically ill intensive care unit (ICU) patients with severe sepsis develop ICU-acquired weakness (ICUAW) characterized by loss of muscle mass, reduction in myofiber size and decreased muscle strength leading to persisting physical impairment. This phenotype results from a dysregulated protein homeostasis with increased protein degradation and decreased protein synthesis, eventually causing a decrease in muscle structural proteins. The ubiquitin proteasome system (UPS) is the predominant protein-degrading system in muscle that is activated during diverse muscle atrophy conditions, e.g., inflammation. The specificity of UPS-mediated protein degradation is assured by E3 ubiquitin ligases, such as atrogin-1 and MuRF1, which target structural and contractile proteins, proteins involved in energy metabolism and transcription factors for UPS-dependent degradation. Although the regulation of activity and function of E3 ubiquitin ligases in inflammation-induced muscle atrophy is well perceived, the contribution of the proteasome to muscle atrophy during inflammation is still elusive. During inflammation, a shift from standard- to immunoproteasome was described; however, to which extent this contributes to muscle wasting and whether this changes targeting of specific muscular proteins is not well described. This review summarizes the function of the main proinflammatory cytokines and acute phase response proteins and their signaling pathways in inflammation-induced muscle atrophy with a focus on UPS-mediated protein degradation in muscle during sepsis. The regulation and target-specificity of the main E3 ubiquitin ligases in muscle atrophy and their mode of action on myofibrillar proteins will be reported. The function of the standard- and immunoproteasome in inflammation-induced muscle atrophy will be described and the effects of proteasome-inhibitors as treatment strategies will be discussed.

The effects of dietary selenium supplementation on inflammatory markers among patients with metabolic diseases: a systematic review and meta-analysis of randomized controlled trials

Purpose

Selenium (Se) is a trace element having significant effects on human metabolism. Recent studies suggest that Se supplementation have a pivotal effect on the inflammatory markers. Therefore, the aim of this study was to assess the effect of Se supplementation on plasma inflammatory markers including C-reactive protein (CRP) and high-sensitivity C-reactive protein (hs-CRP) and nitric oxide (NO) as a stress oxidative index, among patients with metabolic diseases.

Methods

To assess the effects of Se on the inflammatory markers, following the PRISMA-P guidelines, we systematically searched ISI/WOS, PubMed/MEDLINE, and Scopus for studies that assessed the effect of Se supplementation on the inflammatory markers. Data extraction was performed by two independent investigators. Using the random effects or fixed-effects model depending on the results of heterogeneity tests was used to estimate the pooled standardized mean difference (SMD). Heterogeneity between studies was assessed using Cochran's Q test and I² index.

Results

The initial search revealed 3,320 papers. After screening process and considering inclusion criteria, 7 publications were eligible for inclusion in the meta-analysis. The meta-analysis results showed that Se supplementation did not significantly affect CRP and hs-CRP concentrations (mean difference (MD) = -0.15; 95% CI: -0.55- 0.23; P = 0.43). Subgroup analysis of CRP type showed that Se supplementation significantly decreased hs-CRP level (pooled SMD = -0.44; 95% CI: -0.67-0.21). Moreover, no significant change was observed in NO level by continuing to take Se supplementation, (pooled SMD: 0.003, 95%CI: -0.26, 0.26).

Conclusions

This study revealed that Se supplementation would have desirable effects on cardio-metabolic indicators through affecting the levels of inflammatory markers. Given the importance of concerns, more attention should be given to more prospective studies with longer follow-up.

Role of Macrophages in Cytotoxicity, Reactive Oxygen Species Production and DNA Damage in 1,2-Dichloropropane-Exposed Human Cholangiocytes In Vitro

1,2-Dichloropropane (1,2-DCP), a synthetic chlorinated organic compound, was extensively used in the past in offset color proof-printing. In 2014, the International Agency for Research on Cancer (IARC) reclassified 1,2-DCP from its initial Group 3 to Group 1. Prior to the reclassification, cholangiocarcinoma was diagnosed in a group of workers exposed to 1,2 -DCP in an offset color proof-printing company in Japan. In comparison with other forms of cholangiocarcinoma, 1,2-DCP-induced cholangiocarcinoma was of early onset and accompanied by extensive pre-cancerous lesions in large bile ducts. However, the mechanism of 1,2-DCP-induced cholangiocarcinoma is poorly understood. Inflammatory cell proliferation was observed in various sites of the bile duct in the noncancerous hepatic tissues of the 1,2-DCP-induced cholangiocarcinoma. The aim of this study was to enhance our understanding of the mechanism of 1,2-DCP-related cholangiocarcinogenesis. We applied an in vitro system to investigate the effects of 1,2-DCP, using MMNK-1 cholangiocytes cultured alone or with THP-1 macrophages. The cultured cells were exposed to 1,2-DCP at 0, 0.1, 0.2, 0.4, and 0.8 mM for 24 h, and then assessed for cell proliferation, cell cytotoxicity, DNA damage, and ROS production. Exposure to 1,2-DCP increased proliferation of MMNK-1 cholangiocytes cultured alone, but not those cultured with macrophages. 1,2-DCP also increased LDH cytotoxicity, DNA damage, and ROS production in MMNK-1 cholangiocytes co-cultured with macrophages but not those cultured alone. 1,2-DCP increased TNFα and IL-1β protein expression in macrophages. The results highlight the role of macrophages in enhancing the effects of 1,2-DCP on cytotoxicity, ROS production, and DNA damage in cholangiocytes.

Nephropathogenic Infectious Bronchitis Virus Infection Altered the Metabolome Profile and Immune Function of the Bursa of Fabricius in Chicken

Infectious bronchitis is a highly contagious, acute viral respiratory disease of chickens, regardless of the strain, and its infection may lead to considerable economic losses to the poultry industry. New nephropathogenic infectious bronchitis virus (NIBV) strains have increasingly emerged in recent years; hence, evaluating their infection-influenced immune function changes and the alteration of metabolite profiling is important. Initially, chickens were randomly distributed into two groups: the control group (Con) and the disease group (Dis). Here, the partial cytokines were examined, and the metabolome alterations of the bursa of Fabricius (BF) in NIBV infections in chickens were profiled by gas chromatography time-of-flight/mass spectrometry (GC-TOF/MS). The results revealed that the NIBV infection promotes the mRNA expression of inflammatory cytokines. Metabolic profile analysis indicated that clustering differed between the two groups and there were 75 significantly different metabolites detected between the two groups, suggesting that the host metabolism was significantly changed by NIBV infection. Notably, the following 12 metabolites were identified as the potential biomarkers: 3-phenyllactic acid, 2-deoxytetronic acid, aminomalonic acid, malonamide 5, uric acid, arachidonic acid, 2-methylglutaric acid, linoleic acid, ethanolamine, stearic acid, N-alpha-acetyl-l-ornithine, and O-acetylserine. Furthermore, the results of the correlation analysis showed that a strong correlation existed between metabolic biomarkers and inflammatory cytokines. Our results describe an immune and metabolic profile for the BF of chickens when infected with NIBV and provide new biomarkers of NIBV infection as potential targets and indicators of indicating therapeutic efficacy.

Interleukin-1β in hypothalamic paraventricular nucleus mediates excitatory renal reflex

Chemical stimulation of kidney causes sympathetic activation and pressor responses in rats. The excitatory renal reflex (ERR) is mediated by angiotensin type 1 receptor (AT₁R) and superoxide anions in hypothalamic paraventricular nucleus (PVN). The aim of this study is to determine whether interleukin-1β (IL-1β) in the PVN mediates the ERR, and whether the IL-1β production in the PVN is dependent on the AT₁R-superoxide anion signaling. Experiments were performed in adult rats under anesthesia. The ERR was induced by renal infusion of capsaicin, and evaluated by the responses of the contralateral renal sympathetic nerve activity (RSNA) and mean arterial pressure (MAP). Inhibition of IL-1β production with MCC950 in the PVN dose-dependently inhibited the capsaicin-induced ERR and sympathetic activation. The PVN microinjection of IL-1 receptor antagonist IL-1Ra or specific IL-1β antibody abolished the capsaicin-induced ERR, while IL-1β enhanced the ERR. Renal infusion of capsaicin promoted p65-NFκB phosphorylation and IL-1β production in the PVN, which were prevented by PVN microinjection of NADPH oxidase inhibitor apocynin or the superoxide anion scavenger tempol. The PVN microinjection of NFκB inhibitor BMS-345541 abolished the capsaicin induced-ERR and IL-1β production, but not the NADPH oxidase activation and superoxide anion production. Furthermore, capsaicin-induced p65-NFκB phosphorylation and IL-1β production in the PVN were prevented by AT₁R antagonist losartan, or angiotensin converting enzyme inhibitor captopril. These results indicate that capsaicin-induced ERR and sympathetic activation are mediated by IL-1β in the PVN. The IL-1β production in the PVN is dependent on the AT₁R-mediated superoxide anion generation and NFκB activation.

Effect of mobile phone radiation on oxidative stress, inflammatory response, and contextual fear memory in Wistar rat

In the present lifestyle, we are continuously exposed to radiofrequency electromagnetic field (RF-EMF) radiation generated mainly by mobile phones (MP). Among other organs, our brain and hippocampus in specific, is the region where effect of any environmental perturbation is most pronounced. So, this study was aimed to examine changes in major parameters (oxidative stress, level of pro-inflammatory cytokines (PICs), hypothalamic-pituitary-adrenal (HPA) axis hormones, and contextual fear conditioning) which are linked to hippocampus directly or indirectly, upon exposure to mobile phone radiofrequency electromagnetic field (MP-RF-EMF) radiation. Exposure was performed on young adult male Wistar rats for 16 weeks continuously (2 h/day) with MP-RF-EMF radiation having frequency, power density, and specific absorption rate (SAR) of 1966.1 MHz, 4.0 mW/cm², and 0.36 W/kg, respectively. Another set of animals kept in similar conditions without any radiation exposure serves as control. Towards the end of exposure period, animals were tested for fear memory and then euthanized to measure hippocampal oxidative stress, level of circulatory PICs, and stress hormones. We observed significant increase in hippocampal oxidative stress (p < 0.05) and elevated level of circulatory PICs viz. IL-1beta (p < 0.01), IL-6 (p < 0.05), and TNF-alpha (p < 0.001) in experimental animals upon exposure to MP-RF-EMF radiation. Adrenal gland weight (p < 0.001) and level of stress hormones viz. adrenocorticotropic hormone (ACTH) (p < 0.01) and corticosterone (CORT) (p < 0.05) were also found to increase significantly in MP-RF-EMF radiation-exposed animals as compared with control. However, alteration in contextual fear memory was not significant enough. In conclusion, current study shows that chronic exposure to MP-RF-EMF radiation emitted from mobile phones may induce oxidative stress, inflammatory response, and HPA axis deregulation. However, changes in hippocampal functionality depend on the complex interplay of several opposing factors that got affected upon MP-RF-EMF exposure.

Evaluation of Glutathione Bioactivity on Toxoplasma Gondii in BALB/c Mice Post Impact of Selenium and Calcium Supplementation

BACKGROUND

Studies have shown that selenium is an essential component of glutathione as an important antioxidant to reduce oxidative stress and inhibit intracellular parasites' growth. In contrast, calcium in the cytosol of such parasites plays a key role in the entry of the parasite into the host cell and its primary motility.

AIMS AND OBJECTIVES

The present study was designed to evaluate and compare glutathione peroxidase bioactivity effects post administration of selenium and calcium in BALB/c mice infected by Toxoplasma gondii.

METHODS

Sixty BALB/c mice susceptible to T. gondii were randomly divided into twelve groups of case and control groups. There were six control groups including two positive controls infected only with the parasites either 10⁴ or 5×10⁴, non-infected and untreated groups. Treated controls received only calcium, selenium, or both respectively. Case groups were infected with 10⁴ or 5×10⁴ parasites. While each set of three case groups separately received minerals alone or together. Mice were orally fed with 200 μg selenium, 50 μg calcium or their combination for 7 days. Mice were infected by parasite's tachyzoites. Sera of mice were kept and the peritoneal macrophages were isolated for counting tachyzoites during infection.

RESULTS

The results showed that selenium unlike calcium was significantly effective in reducing Toxoplasma tachyzoites compared to control groups. Moreover, glutathione peroxidase [GPX] activity was elevated in mice treated with selenium and vice versa decreased in mice treated with calcium.

CONCLUSION

Administration of selenium unlike calcium reduced Toxoplasma tachyzoites proliferation by elevating bioactivity of selenium-dependent detoxification enzyme, GPX.

The Effects of Selenium Supplementation on Clinical Symptoms and Gene Expression Related to Inflammation and Vascular Endothelial Growth Factor in Infertile Women Candidate for In Vitro Fertilization

This study was performed to determine the effects of selenium supplementation on clinical symptoms and gene expression related to inflammatory markers in infertile women with polycystic ovary syndrome (PCOS) who were candidate for in vitro fertilization (IVF). Thirty-six women candidate for IVF were recruited in this randomized double-blinded, placebo-controlled trial. They (n = 18/group) were randomly assigned into intervention groups to take either 200 μg/day of selenium or placebo for 8 weeks. RT-PCR findings indicated that selenium supplementation downregulated gene expression of interleukin-1 (IL-1) (P < 0.004) and tumor necrosis factor alpha (TNF-α) (P = 0.02) in lymphocytes of patients with PCOS compared with the placebo. In addition, selenium supplementation upregulated gene expression of vascular endothelial growth factor (VEGF) (P = 0.001) in lymphocytes of patients with PCOS compared with the placebo. Selenium supplementation had no significant effect on clinical symptoms and gene expression of IL-8 (P = 0.10) and transforming growth factor beta (TGF-β) (P = 0.63). Overall, our findings documented that selenium supplementation for 8 weeks to infertile women candidate for IVF improved IL-1, TNF-α, and VEGF gene expression, though selenium had no effect on clinical symptoms and, IL-8 and TGF-β gene expression. Clinical trial registration number: http://www.irct.ir: IRCT20170513033941N23.

Selenium Deficiency Affects Immune Function by Influencing Selenoprotein and Cytokine Expression in Chicken Spleen

Se is an important bioelement essential for a healthy immune system. Dietary Se influences both innate and adaptive immune responses. However, the effects of Se deficiency in chicken spleen are still unknown; thus, we designed an experiment to study the role of Se in chicken spleen. A total of 180 one-day-old sea blue white laying hens were randomly allocated into two groups (a control group and a Se-deficient group). The control group was fed a diet supplemented with sodium selenite with a final Se content of 0.15 mg/kg, and the Se-deficient group was fed a Se-deficient diet with a Se content of 0.033 mg/kg. Twenty selenoproteins and ten cytokines were investigated in detail. The expression levels of selenoproteins in spleen were determined via real-time qPCR at 15, 35, and 55 days, and cytokine levels were determined using ELISA at 15, 35, and 55 days. Protein-protein interaction predictions and principal component analysis were performed. We found that the selenoprotein mRNA levels were significantly lower (P < 0.05) in the Se-deficient group compared with the control group. The expression levels of IL-2, IL-1β, IL-6, IFN-α, and IL-17 were significantly lower (P < 0.05), and the levels of IL-8, IL-10, IFN-γ, IFN-β, and TNF-α were significantly higher (P < 0.05) in the Se-deficient group. These selenoproteins were positively correlated with component 1 and component 2 of the PCA, but the relationship between cytokines and principal components in spleens was very complex. The investigation showed that Se deficiency caused a reduction in selenoprotein gene expression and further affected certain cytokines levels. Our results provide some compensatory data about selenoproteins and cytokines in spleens of Se-deficient chickens and provide clues for further research on the relationship between selenoproteins and cytokines.

Apigenin Suppresses the IL-1β-Induced Expression of the Urokinase-Type Plasminogen Activator Receptor by Inhibiting MAPK-Mediated AP-1 and NF-κB Signaling in Human Bladder Cancer T24 Cells

The urokinase-type plasminogen activator receptor (uPAR), a glycoprotein localized on the cell surface with a glycosylphosphatidylinositol anchor, plays a crucial role in cell invasion, and the metastasis of several cancers, including bladder cancer, and its expression are significantly negatively correlated with patient survival rates. Apigenin, a naturally produced phytochemical compound found in fruits, vegetables, and plant leaves, has been shown to mediate a variety of cancer-metastasis-related molecules in various cancers. The effect of apigenin on uPAR expression is still unknown. In this study, we examined the effects of apigenin on IL-1β-induced uPAR expression and investigated its potential mechanisms. We discovered in this study that IL-1β could remarkably induce uPAR expression in bladder cancer T24 cells and that apigenin-inhibited IL-1β could induce uPAR expression concentration-dependently. Interestingly, NF-κB and AP-1 transcription factors were critically required for IL-1β-induced high uPAR expression. Apigenin suppressed the transcriptional activity of both AP-1 and NF-κB by inhibiting ERK1/2 and JNK signaling pathways. These results suggest that apigenin can exert anti-invasion effects by inhibiting uPAR expression via mediating (ERK1/2, JNK)/AP-1 and (ERK1/2, JNK)/NF-κB signaling pathways in human T24 cells. Our present study generated novel and valuable biological insight into anti-invasion through treatment with a small native compound.

Selenium supplementation lowers insulin resistance and markers of cardio-metabolic risk in patients with congestive heart failure: a randomised, double-blind, placebo-controlled trial

This study was carried out to evaluate the effects of Se supplementation on metabolic profiles in patients with congestive heart failure (CHF). This randomised double-blind, placebo-controlled trial was performed among fifty-three subjects with CHF, aged 45–85 years old. Subjects were randomly allocated into two groups to take either 200 µg/d of Se as Se yeast (n 26) or placebo (n 27) for 12 weeks. Metabolic profiles were assessed at baseline and at the end of trial. Compared with the placebo, Se supplementation led to significant reductions in serum insulin (−18·41 (sd 27·53) v. +13·73 (sd 23·63) pmol/l, P<0·001), homoeostatic model of assessment for insulin resistance (−1·01 (sd 1·61) v. +0·55 (sd 1·20), P<0·001) and a significant increase in quantitative insulin sensitivity check index (QUICKI) (+0·007 (sd 0·03) v. −0·01 (sd 0·01), P=0·007). In addition, Se supplementation significantly decreased LDL-cholesterol (−0·23 (sd 0·29) v. −0·04 (sd 0·28) mmol/l, P=0·03) and total-:HDL-cholesterol ratio (−0·47 (sd 0·31) v. −0·06 (sd 0·42), P<0·001), and significantly increased HDL-cholesterol levels (+0·18 (sd 0·19) v. +0·02 (sd 0·13) mmol/l, P=0·001) compared with the placebo. In addition, taking Se supplements was associated with a significant reduction in high-sensitivity C-reactive protein (hs-CRP) (−1880·8 (sd 3437·5) v. +415·3 (sd 2116·5) ng/ml, P=0·01), and a significant elevation in plasma total antioxidant capacity (TAC) (+30·9 (sd 118·0) v. −187·9 (sd 412·7) mmol/l, P=0·004) and total glutathione levels (+33·7 (sd 130·4) v. −39·2 (sd 132·8) µmol/l, P=0·003) compared with the placebo. When we applied Bonferroni correction for multiple outcome testing, QUICKI (P=0·11), LDL-cholesterol (P=0·51), hs-CRP (P=0·17), TAC (P=0·06) and GSH (P=0·05) became non-significant, and other metabolic profiles did not alter. Overall, our study supported that Se supplementation for 12 weeks to patients with CHF had beneficial effects on insulin metabolism and few markers of cardio-metabolic risk.

Establishment of an in vivo simulating co-culture assay platform for genotoxicity of multi-walled carbon nanotubes

Engineered nanomaterials (ENM) are now used in a wide variety of fields, and, thus, their safety should urgently be assessed and secured. It has been suggested that inflammatory responses via the phagocytosis of ENM by macrophages is a key mechanism for their genotoxicity. The present study was conducted to establish a mechanism‐based assay to evaluate the genotoxicity of ENM under conditions simulating an in vivo situation, featuring a co‐culture system of murine lung resident cells (GDL1) and immune cells (RAW264.7). GDL1 were cultured with or without RAW264.7, exposed to a multi‐walled carbon nanotube (MWCNT), and then analyzed for mutagenicity and underlying mechanisms. Mutation frequencies induced in GDL1 by the MWCNT were significantly greater with the co‐existence of RAW264.7 than in its absence. Mutation spectra observed in GDL1 co‐cultured with RAW264.7 were different from those seen in GDL1 cultured alone, but similar to those observed in the lungs of mice exposed to the MWCNT in vivo. Inflammatory cytokines, such as IL‐1β and TNF‐α, were produced from RAW264.7 cells treated with the MWCNT. The generation of reactive oxygen species and the formation of 8‐oxodeoxyguanosine in GDL1 exposed to the MWCNT were greater in the co‐culture conditions than in the single culture conditions. Based on these findings, it is indicated that inflammatory responses are involved in the genotoxicity of MWCNT, and that the presently established, novel in vitro assay featuring a co‐culture system of tissue resident cells with immune cells is suitable to evaluate the genotoxicity of ENM.

Role of glutathione metabolism in host defense against Borrelia burgdorferi infection

Pathogen-induced changes in host cell metabolism are known to be important for the immune response. In this study, we investigated how infection with the Lyme disease-causing bacterium Borrelia burgdorferi (Bb) affects host metabolic pathways and how these metabolic pathways may impact host defense. First, metabolome analysis was performed on human primary monocytes from healthy volunteers, stimulated for 24 h with Bb at low multiplicity of infection (MOI). Pathway analysis indicated that glutathione (GSH) metabolism was the pathway most significantly affected by Bb Specifically, intracellular levels of GSH increased on average 10-fold in response to Bb exposure. Furthermore, these changes were found to be specific, as they were not seen during stimulation with other pathogens. Next, metabolome analysis was performed on serum samples from patients with early-onset Lyme disease in comparison with patients with other infections. Supporting the in vitro analysis, we identified a cluster of GSH-related metabolites, the γ-glutamyl amino acids, specifically altered in patients with Lyme disease, and not in other infections. Lastly, we performed in vitro experiments to validate the role for GSH metabolism in host response against Bb. We found that the GSH pathway is essential for Bb-induced cytokine production and identified glutathionylation as a potential mediating mechanism. Taken together, these data indicate a central role for the GSH pathway in the host response to Bb GSH metabolism and glutathionylation may therefore be important factors in the pathogenesis of Lyme disease and potentially other inflammatory diseases as well.

Antioxidant functionalized polymer capsules to prevent oxidative stress

Polymeric capsules exhibit significant potential for therapeutic applications as microreactors, where the bio-chemical reactions of interest are efficiently performed in a spatial and time defined manner due to the encapsulation of an active biomolecule (e.g., enzyme) and control over the transfer of reagents and products through the capsular membrane. In this work, catalase loaded polymer capsules functionalized with an external layer of tannic acid (TA) are fabricated via a layer-by-layer approach using calcium carbonate as a sacrificial template. The capsules functionalised with TA exhibit a higher scavenging capacity for hydrogen peroxide and hydroxyl radicals, suggesting that the external layer of TA shows intrinsic antioxidant properties, and represents a valid strategy to increase the overall antioxidant potential of the developed capsules. Additionally, the hydrogen peroxide scavenging capacity of the capsules is enhanced in the presence of the encapsulated catalase. The capsules prevent oxidative stress in an in vitro inflammation model of degenerative disc disease. Moreover, the expression of matrix metalloproteinase-3 (MMP-3), and disintegrin and metalloproteinase with thrombospondin motif-5 (ADAMTS-5), which represents the major proteolytic enzymes in intervertebral disc, are attenuated in the presence of the polymer capsules. This platform technology exhibits potential to reduce oxidative stress, a key modulator in the pathology of a broad range of inflammatory diseases.

STATEMENT OF SIGNIFICANCE

Oxidative stress damages important cell structures leading to cellular apoptosis and senescence, for numerous disease pathologies including cancer, neurodegeneration or osteoarthritis. Thus, the development of biomaterials-based systems to control oxidative stress has gained an increasing interest. Herein, polymer capsules loaded with catalase and functionalized with an external layer of tannic acid are fabricated, which can efficiently scavenge important reactive oxygen species (i.e., hydroxyl radicals and hydrogen peroxide) and modulate extracellular matrix activity in an in vitro inflammation model of nucleus pulposus. The present work represents accordingly, an important advance in the development and application of polymer capsules with antioxidant properties for the treatment of oxidative stress, which is applicable for multiple inflammatory disease targets.

Effect of Boron on Thymic Cytokine Expression, Hormone Secretion, Antioxidant Functions, Cell Proliferation, and Apoptosis Potential via the Extracellular Signal-Regulated Kinases 1 and 2 Signaling Pathway

Boron is an essential trace element in animals. Appropriate boron supplementation can promote thymus development; however, a high dose of boron can lead to adverse effects and cause toxicity. The influencing mechanism of boron on the animal body remains unclear. In this study, we examined the effect of boron on cytokine expression, thymosin and thymopoietin secretion, antioxidant function, cell proliferation and apoptosis, and extracellular signal-regulated kinases 1 and 2 (ERK1/2) pathway in the thymus of rats. We found that supplementation with 10 and 20 mg/L boron to the drinking water significantly elevated levels of interleukin 2 (IL-2), interferon γ (IFN-γ), interleukin 4 (IL-4), and thymosin α1 in the thymus of rats (p < 0.05), increased the number of positive proliferating cell nuclear antigen (PCNA⁺) cells and concentrations of glutathione peroxidase (GSH-Px) and phosphorylated extracellular signal-regulated kinase (p-ERK) (p < 0.05), and promoted mRNA expression of PCNA and ERK1/2 in thymocytes (p < 0.05). However, the number of caspase-3⁺ cells and the expression level of caspase-3 mRNA were reduced (p < 0.05). Supplementation with 40, 80, and 160 mg/L boron had no apparent effect on many of the above indicators. In contrast, supplementation with 480 and 640 mg/L boron had the opposite effect on the above indicators in rats and elevated levels of pro-inflammatory cytokines, such as interleukin 6 (IL-6), interleukin 1β (IL-1β), and tumor necrosis factor α (TNF-α) (p < 0.05). Our study showed that supplementation of various doses of boron to the drinking water had a U-shaped dose-effect relationship with thymic cytokine expression, hormone secretion, antioxidant function, cell proliferation, and apoptosis. Specifically, supplementation with 10 and 20 mg/L boron promoted thymocyte proliferation and enhanced thymic functions. However, supplementation with 480 and 640 mg/L boron inhibited thymic functions and increased the number of apoptotic thymocytes, suggesting that the effects of boron on thymic functions may be caused via the ERK1/2 signaling pathway.

Typhonium giganteum Lectin Exerts A Pro-Inflammatory Effect on RAW 264.7 via ROS and The NF-κB Signaling Pathway

Typhonii rhizoma, a widely used herb in traditional Chinese medicine, has acute irritating toxicity related to Typhonium giganteum lectin (TGL). TGL exhibits acute inflammatory effects, but the underlying molecular mechanisms are largely unknown. This paper is designed to assess the pro-inflammatory response of TGL on RAW 264.7 cells. RAW 264.7 treated with 6.25, 12.5, 25, and 50 µg/mL TGL showed elevated levels of inflammatory factors (TNF-α, IL-1β) and of p-IκB and p-p65, all dose-dependent, indicating that TGL had a substantial inflammatory effect and mobilized the nuclear factor-κB (NF-κB) pathway. All four TGL treatments also induced the up-regulation of reactive oxygen species (ROS) and cytosolic free Ca²⁺ and down-regulation of mitochondrial membrane potential (MMP). The production of cytokines and p-IκB, p-p65 were reduced by N-acetylcysteine (NAC), an ROS scavenger, which somewhat abrogated ROS production. The results showed the TGL-activated inflammatory signaling pathway NF-κB to be associated with the overproduction of ROS. Moreover, 50 μg/mL treatment with TGL led to cell apoptosis after 1 h and increased necrosis over time. These results provided potential molecular mechanisms for the observed inflammatory response to TGL including up-regulation of ROS and cytosolic free Ca²⁺, down-regulation of MMP, the mobilization of the NF-κB pathway, and the subsequent overproduction of pro-inflammatory factors resulting in apoptosis. Long-term stimulation with TGL resulted in strong toxic effects related to inflammation that induced necrosis in macrophages.

Clinical and Metabolic Response to Selenium Supplementation in Pregnant Women at Risk for Intrauterine Growth Restriction: Randomized, Double-Blind, Placebo-Controlled Trial

Data on the effects of selenium supplementation on clinical signs and metabolic profiles in women at risk for intrauterine growth restriction (IUGR) are scarce. This study was designed to assess the effects of selenium supplementation on clinical signs and metabolic status in pregnant women at risk for IUGR. This randomized double-blind placebo-controlled clinical trial was performed among 60 women at risk for IUGR according to abnormal uterine artery Doppler waveform. Participants were randomly assigned to intake either 100 μg selenium supplements as tablet (n = 30) or placebo (n = 30) for 10 weeks between 17 and 27 weeks of gestation. After 10 weeks of selenium administration, a higher percentage of women in the selenium group had pulsatility index (PI) of <1.45) (P = 0.002) than of those in the placebo group. In addition, changes in plasma levels of total antioxidant capacity (TAC) (P < 0.001), glutathione (GSH) (P = 0.008), and high-sensitivity C-reactive protein (hs-CRP) (P = 0.004) in the selenium group were significant compared with the placebo group. Additionally, selenium supplementation significantly decreased serum insulin (P = 0.02), homeostasis model of assessment-estimated insulin resistance (HOMA-IR) (P = 0.02), and homeostatic model assessment for B-cell function (HOMA-B) (P = 0.02) and significantly increased quantitative insulin sensitivity check index (QUICKI) (P = 0.04) and HDL-C levels (P = 0.02) compared with the placebo. We did not find any significant effect of selenium administration on malondialdehyde (MDA), nitric oxide (NO), fasting plasma glucose (FPG), and other lipid profiles. Overall, selenium supplementation in pregnant women at risk for IUGR resulted in improved PI, TAC, GSH, hs-CRP, and markers of insulin metabolism and HDL-C levels, but it did not affect MDA, NO, FPG, and other lipid profiles.Clinical trial registration number http://www.irct.ir : IRCT201601045623N64.

CGRP attenuates hyperoxia-induced oxidative stress-related injury to alveolar epithelial type II cells via the activation of the Sonic hedgehog pathway

The aim of this study was to examine the effect of calcitonin gene-related peptide (CGRP) on primary alveolar epithelial type II (AECII) cells and expression of Sonic hedgehog (SHH) signaling pathway components following exposure to hyperoxia. The AECII cells were isolated and purified from premature rats and exposed to air (21% oxygen), air + CGRP, hyperoxia (95% oxygen) or hyperoxia + CGRP. The production of intracellular reactive oxygen species (ROS) was determined using the 2',7'-dichlorofluorescin diacetate molecular probe. The levels of malondialdehyde (MDA) and superoxide dismutase (SOD) in the culture supernatant were detected by spectrophotometry. The apoptosis of AECII cells was assayed by flow cytometry, and the mRNA and protein expression levels of Shh and Ptc1 in the AECII cells were detected by reverse transcription-quantitative polymerase chain reaction (RT-qPCR), western blot analysis and immunofluorescence, respectively. The cellular pathological changes partly improved and apoptosis was markedly decreased upon treatment with CGRP under hyperoxic conditions. The levels of ROS in the hyperoxia + CGRP group were significantly lower than thoe in the hyperoxia group. In addition, the hyperoxia-induced increase in MDA levels and the decrease in SOD activity in the culture supernatant of the AECII cells were attenuated by CGRP. Compared with the cells exposed to air, hyperoxia markedly inhibited the mRNA and protein expression levels of Shh and Ptc1 in the AECII cells; however, this inhibition was partly attenuated by treatment with CGRP. On the whole, our data suggest that CGRP can partly protect AECII cells from hyperoxia-induced injury, and the upregulation of CGRP may be a potential therapeutic approach with which to combat hyperoxia-induced lung injury, which may be associated with the activation of the SHH signaling pathway.

Effect of physicochemical character differences on the genotoxic potency of kaolin

BACKGROUND

Kaolin is white clay mineral with the chemical composition Al2Si2O5(OH)4, and many varieties of kaolins having different crystal structures are utilized in industrial, cosmetic and medical fields. To evaluate the effect of physicochemical character differences on the genotoxicity of kaolin, two types of kaolin, kaolin-S with smooth, sphere-shaped crystals, and kaolin-P with clusters of thin pseudohexagonal plates, were used in the study.

RESULTS

ICR mice were intratracheally instilled with the kaolins (0.05 and 0.2 mg/mouse), and comet assay was performed on their lungs. Both kaolins showed DNA damage in the lungs of the mice, however the DNA damaging potency was much higher with kaolin-P than that with kaolin-S. In order to clarify the mechanisms for the different genotoxic potency, we examined the incorporation rate and ROS generation of these two types of kaolin in alveolar epithelial A549 and macrophage-like RAW264 cells, using flow cytometric (FCM) analysis. Kaolin-P showed a higher incorporation rate into the mammalian cells and ROS generation than that of kaolin-S. Especially, RAW264 cells aggressively incorporated kaolins, and generated ROS, whereas almost no ROS generation was observed in A549 cells. In addition, inflammatory cytokines were quantified, using the ELISA method, to understand further genotoxic potency differences of kaolins. Concentrations of interleukin-1β (IL-1β) and tumor necrosis factor-α (TNF-α) in the media were increased by exposure to both kaolins, but in the case of kaolin-P, these inflammatory cytokines were significantly elevated. Based on these findings, differences of genotoxic potency may contribute to incorporation rates into immune cells. Furthermore, it is likely that immune cells and epithelial cells might closely interact with each other for the appearance of genotoxocity in vivo. In order to clarify the interaction between epithelial and immune cells, A549 and RAW264 were co-cultured and RAW264 cells only were exposed to kaolins, then subsequently A549 was applied to FCM analysis and comet assay. DNA damage observed in the A549 cells markedly increased in the presence of kaolin-exposed RAW264 cells compared to the single culture.

CONCLUSION

From these observations, it is suggested that mechanisms of kaolin genotoxicity against epithelial cells are through the activation of macrophage cells. Therefore, it is thought that interactions between epithelial and immune cells would be very important for evaluation of the genotoxicity of fine particulate matter. We also showed here that co-culture models of epithelial and immune cells could be used as suitable models for evaluation of lung genotoxicity of fine particulate matter, including nanomaterials, as in vivo mimicking systems.

High dietary selenium intake is associated with less insulin resistance in the Newfoundland population

As an essential nutrient, Selenium (Se) is involved in many metabolic activities including mimicking insulin function. Data on Se in various biological samples and insulin resistance are contradictory, moreover there is no large study available regarding the relationship of dietary Se intake with insulin resistance in the general population. To investigate the association between dietary Se intake and variation of insulin resistance in a large population based study, a total of 2420 subjects without diabetes from the CODING (Complex Diseases in the Newfoundland Population: Environment and Genetics) study were assessed. Dietary Se intake was evaluated from the Willett Food Frequency questionnaire. Fasting blood samples were used for the measurement of glucose and insulin. Insulin resistance was determined with the homeostasis model assessment (HOMA-IR). Body composition was measured using dual energy X-ray absorptiometry. Analysis of covariance showed that high HOMA-IR groups in both males and females had the lowest dietary Se intake (μg/kg/day) (p < 0.01), being 18% and 11% lower than low HOMA-IR groups respectively. Insulin resistance decreased with the increase of dietary Se intake in females but not in males after controlling for age, total calorie intake, physical activity level, serum calcium, serum magnesium, and body fat percentage (p < 0.01). Partial correlation analysis showed that dietary Se intake was negatively correlated with HOMA-IR after adjusting for the Se confounding factors in subjects whose dietary Se intake was below 1.6 μg/kg/day (r = -0.121 for males and -0.153 for females, p < 0.05). However, the negative correlation was no longer significant when dietary Se intake was above 1.6 μg/kg/day. Our findings suggest that higher dietary Se intake is beneficially correlated with lower insulin resistance when total dietary Se intake was below 1.6 μg/kg/day. Above this cutoff, this beneficial effect disappears.

Calcitonin gene-related peptide protects type II alveolar epithelial cells from hyperoxia-induced DNA damage and cell death

Hyperoxia therapy for acute lung injury (ALI) may unexpectedly lead to reactive oxygen species (ROS) production and cause additional ALI. Calcitonin gene-related peptide (CGRP) is a 37 amino acid neuropeptide that regulates inflammasome activation. However, the role of CGRP in DNA damage during hyperoxia is unclear. Therefore, the aim of the present study was to investigate the effects of CGRP on DNA damage and the cell death of alveolar epithelial type II cells (AEC II) exposed to 60% oxygen. AEC II were isolated from 19–20 gestational day fetal rat lungs and were exposed to air or to 60% oxygen during treatment with CGRP or the specific CGRP receptor antagonist CGRP_8–37. The cells were evaluated using immunofluorescence to examine surfactant protein-C and ROS levels were measured by probing with 2′,7′-dichlorofluorescin diacetate. The apoptosis rate and cell cycle of AEC II were analyzed by flow cytometry, and apoptosis was determined by western blotting analysis of activated caspase 3. The DNA damage was confirmed with immunofluorescence of H2AX via high-content analysis. The ROS levels, apoptotic cell number and the expression of γH2AX were markedly increased in the hyperoxia group compared with those in the air group. Concordantly, ROS levels, apoptotic cell number and the expression of γH2AX were significantly lower with a significant arrest of S and G2/M phases in the CGRP/O₂ group than in the hyperoxia or CGRP_8–37/O₂ groups. CGRP was concluded to protect lung epithelium cells against hyperoxic insult, and upregulation of CGRP may be a possible novel therapeutic target to treat hyperoxic lung injury.

Deletion of Nlrp3 protects from inflammation-induced skeletal muscle atrophy

Background

Critically ill patients develop atrophic muscle failure, which increases morbidity and mortality. Interleukin-1β (IL-1β) is activated early in sepsis. Whether IL-1β acts directly on muscle cells and whether its inhibition prevents atrophy is unknown. We aimed to investigate if IL-1β activation via the Nlrp3 inflammasome is involved in inflammation-induced atrophy.

Methods

We performed an experimental study and prospective animal trial. The effect of IL-1β on differentiated C2C12 muscle cells was investigated by analyzing gene-and-protein expression, and atrophy response. Polymicrobial sepsis was induced by cecum ligation and puncture surgery in Nlrp3 knockout and wild type mice. Skeletal muscle morphology, gene and protein expression, and atrophy markers were used to analyze the atrophy response. Immunostaining and reporter-gene assays showed that IL-1β signaling is contained and active in myocytes.

Results

Immunostaining and reporter gene assays showed that IL-1β signaling is contained and active in myocytes. IL-1β increased Il6 and atrogene gene expression resulting in myocyte atrophy. Nlrp3 knockout mice showed reduced IL-1β serum levels in sepsis. As determined by muscle morphology, organ weights, gene expression, and protein content, muscle atrophy was attenuated in septic Nlrp3 knockout mice, compared to septic wild-type mice 96 h after surgery.

Conclusions

IL-1β directly acts on myocytes to cause atrophy in sepsis. Inhibition of IL-1β activation by targeting Nlrp3 could be useful to prevent inflammation-induced muscle failure in critically ill patients.

Electronic supplementary material

The online version of this article (doi:10.1186/s40635-016-0115-0) contains supplementary material, which is available to authorized users.

Apoptosis signaling pathways in osteoarthritis and possible protective role of melatonin

Osteoarthritis (OA) is a degenerative joint disease characterized by progressive erosion of articular cartilage. As chondrocytes are the only cell type forming the articular cartilage, their gradual loss is the main cause of OA. There is a substantial body of published research that suggests reactive oxygen species (ROS) are major causative factors for chondrocyte damage and OA development. Oxidative stress elicited by ROS is capable of oxidizing and subsequently disrupting cartilage homeostasis, promoting catabolism via induction of cell death and damaging numerous components of the joint. IL-1β and TNF-α are crucial inflammatory factors that play pivotal roles in the pathogenesis of OA. In this process, the mitochondria are the major source of ROS production in cells, suggesting a role of mitochondrial dysfunction in this type of arthritis. This may also be promoted by inflammatory cytokines such as IL-1β and TNF-α which contribute to chondrocyte death. In patients with OA, the expression of endoplasmic reticulum (ER) stress-associated molecules is positively correlated with cartilage degeneration. Melatonin and its metabolites are broad-spectrum antioxidants and free radical scavengers which regulate a variety of molecular pathways such as inflammation, proliferation, apoptosis, and metastasis in different pathophysiological situations. Herein, we review the effects of melatonin on OA, focusing on its ability to regulate apoptotic processes and ER and mitochondrial activity. We also evaluate likely protective effects of melatonin on OA pathogenesis.

Reactive Oxygen Species: Physiological and Physiopathological Effects on Synaptic Plasticity

In the mammalian central nervous system, reactive oxygen species (ROS) generation is counterbalanced by antioxidant defenses. When large amounts of ROS accumulate, antioxidant mechanisms become overwhelmed and oxidative cellular stress may occur. Therefore, ROS are typically characterized as toxic molecules, oxidizing membrane lipids, changing the conformation of proteins, damaging nucleic acids, and causing deficits in synaptic plasticity. High ROS concentrations are associated with a decline in cognitive functions, as observed in some neurodegenerative disorders and age-dependent decay of neuroplasticity. Nevertheless, controlled ROS production provides the optimal redox state for the activation of transductional pathways involved in synaptic changes. Since ROS may regulate neuronal activity and elicit negative effects at the same time, the distinction between beneficial and deleterious consequences is unclear. In this regard, this review assesses current research and describes the main sources of ROS in neurons, specifying their involvement in synaptic plasticity and distinguishing between physiological and pathological processes implicated.

Effect of Selenium Supplementation on Glycemic Control and Lipid Profiles in Patients with Diabetic Nephropathy

To our knowledge, data on the effects of selenium supplementation on glycemic control and lipid concentrations in patients with diabetic nephropathy (DN) are scarce. The current study was done to determine the effects of selenium supplementation on glycemic control and lipid concentrations in patients with DN. This was a randomized double-blind placebo-controlled clinical trial in which 60 patients with DN were randomly allocated into two groups to receive either 200 μg of selenium supplements (n = 30) or placebo (n = 30) daily for 12 weeks. Blood sampling was performed for the quantification of glycemic indicators and lipid profiles at the onset of the study and after 12 weeks of intervention. Selenium supplementation for 12 weeks resulted in a significant decrease in serum insulin levels (P = 0.01), homeostasis model of assessment-estimated insulin resistance (HOMA-IR) (P = 0.02), homeostasis model of assessment-estimated B cell function (HOMA-B) (P = 0.009) and a significant rise in plasma glutathione peroxidase (GPx) (P = 0.001) compared with the placebo. Taking selenium supplements had no significant effects on fasting plasma glucose (FPG), quantitative insulin sensitivity check index (QUICKI) and lipid profiles compared with the placebo. Overall, our study demonstrated that selenium supplementation for 12 weeks among patients with DN had beneficial effects on plasma GPx, serum insulin levels, HOMA-IR, and HOMA-B, while it did not affect FPG, QUICKI, and lipid profiles.

Effect of pecan phenolics on the release of nitric oxide from murine RAW 264.7 macrophage cells

Inflammation is linked to numerous chronic disease states. Phenolic compounds have attracted attention because a number of these compounds possess anti-inflammatory properties. A phenolic crude extract was prepared from pecans and separated by Sephadex LH-20 column chromatography into low- and high-molecular-weight (LMW/HMW) fractions. Anti-inflammatory properties of these fractions were assessed in LPS-stimulated RAW 264.7 murine macrophage cells. NO and reactive oxygen species (ROS) production was monitored after 3 different experimental protocols: (1) pre-treatment with Escherichia coli O111:B4 lipopolysaccharide (LPS); (2) pre-treatment with a pecan crude extract and its fractions; and (3) co-incubation of LPS with a pecan crude extract and its fractions. The LMW fraction displayed a dose-dependent decrease in NO production and a significant decrease from the LPS control in ROS production when cells were either co-incubated with or pre-treated with LPS. The phenolics were characterized by HPLC to help identify those responsible for the observed effect.

Selenium Supplementation Affects Insulin Resistance and Serum hs-CRP in Patients with Type 2 Diabetes and Coronary Heart Disease

To our knowledge, this study is the first indicating the effects of selenium supplementation on metabolic status of patients with type 2 diabetes mellitus (T2DM) and coronary heart disease (CHD). This study was conducted to evaluate the effects of selenium supplementation on metabolic profiles, biomarkers of inflammation, and oxidative stress of patients with T2DM and CHD. This randomized, double-blind, placebo-controlled trial was performed among 60 patients with T2DM and CHD aged 40-85 years. Participants were randomly divided into 2 groups. Group A received 200 μg selenium supplements (n=30) and group B received placebo per day (n=30) for 8 weeks. Fasting blood samples were taken at the beginning of the study and after 8-week intervention to quantify metabolic profiles. After 8 weeks, compared with the placebo, selenium supplementation resulted in a significant decrease in serum insulin levels (- 2.2±4.6 vs. + 3.6±8.4 μIU/ml, p=0.001), homeostasis model of assessment-insulin resistance (HOMA-IR) (- 0.7±1.3 vs. + 0.9±2.4, p=0.004), homeostatic model assessment-beta cell function (HOMA-B) (- 7.5±17.2 vs. + 15.1±34.5, p=0.002) and a significant increase in quantitative insulin sensitivity check index (QUICKI) (+0.01±0.03 vs. - 0.01±0.03, p=0.02). In addition, patients who received selenium supplements had a significant reduction in serum high-sensitivity C-reactive protein (hs-CRP) (- 1 372.3±2 318.8 vs. - 99.8±1 453.6 ng/ml, p=0.01) and a significant rise in plasma total antioxidant capacity (TAC) concentrations (+ 301.3±400.6 vs. - 127.2±428.0 mmol/l, p<0.001) compared with the placebo. A 200 μg/day selenium supplementation among patients with T2DM and CHD resulted in a significant decrease in insulin, HOMA-IR, HOMA-B, serum hs-CRP, and a significant increase in QUICKI score and TAC concentrations.

Effects of selenium supplementation on glucose homeostasis and free androgen index in women with polycystic ovary syndrome: A randomized, double blinded, placebo controlled clinical trial

BACKGROUND/OBJECTIVES

Insulin resistance (IR) is a main pathophysiologic feature in polycystic ovary syndrome (PCOS) patients which is triggered by elevated oxidative stress in these patients. Selenium, an essential micronutrient, is a major constituent of antioxidant enzymes such as glutathione peroxidase. Recently, decreased plasma selenium concentrations were reported in PCOS patients. So, the present study was carried out in order to assess whether selenium consumption can improve the metabolic response to insulin and reduce the insulin resistance in these women.

SUBJECTS/METHODS

A total of 53 PCOS patients (diagnosed by Rotterdam criteria), 18-42 years old, participated in this randomized, double-blind and placebo controlled trial for 12 weeks (selenium, n=26; placebo, n=27). The effects of daily administration of 200 μg selenium or placebo on serum glucose, total testosterone (tT), sex hormone binding globulin (SHBG) and free androgen index (FAI) in fasting state were evaluated.

RESULTS

At the end of the study, insulin resistance was significantly increased in selenium recipients when compared with the placebo group (2.05 ± 0.39 when compared with 1.81 ± 0.25, p=0.017). Also, selenium supplementation resulted in marginally significant increase (p=0.056) in insulin level when compared with the placebo group. There were no statistically significant changes in other study endpoints, when comparing the two groups.

CONCLUSION

This study showed that selenium supplementation in PCOS patients may worsen insulin resistance in them. Until the results of larger studies become available, indiscriminate consumption of selenium supplements in PCOS patients will warrant caution.

Selenoproteins and heat shock proteins play important roles in immunosuppression in the bursa of Fabricius of chickens with selenium deficiency

Selenium (Se) is necessary for the immune system in chicken and mediates its physiological functions through selenoproteins. Heat shock proteins (Hsps) are indispensable for maintaining normal cell function and for directing the immune response. The aim of the present study was to investigate the effects of Se deficiency on the messenger ribonucleic acid (mRNA) expression levels of selenoproteins and Hsps as well as immune functions in the chicken bursa of Fabricius. Two groups of chickens, namely the control and Se-deficient (L group) groups, were reared for 55 days. The chickens were offered a basal diet, which contained 0.15 mg Se/kg in the diet fed to the control group and 0.033 mg Se/kg in the diet fed to the L group. We performed real-time quantitative polymerase chain reaction to detect the mRNA expression levels of selenoproteins and Hsps on days 15, 25, 35, 45 and 55. Western blotting was used to determine the protein expression levels of Hsps on days 35, 45 and 55, and immune functions were assessed through an enzyme-linked immunosorbent assay on days 15, 35, and 55. The data showed that the mRNA expression levels of selenoproteins, such as Txnrd1, Txnrd2, Txnrd3, Dio1, Dio2, Dio3, GPx1, GPx2, GPx3 GPx4, Sepp1, Selo, Sel-15, Sepx1, Sels, Seli, Selu, Selh, and SPS2, were significantly lower (P < 0.05) in the L group compared with the control group. Additionally, the mRNA and protein expression levels of Hsps (Hsp27, Hsp40, Hsp60, Hsp70, and Hsp90) were also significantly higher (P < 0.05) in the L group. The expression levels of IL-2, IL-6, IL-8, IL-10, IL-17, IL-1β, IFN-α, IFN-β, and IFN-γ were significantly lower (P < 0.05) and TNF-α was significantly higher (P < 0.05) in the L group compared with the control group. Our results show that immunosuppression was accompanied by a downregulation of mRNA expression levels of selenoproteins and an upregulation of the Hsp mRNA expression levels. Thus, Se deficiency causes defects in the chicken bursa of Fabricius, and selenoproteins and Hsps play important roles in immunosuppression in the bursa of Fabricius of chickens with Se deficiency.

The favourable effects of long-term selenium supplementation on regression of cervical tissues and metabolic profiles of patients with cervical intraepithelial neoplasia: a randomised, double-blind, placebo-controlled trial

This study was conducted to assess the effects of long-term Se administration on the regression and metabolic status of patients with cervical intraepithelial neoplasia grade 1 (CIN1). This randomised, double-blind, placebo-controlled trial was carried out among fifty-eight women diagnosed with CIN1. To diagnose CIN1, we used specific diagnostic procedures of biopsy, pathological diagnosis and colposcopy. Patients were randomly assigned to two groups to receive 200 μg Se supplements as Se yeast (n 28) or placebo (n 28) daily for 6 months. After 6 months of taking Se supplements, a greater percentage of women in the Se group had regressed CIN1 (88·0 v. 56·0 %; P=0·01) compared with those in the placebo group. Long-term Se supplementation, compared with the placebo, resulted in significant decreases in fasting plasma glucose levels (-0·37 (sd 0·32) v. +0·07 (sd 0·63) mmol/l; P=0·002), serum insulin levels (-28·8 (sd 31·2) v. +13·2 (sd 40·2) pmol/l; P<0·001), homeostatic model assessment of insulin resistance values (-1·3 (se 1·3) v. +0·5 (se 1·4); P<0·001) and a significant elevation in quantitative insulin sensitivity check index (+0·03 (sd 0·03) v. -0·01 (sd 0·01); P<0·001). In addition, patients who received Se supplements had significantly decreased serum TAG (-0·14 (sd 0·55) v. +0·15 (sd 0·38) mmol/l; P=0·02) and increased HDL-cholesterol levels (+0·13 (sd 0·21) v. -0·01 (sd 0·15) mmol/l; P=0·003). In addition, compared with the placebo group, there were significant rises in plasma total antioxidant capacity (+186·1 (sd 274·6) v. +42·8 (sd 180·4) mmol/l; P=0·02) and GSH levels (+65·0 (sd 359·8) v. -294·2 (sd 581·8) μmol/l; P=0·007) and a significant decrease in malondialdehyde levels (-1·5 (sd 2·1) v. +0·1 (sd 1·4) μmol/l; P=0·001) among those who took Se supplements. Overall, taking Se supplements among patients with CIN1 led to its regression and had beneficial effects on their metabolic profiles.

Selenium Deficiency Downregulates Selenoproteins and Suppresses Immune Function in Chicken Thymus

Selenoproteins and selenium (Se) play important roles in the immune system. Selenoprotein expression in the immune system of mammals is sensitive to dietary Se levels; however, little is known about the expression of selenoproteins and their immune functions in the chicken thymus. We assessed selenoprotein gene expression and cytokine content in the chicken thymus in this study. The animals were randomly assigned to two groups as follows: the Se-deficient group (L group) was fed a diet containing 0.033 mg Se/Kg, and the control group was fed the same basal diet supplemented with Se at 0.15 mg/kg (sodium selenite). Real-time qPCR was used to investigate the expression level of selenoproteins on days 15, 25, 35, 45, and 55, and ELISA was used to evaluate the cytokine content on days 15, 35, and 55. The messenger RNA (mRNA) levels of Txnrd1, Txnrd2, Txnrd3, Dio1, Dio2, Dio3, GPx1, GPx2, GPx3, Gpx4, Sepp1, Selo, Sep15, Sepx1, Sels, Seli, Selu, Selh, and SPS2 were all significantly decreased (P < 0.05) in the L group compared to the control group. A significant decrease in IL-2, IL-10, IL-17, IL-1β, IFN-α, and IFN-β was observed in the L group, and there was also a significant increase in IL-6, IL-8, IFN-γ, and TNF-α in the L group. In summary, Se deficiency results in significant changes in the expression of selenoproteins, which may cause oxidative stress in the chicken thymus tissue. Moreover, immunological changes and immune stress may occur because of Se deficiency in the chicken thymus.

Metabolic response to selenium supplementation in women with polycystic ovary syndrome: a randomized, double-blind, placebo-controlled trial

OBJECTIVE

We are aware of no study examining the effects of selenium supplementation on metabolic profiles of patients with polycystic ovary syndrome (PCOS). This study was conducted to evaluate the effects of selenium supplementation on glucose homeostasis parameters and lipid concentrations in women with PCOS.

DESIGN, PATIENTS AND MEASUREMENTS

This randomized, double-blind, placebo-controlled trial was conducted among 70 women diagnosed with PCOS and aged 18-40 years old. Participants were randomly divided into two groups to receive 200 μg per day selenium supplements (N = 35) or placebo (N = 35) for 8 weeks. Fasting blood samples were taken at baseline and after 8 weeks intervention to quantify glucose, insulin and lipid concentrations.

RESULTS

After 8 weeks of intervention, subjects who received selenium supplements had significantly decreased serum insulin levels (-29·83 ± 47·29 vs +9·07 ± 77·12 pmol/l, P = 0·013), homeostasis model of assessment-insulin resistance (HOMA-IR) (-1·15 ± 1·81 vs +0·42 ± 3·09, P = 0·011), homeostatic model assessment-beta-cell function (HOMA-B) (-19·06 ± 30·95 vs +4·55 ± 47·99, P = 0·017) and increased quantitative insulin sensitivity check index (QUICKI) (+0·03 ± 0·04 vs +0·0009 ± 0·05, P = 0·032) compared with placebo. In addition, supplementation with selenium resulted in a significant reduction in serum triglycerides (-0·14 ± 0·55 vs +0·11 ± 0·30 mmol/l, P = 0·025) and VLDL-C concentrations (-0·03 ± 0·11 vs +0·02 ± 0·06 mmol/l, P = 0·025) compared with placebo.

CONCLUSIONS

In conclusion, 200 microgram per day selenium supplementation for 8 weeks among PCOS women had beneficial effects on insulin metabolism parameters, triglycerides and VLDL-C levels; however, it did not affect FPG and other lipid profiles.

Effects of selenium supplementation on glucose homeostasis, inflammation, and oxidative stress in gestational diabetes: Randomized, double-blind, placebo-controlled trial

OBJECTIVE

To our knowledge, no reports are available indicating the effects of selenium supplementation on metabolic parameters, inflammatory factors, and oxidative stress in gestational diabetes mellitus (GDM). The aim of this study was to assess the effects of selenium supplementation on metabolic status in pregnant women with GDM who were not on oral hypoglycemic agents.

METHODS

This randomized, double-blind, placebo-controlled clinical trial was performed with 70 women with GDM. Patients were randomly assigned to receive either 200 μg selenium supplements as tablet (n = 35) or placebo (n = 35) for 6 wk from weeks 24 to 28 of gestation. Fasting plasma samples were taken at study baseline and after 6 wk of intervention to quantify related variables.

RESULTS

Selenium supplementation, compared with placebo, resulted in a significant reduction in fasting plasma glucose (-10.5 ± 11.9 versus +4.5 ± 12.9 mg/dL; P < 0.001), serum insulin levels (-1.98 ± 11.25 versus +5.26 ± 9.33 μIU/mL; P = 0.005), homeostasis model of assessment (HOMA)-insulin resistance (-0.84 ± 2.76 versus +1.47 ± 2.46; P < 0.001) and a significant increase in quantitative insulin sensitivity check index (+0.008 ± 0.03 versus -0.01 ± 0.01; P = 0.009). Additionally, a significant decrease in serum high-sensitivity C-reactive protein (hs-CRP) levels (-791.8 ± 2271.8 versus +500.5 ± 2563.3 ng/mL; P = 0.02) was seen after the administration of selenium supplements compared with placebo. Additionally, we observed a significant elevation in plasma glutathione (+52.14 ± 58.31 versus -39.93 ± 153.52 μmol/L; P = 0.002) and a significant reduction in plasma malondialdehyde levels (-0.01 ± 0.36 versus +0.67 ± 1.90 μmol/L; P = 0.04) after consumption of selenium supplements compared with placebo. We did not find any significant effect of taking selenium supplements on HOMA β-cell function, lipid profiles, plasma nitric oxide, or total antioxidant capacity concentrations.

CONCLUSION

Selenium supplementation in pregnant women with GDM demonstrated beneficial effects on glucose metabolism, hs-CRP levels, and biomarkers of oxidative stress.

Clonorchis sinensis ferritin heavy chain triggers free radicals and mediates inflammation signaling in human hepatic stellate cells

Clonorchiasis, caused by direct and continuous contact with Clonorchis sinensis, is associated with hepatobiliary damage, inflammation, periductal fibrosis, and the development of cholangiocarcinoma. Hepatic stellate cells respond to liver injury through production of proinflammatory mediators which drive fibrogenesis; however, their endogenous sources and pathophysiological roles in host cells were not determined. C. sinensis ferritin heavy chain (CsFHC) was previously confirmed as a component of excretory/secretory products and exhibited a number of extrahepatic immunomodulatory properties in various diseases. In this study, we investigated the expression pattern and biological role of CsFHC in C. sinensis. CsFHC was expressed throughout life stages of C. sinensis. More importantly, we found that treatment of human hepatic stellate cell line LX-2 with CsFHC triggered the production of free radicals via time-dependent activation of NADPH oxidase, xanthine oxidase, and inducible nitric oxide synthase. The increase in free radicals substantially promoted the degradation of cytosolic IκBα and nuclear translocation of NF-κB subunits (p65 and p50). CsFHC-induced NF-κB activation was markedly attenuated by preincubation with specific inhibitors of corresponding free radical-producing enzyme or the antioxidant. In addition, CsFHC induced an increased expression level of proinflammatory cytokines, IL-1β and IL-6, in NF-κB-dependent manner. Our results indicate that CsFHC-triggered free radical-mediated NF-κB signaling is an important factor in the chronic inflammation caused by C. sinensis infection.

Phototoxic effects of an operating microscope on the ocular surface and tear film

PURPOSE

We evaluated light exposure-induced dry eye syndrome by investigating the phototoxic effects of an operating microscope on the ocular surface and tear film in rabbits.

METHODS

Sixty eyes of 30 rabbits were divided into 3 groups based on the intensity of light exposure received from an operating microscope: Control group, no exposure to light; group A, 40,000-lx intensity for 30 minutes; and group B, 100,000-lx intensity for 30 minutes. To evaluate the potential damage to the ocular surface and tear film, Schirmer tests, rose bengal staining, and conjunctival impression cytology were performed before the light exposure and at 1, 3, and 5 days afterward. In addition, the expression of interleukin 1-beta was analyzed in tear samples. The expression of mucin 5AC was evaluated using immunofluorescence staining, and periodic acid-Schiff staining was conducted on conjunctival tissues. Corneal and conjunctival tissues were observed by means of electron microscopy.

RESULTS

Potential damage to the ocular surface and tear film was found in the light-exposed groups as evidenced by decreased aqueous tear production, devitalized corneal and conjunctival epithelial cells, squamous metaplasia of conjunctival epithelial cells, decreased conjunctival goblet cell density, decreased expression of mucin 5AC, ultrastructural cellular damage to corneal and conjunctival tissues, and increased interleukin 1-beta expression in tears. This damage was more noticeable in group B than in group A (P < 0.05).

CONCLUSIONS

Light exposure from an operating microscope had phototoxic effects on the ocular surface and tear film in this in vivo experiment. These changes seemed to intensify as the intensity of the light increased. Therefore, excessive light exposure during ophthalmic procedures could be a pathogenic factor in dry eye syndrome after a surgery is performed.

Effects of oxidative stress on immunosuppression induced by selenium deficiency in chickens

Selenium (Se) is an important nutritional trace element possessing immune-stimulatory properties. The aim of this 75-day study was to investigate effect of oxidative stress on immunosuppression induced by selenium deficiency by determining antioxidative function, morphological changes, DNA damage, and immune function in immune organ of chickens. One hundred sixty 1-day-old chickens (egg-type birds) were randomly assigned to two groups of 80 each and were fed on a low-Se diet (0.032 mg/kg Se) or a control diet (0.282 mg/kg Se, sodium selenite), respectively. Se contents in blood and immune organ (thymus, spleen, bursa of Fabricius) were determined on days 30, 45, 60, and 75, respectively. Antioxidative function was examined by total antioxidant capacity (T-AOC), superoxide dismutase (SOD), glutathione peroxidase (GSH-Px), and xanthine oxidase (XOD), and oxidative damage was examined by malondialdehyde (MDA) detection. DNA damage was measured by comet assay, and immune function was examined by determining serum interleukin-1β (IL-1β), interleukin-2 (IL-2), and tumor necrosis factor (TNF) contents. The results showed that Se concentrations in the low-Se group were significantly lower (P < 0.05) than in the control group. Low-Se diet caused a decrease in the activities of T-AOC, SOD, GSH-Px, and an increase in XOD activity and MDA content. Pathological lesions and DNA damage of immune tissues were observed in low-Se group, while the serum IL-1β and IL-2 contents decreased, and TNF content increased. The present study demonstrated that chickens fed deficient in Se diets exhibited lesions in immune organs, decreased serum IL-1β, IL-2 content, and serum TNF content, indicating that oxidative stress inhibited the development of immune organs and finally impaired the immune function of chickens.

Interleukin-6 counteracts therapy-induced cellular oxidative stress in multiple myeloma by up-regulating manganese superoxide dismutase

IL (interleukin)-6, an established growth factor for multiple myeloma cells, induces myeloma therapy resistance, but the resistance mechanisms remain unclear. The present study determines the role of IL-6 in re-establishing intracellular redox homoeostasis in the context of myeloma therapy. IL-6 treatment increased myeloma cell resistance to agents that induce oxidative stress, including IR (ionizing radiation) and Dex (dexamethasone). Relative to IR alone, myeloma cells treated with IL-6 plus IR demonstrated reduced annexin/propidium iodide staining, caspase 3 activation, PARP [poly(ADP-ribose) polymerase] cleavage and mitochondrial membrane depolarization with increased clonogenic survival. IL-6 combined with IR or Dex increased early intracellular pro-oxidant levels that were causally related to activation of NF-κB (nuclear factor κB) as determined by the ability of N-acetylcysteine to suppress both pro-oxidant levels and NF-κB activation. In myeloma cells, upon combination with hydrogen peroxide treatment, relative to TNF (tumour necrosis factor)-α, IL-6 induced an early perturbation in reduced glutathione level and increased NF-κB-dependent MnSOD (manganese superoxide dismutase) expression. Furthermore, knockdown of MnSOD suppressed the IL-6-induced myeloma cell resistance to radiation. MitoSOX Red staining showed that IL-6 treatment attenuated late mitochondrial oxidant production in irradiated myeloma cells. The present study provides evidence that increases in MnSOD expression mediate IL-6-induced resistance to Dex and radiation in myeloma cells. The results of the present study indicate that inhibition of antioxidant pathways could enhance myeloma cell responses to radiotherapy and/or chemotherapy.

Inhibition of rotavirus infection in cultured cells by N-acetyl-cysteine, PPARγ agonists and NSAIDs

Although the current rotavirus vaccines have shown good tolerance and significant efficacy, it would be useful to develop alternative or complementary strategies aimed at preventing or treating acute diarrhoeal disease caused by this viral agent. A variety of antiviral strategies other than vaccines have been assayed for rotavirus infection management. The recently demonstrated sensitivity of rotavirus infectivity to thiol/disulfide reagents prompted assays for screening drugs that potentially affect cellular redox reactions. MA104 or Caco-2 cells were inoculated with the rotavirus strains RRV, Wa, Wi or M69 and then incubated with different concentrations of drugs belonging to a selected group of 60 drugs that are currently used in humans for purposes other than rotavirus infection treatment. Eighteen of these drugs were able to inhibit rotavirus infectivity to different extents. A more systematic evaluation was performed with drugs that could be used in children such as N-acetylcysteine and ascorbic acid, in addition to ibuprofen, pioglitazone and rosiglitazone, all of which affecting cellular pathways potentially needed by the rotavirus infection process. Evidence is provided here that rotavirus infectivity is significantly inhibited by NAC in different cell-culture systems. These findings suggest that NAC has the potential to be used as a therapeutic tool for treatment and prevention of rotavirus disease in children.

Peroxisome proliferator-activated receptor-γ activation reduces cyclooxygenase-2 expression in vascular smooth muscle cells from hypertensive rats by interfering with oxidative stress

AIMS

Hypertension is associated with increased plasma inflammatory markers such as cytokines and increased vascular cyclooxygenase-2 (COX-2) expression. The ability of peroxisome proliferator-activated receptor-γ (PPARγ) agonists to reduce oxidative stress seems to contribute to their anti-inflammatory properties. This study analyzes the effect of pioglitazone, a PPARγ agonist, on interleukin-1β-induced COX-2 expression and the role of reactive oxygen species (ROS) on this effect.

METHODS AND RESULTS

Vascular smooth muscle cells from hypertensive rats stimulated with interleukin-1β (10 ng/ml, 24 h) were used. Interleukin-1β increased: 1) COX-2 protein and mRNA levels; 2) protein and mRNA levels of the NADPH oxidase subunit NOX-1, NADPH oxidase activity and ROS production; and 3) phosphorylation of inhibitor of nuclear factor kappa B (IκB) kinase (IKK) nuclear expression of the p65 nuclear factor kappa B (NF-κB) subunit and cell proliferation, all of which were reduced by apocynin (30 μmol/l). Interleukin-1β-induced COX-2 expression was reduced by apocynin, tempol (10 μmol/l), catalase (1000 U/ml) and lactacystin (5 μmol/l). Moreover, H2O2 (50 μmol/l, 90 min) induced COX-2 expression, which was reduced by lactacystin. Pioglitazone (10 μmol/l) reduced the effects of interleukin-1β on: 1) COX-2 protein and mRNA levels; 2) NOX-1 protein and mRNA levels, NADPH oxidase activity and ROS production; and 3) p-IKK, p65 expressions and cell proliferation. Pioglitazone also reduced the H2O2-induced COX-2 expression and increased Cu/Zn and Mn-superoxide dismutase protein expression. PPARγ small interfering RNA (5 nmol/l) further increased interleukin-1β-induced COX-2 and NOX-1 mRNA levels. In addition, pioglitazone increased the interleukin-1β-induced PPARγ mRNA levels.

CONCLUSION

PPARγ activation with pioglitazone reduces interleukin-1β-induced COX-2 expression by interference with the redox-sensitive transcription factor NF-κB.

The role of melatonin as an antioxidant in the follicle

Melatonin (N-acetyl-5-methoxytryptamine) is secreted during the dark hours at night by pineal gland, and it regulates a variety of important central and peripheral actions related to circadian rhythms and reproduction. It has been believed that melatonin regulates ovarian function by the regulation of gonadotropin release in the hypothalamus-pituitary gland axis via its specific receptors. In addition to the receptor mediated action, the discovery of melatonin as a direct free radical scavenger has greatly broadened the understanding of melatonin's mechanisms which benefit reproductive physiology. Higher concentrations of melatonin have been found in human preovulatory follicular fluid compared to serum, and there is growing evidence of the direct effects of melatonin on ovarian function especially oocyte maturation and embryo development. Many scientists have focused on the direct role of melatonin on oocyte maturation and embryo development as an anti-oxidant to reduce oxidative stress induced by reactive oxygen species, which are produced during ovulation process. The beneficial effects of melatonin administration on oocyte maturation and embryo development have been confirmed by in vitro and in vivo experiments in animals. This review also discusses the first application of melatonin to the clinical treatment of infertile women and confirms that melatonin administration reduces intrafollicular oxidative damage and increase fertilization rates. This review summarizes our recent works and new findings related to the reported beneficial effects of melatonin on reproductive physiology in its role as a reducer of oxidative stress, especially on oocyte maturation and embryo development.