Stress In Various Diseases Research Articles

Photoactive nanocatalysts as DTT-assisted BSA-AuNCs with enhanced oxidase-mimicking ability for sensitive fluorometric detection of antioxidants

Redox imbalance and oxidative stress are increasingly recognized as significant factors in health disorders such as neurodegenerative disorders, premature aging and cancer. However, detecting antioxidant levels that is crucial for managing oxidative stress, can be challenging due to existing assays’ limitations, such as insensitivity to thiol-containing antioxidants. This study presents a simple fluorescence-based assay for antioxidant detection employing the enhanced photocatalytic oxidase-like activity of dithiothreitol (DTT)-assisted bovine serum albumin (BSA)-stabilized gold nanoclusters (DTT@BSA-AuNCs). The reported nanozyme exhibits remarkable stability, versatility, and catalytic activity. Under LED irradiation, DTT@BSA-AuNCs generate singlet oxygen, which converts non-fluorescent thiamine to fluorescent thiochrome, utilizing dissolved oxygen for catalysis. Antioxidants inhibit thiochrome formation, leading to fluorescence quenching. This method enables sensitive detection of antioxidants such as ascorbic acid and glutathione with limits of detection of 0.08 µM and 0.32 µM, respectively, under neutral pH, outperforming previous studies. The assay successfully detects antioxidants in human saliva and cancer cell models. The DTT@BSA-AuNCs-based assay offers a cost-effective, sensitive, and straightforward approach for detecting antioxidants in biological samples, facilitating improved monitoring of oxidative stress in various diseases.

Anti-Inflammatory and Antioxidant Effects of Irigenen Alleviate Osteoarthritis Progression through Nrf2/HO-1 Pathway.

Osteoarthritis (OA) is a prevalent degenerative disease globally, characterized by cartilage degradation and joint dysfunction. Current treatments are insufficient for halting OA progression. Irigenin (IRI), a flavonoid extracted from natural plants with anti-inflammatory and antioxidant properties, has demonstrated potential in mitigating inflammation and oxidative stress in various diseases; however, its effects on OA remain unexplored. This study aims to evaluate the therapeutic effects of IRI on OA through in vivo and in vitro experiments and to elucidate the underlying molecular mechanisms. In vitro, chondrocytes were exposed to hydrogen peroxide (H2O2) to induce an oxidative stress environment and were then treated with IRI. Western blotting, RT-qPCR, immunofluorescence staining assays, flow cytometry, and apoptosis assays were employed to assess the effects of IRI on chondrocyte matrix homeostasis, inflammatory response, and apoptosis. In vivo, an OA rat model was treated with regular IRI injections, and therapeutic effects were evaluated using micro-CT, histological staining, and immunohistochemistry assays. IRI treatment restored matrix homeostasis in chondrocytes and effectively suppressed H2O2-induced inflammation and apoptosis. Subsequent studies further revealed that IRI exerts its therapeutic effects by activating the Nrf2/HO-1 pathway. Inhibition of Nrf2 expression in chondrocytes partially blocked the anti-inflammatory and antioxidant effects of IRI. In the OA rat model, regular IRI injections effectively ameliorated cartilage degeneration. This study identifies IRI as a promising strategy for OA treatment by modulating inflammation and apoptosis through the Nrf2/HO-1 pathway.

Melatonin regulates endoplasmic reticulum stress in diverse pathophysiological contexts: A comprehensive mechanistic review.

The endoplasmic reticulum (ER) is crucial for protein quality control, and disruptions in its function can lead to various diseases. ER stress triggers an adaptive response called the unfolded protein response (UPR), which can either restore cellular homeostasis or induce cell death. Melatonin, a safe and multifunctional compound, shows promise in controlling ER stress and could be a valuable therapeutic agent for managing the UPR. By regulating ER and mitochondrial functions, melatonin helps maintain cellular homeostasis via reduction of oxidative stress, inflammation, and apoptosis. Melatonin can directly or indirectly interfere with ER-associated sensors and downstream targets of the UPR, impacting cell death, autophagy, inflammation, molecular repair, among others. Crucially, this review explores the mechanistic role of melatonin on ER stress in various diseases including liver damage, neurodegeneration, reproductive disorders, pulmonary disease, cardiomyopathy, insulin resistance, renal dysfunction, and cancer. Interestingly, while it alleviates the burden of ER stress in most pathological contexts, it can paradoxically stimulate ER stress in cancer cells, highlighting its intricate involvement in cellular homeostasis. With numerous successful studies using in vivo and in vitro models, the continuation of clinical trials is imperative to fully explore melatonin's therapeutic potential in these conditions.

Rapid and reliable quantification of urinary malondialdehyde by HILIC-MS/MS: A derivatization-free breakthrough approach

BackgroundThe development of fast analytical methods is crucial for the research, discovery, and confirmation of crucial biomarkers. Furthermore, the implementation of fast analytical strategies contributes to efficient and time-effective procedures. In this sense, analysis of malondialdehyde (MDA) has become an important tool for understanding the role of oxidative stress in various diseases and for evaluating the efficacy of therapeutic interventions. ResultsA rapid and robust liquid chromatography tandem mass spectrometry method (HPLC-MS/MS) has been developed to determine endogenous amounts of malondialdehyde (MDA) in human urine without any associated derivatization reaction. MDA was separated in 4 min through a Urea-HILIC column and was analyzed using a triple quadrupole mass spectrometer in negative electrospray ionization mode. With a 50-fold dilution as the only sample pretreatment after alkaline hydrolysis, no matrix effect was present, which allowed for a fast and simple quantification by means of an external standard calibration with a limit of detection of 0.20 ng mL−1. The whole methodology was validated by analyzing unspiked and spiked urine samples from ten healthy individuals and comparing with the results obtained by the standard addition method. MDA was detected in all cases, with natural concentrations varying from 0.11 ± 0.03 to 0.31 ± 0.03 mg g−1 creatinine. Accuracies were found to be satisfactory, ranging from 95 % to 101 %. The proposed method also exhibited good repeatability and reproducibility (RSD<15 %) for four quality control levels. SignificanceThe main significance of this method is the avoidance of a derivatization reaction for the determination of urinary MDA, this constituting a step forward when compared with previous literature. This breakthrough not only streamlines time analysis to less than 5 min per sample but also results in a more robust procedure. Consequently, the method here developed could be applied to subsequent future research involving the determination of MDA as a lipid peroxidation biomarker, where simple, rapid, and reliable methods could represent a significant improvement.

Laquinimod attenuates oxidative stress-induced mitochondrial injury and alleviates intervertebral disc degeneration by inhibiting the NF-κB signaling pathway

BackgroundLow back pain (LBP) caused by intervertebral disc degeneration (IVDD) is a significant global health concern. It is necessary to investigate the underlying pathological mechanisms leading to IVDD and develop precise treatment strategies for this condition. Considering the well-established anti-inflammatory properties and ability to reduce oxidative stress in various diseases, for the first time we aim to explore the potential of Laquinimod in alleviating IVDD. MethodsWe used hydrogen peroxide (H2O2) to simulate the oxidative stress microenvironment in IVDD, and Laquinimod for intervention purposes. Western blot analysis, quantitative real-time polymerase chain reaction (qRT-PCR), enzyme-linked immunosorbent assay (ELISA), and immunofluorescence assay were used to measure the expression levels of inflammatory cytokines, catabolic enzymes, and markers of extracellular matrix (ECM) synthesis in nucleus pulposus (NP) cells. In addition, dichlorofluorescin-diacetate (DCFH-DA) and JC-1 fluorescent probes, flow cytometry analysis, and qRT-PCR were used to measure mitochondrial function and apoptosis in NP cells under conditions of oxidative stress. An acupuncture-induced rat model of IVDD was established to further evaluate the efficacy of Laquinimod in alleviating IVDD in vivo. ResultsOur findings showed that Laquinimod significantly reduced the oxidative stress-induced inflammatory response in NP cells, downregulated the expression of catabolic enzymes, and markedly enhanced ECM degradation by inhibiting the NF-κB signaling pathway. The administration of Laquinimod concurrently improved the mitochondrial functional state and reduced apoptosis in NP cells. Additionally, in vivo experiments in rats showed that Laquinimod significantly alleviated acupuncture-induced IVDD. ConclusionsCollectively, the findings of this study provide new insights into the therapeutic potential of Laquinimod as a treatment for oxidative stress-induced IVDD.

Exploring the Role of Endoplasmic Reticulum Stress in Various Diseases: Implications and Potential Therapeutic Strategies

This study examines prospective therapeutic approaches to modulate Endoplasmic reticulum stress (ER stress) for disease intervention and emphasizes the significant role of ER stress in the pathophysiology of numerous diseases. ER stress is an intracellular stress response when the ER fails to properly fold and repair proteins. This cellular stress response holds crucial relevance in developing many diseases, such as metabolic-related diseases, neurodegenerative diseases, and cardiovascular diseases. This work reviews the underlying mechanisms of ER stress and summarizes its association with various diseases. ER stress can lead to the disordered accumulation of intracellular proteins and the abnormality of cell function, impairing the normal physiological function of cells. These abnormal processes are closely related to disease development.Furthermore, several potential therapeutic options have been described, aiming to modulate ER stress and alleviate symptoms of associated diseases. These therapeutic options include small molecules, chemical chaperones, modulation of the UPR signaling pathway, gene therapy, and more. By modulating ER stress, researchers can intervene in disease development and provide new ideas and methods for preventing and treating these diseases.

Synthesis and Biological Properties of Polyphenol-Containing Linear and Dendrimeric Cationic Peptides.

Natural polyphenols are promising compounds for the pharmacological control of oxidative stress in various diseases. However, low bioavailability and rapid metabolism of polyphenols in a form of glycosides or aglycones have stimulated the search for the vehicles that would provide their efficient delivery to the systemic circulation. Conjugation of polyphenols with cationic amphiphilic peptides yields compounds with a strong antioxidant activity and ability to pass through biological barriers. Due to a broad range of biological activities characteristic of polyphenols and peptides, their conjugates can be used in the antioxidant therapy, including the treatment of viral, oncological, and neurodegenerative diseases. In this work, we synthesized linear and dendrimeric cationic amphiphilic peptides that were then conjugated with gallic acid (GA). GA is a non-toxic natural phenolic acid and an important functional element of many flavonoids with a high antioxidant activity. The obtained GA-peptide conjugates showed the antioxidant (antiradical) activity that exceeded 2-3 times the antioxidant activity of ascorbic acid. GA attachment had no effect on the toxicity and hemolytic activity of the peptides. GA-modified peptides stimulated the transmembrane transfer of the pGL3 plasmid encoding luciferase reporter gene, although GA attachment at the N-terminus of peptides reduced their transfection activity. Several synthesized conjugates demonstrated the antibacterial activity in the model of Escherichia coli Dh5α growth inhibition.

Esculentoside A ameliorates DNCB-induced atopic dermatitis by suppressing the ROS-NLRP3 axis via activating the Nrf2 pathway.

Atopic dermatitis (AD) is a chronic inflammatory skin condition with a high prevalence. Inflammation and oxidative stress are strongly associated with AD progression. Esculentoside A (EsA) inhibits inflammation and oxidative stress in various diseases. However, whether EsA mitigates AD by suppressing inflammation and oxidative stress remains unknown. A mouse model of AD was constructed by the induction of 1-chloro-2,4-dinitrochlorobenzene (DNCB). The mechanism of EsA and its effects on AD symptoms, pathology, inflammation and oxidative stress were investigated through histopathological staining, enzyme-linked immunosorbent assay, blood cells analysis, colorimetric measurement and western blot analysis. EsA improved the clinical symptoms and increased clinical skin scores in AD mice. Skin thickening of the epidermis and dermal tissues and the mast cell numbers in AD mice were reduced with the EsA treatment. EsA decreased the relative mRNA level of thymic stromal lymphopoietin, interleukin (IL)-4, IL-5 and IL-13; the serum concentrations of immunoglobulin E (IgE) and IL-6; and the numbers of white blood cells (WBC) and WBC subtypes, including basophil, lymphocytes, eosinophil, neutrophil and monocytes in DNCB-induced mice. DNCB caused higher levels of oxidative stress, which was reversed with the administration of EsA. Mechanically, EsA upregulated the expression of Nrf2 but downregulated the level of NLRP3 inflammasome in AD mice. The inhibitor of Nrf2 significantly recovered the EsA-induced changes in the NLRP3 inflammasome proteins in DNCB-treated mice. Therefore, EsA improved the clinical and pathological symptoms, inflammation and oxidative stress experienced by DNCB-induced mice and was involved in the inactivation of NLRP3 inflammasome by activating Nrf2.

Rola lekarza rodzinnego i ginekologa w opiece nad kobietą

The risk of many gynecological diseases can be remarkably reduced by making several changes in patients’ lifestyles. In this respect, emphasize the importance of family doctor care. Even if only through education on hygiene, proper diet, and physical activity. From the point of view of prevention and treatment, it is essential to understand the factors contributing to inflammation and oxidative stress in various diseases. Moreover, clinicians should know the patient’s body’s defense mechanisms. Undoubtedly, it is also crucial to ensure universal access to women’s reproductive health services, including in rural areas. The importance of early detection of neoplastic lesions at any age is emphasized, especially in genetically predisposed individuals with an increased risk of cancer. In this case, more frequent medical examinations are recommended from the patient’s childhood.

Potential Functions of the tRNA-Derived Fragment tRF-Gly-GCC Associated With Oxidative Stress in Radiation-Induced Lung Injury.

ObjectiveTransfer RNA-derived small RNAs (tsRNAs) are a novel type of non-coding RNA with various regulatory functions. They are associated with oxidative stress in various diseases, but their potential functions in radiation-induced lung injury (RILI) remain uncertain.MethodsTo explore the role of tsRNAs in RILI, we used X-rays to irradiate human bronchial epithelial cells and examined the expression profile of altered tsRNAs by RNA sequencing and bioinformatics analysis. Sequencing results were verified by qRT-PCR. tsRNA functions were explored using several methods, including CCK-8, reactive oxygen species (ROS) assays, cell transfection, and western blotting.ResultsEighty-six differentially expressed tRNA-derived fragments (tRFs) were identified: 64 were upregulated, and 22 were downregulated. Among them, the regulation of tRF-Gly-GCC, associated with oxidative stress, may be mediated by the inhibition of cell proliferation, promotion of ROS production, and apoptosis in the occurrence and development of RILI. A Kyoto Encyclopedia of Genes and Genomes (KEGG) analysis suggested that the underlying molecular mechanism may involve the PI3K/AKT and the FOXO1 signaling pathways.ConclusionOur findings provide new insights into the molecular mechanisms underpinning RILI, advancing the clinical prevention and treatment of this disease.

MicroRNA-7a-5p ameliorates diabetic peripheral neuropathy by regulating VDAC1/JNK/c-JUN pathway.

The pathogenesis of diabetic peripheral neuropathy (DPN) is complex, and its treatment is extremely challenging. MicroRNA-7a-5p (miR-7a-5p) has been widely reported to alleviate apoptosis and oxidative stress in various diseases. This study aimed to investigate the mechanism of miR-7a-5p in DPN. DPN cell model was constructed with high-glucose-induced RSC96 cells. Cell apoptosis and viability were detected by flow cytometry analysis and cell counting kit-8 (CCK-8) assay respectively. The apoptosis and Jun N-terminal kinase (JNK)/c-JUN signalling pathway-related proteins expression were detected by Western blotting. The intracellular calcium content and oxidative stress levels were detected by flow cytometry and reagent kits. Mitochondrial membrane potential was evaluated by tetrechloro-tetraethylbenzimidazol carbocyanine iodide (JC-1) staining. The targeting relationship between miR-7a-5p and voltage-dependent anion-selective channel protein 1 (VDAC1) was determined by RNA pull-down assay and dual-luciferase reporter gene assay. The streptozotocin (STZ) rat model was constructed to simulate DPN in vivo. The paw withdrawal mechanical threshold (PTW) was measured by Frey capillary line, and the motor nerve conduction velocity (MNCV) was measured by electromyography. MiR-7a-5p expression was decreased, while VDAC1 expression was increased in HG-induced RSC96 cells and STZ rats. In HG-induced RSC96 cells, miR-7a-5p overexpression promoted cell proliferation, inhibited apoptosis, down-regulated calcium release, improved mitochondrial membrane potential and repressed oxidative stress response. MiR-7a-5p negatively regulated VDAC1 expression. VDAC1 knockdown improved cell proliferation activity, suppressed cell apoptosis and mitochondrial dysfunction by inhibiting JNK/c-JUN pathway activation. MiR-7a-5p overexpression raised PTW, restored MNCV and reduced oxidative stress levels and nerve cell apoptosis in STZ rats. MiR-7a-5p overexpression ameliorated mitochondrial dysfunction and inhibited apoptosis in DPN by regulating VDAC1/JNK/c-JUN pathway.

Sulforaphane Attenuates Chronic Intermittent Hypoxia-Induced Brain Damage in Mice via Augmenting Nrf2 Nuclear Translocation and Autophagy.

Obstructive sleep apnea–hypopnea syndrome (OSAHS), typically characterized by chronic intermittent hypoxia (CIH), is associated with neurocognitive dysfunction in children. Sulforaphane (SFN), an activator of nuclear factor E2-related factor 2 (Nrf2), has been demonstrated to protect against oxidative stress in various diseases. However, the effect of SFN on OSAHS remains elusive. In this research, we investigated the neuroprotective role of SFN in CIH-induced cognitive dysfunction and underlying mechanisms of regulation of Nrf2 signaling pathway and autophagy. CIH exposures for 4 weeks in mice, modeling OSAHS, contributed to neurocognitive dysfunction, manifested as increased working memory errors (WMEs), reference memory errors (RMEs) and total memory errors (TEs) in the 8-arm radial maze test. The mice were intraperitoneally injected with SFN (0.5 mg/kg) 30 min before CIH exposure everyday. SFN treatment ameliorated neurocognitive dysfunction in CIH mice, which demonstrates less RME, WME, and TE. Also, SFN effectively alleviated apoptosis of hippocampal neurons following CIH by decreased TUNEL-positive cells, downregulated cleaved PARP, cleaved caspase 3, and upregulated Bcl-2. SFN protects hippocampal tissue from CIH-induced oxidative stress as evidenced by elevated superoxide dismutase (SOD) activities and reduced malondialdehyde (MDA). In addition, we found that SFN enhanced Nrf2 nuclear translocation to hold an antioxidative function on CIH-induced neuronal apoptosis in hippocampus. Meanwhile, SFN promoted autophagy activation, as shown by increased Beclin1, ATG5, and LC3II/LC3I. Overall, our findings indicated that SFN reduced the apoptosis of hippocampal neurons through antioxidant effect of Nrf2 and autophagy in CIH-induced brain damage, which highlights the potential of SFN as a novel therapy for OSAHS-related neurocognitive dysfunction.

Roles of PRR-Mediated Signaling Pathways in the Regulation of Oxidative Stress and Inflammatory Diseases.

Oxidative stress is a major contributor to the pathogenesis of various inflammatory diseases. Accumulating evidence has shown that oxidative stress is characterized by the overproduction of reactive oxygen species (ROS). Previous reviews have highlighted inflammatory signaling pathways, biomarkers, molecular targets, and pathogenetic functions mediated by oxidative stress in various diseases. The inflammatory signaling cascades are initiated through the recognition of host cell-derived damage associated molecular patterns (DAMPs) and microorganism-derived pathogen associated molecular patterns (PAMPs) by pattern recognition receptors (PRRs). In this review, the effects of PRRs from the Toll-like (TLRs), the retinoic acid-induced gene I (RIG-I)-like receptors (RLRs) and the NOD-like (NLRs) families, and the activation of these signaling pathways in regulating the production of ROS and/or oxidative stress are summarized. Furthermore, important directions for future studies, especially for pathogen-induced signaling pathways through oxidative stress are also reviewed. The present review will highlight potential therapeutic strategies relevant to inflammatory diseases based on the correlations between ROS regulation and PRRs-mediated signaling pathways.

Vagus Nerve Stimulation Attenuates Early Traumatic Brain Injury by Regulating the NF-κB/NLRP3 Signaling Pathway

Background Traumatic brain injury (TBI) is a major cause of death and disability worldwide. Oxidative stress, inflammation, and apoptosis are vital pathophysiological features post-TBI. Objectives Research has shown that vagus nerve stimulation (VNS) can attenuate oxidative stress in various diseases. However, the critical role of VNS in TBI is still not completely understood. This study investigated the protective effects and potential mechanism of VNS on TBI. Methods Male Sprague-Dawley rats were randomized into 3 groups: sham, TBI, and TBI + VNS. The TBI model was induced in rats by the free-fall drop method. The vagal nerve trunk was separated, and VNS was performed after establishing the TBI model. Results The results showed that VNS significantly ameliorated tissue damage, neurological deficits, and cerebral edema, compared with the sham VNS group. Additionally, VNS alleviated oxidative stress, inflammation, and apoptosis in the pericontusive cortex of rats after TBI. VNS also significantly suppressed expression of the nuclear factor-κB (NF-κB) protein in the nucleus and activation of the nucleotide-binding domain–like receptor protein 3 (NLRP3) inflammasome. Conclusions Taken together, the present study indicates that VNS may attenuate brain damage after TBI by inhibiting oxidative stress, inflammation, and apoptosis, possibly through the NF-κB/NLRP3 signaling pathway.

Proline improves cardiac remodeling following myocardial infarction and attenuates cardiomyocyte apoptosis via redox regulation

At present, ischemic heart failure (HF) caused by coronary heart disease (CHD) has a high morbidity and mortality, placing a heavy burden on global human health. L-Proline (Pro), a nonessential amino acid and the foundation of proteins in the human body, was found to be protective against oxidative stress in various diseases. However, the role of Pro in cardiovascular disease (CVD) remains unclear. In vivo, adult mice were subjected to left anterior descending (LAD) artery ligation for 4 weeks with or without Pro treatment. In vitro, H9c2 cardiomyocytes were pretreated with or without Pro, followed by treatment with hydrogen peroxide (H2O2) (200 μM) for 6 and 12 h. Our data showed that Pro metabolism was disturbing after myocardial infarction (MI). Pro treatment improved cardiac remodeling, reduced infarct size, and decreased oxidative stress and apoptosis in mouse hearts after MI. Pro inhibited the H2O2-induced increase in reactive oxygen species (ROS) in H9c2 cells and protected against H2O2-induced apoptosis. Mechanistically, by RNA sequencing (RNA-seq) and pathway analysis, Pro was shown to exert a protective effect through H2O2 catabolic processes and apoptotic processes, especially oxidative phosphorylation (OXPHOS). Taken together, our findings suggested that Pro protects against MI injury at least partially via redox regulation, highlighting the potential of Pro as a novel therapy for ischemic HF caused by CHD.

Moderate Step Over Sensitive Move Towards Mental Stress

Data classification study is applied in a profound manner to find some statistical classifier to analyze the higher order and lower order priors, like a hood to perform the posterior using Bayesian classifiers. The rough set approaches planned with functional and to determine the existence of the attribute with the level to correlation among them. Approximations towards the set of some logical factors were filtered towards to detect the mental stress through data collection mainly from the working people sector. Significant analyses to quantify the features of mental stress in various diseases cataloging manner with its technical aspects with its classification types based on the class value. As a proposed system of suggested hypothesis planned to predict the classifier model to reduce the stress dependency for the working people as much as possible in a smoother way

Moderate Step Over Sensitive Move Towards Mental Stress

Data classification study is applied in a profound manner to find some statistical classifier to analyze the higher order and lower order priors, like a hood to perform the posterior using Bayesian classifiers. The rough set approaches planned with functional and to determine the existence of the attribute with the level to correlation among them. Approximations towards the set of some logical factors were filtered towards to detect the mental stress through data collection mainly from the working people sector. Significant analyses to quantify the features of mental stress in various diseases cataloging manner with its technical aspects with its classification types based on the class value. As a proposed system of suggested hypothesis planned to predict the classifier model to reduce the stress dependency for the working people as much as possible in a smoother way.

Cucurbita argyrosperma seed extract ameliorating oxidative stress in H9c2 cardiomyocytes through suppression of intracellular reactive oxygen species production

Background: Oxidative stress induced by the excessive reactive oxygen species (ROS) generation is involved in the pathogenesis of various diseases. Methanol extract from Cucurbita argyrosperma (CM) was used to test for antioxidant and antioxidative stress. Materials and Methods: The radical scavenging potential was determined using eight different in vitro assays: 1,1-diphenyl-2-picrylhydrazyl (DPPH), 2,2'-Azino-bis-3-ethylbenzothiazoline-6-sulfonic acid (ABTS) radical, β-carotene-linoleic acid, chelating activity, ferric reducing antioxidant power (FRAP), hydroxyl radical, nitric oxide (NO) radical, and superoxide anion radicals, palmitate (PA) on H9c2 cells, and H2O2-induced cell damage on H9c2 cardiomyocytes. Results: CM showed antioxidant activity with DPPH radical values of EC507.6 ± 5.38 mg/mL, β-carotene-linoleic acid EC50 of 279.4 ± 36.32 mg/ml, chelating activity EC50 of 301.2 ± 9.78 mg/ml, FRAP EC50 of 101.3 ± 3.10 mg/ml, hydroxyl EC50 of 42.6 ± 8.6 mg/mL, superoxide EC50 of 50.6 ± 8.66 mg/ml, NO EC50 of 101.2 ± 19.74 mg/ml, and ABTS EC50 of 13.2 ± 4.9 mg/ml. The methanol extract preincubation decreases the intracellular ROS induced by H2O2 and PA in H9c2 cells in a concentration-dependent manner. The methanol extract could also protect H9c2 cells and inhibit the activity of xanthine oxidase, malondialdehyde, and lactate dehydrogenase which increases cell viability, heme oxygenase-1, glutathione/oxidized glutathione, superoxide dismutase-1, catalase, and GSH-Px? levels. Conclusions: The finding suggests that methanol extract can protect the oxidative stress-induced cardiomyocyte damage through ROS regulation and can be used as a therapeutic agent for the improvement of oxidative stress in various diseases. Abbreviations used: ABTS radical: 2,2'-Azino-bis-3-ethylbenzothiazoline-6-sulfonic acid; CAT: Catalase; DCFH-DA: 2',7'-dichlorodihydrofluorescein diacetate; DMSO: Dimethyl sulfoxide; MTT: 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide; DPPH: 1,1-diphenyl-2-picrylhydrazyl; DCFH-DA: 2',7'-dichlorofluorescin diacetate; FRAP: Ferric reducing antioxidant power; GSH: Glutathione; GSH-Px: Glutathione peroxidase; HO-1: Heme oxygenase-1; OH−: Hydroxyl; LDH: Lactate dehydrogenase; LOOH: Lipid peroxide; LOO•: Lipid peroxyl; MDA: Malondialdehyde; NO: Nitric oxide; GSSG: Oxidized glutathione; O2−1: Oxygen; O3 Ozone; PA: Palmitate; RO2−: Peroxyl; PBS: Phosphate-buffered saline; ROS: Reactive oxygen species; O2•: Superoxide; SOD: Superoxide dismutase; TFs: Total flavonoids; TP: Total phenolic; TCA: Trichloroacetic acid; XO: Xanthine oxidase.

Liquid Chromatographic Determination of Malondialdehyde in Plasma Samples After Liquid–Liquid Microextraction

Background: Malondialdehyde is a product of lipid peroxidation of polyunsaturated fatty acids in foods and biological samples and widely used as biomarker of oxidative stress in various diseases. We describe the validation of a new microextraction-LC-UV method for the determination of malondialdehyde (MDA) in the form of 2,4-dinitrophenylhydrazine (DNPH) derivatization in plasma samples. Objective: A new microextraction technique called vortex and N2 assisted liquid-liquid microextraction has been developed for the determination MDA in plasma samples. Method: The DNPH-derivatized MDA was extracted into ethyl acetate as an extraction solvent and measured by LC-UV at 310 nm after evaporation of ethyl acetate and re-dissolving in mobile phase composed of 0.2% acetic acid–acetonitrile (50:50; v/v). This method validated according to U.S. Food and Drug Administration guidelines. Results: The limit of detection of MDA was 0.038 µmol L-1 (2.74 µg L-1) and the intra and interday relative standard deviations were in the range of 3.8-5.0% and 5.5-9.4%, respectively for different concentrations of MDA. Conclusion: A precise and valid method to measure MDA as DNPH derivatization in plasma samples using LC was proposed. Keywords: Malondialdehyde, 2, 4-dinitrophenylhydrazine, vortex assisted liquid liquid microextraction, N2 assisted liquid liquid microextraction, validation, samples.

CAAT/enhancer binding protein-homologous protein deficiency attenuates liver ischemia/reperfusion injury in mice.

Ischemia/reperfusion injury (IRI) is one of the main causes of liver dysfunction after liver surgery. Involvement of endoplasmic reticulum (ER) stress in various diseases has been demonstrated, and CAAT/enhancer binding protein-homologous protein (CHOP) is a transcriptional regulator that is induced by ER stress. It is also a key regulator of ER stress-mediated apoptosis. The aim of this study was to investigate the role of CHOP in liver IRI. Wild type (WT) and CAAT/enhancer binding protein-homologous protein knockout (CHOP-/-) mice were subjected to 70% liver warm ischemia/reperfusion for 60 minutes. At different times after reperfusion, liver tissues and blood samples were collected for evaluation. Induction of ER stress including CHOP expression was ascertained. Liver damage was evaluated based on serum liver enzymes, liver histology, and neutrophil infiltration. Hepatocyte death including apoptosis was assessed. Liver warm IRI induced ER stress in both WT and CHOP-/- mice. In addition, CHOP expression was up-regulated in WT mice. At 6 hours after reperfusion, liver damage was attenuated in CHOP-/- mice. On the basis of terminal deoxynucleotidyl transferase-mediated deoxyuridine triphosphate nick-end labeling staining, apoptotic and necrotic cells were significantly reduced in CHOP-/- mice. CHOP deficiency also reduced the cleavage of caspase 3 and expression of the proapoptotic protein B cell lymphoma 2-associated X protein. Liver IRI induces CHOP expression, and CHOP deficiency attenuates liver IRI by inhibiting apoptosis. Elucidation of the function of CHOP in liver IRI may contribute to further investigation for a therapy against liver IRI associated with the ER stress pathway. Liver Transplantation 24 645-654 2018 AASLD.