OBJECTIVES: To investigate the mechanism through which N-acetylneuraminic acid (Neu5Ac) exacerbates hypoxia/reoxygenation (H/R) injury in rat cardiomyocytes (H9C2 cells). METHODS: H9C2 cells were cultured in hypoxia and glucose deprivation for 8 h followed by reoxygenation for different durations to determine the optimal reoxygenation time. Under the optimal H/R protocol, the cells were treated with 0, 5, 10, 20, 30, 40, 50, and 60 mmol/L Neu5Ac during reoxygenation to explore the optimal drug concentration. The cells were then subjected to H/R injury followed by treatment with Neu5Ac, Fer-1 (a ferroptosis inhibitor), or both. The changes in SOD activity, intracellular Fe²⁺ and lipid ROS levels in the cells were evaluated, and the cellular expressions of Nrf2, GPX4, HO-1, FSP1, and xCT proteins were detected using Western blotting. RESULTS: Following hypoxia and glucose deprivation for 8 h, the cells with reoxygenation for 6 h, as compared with other time lengths of reoxygenation except for 9 h, showed the lowest expression levels of Nrf2, GPX4, HO-1, and FSP1 proteins (P<0.001). Neu5Ac treatment of dose-dependently decreased the viability of the cells with H/R injury with an IC₅₀ of 30.07 mmol/L. Reoxygenation for 3 h with normal glucose supplementation and a Neu5Ac concentration of 30 mmol/L were selected as the optimal conditions in the subsequent experiments. The results showed that Neu5Ac could significantly increase SOD activity, Fe²⁺ and lipid ROS levels and reduce Nrf2, GPX4, HO-1, and FSP1 protein expressions in H9C2 cells with H/R injury, but its effects were significantly attenuated by treatment with Fer-1. CONCLUSIONS Neu5Ac exacerbates ferroptosis of myocardial cells with H/R injury by inhibiting the Nrf2 axis to promote the production of ROS and lipid ROS.
Ferroptosis/drug effects* ; Myocytes, Cardiac/cytology* ; Animals ; NF-E2-Related Factor 2/metabolism* ; Rats ; N-Acetylneuraminic Acid/pharmacology* ; Cell Hypoxia ; Reactive Oxygen Species/metabolism* ; Cell Line ; Myocardial Reperfusion Injury/metabolism*

OBJECTIVES: To investigate the antioxidative mechanism of snake venom-derived protein C activator (PCA) in mitigating vascular endothelial cell injury. METHODS: Human umbilical vein endothelial cells (HUVECs) were cultured in DMEM containing 1.0 g/L D-glucose and exposed to hypoxia (1% O₂) for 6 h followed by reoxygenation for 2 h to establish a cell model of oxygen-glucose deprivation/reoxygenation (OGD/R). The cell model was treated with 2 μg/mL PCA alone or in combination with 2-ME2 (a HIF-1α inhibitor) or DMOG (a HIF-1α stabilizer), and intracellular production of reactive oxygen species (ROS) and protein expression levels of HIF-1α, BNIP3, and Beclin-1 were detected using DCFH-DA fluorescence probe, flow cytometry, and Western blotting. The OGD/R cell model was transfected with a BNIP3-specific siRNA or a scrambled control sequence prior to PCA treatment, and the changes in protein expressions of HIF-1α, BNIP3 and Beclin-1 and intracellular ROS production were examined. RESULTS: In the OGD/R cell model, PCA treatment significantly upregulated HIF-1α, BNIP3 and Beclin-1 expressions and reduced ROS production. The effects of PCA were obviously attenuated by co-treatment with 2-ME2 but augmented by treatment with DMOG (a HIF-1α stabilizer). In the cell model with BNIP3 knockdown, PCA treatment increased BNIP3 expression and decreased ROS production without causing significant changes in HIF-1α expression. Compared with HUVECs with PCA treatment only, the cells with BNIP3 knockdown prior to PCA treatment showed significantly lower Beclin-1 expression and higher ROS levels. CONCLUSIONS Snake venom PCA alleviates OGD/R-induced endothelial cell injury by upregulating HIF-1α/BNIP3 signaling to suppress ROS generation, suggesting its potential as a therapeutic agent against oxidative stress in vascular pathologies.
Humans ; Reactive Oxygen Species/metabolism* ; Hypoxia-Inducible Factor 1, alpha Subunit/metabolism* ; Human Umbilical Vein Endothelial Cells/drug effects* ; Membrane Proteins/metabolism* ; Proto-Oncogene Proteins/metabolism* ; Up-Regulation ; Cell Hypoxia ; Cells, Cultured ; Snake Venoms/chemistry* ; Beclin-1

OBJECTIVES: To evaluate the correlation of mean arterial oxygen tension (PaO₂) during the first 24 h following intensive care unit (ICU) admission with mortality in critically ill patients with acute kidney injury (AKI) and determine the optimal PaO₂ threshold for devising oxygen therapy strategies for these patients. METHODS: We collected the clinical data of ICU patients with AKI from the MIMIC-IV database. Based on the optimal first 24-h PaO₂ threshold determined by receiver operating characteristic (ROC) curve analysis and the Youden index maximization principle, we classified the patients into hyperoxia group (with PaO₂ ≥137.029 mmHg) and hypoxemia group (PaO₂<137.029 mm Hg). Multivariable logistic regression and propensity score matching were used to evaluate the correlation of first 24-h PaO₂ levels with in-hospital mortality of the patients. RESULTS: Among the 18 335 patients, 46.7% were in the hyperoxia group, who had an overall mortality rate of 16.9%. The optimal PaO₂ threshold (137.029 mm Hg) had a sensitivity of 78.3%, a specificity of 63.7%, and an AUC of 0.76 (95% CI: 0.74=0.78). Hyperoxia within the first 24 h after ICU admission was associated with a significantly lower in-hospital mortality (OR=0.78) and 90-day mortality (OR=0.77), particularly in stage 1 AKI patients. A non-linear relationship was identified between PaO₂ and mortality of the patients (P<0.001). Kaplan-Meier survival curves indicated a significantly increased 90-day survival rate in the patients in hyperoxia group (P<0.001), who also had shorter durations of mechanical ventilation, less vasopressor use, and shorter lengths of hospital/ICU stay. CONCLUSIONS Maintenance of a PaO₂ level ≥137.029 mmHg within 24 h after ICU admission may improve clinical outcomes of critically ill AKI patients, which underscores the importance of targeted oxygen delivery in ICU care.
Humans ; Acute Kidney Injury/blood* ; Male ; Female ; Middle Aged ; Intensive Care Units ; Aged ; Oxygen/blood* ; Hospital Mortality ; Partial Pressure ; Adult ; Databases, Factual

OBJECTIVES: To investigate the effect of downregulation of medium-chain acyl-coenzyme A dehydrogenase (ACADM) on invasion and migration of estrogen receptor-positive breast cancer cells and the underlying mechanism. METHODS: The Kaplan-Meier Plotter database was used to analyze the ACADM expression levels in breast cancer and normal tissues and their association with patient prognosis. Human breast cancer MCF-7 and T47D cell lines with lentivirus-mediated ACADM knockdown were established, and their in situ tumor formation and metastasis after tail vein injection were evaluated in nude mice. The MCF-7 and T47D cells with ACADM knockdown and their unmodified parental cells were examined with oil-red O staining assay, ROS assay, mitochondrial respiratory chain function assay before and after treatments with ROS scavenger, Elamipretide (a cardiolipin oxidation inhibitor) or SC79 (an AKT activator), and the changes in migration and invasion abilities of the treated cells were analyzed with Transwell invasion assay and Boyden chamber assay. Western blotting was used to detect protein expression levels of related signaling pathways in the treated cells. RESULTS: ACADM overexpression was associated with a significantly shorter overall survival of breast cancer patients. In MCF-7 and T47D cells, ACADM knockdown resulted in downregulation of N calnexin, vimentin, p-P13K and p-AKT proteins, increased levels of free fatty acids and reactive oxygen species, lowered activities of mitochondrial respiratory chain complex III and V, and reduced mitochondrial inner phospholipids. ACADM knockdown significantly decreased the invasive capacity of the cells, which were obviously reversed by treatment with ROS scavenger, Elamipretide, and SC79. CONCLUSIONS Down-regulation of ACADM inhibits migration and invasion ability of estrogen receptor-positive breast cancer cells by lowering lipotoxicity and impairing mitochondrial function through the ROS/PI3K/AKT pathway.
Humans ; Breast Neoplasms/metabolism* ; Female ; Mice, Nude ; Down-Regulation ; Neoplasm Invasiveness ; Animals ; Mice ; Receptors, Estrogen/metabolism* ; MCF-7 Cells ; Cell Movement ; Cell Line, Tumor ; Reactive Oxygen Species/metabolism* ; Acyl-CoA Dehydrogenase/genetics* ; Signal Transduction ; Neoplasm Metastasis ; Proto-Oncogene Proteins c-akt/metabolism*

OBJECTIVES: To investigate the role of sphingosine-1-phosphate receptor 5 (S1PR5) in modulating barrier function of mouse brain microvascular endothelial cells with oxygen-glucose deprivation and reoxygenation (OGD/R). METHODS: Mouse brain microvascular endothelial cells (bEnd.3) were exposed to OGD/R to induce barrier dysfunction following treatment with S1PR5-specific agonist A971432 or lentivirus-mediated transfection with a S1PR5-specific siRNA, a S1PR5-overexpressing plasmid, or their respective negative control sequences. The changes in viability and endothelial barrier permeability of the treated cells were evaluated with CCK-8 assay and FITC-dextran permeability assay; the levels of intracellular reactive oxygen species (ROS) and localization and expression levels of the proteins related with barrier function and oxidative stress were detected using immunofluorescence staining, DCFH-DA probe and Western blotting. RESULTS: S1PR5 activation obviously enhanced viability of bEnd.3 cells exposed to OGD/R (P<0.0001). Both activation and overexpression of S1PR5 reduced FITC-dextran leakage, while S1PR5 knockdown significantly increased FITC-dextran leakage in the exposed bEnd.3 cells. Activation and overexpression of S1PR5 both increased the cellular expressions of the barrier proteins ZO-1 and occludin, while S1PR5 knockdown produced the opposite effect. In cells exposed to OGD/R, ROS production was significantly reduced by S1PR5 activation and overexpression but increased following S1PR5 knockdown. Overexpression of S1PR5 obviously increased the expressions of the antioxidant proteins Nrf2, HO-1 and SOD2 in the exposed cells. CONCLUSIONS S1PR5 activation and overexpression significantly improve cell viability and reduce permeability of a mouse brain microvascular endothelial cell model of OGD/R, the mechanism of which may involve the reduction in ROS production and upregulation of the antioxidant proteins.
Animals ; Mice ; Oxidative Stress ; Endothelial Cells/cytology* ; Brain/blood supply* ; Reactive Oxygen Species/metabolism* ; Receptors, Lysosphingolipid/metabolism* ; Sphingosine-1-Phosphate Receptors ; Blood-Brain Barrier/metabolism* ; Glucose ; Cell Line ; Oxygen/metabolism* ; NF-E2-Related Factor 2/metabolism*

OBJECTIVES: To explore the mechanism of cinnamic acid (CA) for improving doxorubicin-induced myocardial injury (DIC) in mice. METHODS: Network pharmacology analysis was used to obtain the key targets of CA and DIC. Male C57BL/6J mice were randomized into Sham, DOX, CA (25, 50 and 100 mg/kg)+DOX, and CA+Ferrostatin-1+DOX groups, and their myocardial function and pathology were examined by echocardiography and HE staining. Serum levels of CK-MB, LDH, MDA, IL-6, TNF‑α and myocardial ROS level were detected, and the expression levels of TLR4 and ferroptosis pathway proteins in myocardial tissue were detected by Western blotting. Cultured murine cardiomyocytes (HL-1 cells) with or without transfection with a small interfering RNA targeting TLR4 (si-TLR4) were treated with DOX or Erastin, and the cellular ROS content was measured by DCFH-DA staining; the expression level of GPX4 was detected using immunofluorescence staining. RESULTS: Network pharmacology analysis suggested that CA may improve DIC through TLR4 signaling. DOX treatment caused obvious myocardial injury in mice, which showed significantly increased serum levels of CK-MB, LDH, MDA, IL-6, TNF-α and myocardial ROS level with decreased myocardial levels of SLC7A11 and GPX4 proteins and increased levels of TLR4 and PTGS2 proteins. All these changes in the mouse models were significantly alleviated by treatment with CA, and the mice receiving CA or ferrostatin-1 treatment exhibited increased myocardial expressions of SLC7A11 and GPX4 proteins and lowered expressions of TLR4 and PTGS2 proteins. In cultured HL-1 cells, treatment with DOX and Erastin both obviously increased intracellular ROS level and decreased cellular GPX4 expression level, and these changes were strongly attenuated by TLR4 interference. CONCLUSIONS CA, as a potent herbal monomer, can effectively alleviate DIC in mice by inhibiting TLR4-mediated ferroptosis.
Animals ; Ferroptosis/drug effects* ; Toll-Like Receptor 4/metabolism* ; Myocytes, Cardiac/metabolism* ; Mice, Inbred C57BL ; Mice ; Male ; Doxorubicin/adverse effects* ; Cinnamates/pharmacology* ; Signal Transduction ; Reactive Oxygen Species/metabolism*

OBJECTIVES: To investigate the effects of Naoluo Xintong Decoction (NLXTD) on proliferation of rat brain microvascular endothelial cells (BMECs) after oxygen-glucose deprivation/reoxygenation (OGD/R) injury and role of the HIF-1α/VEGF pathway in mediating its effect. METHODS: Using a BMEC model of OGD/R, we tested the effects of 10% NLXTD-medicated rat serum, alone or in combination with 2ME2 or 10% NAKL, on cell proliferation, migration, tube-forming ability and permeability using CCK-8 assay, Transwell chamber assay, tube formation assay and permeability assay. Cellular expressions of VEGF and Notch were detected using ELISA and laser confocal immunofluorescence analysis, and the expressions of HIF-1α, VEGFR2, Notch1, ERK and P-ERK1/2 proteins were detected with Western blotting. RESULTS: OGD/R injury significantly decreased viability of BMECs. NLXTD treatment of the cells with OGD/R could significantly promoted cell proliferation, migration and tube formation ability, but these effects were strongly attenuated by application of 2ME2. NLXTD treatment also significantly increased the percentages of VEGF- and Notch-positive cells in the cell models and obviously enhanced the expression levels of HIF-1α, VEGFR2, Notch1 and P-ERK1/2. CONCLUSIONS NLXTD promotes proliferation, migration, and tube formation of rat BMECs after OGD/R injury possibly by activating the HIF-1α/VEGF signaling pathway.
Animals ; Hypoxia-Inducible Factor 1, alpha Subunit/metabolism* ; Drugs, Chinese Herbal/pharmacology* ; Vascular Endothelial Growth Factor A/metabolism* ; Endothelial Cells/metabolism* ; Rats ; Cell Proliferation/drug effects* ; Signal Transduction/drug effects* ; Glucose ; Brain/blood supply* ; Cells, Cultured ; Rats, Sprague-Dawley ; Vascular Endothelial Growth Factor Receptor-2/metabolism* ; Oxygen/metabolism* ; Cell Hypoxia

OBJECTIVES: To investigate the efficacy of Lactobacillus plantarum ZG03 (L. plantarum ZG03) for ameliorating oxidative stress in zebrafish. METHODS: We evaluated the growth pattern of L. plantarum ZG03, observed its morphology using field emission scanning electron microscopy, and assessed its safety and potential efficacy with whole-genome sequencing for genetic analysis. FITC-labeled ZG03 was used to observe its intestinal colonization in zebrafish. In a zebrafish model of 2% glucose-induced oxidative stress, the effect of ZG03 was evaluated by assessing the changes in neutrophils in the caudal hematopoietic tissue (CHT), superoxide dismutase (SOD) activity, reactive oxygen species (ROS) levels, and malondialdehyde (MDA) content. Liquid chromatography-mass spectrometry-based targeted metabolomics was used for analyzing short-chain fatty acids (SCFAs) in the zebrafish, and the antioxidant effects of the key metabolites (acetate, propionate, and caproate) were tested. RESULTS: On MRS agar, L. plantarum ZG03 formed circular, smooth, moist, and milky-white colonies with a rod-shaped cell morphology. Genomic analysis revealed abundant sugar metabolism gene clusters. After inoculation of FITC-labeled L. plantarum ZG03 in zebrafish, green fluorescence was clearly observed in the intestinal bulb, mid-intestine, and hind intestine. In zebrafish with glucose-induced oxidative stress, L. plantarum ZG03 significantly reduced ROS levels and the number of neutrophils in the CHT with increased SOD activity. L.plantarum ZG03 significantly increased the content of SCFAs including acetic acid, propionic acid, and caproic acid in zebrafish metabolites. In addition, sodium acetate, sodium propionate, and sodium caproate in the SCFAs significantly increased SOD activity in the zebrafish models. CONCLUSIONS L. plantarum ZG03 ameliorates oxidative stress in a glucose-induced zebrafish model through its metabolites, particularly the SCFAs including acetic acid, propionic acid and caproic acid.
Animals ; Zebrafish/metabolism* ; Oxidative Stress ; Lactobacillus plantarum/metabolism* ; Fatty Acids, Volatile/metabolism* ; Probiotics ; Reactive Oxygen Species/metabolism* ; Superoxide Dismutase/metabolism*

OBJECTIVES: To explore the mechanism by which astragaloside IV (AS-IV) alleviates D-galactose (D-GAL)-induced senescence in human umbilical vein endothelial cells (HUVECs). METHODS: Cultured HUVECs were treated with D-GAL (40 g/L), AS-IV (200 μmol/L), D-GAL+AS-IV, or D-GAL+AS-IV+MTK458 (a mitochondrial autophagy agonist, 25 μmol/L) for 48 h, and the changes in cell proliferation, migration, and angiogenesis capacity were evaluated. Cell apoptosis, reactive oxygen species (ROS) levels, mitochondrial membrane potential, and expressions of autophagy-related proteins (LC3-II/LC3-I) and PINK1/Parkin pathway proteins in the treated cells were detected. RESULTS: AS-IV treatment significantly reduced the inhibitory effect of D-GAL on HUVEC viability, effectively alleviated D-GAL-induced impairment of tube-forming ability, and promoted angiogenesis and migration ability of the cells. AS-IV also significantly reduced the rate of D-GAL-induced HUVECs positive for senescence-associated β-galactosidase (SA-β-Gal) staining and inhibited the expression of senescence-related genes P21 and P53. AS-IV restored mitochondrial membrane potential and reduced intracellular ROS levels in D-GAL-induced HUVECs, and inhibited the fusion of autophagosomes and lysosomes to prevent the completion of autophagic flux. In HUVECs treated with both D-GAL and AS-IV, the application MTK458 significantly increased the number of yellow spots and enhanced the expressions of P21, P53, PINK1, Parkin, LC3, and Beclin proteins. CONCLUSIONS AS-IV alleviates D-GAL-induced endothelial cell senescence by inhibiting the PINK1/Parkin pathway to regulate mitochondrial autophagy.
Humans ; Human Umbilical Vein Endothelial Cells/drug effects* ; Cellular Senescence/drug effects* ; Autophagy/drug effects* ; Saponins/pharmacology* ; Ubiquitin-Protein Ligases/metabolism* ; Mitochondria/drug effects* ; Triterpenes/pharmacology* ; Protein Kinases/metabolism* ; Galactose/pharmacology* ; Reactive Oxygen Species/metabolism* ; Signal Transduction/drug effects* ; Cells, Cultured ; Apoptosis/drug effects* ; Membrane Potential, Mitochondrial ; Cell Proliferation/drug effects*

OBJECTIVE: To observe the effect of electroacupuncture (EA) pretreatment of "biaoben acupoint combination" on cardiomyocyte mitochondrial fission in the rats with myocardial ischemia-reperfusion injury (MIRI) and explore its mechanism. METHODS: Fifty male SD rats were randomly divided into a sham-operation group, a model group, an EA pretreatment group, an EA pretreatment + Compound C group and an EA pretreatment+ML385 group, 10 rats in each group. In the EA pretreatment, the EA pretreatment + Compound C group and the EA pretreatment+ML385 group, EA was delivered at bilateral "Neiguan" (PC6), "Zusanli" (ST36) and "Guanyuan" (CV4) for 20 min, with continuous wave and 2 Hz of frequency, 1 mA of current, once daily for consecutive 7 days. On day 8, in the EA pretreatment + Compound C group and the EA pretreatment+ML385 group, 30 min before model preparation, the intraperitoneal injection with Compound C (0.3 mg/kg) and ML385 (30 mg/kg) was administered respectively. Except in the sham-operation group, the ligation of the left anterior descending coronary artery was performed to prepare MIRI rat model in the rest groups. In the sham-operation group, the thread was not ligated. After modeling, the content of reactive oxygen species (ROS) in the ischemic area was measured by flow cytometry, superoxide dismutase (SOD) was detected using xanthine oxidase method, and malondialdelyde (MDA) was detected using thiobarbituric acid (TBA) chromatometry. The morphology of myocardial tissue in the ischemic area was observed with HE staining, and the mitochondria ultrastructure of cardiomyocytes observed under transmission electron microscopy. Using immunofluorescence analysis, the positive expression of mitochondrial fission factor (MFF), mitochondrial fission 1 protein antibody (Fis1) and dynamin-related protein 1 (Drp1) was detected; and with immunohistochemical method used, the protein expression of adenosine monophosphate-activated protein kinase (AMPK), nuclear factor E2-associated factor2 (Nrf2) and Drp1 in the ischemic area was detected. RESULTS: Compared with the sham-operation group, the content of ROS and MDA in the myocardial tissue of the ischemic area, and the positive expression of MFF, Fis1 and Drp1 increased in the model group (P<0.01); the content of SOD and the protein expression of AMRK and Nrf2 decreased (P<0.01), and the protein expression of Drp1 elevated (P<0.01). Compared with the model group, the content of ROS and MDA in the myocardial tissue of the ischemic area, and the positive expression of MFF, Fis1 and Drp1 were dropped in the EA pretreatment group (P<0.01); the content of SOD and the protein expression of AMRK and Nrf2 rose (P<0.01), and the protein expression of Drp1 declined (P<0.01); and in the EA pretreatment+Compound C group and the EA pretreatment+ML385 group, the positive expression of MFF, Fis1 and Drp1, and the protein expression of Drp1 were all reduced (P<0.01). When compared with the EA pretreatment + Compound C group and the EA pretreatment+ML385 group, the content of ROS and MDA in the myocardial tissue of the ischemic area, and the positive expression of MFF, Fis1 and Drp1 were dropped in the EA pretreatment group (P<0.01); the content of SOD and the protein expression of AMRK and Nrf2 rose (P<0.01, P<0.05), and the protein expression of Drp1 decreased (P<0.05). In comparison with the model group, the EA pretreatment+Compound C group and the EA pretreatment+ML385 group, the cardiac muscle fiber rupture, cell swelling and mitochondrial disorders were obviously alleviated in the EA pretreatment group. The morphological changes were similar among the model group, the EA pretreatment+Compound C group and the EA pretreatment+ML385 group. CONCLUSION Electroacupuncture pretreatment of "biaoben acupoint combination" attenuates myocardial injury in MIRI rats, probably through promoting the phosphorylation of AMPK and Nrf2, inhibiting the excessive mitochondrial fission induced by Drp1, and reducing mitochondrial dysfunction caused by mitochondrial fragmentation and vacuolation.
Animals ; Electroacupuncture ; Male ; Rats, Sprague-Dawley ; Myocardial Reperfusion Injury/physiopathology* ; Myocytes, Cardiac/cytology* ; Rats ; Acupuncture Points ; Mitochondrial Dynamics ; Humans ; Reactive Oxygen Species/metabolism* ; NF-E2-Related Factor 2/genetics* ; Superoxide Dismutase/metabolism*