Abstract 522: Contribution of Reactive Oxygen Species and Rho Kinase in Sphingosine-1-phosphate Mediated Afferent Arteriolar Vasoconstriction of Ischemia-Reperfusion Rats

Hypertension ◽  
2014 ◽  
Vol 64 (suppl_1) ◽  
Author(s):  
Zhengrong Guan ◽  
Edward W. Inscho
Keyword(s):  
Reactive Oxygen Species ◽  
Kinase Inhibitor ◽  
Ischemia Reperfusion ◽  
Rho Kinase ◽  
Reactive Oxygen ◽  
Kidney Injury ◽  
Oxygen Species ◽  
Sphingosine 1 Phosphate ◽  
Arteriolar Tone

Our recent studies indicate that sphingosine-1-phosphate (S1P) is a potent vasoconstrictor of afferent arterioles (AA) and is enhanced in renal ischemia-reperfusion (IR) injury. We hypothesized that renal IR-induced increases in reactive oxygen species (ROS) and activation of the rho kinase pathway contribute to the enhanced S1P sensitivity of AA in IR rats. IR injury was induced by bilateral renal artery occlusion for 60 min followed by 24 hrs reperfusion. Renal function was assessed by plasma creatinine (Cr) or glomerular filtration rate (GFR). The AA response to S1P was assessed using the in vitro blood-perfused juxtamedullary nephron preparation with and without superfusion with the ROS scavenger, Tempol, or the rho kinase inhibitor, Y27623. Plasma Cr was markedly increased in IR (3.86±0.20 vs. 0.93±0.07 mg/L in sham, n=5-7, P < 0.05). GFR, calculated from the half time (T 1/2 ) of sinistrin clearance, was significantly reduced in IR rats. The T 1/2 averaged 166±28 min in IR vs. 25±4 min in sham rats corresponding to GFRs of 0.20±0.02 and 1.33±0.23 ml/min (P < 0.05, n=3 each), respectively. The basal AA diameter was significantly decreased in IR compared to sham rats (10.2±0.5 vs. 15.0±0.4 μm, P < 0.05, n=9 each). Superfusion of Tempol (10 -4 M) did not alter the basal AA diameter in sham but increased diameter in IR by 8±1% (P < 0.05, n=6 each). S1P superfusion evoked concentration-dependent AA vasoconstriction in both groups, however, Tempol significantly shifted the S1P response curve to the right in IR. Increasing concentrations of S1P (10 -10 -10 -5 M) reduced AA diameter to 98±2, 96±2, 98±2, 94±3, 81±9 and 59±5% of control in IR rats similar to the response in Tempol-treated sham rats (99±1, 99±2, 96±2, 88±5, 65±6 and 48±4%, respectively, P > 0.05). In contrast, superfusion of Y27632 (10 -5 M) markedly increased the basal AA diameter in both groups. AA diameter increased by 81±17% from 10.6±1.3 to 19.2±3.3 μm in IR vs. a 53±21% increase in sham rats (P > 0.05, n=3 each). Y27632 also significantly blunted S1P-mediated AA vasoconstriction similarly in both groups. These results indicate a significant contribution of ROS and rho kinase to both the elevated afferent arteriolar tone and the enhanced S1P sensitivity of AA in IR induced acute kidney injury.

scholarly journals Salvianolic Acid A Protects Against Oxidative Stress and Apoptosis Induced by Intestinal Ischemia-Reperfusion Injury Through Activation of Nrf2/HO-1 Pathways

2018 ◽  
Vol 49 (6) ◽  
pp. 2320-2332 ◽  
Author(s):  
Guo Zu ◽  
Tingting Zhou ◽  
Ningwei Che ◽  
Xiangwen Zhang
Keyword(s):  
Reactive Oxygen Species ◽  
Glutathione Peroxidase ◽  
Ischemia Reperfusion ◽  
Reactive Oxygen ◽  
Oxygen Species ◽  
Salvianolic Acid ◽  
Salvianolic Acid A ◽  
Tnf Α

Background/Aims: Ischemia-reperfusion (I/R) adversely affects the intestinal mucosa. The major mechanisms of I/R are the generation of reactive oxygen species (ROS) and apoptosis. Salvianolic acid A (SalA) is suggested to be an effective antioxidative and antiapoptotic agent in numerous pathological injuries. The present study investigated the protective role of SalA in I/R of the intestine. Methods: Adult male Sprague-Dawley rats were subjected to intestinal I/R injury in vivo. In vitro experiments were performed in IEC-6 cells subjected to hypoxia/ reoxygenation (H/R) stimulation to simulate intestinal I/R. TNF-α, IL-1β, and IL-6 levels were measured using enzyme-linked immunosorbent assay. Malondialdehyde and myeloperoxidase and glutathione peroxidase levels were measured using biochemical analysis. Apoptosis was measured by terminal deoxynucleotidyl transferase mediated dUTP nick-end labeling staining or flow cytometry in vivo and in vitro. The level of reactive oxygen species (ROS) was measured by dichlorodihydrofluorescin diacetate (DCFH-DA) staining. Western blotting was performed to determine the expression of heme oxygenase-1 (HO-1), Nrf2 and proteins associated with apoptosis. The mRNA expressions of Nrf2 and HO-1 were detected by quantitative real-time polymerase chain reaction in vivo and in vitro. Results: Malondialdehyde level and myeloperoxidase and glutathione peroxidase, TNF-α, IL-1β, and IL-6 levels group in intestinal tissue decreased significantly in the SalA pretreatment groups compared to the I/R group. SalA markedly abolished intestinal injury compared to the I/R group. SalA significantly attenuated apoptosis and increased Nrf2/HO-1 expression in vivo and in vitro. However, Nrf2 siRNA treatment partially abrogated the above mentioned effects of SalA in H/R-induced ROS and apoptosis in IEC-6 cells. Conclusion: The present study demonstrated that SalA ameliorated oxidation, inhibited the release of pro-inflammatory cytokines and alleviated apoptosis in I/R-induced injury and that these protective effects may partially occur via regulation of the Nrf2/ HO-1 pathways.

Activation of Rho/Rho kinase signaling pathway by reactive oxygen species in rat aorta

2004 ◽  
Vol 287 (4) ◽  
pp. H1495-H1500 ◽  
Author(s):  
Liming Jin ◽  
Zhekang Ying ◽  
R. Clinton Webb
Keyword(s):  
Reactive Oxygen Species ◽  
Signaling Pathway ◽  
Kinase Inhibitor ◽  
Isometric Force ◽  
Rho Kinase ◽  
Reactive Oxygen ◽  
Dependent Manner ◽  
Oxygen Species ◽  
Kinase Signaling ◽  
Kinase Signaling Pathway

Evidence indicates that both the Rho/Rho kinase signaling pathway and reactive oxygen species (ROS) such as superoxide and H2O2 are involved in the pathogenesis of hypertension. This study aimed to determine whether ROS-induced vascular contraction is mediated through activation of Rho/Rho kinase. Rat aortic rings (endothelium denuded) were isolated and placed in organ chambers for measurement of isometric force development. ROS were generated by a xanthine (X)-xanthine oxidase (XO) mixture. The antioxidants tempol (3 mM) and catalase (1,200 U/ml) or the XO inhibitor allopurinol (400 μM) significantly reduced X/XO-induced contraction. A Rho kinase inhibitor, (+)-( R)- trans-4-(1-aminoethyl- N-4-pyridil)cyclohexanecarboxamide dihydrochloride (Y-27632), decreased the contraction in a concentration-dependent manner; however, the Ca2+-independent protein kinase C inhibitor rottlerin did not have an effect on X/XO-induced contraction. Phosphorylation of the myosin light chain phosphatase target subunit (MYPT1) was increased by ROS, and preincubation with Y-27632 blocked this increased phosphorylation. Western blotting for cytosolic and membrane-bound fractions of Rho showed that Rho was increased in the membrane fraction by ROS, suggesting activation of Rho. These observations demonstrate that ROS-induced Ca2+ sensitization is through activation of Rho and a subsequent increase in Rho kinase activity but not Ca2+-independent PKC.

scholarly journals BAM15 treats mouse sepsis and sepsis-AKI, linking circulating mitochondrial DNA and tubule reactive oxygen species

2021 ◽  
Author(s):  
Naoko Tsuji ◽  
Takayuki Tsuji ◽  
Tetsushi Yamashita ◽  
Xuzhen Hu ◽  
Peter S.T. Yuen ◽  
...  
Keyword(s):  
Reactive Oxygen Species ◽  
Mitochondrial Dna ◽  
Precision Medicine ◽  
Cecal Ligation ◽  
Reactive Oxygen ◽  
Kidney Injury ◽  
Experimental Sepsis ◽  
Oxygen Species ◽  
Clinical Sepsis

The pathogenesis of sepsis is complex and heterogeneous; hence, a precision medicine strategy may be required. Acute kidney injury (AKI) following sepsis portends higher mortality. Overproduction of mitochondrial reactive oxygen species (mtROS) is a potential mediator of sepsis and sepsis-induced AKI. BAM15 is a chemical uncoupler that dissipates the mitochondrial proton gradient without generating mtROS, and improves experimental renal ischemic injury. We injected BAM15 into mice at 0 or 6 hours after cecal ligation and puncture (CLP) treated with fluids and antibiotics. BAM15 reduced mortality, even when started at 6 hours, when mice were ill, and reduced kidney damage but did not affect other organs. Serial plasma and urinary levels of mitochondrial DNA (mtDNA) were increased following CLP, and decreased after BAM15 (at 0 and at 6 hours). In vitro BAM15 prevented mtROS overproduction and mtDNA release from septic kidney tubule cells; mtROS generation correlated with mtDNA release. BAM15 also promotes mitochondrial biogenesis signaling. We conclude that BAM15 is an effective preventive and therapeutic candidate in experimental sepsis, and that BAM15 and mtDNA are mechanistically linked via mtROS, which may form a drug-companion diagnostic pair to improve precision medicine approaches to diagnosing and treating clinical sepsis.

scholarly journals Tannic Acid Improves Renal Function Recovery after Renal Warm Ischemia–Reperfusion in a Rat Model

Biomolecules ◽  
2020 ◽  
Vol 10 (3) ◽  
pp. 439
Author(s):  
Louise Alechinsky ◽  
Frederic Favreau ◽  
Petra Cechova ◽  
Sofiane Inal ◽  
Pierre-Antoine Faye ◽  
...  
Keyword(s):  
Reactive Oxygen Species ◽  
Tannic Acid ◽  
Rat Model ◽  
Ischemia Reperfusion ◽  
Reactive Oxygen ◽  
Warm Ischemia ◽  
Endothelial Cell Migration ◽  
Oxygen Species ◽  
Cold Ischemia

Background and purpose: Ischemia–reperfusion injury is encountered in numerous processes such as cardiovascular diseases or kidney transplantation; however, the latter involves cold ischemia, different from the warm ischemia found in vascular surgery by arterial clamping. The nature and the intensity of the processes induced by ischemia types are different, hence the therapeutic strategy should be adapted. Herein, we investigated the protective role of tannic acid, a natural polyphenol in a rat model reproducing both renal warm ischemia and kidney allotransplantation. The follow-up was done after 1 week. Experimental approach: To characterize the effect of tannic acid, an in vitro model of endothelial cells subjected to hypoxia–reoxygenation was used. Key results: Tannic acid statistically improved recovery after warm ischemia but not after cold ischemia. In kidneys biopsies, 3 h after warm ischemia–reperfusion, oxidative stress development was limited by tannic acid and the production of reactive oxygen species was inhibited, potentially through Nuclear Factor erythroid-2-Related factor 2 (NRF2) activation. In vitro, tannic acid and its derivatives limited cytotoxicity and the generation of reactive oxygen species. Molecular dynamics simulations showed that tannic acid efficiently interacts with biological membranes, allowing efficient lipid oxidation inhibition. Tannic acid also promoted endothelial cell migration and proliferation during hypoxia. Conclusions: Tannic acid was able to improve renal recovery after renal warm ischemia with an antioxidant effect putatively extended by the production of its derivatives in the body and promoted cell regeneration during hypoxia. This suggests that the mechanisms induced by warm and cold ischemia are different and require specific therapeutic strategies.

Abstract 1623: Reactive Oxygen Species increases Intracellular Calcium, alters the Electrophysiological Properties and Synaptic Transmission in Intrinsic Cardiac Ganglion Neurons: in vitro

Circulation ◽  
2008 ◽  
Vol 118 (suppl_18) ◽  
Author(s):  
Jhansi Dyavanapalli ◽  
Katrina Rimmer ◽  
Alexander A Harper
Keyword(s):  
Reactive Oxygen Species ◽  
Synaptic Transmission ◽  
Ischemia Reperfusion ◽  
Reactive Oxygen ◽  
Simultaneous Recording ◽  
Oxygen Species ◽  
Home Office ◽  
Electrophysiological Properties ◽  
Ganglion Neurons

Anerobic metabolism generates reactive oxygen species (ROS) as by-products and this is increased during ischemia. ROS have been shown to interact with and impair the functioning of membrane proteins such as ion channels and transporters and cause disturbances in intracellular Ca 2+ homeostasis. We have investigated the effects of ROS upon [Ca 2+ ] i , the intrinsic electrophysiological characteristics and synaptic transmission in neurons of the ICG regulating the sinoatrial node. The hypothesis is that ROS-induced damage increases [Ca 2+ ] i and attenuates synaptic transmission in ICG. used a whole-mount adult rat ICG preparation, in vitro (rats were killed by stunning and cervical dislocation, according to current UK Home Office guidelines). Intracellular recordings were made using sharp glass microelectrodes filled with Oregon Green 488 BAPTA-1, allowing simultaneous recording of electrical properties and measurement of [Ca 2+ ] i . Signals resulting from [Ca 2+ ] i changes were expressed as the ratio of fluorescence changes over baseline fluorescence, (f-fo)/fo . The ROS-donors hydrogen peroxide (H 2 O 2 , 1 mM) and tert-butyl hydroperoxide ( t -BHP, 1mM) had broadly similar actions on postganglionic somata, both producing membrane potential hyperpolarization (from −48.4 mV ± 6.5 S.D control to −69.9 mV ± 7.9 H 2 O 2 , n=7; and from −51.9 mV ± 7.1 control to −59.2 mV ± 7.9 t -BHP, n=17, p<0.001). Considering the somatic action potential (AP), t -BHP decreased the rate of rise (from 159 V/sec ± 79 control to 117 V/sec ± 53, n=6, p<0.05), but did not alter the rate of fall and increased AP duration (measured at 0 mV) from 0.7ms (± 0.2) control to 1.1ms (± 0.3, n=5, p<0.05). In addition, t -BHP reduced the AP afterhyper-polarization (AHP) amplitude (from 15.5 mV ± 5.2 control to 9.9 mV ± 4.5, n=10, p<0.001) but had no impact on AP overshoot or AHP duration. t -BHP and H 2 O 2 markedly increased resting [Ca 2+ ] i to 1.59 (± 0.03, n=8,p<0.001) and 2.36 (± 0.04, n=3, p<0.05) respectively, of control values (~ 60 nM ). H 2 O 2 blocked synaptic transmission in 3 /4 neurons. In contrast, t -BHP had no significant action on synaptic transmission. Together, these data demonstrate that ROS alters the excitability of ICG neurons attenuating parasympathetic control of the heart during ischemia/ reperfusion.

scholarly journals Ambra1 Alleviates Hypoxia/Reoxygenation Injury in H9C2 Cells by Regulating Autophagy and Reactive Oxygen Species

2020 ◽  
Vol 2020 ◽  
pp. 1-12
Author(s):  
Lin Zhao ◽  
Liting Cheng ◽  
Yongquan Wu
Keyword(s):  
Reactive Oxygen Species ◽  
Ischemia Reperfusion Injury ◽  
Ischemia Reperfusion ◽  
Reactive Oxygen ◽  
Reperfusion Therapy ◽  
Oxygen Species ◽  
H9c2 Cells ◽  
Reoxygenation Injury ◽  
Myocardial Ischemia Reperfusion

Reperfusion therapy is the most important method for treating acute myocardial infarction. However, myocardial ischemia reperfusion injury (MIRI) can offset the benefit of reperfusion therapy and worsen the outcome. In both ischemia and reperfusion, autophagy remains problematic. Activating molecule in Beclin1-regulated autophagy (Ambra1) is an important protein in autophagy regulation, and its function in MIRI remains unclear. Thus, we used H9C2 cells to investigate the function of Ambra1 in MIRI and the underlying mechanisms involved. Hypoxia and reoxygenation of H9C2 cells were used to mimic MIRI in vitro. During hypoxia, autophagy flux was blocked, then recovered in reoxygenation. Ambra1 overexpression increased autophagy in the H9C2 cells, as the LC3B II/I ratio increased, and alleviated cellular necrosis and apoptosis during hypoxia and reoxygenation. This effect was counteracted by an autophagy inhibitor. Knocking down Ambra1 can block autophagy which P62 sediment/supernatant ratio increased while the ratio of LC3B II/I decreased, and worsen outcomes. Ambra1 enhances autophagy in H9C2 cells by improving the stability and activity of the ULK1 complex. Reactive oxygen species (ROS) are an important cause of MIRI. ROS were reduced when Ambra1 was overexpressed and increased when Ambra1 was knocked down, indicating that Ambra1 can protect against hypoxia and reoxygenation injury in H9C2 cells by promoting autophagy and reducing ROS.

Role of Cyclooxygenase and Derived Reactive Oxygen Species in ρ-Kinase-Mediated Impairment of Endothelium-Dependent Vasodilation and Blood Flow after Ischemia-Reperfusion of the Rat Kidney

2010 ◽  
Vol 114 (1) ◽  
pp. e1-e6 ◽  
Author(s):  
Amanda M.G. Versteilen ◽  
Iolente J.M. Korstjens ◽  
Ren&eacute; J.P. Musters ◽  
A.B. Johan Groeneveld ◽  
Pieter Sipkema
Keyword(s):  
Reactive Oxygen Species ◽  
Blood Flow ◽  
Rat Kidney ◽  
Ischemia Reperfusion ◽  
Rho Kinase ◽  
Reactive Oxygen ◽  
Oxygen Species

scholarly journals PER2 Regulates Reactive Oxygen Species Production in the Circadian Susceptibility to Ischemia/Reperfusion Injury in the Heart

2021 ◽  
Vol 2021 ◽  
pp. 1-11
Author(s):  
Yaqian Weng ◽  
Hui Li ◽  
Lin Gao ◽  
Wenjing Guo ◽  
Shiyuan Xu ◽  
...  
Keyword(s):  
Reactive Oxygen Species ◽  
Ischemia Reperfusion Injury ◽  
Ischemia Reperfusion ◽  
Reactive Oxygen ◽  
Oxygen Species ◽  
H9c2 Cells ◽  
Oxidative Balance ◽  
Severity Of Injury

The main objective of this study was to investigate the diurnal differences in Period 2 (PER2) expression in myocardial ischemia-reperfusion (I/R) injury. We investigated diurnal variations in oxidative stress and energy metabolism after myocardial I/R in vitro and in vivo. In addition, we also analyzed the effects of H2O2 treatment and serum shock in H9c2 cells transfected with silencing RNA against Per2 (siRNA-Per2) in vitro. We used C57BL/6 male mice to construct a model of I/R injury at zeitgeber time (ZT) 2 and ZT14 by synchronizing the circadian rhythms. Our in vivo analysis demonstrated that there were diurnal differences in the severity of injury caused by myocardial infarctions, with more injury occurring in the daytime. PER2 was significantly reduced in heart tissue in the daytime and was higher at night. Our results also showed that more severe injury of mitochondrial function in daytime produced more reactive oxygen species (ROS) and less ATP, which increased myocardial injury. In vitro, our findings presented a similar trend showing that apoptosis of H9c2 cells was increased when PER2 expression was lower. Meanwhile, downregulation of PER2 disrupted the oxidative balance by increasing ROS and mitochondrial injury. The result was a reduction in ATP and failure to provide sufficient energy protection for cardiomyocytes.

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