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Gao R, Wang W, Wang Z, Fan Y, Zhang L, Sun J, Hong M, Pan M, Wu J, Mei Q, Wang Y, Qiao L, Liu J, Tong F. Hibernating/Awakening Nanomotors Promote Highly Efficient Cryopreservation by Limiting Ice Crystals. Adv Healthc Mater 2024:e2401833. [PMID: 39101314 DOI: 10.1002/adhm.202401833] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2024] [Revised: 07/20/2024] [Indexed: 08/06/2024]
Abstract
The disruptions caused by ice crystal formation during the cryopreservation of cells and tissues can cause cell and tissue damage. Thus, preventing such damage during cryopreservation is an important but challenging goal. Here, a hibernating/awakening nanomotor with magnesium/palladium covering one side of a silica platform (Mg@Pd@SiO2) is proposed. This nanomotor is used in the cultivation of live NCM460 cells to demonstrate a new method to actively limit ice crystal formation and enable highly efficient cryopreservation. Cooling Mg@Pd@SiO2 in solution releases Mg2+/H2 and promotes the adsorption of H2 at multiple Pd binding sites on the cell surface to inhibit ice crystal formation and cell/tissue damage; additionally, the Pd adsorbs and stores H2 to form a hibernating nanomotor. During laser-mediated heating, the hibernating nanomotor is activated (awakened) and releases H2, which further suppresses recrystallization and decreases cell/tissue damage. These hibernating/awakening nanomotors have great potential for promoting highly efficient cryopreservation by inhibiting ice crystal formation.
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Affiliation(s)
- Rui Gao
- Department of Pharmacology, School of Pharmacy, Binzhou Medical University, Yantai, 264003, P. R. China
| | - Weixin Wang
- Department of Pharmacology, School of Pharmacy, Binzhou Medical University, Yantai, 264003, P. R. China
| | - Zhongchao Wang
- Institute of Cardiovascular Disease, Shanxi Medical University, Taiyuan, 030001, P. R. China
| | - Yapeng Fan
- Key Laboratory of Tropical Biological Resources of Ministry of Education, School of Pharmaceutical Sciences, Hainan University, Haikou, 570228, P. R. China
| | - Lin Zhang
- Department of Pharmacology, School of Pharmacy, Binzhou Medical University, Yantai, 264003, P. R. China
| | - Jiahui Sun
- Department of Pharmacology, School of Pharmacy, Binzhou Medical University, Yantai, 264003, P. R. China
| | - Miaofang Hong
- Department of Pharmacology, School of Pharmacy, Binzhou Medical University, Yantai, 264003, P. R. China
| | - Min Pan
- Department of Pharmacology, School of Pharmacy, Binzhou Medical University, Yantai, 264003, P. R. China
| | - Jianming Wu
- Education Ministry Key Laboratory of Medical Electrophysiology, Sichuan Key Medical Laboratory of New Drug Discovery and Druggability Evaluation, Key Laboratory of Activity Screening and Druggability Evaluation for Chinese Materia Medica, School of Pharmacy, Southwest Medical University, Luzhou, 646000, P. R. China
| | - Qibing Mei
- Education Ministry Key Laboratory of Medical Electrophysiology, Sichuan Key Medical Laboratory of New Drug Discovery and Druggability Evaluation, Key Laboratory of Activity Screening and Druggability Evaluation for Chinese Materia Medica, School of Pharmacy, Southwest Medical University, Luzhou, 646000, P. R. China
| | - Yini Wang
- Clinical Medical College, Binzhou Medical University, Yantai, 264003, P. R. China
| | - Lingyan Qiao
- Clinical Medical College, Binzhou Medical University, Yantai, 264003, P. R. China
| | - Jin Liu
- Key Laboratory of Tropical Biological Resources of Ministry of Education, School of Pharmaceutical Sciences, Hainan University, Haikou, 570228, P. R. China
| | - Fei Tong
- Department of Pharmacology, School of Pharmacy, Binzhou Medical University, Yantai, 264003, P. R. China
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Tang Y, Zhang K, Zhou H, Zhang C, Liu Z, Chen H, Li H, Chen K. Transplantation of active nucleus pulposus cells with a keep-charging hydrogel microsphere system to rescue intervertebral disc degeneration. J Nanobiotechnology 2023; 21:453. [PMID: 38017517 PMCID: PMC10683266 DOI: 10.1186/s12951-023-02226-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2023] [Accepted: 11/19/2023] [Indexed: 11/30/2023] Open
Abstract
BACKGROUND Cell transplantation has been demonstrated as a promising approach in tissue regeneration. However, the reactive oxygen species (ROS) accumulation and inflammation condition establish a harsh microenvironment in degenerated tissue, which makes the transplanted cells difficult to survive. METHODS In this study, we constructed a keep-charging hydrogel microsphere system to enable cells actively proliferate and function in the degenerated intervertebral disc. Specifically, we combined Mg2+ to histidine-functionalized hyaluronic acid (HA-His-Mg2+) through coordination reaction, which was further intercrossed with GelMA to construct a double-network hydrogel microsphere (GelMA/HA-His-Mg2+, GHHM) with microfluidic methods. In vitro, the GHHM loaded with nucleus pulposus cells (GHHM@NPCs) was further tested for its ability to promote NPCs proliferation and anti-inflammatory properties. In vivo, the ability of GHHM@NPCs to promote regeneration of NP tissue and rescue intervertebral disc degeneration (IVDD) was evaluated by the rat intervertebral disc acupuncture model. RESULTS The GHHM significantly enhanced NPCs adhesion and proliferation, providing an ideal platform for the NPCs to grow on. The loaded NPCs were kept active in the degenerative intervertebral disc microenvironment as charged by the Mg2+ in GHHM microspheres to effectively support the loaded NPCs to reply against the ROS-induced inflammation and senescence. Moreover, we observed that GHHM@NPCs effectively alleviated nucleus pulposus degeneration and promoted its regeneration in the rat IVDD model. CONCLUSION In conclusion, we constructed a keep charging system with a double-network hydrogel microsphere as a framework and Mg2+ as a cell activity enhancer, which effectively maintains NPCs active to fight against the harsh microenvironment in the degenerative intervertebral disc. The GHHM@NPCs system provides a promising approach for IVDD management.
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Affiliation(s)
- Yingchuang Tang
- Department of Orthopedic, First Affiliated Hospital of Soochow University, Suzhou, People's Republic of China
| | - Kai Zhang
- Department of Orthopedic, First Affiliated Hospital of Soochow University, Suzhou, People's Republic of China
| | - Hongyou Zhou
- Department of Orthopedic, First Affiliated Hospital of Soochow University, Suzhou, People's Republic of China
| | - Chenchen Zhang
- Department of Radiology, Second Affiliated Hospital of Soochow University, Suzhou, People's Republic of China
| | - Zixiang Liu
- Department of Orthopedic, First Affiliated Hospital of Soochow University, Suzhou, People's Republic of China
| | - Hao Chen
- Department of Orthopedics, Affiliated Hospital of Yangzhou University, Yangzhou, People's Republic of China.
- Institute of Translational Medicine, Medical College, Yangzhou University, Yangzhou, People's Republic of China.
| | - Hanwen Li
- Department of Orthopedic, First Affiliated Hospital of Soochow University, Suzhou, People's Republic of China.
| | - Kangwu Chen
- Department of Orthopedic, First Affiliated Hospital of Soochow University, Suzhou, People's Republic of China.
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Mitochondrial abnormalities: a hub in metabolic syndrome-related cardiac dysfunction caused by oxidative stress. Heart Fail Rev 2021; 27:1387-1394. [PMID: 33950478 PMCID: PMC9197868 DOI: 10.1007/s10741-021-10109-6] [Citation(s) in RCA: 23] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 04/13/2021] [Indexed: 12/11/2022]
Abstract
Metabolic syndrome (MetS) refers to a group of cardiovascular risk elements comprising insulin resistance, obesity, dyslipidemia, increased glucose intolerance, and increased blood pressure. Individually, all the MetS components can lead to cardiac dysfunction, while their combination generates additional risks of morbidity and mortality. Growing evidence suggests that oxidative stress, a dominant event in cellular damage and impairment, plays an indispensable role in cardiac dysfunction in MetS. Oxidative stress can not only disrupt mitochondrial activity through inducing oxidative damage to mitochondrial DNA, RNA, lipids, and proteins but can also impair cardiomyocyte contractile function via mitochondria-related oxidative modifications of proteins central to excitation-contraction coupling. Furthermore, excessive reactive oxygen species (ROS) generation can lead to the activation of several mitochondria apoptotic signaling pathways, release of cytochrome c, and eventual induction of myocardial apoptosis. This review will focus on such processes of mitochondrial abnormalities in oxidative stress induced cardiac dysfunction in MetS.
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Guardia de Souza e Silva T, do Val de Paulo MEF, da Silva JRM, da Silva Alves A, Britto LRG, Xavier GF, Lopes Sandoval MR. Oral treatment with royal jelly improves memory and presents neuroprotective effects on icv-STZ rat model of sporadic Alzheimer's disease. Heliyon 2020; 6:e03281. [PMID: 32055729 PMCID: PMC7005440 DOI: 10.1016/j.heliyon.2020.e03281] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2018] [Revised: 02/12/2019] [Accepted: 01/08/2020] [Indexed: 02/07/2023] Open
Abstract
Alzheimer's disease (AD) is a neurodegenerative disorder characterized by progressive decline in cognitive function. Intracerebroventricular injection of streptozotocin (icv-STZ) has been used as an experimental model of Sporadic AD (SAD) in rodents and represents a promising tool for etiopathogenic analysis and evaluation of new therapeutic proposals for AD. The icv-STZ model shows many aspects of SAD abnormalities, resulting in decreased brain glucose and energy metabolism, cognitive impairment, oxidative stress, neuronal loss, and amyloid angiopathy. Royal jelly (RJ), a substance produced by worker honeybees of the Apis mellifera species, has been popularly used for more than 30 years in areas related to health eating and natural medicine. Researches indicate that RJ has a several pharmacological activities, including neuroprotective and improvement of cognitive function. The objective of this study was to investigate the effects of oral treatment with royal jelly during 2 weeks in Wistar rats submitted to icv-STZ on a working memory and neuroprotection, as evaluated by neurogenesis, neurodegeneration and oxidative stress. In this study, icv-STZ injection induced deleterious effects in the hippocampus, associated with cognitive impairments, and developed marked neurodegeneration, besides the reduction of neurogenesis and increased oxidative stress. On the other hand, RJ long-term oral administration induced beneficial effects in animals injured by icv-STZ injection, increasing retention time for working spatial memory, reducing neurodegeneration and oxidative stress level and increasing the proliferation of new neurons in the hippocampus. Thus, RJ promotes beneficial effects on cognitive functions and exhibits a neuroprotective action in the STZ experimental model of SAD.
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Affiliation(s)
| | | | | | - Adilson da Silva Alves
- Institute of Biomedical Sciences, University of São Paulo, Av. Prof. Lineu Prestes, 2415, São Paulo, Brazil
| | - Luiz Roberto G. Britto
- Institute of Biomedical Sciences, University of São Paulo, Av. Prof. Lineu Prestes, 2415, São Paulo, Brazil
| | - Gilberto Fernando Xavier
- Institute of Biosciences, University of São Paulo, Rua do Matão, Travessa 14, 101, São Paulo, Brazil
| | - Maria Regina Lopes Sandoval
- Laboratory of Pharmacology, Butantan Institute, Avenida Vital Brasil, 1500, cep 05503-900, São Paulo, Brazil
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Akhtar MJ, Ahamed M, Alhadlaq HA, Alrokayan SA. MgO nanoparticles cytotoxicity caused primarily by GSH depletion in human lung epithelial cells. J Trace Elem Med Biol 2018; 50:283-290. [PMID: 30262293 DOI: 10.1016/j.jtemb.2018.07.016] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/05/2018] [Revised: 07/17/2018] [Accepted: 07/20/2018] [Indexed: 12/14/2022]
Abstract
Bio-response of magnesium oxide nanoparticles (MgO NPs) is emerging, obviously, with a conflicting flavor. This study evaluates the underlying mechanism of bio-responses of MgO NPs in human lung epithelial (A549) cell. TEM size of NPs was 40-50 nm and cuboidal in shape. EDS data showed no detectable impurity. Zeta potential of MgO NPs suggested a fair dispersion in complete culture media and in PBS. MgO NPs induced a concentration dependent cytotoxicity when measured by MTT and NRU. MgO NPs induced cytotoxicity strongly correlated with intracellular depletion of antioxidant GSH. MgO NPs did not induce concentration dependent ROS. All live treatment conditions caused autophagy, a survival mechanism when deprived of nutrients and antioxidant. At highest cytotoxic concentration of MgO NPs, there was significant elevation in MMP and caspase-3 activity. GSH depletion mediated autophagy failure lead to MgO NPs induced death at higher concentrations that might have potentiated by induced ROS. This study suggested a mechanism of cytotoxicity caused by MgO NPs that was primarily dependent on GSH depletion, and ROS induction played secondary role in toxicity. Significantly higher toxicity observed for MgO NPs in comparison to Mg salt clearly indicated the involvement of nanoparticulate form in toxicity.
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Affiliation(s)
- Mohd Javed Akhtar
- King Abdullah Institute for Nanotechnology, King Saud University, Riyadh 11451, Saudi Arabia.
| | - Maqusood Ahamed
- King Abdullah Institute for Nanotechnology, King Saud University, Riyadh 11451, Saudi Arabia
| | - Hisham A Alhadlaq
- Department of Physics and Astronomy, College of Science, King Saud University, Riyadh 11451, Saudi Arabia; King Abdullah Institute for Nanotechnology, King Saud University, Riyadh 11451, Saudi Arabia
| | - Salman A Alrokayan
- Research Chair for Biomedical Applications of Nanomaterials, Biochemistry Department, College of Science, Building 5, PO Box 2455, King Saud University, Riyadh, Saudi Arabia
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Intermittent hypoxia-generated ROS contributes to intracellular zinc regulation that limits ischemia/reperfusion injury in adult rat cardiomyocyte. J Mol Cell Cardiol 2018; 118:122-132. [PMID: 29577873 DOI: 10.1016/j.yjmcc.2018.03.014] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/15/2018] [Revised: 03/05/2018] [Accepted: 03/21/2018] [Indexed: 12/20/2022]
Abstract
Intermittent hypoxia (IH) has been shown to exert cardioprotective effects against ischemia/reperfusion (I/R) injury through the preservation of ion homeostasis. I/R dramatically elevated cytosolic Zn2+ and caused cardiomyocyte death. However, the role of IH exposure in the relationship between Zn2+ regulation and cardioprotection is still unclear. The aim of the present study was to study whether IH exposure could help in intracellular Zn2+ regulation, hence contributing to cardioprotection against I/R injury. Adult rat cardiomyocytes were exposed to IH (5% O2, 5% CO2 and balanced N2) for 30 min followed by 30 min of normoxia (21% O2, 5% CO2 and balanced N2). Changes in intracellular Zn2+ concentration were determined using a Zn2+-specific fluorescent dye, FluoZin-3 or RhodZin-3. Fluorescence was monitored under an inverted fluorescent or confocal microscope. The results demonstrated that I/R or 2,2'-dithiodipyridine (DTDP), a reactive disulphide compound, induced Zn2+ release from metallothioneins (MTs), subsequently causing cytosolic Zn2+ overload, which in turn increased intracellular Zn2+ entry into the mitochondria via a Ca2+ uniporter, hence inducing mitochondrial membrane potential loss, and eventually led to cell death. However, the cytosolic Zn2+ overload and cell death caused by I/R or DTDP was significantly reduced by treatment of cardiomyocytes with IH. The findings from this study suggest that IH might exert its cardioprotective effect through reducing the I/R-induced cytosolic Zn2+ overload and cell death in cardiomyocytes.
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Li ZY, Lin J, Sun F, Li H, Xia J, Li XN, Ge J, Zhang C, Li JL. Transport stress induces weight loss and heart injury in chicks: disruption of ionic homeostasis via modulating ion transporting ATPases. Oncotarget 2018; 8:24142-24153. [PMID: 28445983 PMCID: PMC5421834 DOI: 10.18632/oncotarget.15903] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2017] [Accepted: 02/24/2017] [Indexed: 11/25/2022] Open
Abstract
Transportation is inevitable in the poultry industry, and it can induce stress to chicks in varying degrees, such as mild discomfort, sometimes even death. However, the research about the effects of transport stress on the weight loss and heart injury of chicks is lacking. To elucidate the underlying mechanism of transport stress-induced effects, chicks were transported for 2h, 4h and 8h. The creatinine kinase (CK) activities, the ionic contents, the ATPases activities and the transcription of the ATPase associated subunits in chick heart were detected. The results showed that transport stress increased the weight loss and the CK activity, disturbed the ionic (K+, Ca2+, Mg2+) homeostasis and inhibited the ATPase (Na+-K+-ATPase, Ca2+-ATPase, Mg2+-ATPase and Ca2+-Mg2+-ATPase) activities, increased the ATP content and downregulated the gene expression levels of the ATPase associated subunits in heart. In conclusion, transport stress disturbed the ionic homeostasis via modulating ion transporting ATPases and the transcriptions of the associated subunits, and ultimately induced weight loss and heart injury in chicks.
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Affiliation(s)
- Zhao-Yang Li
- College of Veterinary Medicine, Northeast Agricultural University, Harbin, P. R. China
| | - Jia Lin
- College of Veterinary Medicine, Northeast Agricultural University, Harbin, P. R. China
| | - Feng Sun
- College of Veterinary Medicine, Northeast Agricultural University, Harbin, P. R. China
| | - Hui Li
- College of Veterinary Medicine, Northeast Agricultural University, Harbin, P. R. China.,Harbin Sport University, Harbin, P. R. China
| | - Jun Xia
- College of Veterinary Medicine, Northeast Agricultural University, Harbin, P. R. China.,Department of Heilongjiang for Common Animal Disease Prevention and Treatment, Key Laboratory of the Provincial Education Northeast Agricultural University, Harbin, P. R. China
| | - Xue-Nan Li
- College of Veterinary Medicine, Northeast Agricultural University, Harbin, P. R. China.,Heilongjiang Key Laboratory for Laboratory Animals and Comparative Medicine, Northeast Agricultural University, Harbin, P. R. China
| | - Jing Ge
- College of Veterinary Medicine, Northeast Agricultural University, Harbin, P. R. China.,Heilongjiang Key Laboratory for Laboratory Animals and Comparative Medicine, Northeast Agricultural University, Harbin, P. R. China
| | - Cong Zhang
- College of Veterinary Medicine, Northeast Agricultural University, Harbin, P. R. China.,Department of Heilongjiang for Common Animal Disease Prevention and Treatment, Key Laboratory of the Provincial Education Northeast Agricultural University, Harbin, P. R. China
| | - Jin-Long Li
- College of Veterinary Medicine, Northeast Agricultural University, Harbin, P. R. China.,Department of Heilongjiang for Common Animal Disease Prevention and Treatment, Key Laboratory of the Provincial Education Northeast Agricultural University, Harbin, P. R. China.,Heilongjiang Key Laboratory for Laboratory Animals and Comparative Medicine, Northeast Agricultural University, Harbin, P. R. China
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Toxicity study of oxalicumone A, derived from a marine-derived fungus Penicillium oxalicum, in cultured renal epithelial cells. Mol Med Rep 2017; 15:2611-2619. [PMID: 28260084 PMCID: PMC5428325 DOI: 10.3892/mmr.2017.6283] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2016] [Accepted: 01/13/2017] [Indexed: 12/19/2022] Open
Abstract
Oxalicumone A (POA), a novel dihydrothiophene-condensed chromone, was isolated from the marine-derived fungus Penicillium oxalicum. Previous reports demonstrated that POA exhibits strong activity against human carcinoma cells, thus it has been suggested as a bioactive anticancer agent. To research the toxic effect of POA on cultured normal epithelial human kidney-2 (HK-2) cells and evaluate its clinical safety, cell survival was evaluated by the Cell Counting Kit-8 assay and apoptosis was evaluated by Hoechst 33258 staining, flow cytometry, caspase-3 activity assay and western blotting. 2′,7′-Dichlorofluorescin diacetate and JC-1 dye staining was used to evaluate reactive oxygen species (ROS) production and mitochondrial membrane potential (MMP), respectively. The results indicated that POA inhibited HK-2 cell growth and promoted apoptosis, by increasing levels of Fas cell surface cell receptor and the B-cell lymphoma 2 associated protein X apoptosis regulator (Bax)/B-cell lymphoma 2 apoptosis regulator (Bcl-2) ratio. POA treatment also induced release of ROS and loss of MMP in HK-2 cells. Compared with untreated control, a significant decrease was also demonstrated in superoxide dismutase activity and glutathione content with POA treatment, accompanied by enhanced release of N-acetyl-β-D-glucosaminidase, increased leakage of lactate dehydrogenase, increased malondialdehyde formation and increased release of nitric oxide. In conclusion, the present in vitro study revealed that POA exhibits antiproliferation activity on HK-2 cells, through stimulation of apoptosis and oxidative stress injury, which may be relevant to its clinical application. The present study may, therefore, offer valuable new information regarding the use of POA as a candidate novel antitumor drug for clinical use.
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Ozturk N, Olgar Y, Aslan M, Ozdemir S. Effects of magnesium supplementation on electrophysiological remodeling of cardiac myocytes in L-NAME induced hypertensive rats. J Bioenerg Biomembr 2016; 48:425-36. [PMID: 27193439 DOI: 10.1007/s10863-016-9666-8] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2016] [Accepted: 05/11/2016] [Indexed: 02/07/2023]
Abstract
Hypertension is one of the major risk factors of cardiac hypertrophy and magnesium deficiency is suggested to be a contributing factor in the progression of this complication. In this study, we aimed to investigate the relationship between intracellular free Mg(2+) levels and electrophysiological changes developed in the myocardium of L-NAME induced hypertensive rats. Hypertension was induced by administration of 40 mg/kg of L-NAME for 6 weeks, while magnesium treated rats fed with a diet supplemented with 1 g/kg of MgO for the same period. L-NAME administration for 6 weeks elicited a significant increase in blood pressure which was corrected with MgO treatment; thereby cardiac hypertrophy developing secondary to hypertension was prevented. Cytosolic free magnesium levels of ventricular myocytes were significantly decreased with hypertension and magnesium administration restored these changes. Hypertension significantly decreased the fractional shortening with slowing of shortening kinetics in left ventricular myocytes whereas magnesium treatment was capable of restoring hypertension-induced contractile dysfunction. Long-term magnesium treatment significantly restored the hypertension-induced prolongation in action potentials of ventricular myocytes and suppressed Ito and Iss currents. In contrast, hypertension dependent decrement in intracellular Mg(2+) level did not cause a significant change in L-type Ca(2+) currents, SR Ca(2+) content and NCX activity. Nevertheless, hypertension mediated increase in superoxide anion, hydrogen peroxide and protein oxidation mitigated with magnesium treatment. In conclusion, magnesium administration improves mechanical abnormalities observed in hypertensive rat ventricular myocytes due to reduced oxidative stress. It is likely that, changes in intracellular magnesium balance may contribute to the pathophysiology of chronic heart diseases.
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Affiliation(s)
- Nihal Ozturk
- Faculty of Medicine, Department of Biophysics, Akdeniz University, Antalya, Turkey
| | - Yusuf Olgar
- Faculty of Medicine, Department of Biophysics, Akdeniz University, Antalya, Turkey
| | - Mutay Aslan
- Faculty of Medicine, Department of Biochemistry, Akdeniz University, Antalya, Turkey
| | - Semir Ozdemir
- Faculty of Medicine, Department of Biophysics, Akdeniz University, Antalya, Turkey.
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Kapoor R, Singh S, Tripathi M, Bhatnagar P, Kakkar P, Gupta KC. O-hexadecyl-dextran entrapped berberine nanoparticles abrogate high glucose stress induced apoptosis in primary rat hepatocytes. PLoS One 2014; 9:e89124. [PMID: 24586539 PMCID: PMC3930636 DOI: 10.1371/journal.pone.0089124] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2013] [Accepted: 01/20/2014] [Indexed: 11/19/2022] Open
Abstract
Nanotized phytochemicals are being explored by researchers for promoting their uptake and effectiveness at lower concentrations. In this study, O-hexadecyl-dextran entrapped berberine chloride nanoparticles (BC-HDD NPs) were prepared, and evaluated for their cytoprotective efficacy in high glucose stressed primary hepatocytes and the results obtained compared with bulk berberine chloride (BBR) treatment. The nanotized formulation treated primary hepatocytes that were exposed to high glucose (40 mM), showed increased viability compared to the bulk BBR treated cells. BC-HDD NPs reduced the ROS generation by ∼ 3.5 fold during co-treatment, prevented GSH depletion by ∼ 1.6 fold, reduced NO formation by ∼ 5 fold and significantly prevented decline in SOD activity in stressed cells. Lipid peroxidation was also prevented by ∼ 1.9 fold in the presence of these NPs confirming the antioxidant capacity of the formulation. High glucose stress increased Bax/Bcl2 ratio followed by mitochondrial depolarization and activation of caspase-9/-3 confirming involvement of mitochondrial pathway of apoptosis in the exposed cells. Co- and post-treatment of BC-HDD NPs prevented depolarization of mitochondrial membrane, reduced Bax/Bcl2 ratio and prevented externalization of phosphatidyl-serine confirming their anti-apoptotic capacity in those cells. Sub-G1 phase apparent in high glucose stressed cells was not seen in BC-HDD NPs treated cells. The present study reveals that BC-HDD NPs at ∼ 20 fold lower concentration are as effective as BBR in preventing high glucose induced oxidative stress, mitochondrial depolarization and downstream events of apoptotic cell death.
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Affiliation(s)
- Radhika Kapoor
- Food, Drug and Chemical Toxicology Division, CSIR- Indian Institute of Toxicology Research (CSIR-IITR), Lucknow, Uttar Pradesh, India
| | - Shruti Singh
- Food, Drug and Chemical Toxicology Division, CSIR- Indian Institute of Toxicology Research (CSIR-IITR), Lucknow, Uttar Pradesh, India
| | - Madhulika Tripathi
- Food, Drug and Chemical Toxicology Division, CSIR- Indian Institute of Toxicology Research (CSIR-IITR), Lucknow, Uttar Pradesh, India
| | - Priyanka Bhatnagar
- CSIR- Institute of Genomics and Integrative Biology, Delhi University Campus, Delhi, India
| | - Poonam Kakkar
- Food, Drug and Chemical Toxicology Division, CSIR- Indian Institute of Toxicology Research (CSIR-IITR), Lucknow, Uttar Pradesh, India
| | - Kailash Chand Gupta
- Food, Drug and Chemical Toxicology Division, CSIR- Indian Institute of Toxicology Research (CSIR-IITR), Lucknow, Uttar Pradesh, India
- CSIR- Institute of Genomics and Integrative Biology, Delhi University Campus, Delhi, India
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11
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Szymanski CR, Chiha W, Morellini N, Cummins N, Bartlett CA, O'Hare Doig RL, Savigni DL, Payne SC, Harvey AR, Dunlop SA, Fitzgerald M. Paranode Abnormalities and Oxidative Stress in Optic Nerve Vulnerable to Secondary Degeneration: Modulation by 670 nm Light Treatment. PLoS One 2013; 8:e66448. [PMID: 23840470 PMCID: PMC3686728 DOI: 10.1371/journal.pone.0066448] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2013] [Accepted: 05/05/2013] [Indexed: 11/25/2022] Open
Abstract
Secondary degeneration of nerve tissue adjacent to a traumatic injury results in further loss of neurons, glia and function, via mechanisms that may involve oxidative stress. However, changes in indicators of oxidative stress have not yet been demonstrated in oligodendrocytes vulnerable to secondary degeneration in vivo. We show increases in the oxidative stress indicator carboxymethyl lysine at days 1 and 3 after injury in oligodendrocytes vulnerable to secondary degeneration. Dihydroethidium staining for superoxide is reduced, indicating endogenous control of this particular reactive species after injury. Concurrently, node of Ranvier/paranode complexes are altered, with significant lengthening of the paranodal gap and paranode as well as paranode disorganisation. Therapeutic administration of 670 nm light is thought to improve oxidative metabolism via mechanisms that may include increased activity of cytochrome c oxidase. Here, we show that light at 670 nm, delivered for 30 minutes per day, results in in vivo increases in cytochrome c oxidase activity co-localised with oligodendrocytes. Short term (1 day) 670 nm light treatment is associated with reductions in reactive species at the injury site. In optic nerve vulnerable to secondary degeneration superoxide in oligodendrocytes is reduced relative to handling controls, and is associated with reduced paranode abnormalities. Long term (3 month) administration of 670 nm light preserves retinal ganglion cells vulnerable to secondary degeneration and maintains visual function, as assessed by the optokinetic nystagmus visual reflex. Light at a wavelength of 670 nm may serve as a therapeutic intervention for treatment of secondary degeneration following neurotrauma.
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Affiliation(s)
- Charis R. Szymanski
- Experimental and Regenerative Neurosciences, School of Animal Biology, The University of Western Australia, Crawley, Western Australia, Australia
| | - Wissam Chiha
- Experimental and Regenerative Neurosciences, School of Animal Biology, The University of Western Australia, Crawley, Western Australia, Australia
| | - Natalie Morellini
- Experimental and Regenerative Neurosciences, School of Animal Biology, The University of Western Australia, Crawley, Western Australia, Australia
| | - Nadia Cummins
- Experimental and Regenerative Neurosciences, School of Animal Biology, The University of Western Australia, Crawley, Western Australia, Australia
| | - Carole A. Bartlett
- Experimental and Regenerative Neurosciences, School of Animal Biology, The University of Western Australia, Crawley, Western Australia, Australia
| | - Ryan L. O'Hare Doig
- Experimental and Regenerative Neurosciences, School of Animal Biology, The University of Western Australia, Crawley, Western Australia, Australia
| | - Donna L. Savigni
- Experimental and Regenerative Neurosciences, School of Animal Biology, The University of Western Australia, Crawley, Western Australia, Australia
| | - Sophie C. Payne
- Experimental and Regenerative Neurosciences, School of Animal Biology, The University of Western Australia, Crawley, Western Australia, Australia
| | - Alan R. Harvey
- Experimental and Regenerative Neurosciences, School of Anatomy, Physiology and Human Biology, The University of Western Australia, Crawley, Western Australia, Australia
| | - Sarah A. Dunlop
- Experimental and Regenerative Neurosciences, School of Animal Biology, The University of Western Australia, Crawley, Western Australia, Australia
| | - Melinda Fitzgerald
- Experimental and Regenerative Neurosciences, School of Animal Biology, The University of Western Australia, Crawley, Western Australia, Australia
- * E-mail:
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Kumari A, Kakkar P. Lupeol protects against acetaminophen-induced oxidative stress and cell death in rat primary hepatocytes. Food Chem Toxicol 2012; 50:1781-9. [DOI: 10.1016/j.fct.2012.02.042] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2011] [Revised: 02/21/2012] [Accepted: 02/21/2012] [Indexed: 11/24/2022]
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Yang Y, Gao M, Nie W, Yuan J, Zhang B, Wang Z, Wu Z. Dietary magnesium sulfate supplementation protects heat stress-induced oxidative damage by restoring the activities of anti-oxidative enzymes in broilers. Biol Trace Elem Res 2012; 146:53-8. [PMID: 21947793 DOI: 10.1007/s12011-011-9210-y] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/25/2011] [Accepted: 09/12/2011] [Indexed: 10/17/2022]
Abstract
The purpose of this study was to investigate the effect of dietary magnesium sulfate supplementation on heat stress-induced oxidative damage in broilers. One hundred twenty 14-day-old broilers were randomly assigned into four treatment groups with three replicates of ten birds each. The broilers were reared under normal ambient temperature (24 ± 1°C) fed with a basal (control) diet or reared under high ambient temperature (35 ± 1°C between 1000 and 1800 h, 8 h each day) fed with a basal diet supplemented with magnesium sulfate (0, 2.5 or 5.0 mg/kg of diet) from 14 to 42 days of age. Growth performance and oxidative damage were evaluated in each treatment group. Our results demonstrated that dietary magnesium sulfate supplementation significantly prevented heat stress-induced oxidative damage and improved growth performance in broilers compared with that of control. Mechanistically, this beneficial effect was mediated, at least partly, by restoring the activity of anti-oxidative enzymes. This finding suggests that magnesium sulfate supplementation might be a potential strategy to attenuate heat stress-induced detrimental effects in broilers raised in summer season or tropical areas.
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Affiliation(s)
- Ying Yang
- State key Laboratory of Animal Nutrition, College of Animal Science and Technology, China Agricultural University, Beijing, 100193, People's Republic of China
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Kumari A, Kakkar P. Lupeol prevents acetaminophen-induced in vivo hepatotoxicity by altering the Bax/Bcl-2 and oxidative stress-mediated mitochondrial signaling cascade. Life Sci 2012; 90:561-70. [DOI: 10.1016/j.lfs.2012.01.012] [Citation(s) in RCA: 71] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2011] [Revised: 12/30/2011] [Accepted: 01/13/2012] [Indexed: 11/16/2022]
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Singh BK, Tripathi M, Pandey PK, Kakkar P. Alteration in mitochondrial thiol enhances calcium ion dependent membrane permeability transition and dysfunction in vitro: a cross-talk between mtThiol, Ca(2+), and ROS. Mol Cell Biochem 2011; 357:373-85. [PMID: 21748338 DOI: 10.1007/s11010-011-0908-0] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2011] [Accepted: 05/28/2011] [Indexed: 12/16/2022]
Abstract
Mitochondrial permeability transition (MPT) and dysfunctions play a pivotal role in many patho-physiological and toxicological conditions. The interplay of mitochondrial thiol (mtThiol), MPT, Ca(2+) homeostasis, and resulting dysfunctions still remains controversial despite studies by several research groups. Present study was undertaken to ascertain the correlation between Ca(2+) homeostasis, mtThiol alteration and reactive oxygen species (ROS) in causing MPT leading to mitochondrial dysfunction. mtThiol depletion significantly enhanced Ca(2+) dependent MPT (swelling) and depolarization of mitochondria resulting in release of pro-apoptotic proteins like Cyt c, AIF, and EndoG. mtThiol alteration and Ca(2+) overload caused reduced mitochondrial electron flow, oxidation of pyridine nucleotides (NAD(P)H) and significantly enhanced ROS generation (DHE and DCFH-DA fluorescence). Studies with MPT inhibitor (Cyclosporin A), Ca(2+) uniport blocker (ruthenium red) and Ca(2+) chelator (BAPTA) indicated that mitochondrial dysfunction was more pronounced under dual stress of altered mtThiol and Ca(2+) overload in comparison with single stress of excessive Ca(2+). Transmission electron microscopy confirmed the changes in mitochondrial integrity under stress. Our findings suggest that the Ca(2+) overload itself is not solely responsible for structural and functional impairment of mitochondria. A multi-factorial cross-talk between mtThiol, Ca(2+) and ROS is responsible for mitochondrial dysfunction. Furthermore, minor depletion of mtThiol was found to be an important factor along with Ca(2+) overload in triggering MPT in isolated mitochondria, tilting the balance towards disturbed functionality.
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Affiliation(s)
- Brijesh Kumar Singh
- Herbal Research Section, Indian Institute of Toxicology Research, Formerly-Industrial Toxicology Research Centre, Mahatma Gandhi Marg, Lucknow 226001, Uttar Pradesh, India
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Shin WJ, Kim YK, Bang JY, Cho SK, Han SM, Hwang GS. Lactate and liver function tests after living donor right hepatectomy: a comparison of solutions with and without lactate. Acta Anaesthesiol Scand 2011; 55:558-64. [PMID: 21342149 DOI: 10.1111/j.1399-6576.2011.02398.x] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
BACKGROUND Hyperlactatemia can predict the prognosis of patients undergoing liver resection. The effects of lactated Ringer's solution on liver function have not been evaluated in patients undergoing major liver resection. We therefore compared the effects of two different crystalloid solutions, with and without lactate, on liver function test data and serum lactate level in living donors undergoing right hepatectomy. METHODS A total of 104 donors undergoing right hepatectomy for liver transplantation were randomly allocated to receive lactated Ringer's (LR) solution (n=52) or Plasmalyte (n=52). Anesthetic and fluid management were standardized. Acid-base status, lactate concentration, and liver function tests were analyzed at predetermined time points during the first 5 post-operative days. RESULTS The lactate concentrations were significantly higher in the LR group than in the Plasmalyte group 1 h after hepatectomy [4.2 (3.2-5.7) vs. 3.3 (2.6-4.6) mmol/l; P=0.005, median (interquartile ranges)]. In addition, the nadir concentration of albumin was significantly lower and the peak total bilirubin concentration and prothrombin time were significantly higher in the LR group compared with the Plasmalyte group. However, these changes in the LR group subsided within the first or second post-operative days, without apparent complications or prolongation of hospital stay. Post-operative peak concentrations of lactate were not correlated with nadir albumin concentration, peak bilirubin, or peak prothrombin time, in either group. CONCLUSION This prospective randomized study showed that non-lactate-containing crystalloid solution may have important advantages over LR solution, concerning lactate and liver profiles, in living donors undergoing right hepatectomy.
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Affiliation(s)
- W-J Shin
- Department of Anesthesiology and Pain Medicine, Asan Medical Center, University of Ulsan College of Medicine, Seoul, Korea
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17
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Sato T, Watanabe M, Kishiro M, Nagata S, Shimizu T, Okada T. Intracellular magnesium and tolerance against hypoxia in immature rat heart. Pediatr Int 2010; 52:773-7. [PMID: 20497360 DOI: 10.1111/j.1442-200x.2010.03172.x] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
BACKGROUND Neonatal hearts show greater resistance to hypoxia than adult hearts do, but the mechanism is unclear. In immature rat hearts, we examined the association between high tolerance for hypoxia and the kinetics of magnesium (Mg), which has myocardial protective effects in adult hearts. METHODS The hearts of 1-, 2-, 3-, and 10-week-old rats were Langendorff perfused and subjected to 45 min hypoxia and 30 min reoxygenation. The myocardial Mg content was measured by atomic absorption spectrophotometry. RESULTS In 1-week-old rat hearts, the tension-rate product recovered more immediately with reoxygenation than in the other groups, and aspartate aminotransferase release did not increase throughout the experiment. In 10-week-old rat hearts, total tissue Mg content decreased significantly with reoxygenation (607.0 ± 22.9 µg/g dry weight) from its control level (793.2 ± 16.7 µg/g dry weight). However, in neonates, the total tissue Mg did not decrease with reoxygenation. CONCLUSIONS The high resistance against hypoxia-reoxygenation injury in neonatal rat hearts is caused, at least in part, by a high ability to maintain myocardial Mg.
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Affiliation(s)
- Tomoyuki Sato
- Department of Pediatrics, Juntendo University School of Medicine, Hongo, Tokyo, Japan.
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Belanger KD, Walter D, Henderson TA, Yelton AL, O'Brien TG, Belanger KG, Geier SJ, Fahrenkrog B. Nuclear localisation is crucial for the proapoptotic activity of the HtrA-like serine protease Nma111p. J Cell Sci 2009; 122:3931-41. [DOI: 10.1242/jcs.056887] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Programmed cell death is induced by the activation of a subset of intracellular proteins in response to specific extra- and intracellular signals. In the yeast Saccharomyces cerevisiae, Nma111p functions as a nuclear serine protease that is necessary for apoptosis under cellular stress conditions, such as elevated temperature or treatment of cells with hydrogen peroxide to induce cell death. We have examined the role of nuclear protein import in the function of Nma111p in apoptosis. Nma111p contains two small clusters of basic residues towards its N-terminus, both of which are necessary for efficient translocation into the nucleus. Nma111p does not shuttle between the nucleus and cytoplasm during either normal growth conditions or under environmental stresses that induce apoptosis. The N-terminal half of Nma111p is sufficient to provide the apoptosis-inducing activity of the protein, and the nuclear-localisation signal (NLS) sequences and catalytic serine 235 are both necessary for this function. We provide compelling evidence that intranuclear Nma111p activity is necessary for apoptosis in yeast.
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Affiliation(s)
- Kenneth D. Belanger
- Department of Biology, Colgate University, 13 Oak Drive, Hamilton, NY 13346, USA
| | - David Walter
- M. E. Muller Institute for Structural Biology, Biozentrum, University of Basel, Klingelbergstr. 70, 4056 Basel, Switzerland
| | - Tracey A. Henderson
- Department of Biology, Colgate University, 13 Oak Drive, Hamilton, NY 13346, USA
| | - Allison L. Yelton
- Department of Biology, Colgate University, 13 Oak Drive, Hamilton, NY 13346, USA
| | - Travis G. O'Brien
- Department of Biology, Colgate University, 13 Oak Drive, Hamilton, NY 13346, USA
| | - Karyn G. Belanger
- Department of Biology, Colgate University, 13 Oak Drive, Hamilton, NY 13346, USA
| | - Susan J. Geier
- Department of Biology, Colgate University, 13 Oak Drive, Hamilton, NY 13346, USA
| | - Birthe Fahrenkrog
- M. E. Muller Institute for Structural Biology, Biozentrum, University of Basel, Klingelbergstr. 70, 4056 Basel, Switzerland
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Tripathi M, Singh BK, Mishra C, Raisuddin S, Kakkar P. Involvement of mitochondria mediated pathways in hepatoprotection conferred by Fumaria parviflora Lam. extract against nimesulide induced apoptosis in vitro. Toxicol In Vitro 2009; 24:495-508. [PMID: 19772912 DOI: 10.1016/j.tiv.2009.09.011] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2009] [Revised: 08/19/2009] [Accepted: 09/17/2009] [Indexed: 01/23/2023]
Abstract
Nimesulide, a popular nonsteroidal anti-inflammatory drug, has been associated with serious hepatotoxicity. Reactive oxygen species (ROS) and mitochondrial perturbations have been implicated in drug induced hepatotoxicity, although their role in the pathway needs exploration. Study was undertaken to elucidate the effect of Fumaria parviflora Lam. (Fp) on nimesulide induced cell death in primary rat hepatocyte cultures. Fp extract treated cells showed increased viability as compared to nimesulide stressed cells as assessed by MTT assay. LDH leakage increased significantly at 500microM nimesulide, and the data suggested that apoptosis was the predominant mechanism responsible for cell death. Nimesulide induced apoptosis was further confirmed by DNA fragmentation and chromatin condensation. Nimesulide exposure increased intracellular ROS, translocation of Bax and Bcl2 followed by mitochondrial depolarization and cytochrome c (Cyt c) release along with caspase-9/-3 activity confirming involvement of mitochondria in nimesulide induced apoptosis. Events like membrane depolarization of mitochondria, expression of Bax, Bcl2, externalization of phosphatidyl serine are substantially reversed by the pre-treatment of Fp extract. Thus, the study indicates that Fp extract modulates critical events regulating pro and anti-apoptotic proteins in mitochondria dependent apoptosis induced by nimesulide.
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Affiliation(s)
- Madhulika Tripathi
- Herbal Research Section, Indian Institute of Toxicology Research (CSIR), P.O. Box-80, M.G. Marg, Lucknow 226001, Uttar Pradesh, India
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Portugal-Cohen M, Soroka Y, Ma’or Z, Oron M, Zioni T, Brégégère FM, Neuman R, Kohen R, Milner Y. Protective effects of a cream containing Dead Sea minerals against UVB-induced stress in human skin. Exp Dermatol 2009; 18:781-8. [DOI: 10.1111/j.1600-0625.2009.00865.x] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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Drolet B, Simard C, Gailis L, Daleau P. Ischemic, genetic and pharmacological origins of cardiac arrhythmias: the contribution of the Quebec Heart Institute. Can J Cardiol 2009; 23 Suppl B:15B-22B. [PMID: 17932583 DOI: 10.1016/s0828-282x(07)71006-1] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
Research in the field of basic electrophysiology at the Quebec Heart Institute (Laval Hospital, Quebec City, Quebec) has evolved since its beginning in the 1990s. Interests were focused on cardiac arrhythmias induced by drugs, allelic variants and metabolic factors produced during ischemia. The results have contributed to the creation of new standards in drug development, more specifically, testing all new drugs for their potential effects on cardiac potassium currents, which could produce life-threatening proarrhythmic effects. In a French-Canadian population, three heterozygous single nucleotide polymorphisms in hK(v)1.5, a gene encoding for a major atrial repolarizing current, were found. These variants affect the expression level of the hK(v)1.5 channel and change the inactivation process in the presence of its accessory beta subunit. Because these effects could shorten atrial action potential, their presence was tested in postcoronary bypass patients and a higher prevalence was found in patients with postoperative atrial fibrillation. Finally, three potentially proarrhythmic factors characteristic of ischemia were identified: pH decrease; oxygen free radicals, which both increase the flow of K(+) ions through human ether-a-go-go-related gene and hK(v)1.5, producing a reduction in action potential duration, frequently leading to cardiac arrhythmias; and lysophosphatidylcholine, a metabolite involved in the production of cardiac arrhythmias early during ischemia that was shown to be a major cause of electrical uncoupling. Over the past decade, the Quebec Heart Institute has provided a significant amount of original data in the field of basic cardiac electrophysiology, specifically concerning arrhythmias originating from pharmacological agents, genetic background and cardiac ischemia.
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Silva JP, Proença F, Coutinho OP. Protective role of new nitrogen compounds on ROS/RNS-mediated damage to PC12 cells. Free Radic Res 2009; 42:57-69. [DOI: 10.1080/10715760701787719] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
Affiliation(s)
- João P. Silva
- CBMA—Molecular and Environmental Biology Centre/Biology Department, University of Minho, Campus de Gualtar, 4710-057, Braga, Portugal
| | - Fernanda Proença
- Chemistry Department, University of Minho, Campus de Gualtar, 4710-057, Braga, Portugal
| | - Olga P. Coutinho
- CBMA—Molecular and Environmental Biology Centre/Biology Department, University of Minho, Campus de Gualtar, 4710-057, Braga, Portugal
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Long-term administration of magnesium after acoustic trauma caused by gunshot noise in guinea pigs. Hear Res 2008; 247:137-45. [PMID: 19084059 DOI: 10.1016/j.heares.2008.11.005] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/07/2008] [Revised: 10/23/2008] [Accepted: 11/05/2008] [Indexed: 12/20/2022]
Abstract
In a previous study we observed that a 7-day post-trauma magnesium treatment significantly reduced auditory threshold shifts measured 7 days after gunshot noise exposure. However this improvement was only temporary, suggesting that it could be potentially beneficial to prolong this treatment. The aim of the present study was to evaluate the efficacy of a long-term (1 month) magnesium treatment after an impulse noise trauma, in comparison with either a 7-day magnesium treatment, an administration of methylprednisolone (conventional treatment), or a placebo (NaCl). Guinea pigs were exposed to impulse noise (three blank gunshots, 170 dB SPL peak). They received one of the four treatments, 1 h after the noise exposure. Auditory function was explored by recording the auditory brainstem response (ABR) and measuring the distortion product otoacoustic emissions (DPOAE) over a 3-month recovery period after the gunshot exposure. The functional hearing study was supplemented by a histological analysis. The results showed that a 1-month treatment with magnesium was the most effective treatment in terms of hair cell preservation. The DPOAE confirmed this effectiveness. Methylprednisolone accelerated recovery but its final efficacy remained moderate. It is probable that magnesium acts on the later metabolic processes that occur after noise exposure. Multiple mechanisms could be involved: calcium antagonism, anti-ischaemic effect or NMDA channel blockage. Regardless of the specific mechanism, a 1-month treatment with magnesium clearly attenuates NIHL, and presents the advantage of being safe for use in humans.
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Tripathi M, Singh BK, Kakkar P. Glycyrrhizic acid modulates t-BHP induced apoptosis in primary rat hepatocytes. Food Chem Toxicol 2008; 47:339-47. [PMID: 19084568 DOI: 10.1016/j.fct.2008.11.028] [Citation(s) in RCA: 63] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2008] [Revised: 11/11/2008] [Accepted: 11/13/2008] [Indexed: 11/26/2022]
Abstract
Glycyrrhizic acid (GA) is the main bioactive ingredient of licorice (Glycyrrhiza glabra). The object of this study was to evaluate the protective effects of GA on tert-butyl hydroperoxide (t-BHP) induced oxidative injury leading to apoptosis in cultured primary rat hepatocytes. Throughout the study silymarin was used as positive control. Molecular mechanisms involved in apoptotic pathways induced in hepatocytes by t-BHP at 250 microM were explored in detail. DNA fragmentation, activation of caspases and cytochrome c release were demonstrated. In addition, changes in the mitochondrial membrane potential and ROS generation were detected confirming involvement of mitochondrial pathway. Pre-treatment with GA (4 microg) protected the hepatocytes against t-BHP induced oxidative injury and the results were comparable to the pre-treatment with positive control, i.e. silymarin. The protective potential against cell death was achieved mainly by preventing intracellular GSH depletion, decrease in ROS formation as well as inhibition of mitochondrial membrane depolarization. GA was found to modulate critical end points of oxidative stress induced apoptosis and could be beneficial against liver diseases where oxidative stress is known to play a crucial role.
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Affiliation(s)
- M Tripathi
- Herbal Research Section, Indian Institute of Toxicology Research, PO Box 80, MG Marg, Lucknow 226001, India
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Gorina R, Sanfeliu C, Galitó A, Messeguer A, Planas AM. Exposure of glia to pro-oxidant agents revealed selective Stat1 activation by H2O2 and Jak2-independent antioxidant features of the Jak2 inhibitor AG490. Glia 2007; 55:1313-24. [PMID: 17607690 DOI: 10.1002/glia.20542] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
The JAK/STAT pathway is activated in response to cytokines and growth factors. In addition, oxidative stress can activate this pathway, but the causative pro-oxidant forms are not well identified. We exposed cultures of rat glia to H2O2, FeSO4, nitroprussiate, or paraquat. We assessed oxidative stress by measuring reactive oxygen species (ROS) and oxidated proteins, we determined phosphorylated Stat1 (pStat1), and we evaluated the effect of antioxidants (trolox, propyl gallate, and N-acetylcysteine) and of Jak2 (Janus tyrosine kinases) inhibitors (AG490 and Jak2-Inhibitor-II). Pro-oxidant agents induced ROS and protein oxidation, excluding nitroprussiate that induced protein nitrosylation. H2O2, and to a lesser extent FeSO4, increased the level of pStat1, whereas nitroprussiate and paraquat did not. Trolox and propyl gallate strongly prevented ROS formation but they did not abolish H2O2-induced pStat1. In contrast, NAC did not reduce the level of ROS but it prevented the increase of pStat1 induced by H2O2, evidencing a differential effect on ROS formation and on Stat1 phosphorylation. H2O2 induced pStat1 in mixed glia cultures and, to a lesser extent, in purified astroglia, but not in microglia. Jak2 inhibitors reduced H2O2-induced pStat1, suggesting the involvement of this kinase in the increased phosphorylation of Stat1 by peroxide. Unexpectedly, AG490, but not Jak2-Inhibitor-II, reduced ROS formation, and it abrogated lipid peroxidation in microsomal preparations. Furthermore, AG490 reduced ROS in glial cells that were transfected with siRNA to silence Jak2 expression. These findings reveal previously unrecognized Jak2-independent antioxidant properties of AG490, and show that Jak2-dependent Stat1 activation by peroxide is dissociated from ROS generation.
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Affiliation(s)
- Roser Gorina
- Department of Brain Ischemia and Neurodegeneration, Institut d'Investigacions Biomèdiques de Barcelona (IIBB)-Consejo Superior de Investigaciones Científicas (CSIC), Barcelona, Spain
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Xia Z, Kuo KH, Nagareddy PR, Wang F, Guo Z, Guo T, Jiang J, McNeill JH. N-acetylcysteine attenuates PKCbeta2 overexpression and myocardial hypertrophy in streptozotocin-induced diabetic rats. Cardiovasc Res 2006; 73:770-82. [PMID: 17250813 DOI: 10.1016/j.cardiores.2006.11.033] [Citation(s) in RCA: 83] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/17/2006] [Revised: 11/16/2006] [Accepted: 11/27/2006] [Indexed: 01/02/2023] Open
Abstract
OBJECTIVE Oxidative stress-mediated activation of protein kinase C (PKC) beta(2) in the myocardium has been implicated in the development of cardiomyopathy. Overexpression of PKCbeta(2) is associated with increased expression of connective tissue growth factor (CTGF) in myocardium, resulting in myocardial hypertrophy. We hypothesized that chronic treatment with the antioxidant N-acetylcysteine (NAC) would normalize oxidative stress-mediated overexpression of myocardial PKCbeta(2) and CTGF and attenuate the development of myocardial hypertrophy. METHODS Control and streptozotocin-induced diabetic rats were treated with NAC in drinking water for 8 weeks. At termination rats were surgically prepared for hemodynamic measurement, subsequent to which their hearts were removed to evaluate cardiac performance and histological and biochemical changes. Further, the role of PKCbeta(2) in hyperglycemia-induced cardiomyocyte hypertrophy was tested in cultured neonatal cardiomyocytes. RESULTS Myocardial hypertrophy, characterized by an increased ratio of ventricle weight to body weight and cardiomyocyte cross-sectional area was found to be higher in untreated diabetic rats. Further, in myocardium, increased levels of 15-F(2t)-isoprostane were accompanied by an increased expression of membrane-bound PKCbeta(2) and CTGF. N-acetylcysteine treatment not only attenuated these changes but also prevented hyperglycemia-induced hypertrophy in cultured neonatal rat cardiomyocytes. CONCLUSIONS The results suggest that PKCbeta(2) overexpression represents a mechanism causing hyperglycemia-mediated myocardial hypertrophy, which can be prevented by the antioxidant N-acetylcysteine.
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Affiliation(s)
- Zhengyuan Xia
- Faculty of Pharmaceutical Sciences, Division of Pharmacology, The University of British Columbia, 2146 East mall, Vancouver, BC, Canada
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Sendowski I, Raffin F, Braillon-Cros A. Therapeutic efficacy of magnesium after acoustic trauma caused by gunshot noise in guinea pigs. Acta Otolaryngol 2006; 126:122-9. [PMID: 16428187 DOI: 10.1080/00016480500312547] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
Abstract
CONCLUSIONS The present findings show that magnesium administration can significantly reduce threshold shift 7 days after gunshot noise exposure. However, this improvement seems to be temporary, suggesting a probable advantage in prolonging the treatment. OBJECTIVE To evaluate the therapeutic efficacy of magnesium administration after hearing loss induced by gunshot noise. MATERIAL AND METHODS Forty-eight guinea pigs were exposed to an impulse noise (blank shot from a rifle; 170 or 176 dB SPL peak). The therapeutic efficacy of magnesium was evaluated by administering either the treatment or a placebo to the traumatized animals for 7 days, beginning 1 h after the trauma. Auditory function was explored for up to 14 days of recovery by recording the compound action potential in the round window. The functional study of hearing was supplemented by histological analysis. RESULTS The threshold shifts of the 170-dB SPL group that received magnesium were significantly lower than those of controls after 2 and 7 days of recovery, but no significant difference was evidenced at 14 days in this group, nor at any time in the 176-dB SPL group. Animals treated with magnesium after the 176-dB SPL exposure had a significant reduction in hair cell loss in the basal region.
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Affiliation(s)
- Isabelle Sendowski
- Pôle "Traumatisme Sonore", Département de Radiobiologie, Centre de Recherches du Service de Santé des Armées (CRSSA), La Tronche Cedex, France.
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28
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Fredsted A, Mikkelsen UR, Gissel H, Clausen T. Anoxia induces Ca2+influx and loss of cell membrane integrity in rat extensor digitorum longus muscle. Exp Physiol 2005; 90:703-14. [PMID: 15908508 DOI: 10.1113/expphysiol.2005.030247] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Anoxia can lead to skeletal muscle damage. In this study we have investigated whether an increased influx of Ca2+, which is known to cause damage during electrical stimulation, is a causative factor in anoxia-induced muscle damage. Isolated extensor digitorum longus (EDL) muscles from 4-week-old Wistar rats were mounted at resting length and were either resting or stimulated (30 min, 40 Hz, 10 s on, 30 s off) in the presence of standard oxygenation (95% O2, 5% CO2), anoxia (95% N2, 5% CO2) or varying degrees of reduced oxygenation. At varying extracellular Ca2+ concentrations ([Ca2+]o), 45Ca influx and total cellular Ca2+ content were measured and the release of lactic acid dehydrogenase (LDH) was determined as an indicator of cell membrane leakage. In resting muscles, incubated at 1.3 mM Ca2+, 15-75 min of exposure to anoxia increased 45Ca influx by 46-129% (P<0.001) and Ca2+ content by 20-50% (P<0.001). Mg2+ (11.2 mM) reduced the anoxia-induced increase in 45Ca influx by 43% (P<0.001). In muscles incubated at 20 and 5% O2, 45Ca influx was also stimulated (P<0.001). Increasing [Ca2+]o to 5 mM induced a progressive increase in both 45Ca uptake and LDH release in resting anoxic muscles. When electrical stimulation was applied during anoxia, Ca2+ content and LDH release increased markedly and showed a significant correlation (r2=0.55, P<0.001). In conclusion, anoxia or incubation at 20 or 5% O2 leads to an increased influx of 45Ca. This is associated with a loss of cell membrane integrity, possibly initiated by Ca2+. The loss of cell membrane integrity further increases Ca2+ influx, which may elicit a self-amplifying process of cell membrane leakage.
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Affiliation(s)
- Anne Fredsted
- Department of Physiology, University of Aarhus, Ole Worms Allé 160, DK-8000 Arhus C, Denmark.
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Sharikabad MN, Østbye KM, Brørs O. Effect of hydrogen peroxide on reoxygenation-induced Ca2+ accumulation in rat cardiomyocytes. Free Radic Biol Med 2004; 37:531-8. [PMID: 15256224 DOI: 10.1016/j.freeradbiomed.2004.05.002] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/17/2003] [Revised: 04/14/2004] [Accepted: 05/07/2004] [Indexed: 11/17/2022]
Abstract
Reactive oxygen species (ROS) contribute to cell damage during reperfusion of the heart. ROS may exert their effects partly by interfering with Ca(2+) homeostasis of the myocardium. The purpose of this study was to investigate the effects of hydrogen peroxide (H(2)O(2)) on Ca(2+) accumulation during reoxygenation of isolated adult rat cardiomyocytes exposed to 1 h of hypoxia and to relate the effects to possible changes in release of lactate dehydrogenase (LDH), free intracellular Ca(2+) ([Ca(2+)](i)) and Mg(2+)([Mg(2+)](i)), and mitochondrial membrane potential (Deltapsim). Cell Ca(2+) was determined by (45)Ca(2+) uptake. Free [Mg(2+)](i) and [Ca(2+)](i) and Deltapsim were measured by flow cytometry. Reoxygenation-induced Ca(2+) accumulation was attenuated by 23 and 34% by 10 and 25 microM H(2)O(2), respectively, added at reoxygenation. H(2)O(2) at 100 and 250 microM increased cell Ca(2+) by 50 and 83%, respectively, whereas 500 microM H(2)O(2) decreased cell Ca(2+) by 20%. H(2)O(2) at (25 microM) reduced LDH release and [Mg(2+)](i) and increased Deltapsim, indicating cell protection, whereas 250 microM H(2)O(2) increased LDH release and [Mg(2+)](i) and decreased Deltapsim, indicating cell damage. Clonazepam (100 microM) attenuated the increase in Ca(2+) accumulation, the elevation of [Ca(2+)](i), and the decrease in Deltapsim induced by 100 and 250 microM H(2)O(2) during reoxygenation. We report for the first time that 25 microM H(2)O(2) attenuates Ca(2+) accumulation, LDH release, and dissipation of Deltapsim during reoxygenation of hypoxic cardiomyocytes, indicating cell protection.
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Affiliation(s)
- Mohammad Nouri Sharikabad
- Division of Clinical Pharmacology and Toxicology, Clinical Chemistry Department, Ullevaal University Hospital, Oslo, Norway.
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Tokalov SV, Kind B, Wollenweber E, Gutzeit HO. Biological effects of epicuticular flavonoids from Primula denticulata on human leukemia cells. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2004; 52:239-245. [PMID: 14733502 DOI: 10.1021/jf0347160] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
The biological effects of epicuticular substances in farinose exudates accumulated on inflorescence shafts and calyces of Primula denticulata on human acute myeloid leukemia cells (HL-60) were analyzed. The crude material possessed little antioxidative capacity but strong cytostatic properties. Some of its known components (5-hydroxyflavone, 2'-hydroxyflavone, 5,2'-dihydroxyflavone, and 5,8-dihydroxyflavone) were further tested to identify the biologically active compounds. The effects of these flavones on cell cycle progression, mitochondrial membrane potential, and reactive oxygen species have been investigated by flow cytometry. The flavonol quercetin was included in the study as reference compound because of its known cytostatic properties and its activity as radical scavenger. Compared to quercetin the flavones induced little apoptosis (up to 40 microM), but despite their low toxicity, the Primula flavonoids possessed strong cytostatic properties even at low concentrations. The cell cycle distribution showed a characteristic time-dependent shift, giving evidence of a generally short-lived effect of the test compounds in the exposed cells. The antioxidative properties quantified according to two different methods correlated with the number of hydroxyl groups. Whereas quercetin strongly affected the mitochondrial membrane potential, none of the Primula flavones showed a comparable effect.
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Affiliation(s)
- Sergey V Tokalov
- Institut für Zoologie, Technische Universität Dresden, Mommsenstrasse 13, D-01062 Dresden, Germany
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31
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Chakraborti S, Chakraborti T, Mandal M, Mandal A, Das S, Ghosh S. Protective role of magnesium in cardiovascular diseases: a review. Mol Cell Biochem 2002; 238:163-79. [PMID: 12349904 DOI: 10.1023/a:1019998702946] [Citation(s) in RCA: 173] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
A considerable number of experimental, epidemiological and clinical studies are now available which point to an important role of Mg2+ in the etiology of cardiovascular pathology. In human subjects, hypomagnesemia is often associated with an imbalance of electrolytes such as Na+, K+ and Ca2+. Abnormal dietary deficiency of Mg2+ as well as abnormalities in Mg2+ metabolism play important roles in different types of heart diseases such as ischemic heart disease, congestive heart failure, sudden cardiac death, atheroscelerosis, a number of cardiac arrhythmias and ventricular complications in diabetes mellitus. Mg2+ deficiency results in progressive vasoconstriction of the coronary vessels leading to a marked reduction in oxygen and nutrient delivery to the cardiac myocytes. Numerous experimental and clinical data have suggested that Mg2+ deficiency can induce elevation of intracellular Ca2+ concentrations, formation of oxygen radicals, proinflammatory agents and growth factors and changes in membrane perrmeability and transport processes in cardiac cells. The opposing effects of Mg2+ and Ca2+ on myocardial contractility may be due to the competition between Mg2+ and Ca2+ for the same binding sites on key myocardial contractile proteins such as troponin C, myosin and actin. Stimulants, for example, catecholamines can evoke marked Mg2+ efflux which appears to be associated with a concomitant increase in the force of contraction of the heart. It has been suggested that Mg2+ efflux may be linked to the Ca2+ signalling pathway. Depletion of Mg2+ by alcohol in cardiac cells causes an increase in intracellular Ca2+, leading to coronary artery vasospasm, arrhythmias, ischemic damage and cardiac failure. Hypomagnesemia is commonly associated with hypokalemia and occurs in patients with hypertension or myocardial infarction as well as in chronic alcoholism. The inability of the senescent myocardium to respond to ischemic stress could be due to several reasons. Mg2+ supplemented K+ cardioplegia modulates Ca2+ accumulation and is directly involved in the mechanisms leading to enhanced post ischemic functional recovery in the aged myocardium following ischemia. While many of these mechanisms remain controversial and in some cases speculative, the beneficial effects related to consequences of Mg2+ supplementation are apparent. Further research are needed for the incorporation of these findings toward the development of novel myocardial protective role of Mg2+ to reduce morbidity and mortality of patients suffering from a variety of cardiac diseases.
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Affiliation(s)
- Sajal Chakraborti
- Department of Biochemistry and Biophysics, University of Kalyani, Kalyani, West Bengal, India.
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Zuo L, Clanton TL. Detection of reactive oxygen and nitrogen species in tissues using redox-sensitive fluorescent probes. Methods Enzymol 2002; 352:307-25. [PMID: 12125357 DOI: 10.1016/s0076-6879(02)52028-0] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
The take-home message of this chapter is that the fluorescent probes for ROS and RNS have great potential in improving our understanding of redox behavior within cells and tissues. However, data obtained from studies using these probes must be expressed in the context of the limitations of the chemistry of the probes in the cellular microenvironment, which may change under different conditions, such as cell stress or injury. In most cases, as suggested, results should be described in a general context of reflecting an increase in oxidizing reactions within the cell and not as a quantitative measure of the production of a specific oxidant species. It is highly recommended that results be verified, when possible, with alternative fluorescent probes or preferably using alternative methods, such as electron spin resonance or other newly emerging technology.
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Affiliation(s)
- Li Zuo
- Department of Internal Medicine, Pulmonary and Critical Care Medicine, Davis Heart and Lung Research Institute and Biophysics Program, Ohio State University, Columbus, Ohio 43210, USA
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Samavati L, Monick MM, Sanlioglu S, Buettner GR, Oberley LW, Hunninghake GW. Mitochondrial K(ATP) channel openers activate the ERK kinase by an oxidant-dependent mechanism. Am J Physiol Cell Physiol 2002; 283:C273-81. [PMID: 12055096 DOI: 10.1152/ajpcell.00514.2001] [Citation(s) in RCA: 83] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Extracellular signal-regulated kinases (ERKs) are key regulatory proteins that mediate cell survival, proliferation, and differentiation. Reactive oxygen species (ROS) may play a role in activation of the ERK pathway. Because mitochondria are a major source of ROS, we investigated whether mitochondria-derived ROS play a role in ERK activation. Diazoxide, a potent mitochondrial ATP-sensitive K+ (K(ATP)) channel opener, is known to depolarize the mitochondrial membrane potential and cause a reversible oxidation of respiratory chain flavoproteins, thus increasing mitochondrial ROS production. Using THP-1 cells as a model, we postulated that opening mitochondrial K(ATP) channels would increase production of ROS and, thereby, regulate the activity of the ERK kinase. We found that opening mitochondrial K(ATP) channels by diazoxide induced production of ROS as determined by an increased rate of dihydroethidium and dichlorofluorescein fluorescence. This increased production of ROS was associated with increased phosphorylation of ERK kinase in a time-dependent fashion. The MEK inhibitors PD-98059 and U-0126 blocked ERK activation mediated by diazoxide. N-acetylcysteine, but not diphenyleneiodonium, attenuated ERK activation mediated by diazoxide. Adenovirus-mediated overexpression of manganese superoxide dismutase, which is expressed in mitochondria, decreased the rate of dihydroethidium oxidation as well as ERK activation. We conclude that mitochondrial K(ATP) channel openers trigger ERK activation via mitochondria-derived ROS.
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Affiliation(s)
- Lobelia Samavati
- Department of Medicine, University of Iowa College of Medicine and Veterans Administration Medical Center, Iowa City, Iowa 52242, USA.
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Sharikabad MN, Ostbye KM, Brørs O. Increased [Mg2+]o reduces Ca2+ influx and disruption of mitochondrial membrane potential during reoxygenation. Am J Physiol Heart Circ Physiol 2001; 281:H2113-23. [PMID: 11668073 DOI: 10.1152/ajpheart.2001.281.5.h2113] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Increase in extracellular Mg2+ concentration ([Mg2+]o) reduces Ca2+ accumulation during reoxygenation of hypoxic cardiomyocytes and exerts protective effects. The aims of the present study were to investigate the effect of increased [Mg(2+)](o) on Ca2+ influx and efflux, free cytosolic Ca2+ ([Ca2+]i) and Mg2+ concentrations ([Mg2+]i), Ca2+ accumulation in the presence of inhibitors of mitochondrial or sarcoplasmatic reticulum Ca2+ transport, and finally mitochondrial membrane potential (Delta(psi)m). Isolated adult rat cardiomyocytes were exposed to 1 h of hypoxia and subsequent reoxygenation. Cell Ca2+ was determined by 45Ca2+ uptake, and the levels of [Mg2+]i and [Ca2+]i were determined by flow cytometry as the fluorescence of magnesium green and fluo 3, respectively. Ca2+ influx rate was significantly reduced by approximately 40%, whereas Ca2+ efflux was not affected by increased [Mg2+]o (5 mM) during reoxygenation. [Ca2+]i and [Mg2+]i were increased at the end of hypoxia, fell after reoxygenation, and were unaffected by increased [Mg2+]o. Clonazepam, a selective mitochondrial Na+/Ca2+ exchange inhibitor (100 microM), significantly reduced Ca2+ accumulation by 70% and in combination with increased [Mg2+]o by 90%. Increased [Mg2+]o, clonazepam, and the combination of both attenuated the hypoxia-reoxygenation-induced reduction in Delta(psi)m, determined with the cationic dye JC-1 by flow cytometry. A significant inverse correlation was observed between Delta(psi)m and cell Ca2+ in reoxygenated cells treated with increased [Mg2+]o and clonazepam. In conclusion, increased [Mg2+]o (5 mM) inhibits Ca2+ accumulation by reducing Ca2+ influx and preserves Delta(psi)m without affecting [Ca2+]i and [Mg2+]i during reoxygenation. Preservation of mitochondria may be an important effect whereby increased [Mg2+]o protects the postischemic heart.
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Affiliation(s)
- M N Sharikabad
- Division of Clinical Pharmacology and Toxicology, Clinical Chemistry Department, Ullevaal University Hospital, N-0407 Oslo, Norway.
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