ABSTRACT
Aspergillus funigatus and other pathogenic fungi synthesize a toxic epidithi-odiopiperzine (ETP) metabolite, namely gliotoxin. Gliotoxin commonly react with sulfhydryl groups, and then, forms hydrogen peroxide. These fungal toxins induce apoptotic cell death in various cells. Apoptosis induced by gliotoxin need calcium. Effect of calcium preconditioning was not reported in gliotoxin-induced apoptosis. To examine the effect of protein kinase C (PKC) and calcium which was regulate caspase-3, PKC and calcium preconditioning before gliotoxin treatment, apoptotic agents such as bcl-2 family, caspase-3 and DNA fragmentation in A7r5 cell line from rat smooth muscle cell were studied. These results showed that gliotoxin induces the expression of bad of bcl-2 family, caspase-3 activation and DNA fragmentation in A7r5 cells. Gliotoxin treatment followed by calcium and PKC preconditioning suppress the Bad of bcl-2 family, and inhibited caspase-3 activation, respectively. These results suggest that PKC and calcium preconditioning protect the gliotoxin-induced apoptosis, through the protection of pro-apoptotic bcl-2 family in A7r5 cells.
Subject(s)
Animals , Humans , Rats , Apoptosis , Aspergillus , Calcium , Caspase 3 , Cell Death , Cell Line , DNA Fragmentation , Fungi , Gliotoxin , Hydrogen Peroxide , Muscle, Smooth , Mycotoxins , Myocytes, Smooth Muscle , Protein Kinase CABSTRACT
Paclitaxel (taxol) is known as effective drug inhibition of cell cycle encouraging activity in human ovarian and metastatic breast cancers and malignant melanoma. It is an antimicrotubule agent that is believed to mediate its antineoplastic effects by inducing mitotic arrest followed by apoptosis. The relation between phorbol 12 myristate 13 acetate (PMA), protein kinase C (PKC) activator, and taxol-induced apoptosis is not well understood until now. This study was performed to investigate the effects of PMA on the signal transduction pathways of taxol-induced apoptosis in MCF-7 human breast carcinoma cells. Taxol-induced apoptosis is attenuated by curcumine, JNK inhibitor, and pyrrolidine dithiocarbamate (PDTC), inhibitor of NFkB. Pretreatment with PKC activator (PMA) or protein kinase A (PKA) activators (forskolin and dibutyryl cAMP) inhibited taxol-induced apoptosis in MCF-7 cells. In addition, thapsigargin, a specific inhibitor of endoplasmic reticulum(ER) Ca(2+)-ATPase and CaCl2, also blocked the activation of caspases by taxol. From these results suggest that taxol-induced apoptosis may be mediated via JNK or NFkB pathway and PKC activation.
Subject(s)
Humans , Apoptosis , Breast , Breast Neoplasms , Caspases , Cell Cycle , Curcumin , Cyclic AMP-Dependent Protein Kinases , MCF-7 Cells , Melanoma , Myristic Acid , Paclitaxel , Protein Kinase C , Signal Transduction , ThapsigarginABSTRACT
Nitric oxide (NO) elevates intracellular calcium. But the actions of calcium in NO-induced cell death are not well understood. This study was carried out to investigate the signal transduction pathways of calcium and NO-induced cytotoxicity in H9c2 cardiac myoblasts by using NO donor compounds such as sodium nitroprusside (SNP) and S-nitroso-N-acetylpenicillamine (SNAP). Pretreatment of intracellular calcium chelating agent (BAPTA/AM) or L-type calcium channel blockers (nicardipine, nifedipine, diltiazem and veraparmil) or T-type calcium channel blocker (flunarizine) blocked SNP-induced cytotoxicity respectively only in a three hours. However, thapsigargin (TG), which inhibits endoplasmic reticulum dependent Ca(2+)-ATPase and thereby increases cytosolic Ca(2+), augmented SNP-induced cytotoxicity. The protective effect of BAPTA/AM was inhibited by treatment of protein synthesis inhibitor, cyclohexamide. In addition, pyrrolidine dithiocarbamate (PDTC), NF-kB inhibitor, attenuates the protective effect of BAPTA/AM against SNP-induced cytotoxicity. It is indicated that the protective effect of BAPTA/AM against NO-induced cytotoxicity might be due to the expression of protein related to activation of NFkB. From these results, it is concluded that SNP-induced cytotoxicity is mediated by calcium in a 3 hours via down regulation of protein expression rleated to activation of NFkB.
Subject(s)
Humans , Calcium Channels, L-Type , Calcium Channels, T-Type , Calcium , Cell Death , Cytosol , Diltiazem , Down-Regulation , Endoplasmic Reticulum , Myoblasts, Cardiac , NF-kappa B , Nifedipine , Nitric Oxide , Nitroprusside , S-Nitroso-N-Acetylpenicillamine , Signal Transduction , Thapsigargin , Tissue DonorsABSTRACT
BACKGROUND: The sensorineural hearing loss due to diabetes is progressive and bilateral, and predominantly occurs in the old, although its accurate pathogenesis is still unknown. Objectives: The purpose of this study is to clarify the neurotoxic effect of streptozotocin (STZ) and the neuroprotective effect of insulin-like growth factor-II(IGF-II) on the cultured Schwann cells of cohlear nerve. MATERIALS AND METHODS: MTT assays were performed on cultured mouse Schwann cells which were treated with various concentrations of STZ for 24 hours, and the neuroprotective effect of IGF-II against STZ-induced neurotoxicity were also examined. RESULTS: 1) MTT50 value was the concentration of 40 pM STZ (highly toxic : MTT50<100 pM), 2) Cell viability of cultured mouse Schwann cells treated with STZ markedly decreased in a dose-dependent manner. CONCLUSION: It is suggested that STZ induces a severe toxic effect on cultured Schwann cells of mouse, and selective neurotrophic factors such as IGF-II are very effective in preventing the neurotoxicity induced by STZ.
Subject(s)
Animals , Mice , Cell Survival , Hearing Loss, Sensorineural , Insulin , Insulin-Like Growth Factor II , Nerve Growth Factors , Neuroprotective Agents , Schwann Cells , StreptozocinABSTRACT
BACKGROUND AND OBJECTIVES: Oxygen radical scavengers and inhibitors are known to have protective functions (or roles) against hypoxia and noise exposure in the cochlea and brain. The purpose of this study was to examine the toxic effect of oxygen radicals (xanthine oxidase and hypoxanthine) on cultured mouse facial nerve Schwann cells, and determine if antioxidants (TPEN and DFO) might ptotect Schwann cells from oxidant-induced neurotoxicity. MATERIALS AND METHODS: Dissociated cell cultures were prepared from the facial nerve of a mouse. After dissociation of Schwann cells, isolated cells were washed, resuspended in feeding medium, and plated onto poly-L-lysine-coated Aclar plastic cover slips (12 mm diameter) in petri dishes or in 96 well multichambers at cell density of 2X105 ceIls/coverslip or lX10(5) ceIls/we11. The feeding medium consisted of Eagle's minimum essential medium (MEM) containing 5% horse serum, 5 mg/ml D-glucose, and 25 ng/ml gentamicin. Cultures were grown in 5% CO2/95% atmosphere at 37degreesC, and the medium was renewed twice a week. Cultures grown for 4-5 days were utilized for experiments. Oxygen radical exposure was done using XO and HX, and antioxidant pretreatment was carried out using tetrakis (2-pyridylmethyl) ethylenediamine (TPEN) and desferrioxamine (DFO). Cytotoxicity assay was performed by MTT [3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide cytotoxic assay and inverted microscopy. RESULTS: Cell viability of cultured mouse Schwann cells treated with markedly decreased in a dose-dependent manner. Cultured mouse Schwann cells exposed to XO/HX for 4 hours showed degenerative changes such as the decrease of cell number and process. Pretreatment of 80 uM TPEN for 2 hours increased remarkably the cell viability of cultured Schwann cells exposed to 20 mU/ml XO/0.1 mM HX, while DFO did not show any protective effects on oxidant-induced neurotoxicity in these cultures. CONCLUSION: It is suggested that oxygen radicals induce neurotoxic effect on cultured mouse Schwann cells, and that selective antioxidants such as TPEN is very effective in blocking oxidant-induced neurotoxicity.
Subject(s)
Animals , Mice , Hypoxia , Antioxidants , Atmosphere , Brain , Cell Count , Cell Culture Techniques , Cell Survival , Cochlea , Deferoxamine , Facial Nerve , Gentamicins , Glucose , Horses , Microscopy , Noise , Oxidoreductases , Oxygen , Plastics , Reactive Oxygen Species , Schwann CellsABSTRACT
In order to elucidate the neurotoxic effect of oxygen radicals on cultured mouse cerebral neurons, the neurotoxicity induced by xanthine oxidase (XO) and hypoxanthine (HX), was evaluated by MTT assay. The neuroprotective effect of allopurinol against oxidant -mediated neurotoxicity was also examined in these cultures by MTT assay and neurofilament enzymeimmunoassay (EIA) with light microscopy. The results were as follows: 1. Oxygen radicals induced degenerative changs such as the decrease of cell number and the loss of neurites in cultured mouse cerebral neurons. 2. The value of midcytotoxicity value (MTT50) of oxygen radicals was estimated at a concentration of 20 mU/ml XO and 0.1 mM HX for 4 hours in these cultures. 3. Cell viability of cultured mouse cerebral neurons was significantly decreased by XO/HX in a dose -and time -dependent manners. 4. Allopurinol was very effective in blocking the neurotoxicity induced by XO/HX at a concentration of 30 microM as determined by MTT assay and neurofilament enzymeimmunoas-say. From the above results, it is suggested that oxygen radicals show neurotoxicity, and the selective antioxidant such as allopurinol are very effective in blocking oxidant -mediated neurotoxicity on cultured mouse cerebral neurons.
Subject(s)
Animals , Mice , Allopurinol , Antioxidants , Cell Count , Cell Survival , Hypoxanthine , Microscopy , Neurites , Neurons , Neuroprotective Agents , Oxygen , Reactive Oxygen Species , Xanthine OxidaseABSTRACT
Toxic effect of oxygen radicals and cardioprotective effect of N -methyl -D -aspartate (NMDA) receptor antagonists against xanthine oxidase (XO) and hypoxanthine (HX)-induced cardiotoxicity were measured in order to elucidate the mechanism of cardiotoxicity on cultured mouse myocardial cells. MTT assay was performed after myocardial cells were cultured for 12 hours at various concentrations of XO/HX alone or with D -2 -amino -5 -phosphonovaleric acid (APV) or 6 - cyano -7 -nitroquinoxaline -2,3 -dione (CNQX). In this study, XO/HX was toxic in a time -and dose -dependent manners on cultured myocardial cells, and midcytotoxicity value 50 (MTT50) was at 30 mU/ml XO and 0.1 mM HX after myocardial cells were grown for 12 hours in media containing 1 ~50 mU/ml XO and 0.1 mM HX. When cultures were treated with 30 mU/ml XO and 0.1 mM HX flus 20 80 microM APV for 12 hours, cell viability was increased remarkably, while treatment with 30 mU/ml XO and 0.1 mM HX flus 10 ~50 microM CNQX did not show any protective effect against XO/HX -induced neurotoxicity. From the above results, it is suggested that oxygen radicals are toxic on cultured mouse myocardial cells by the decrease of cell viability, and NMDA receptor antagonists such as APV are very effective in the prevention of myocardial toxicity induced by oxygen radicals.
Subject(s)
Animals , Mice , 6-Cyano-7-nitroquinoxaline-2,3-dione , Cell Survival , Hypoxanthine , N-Methylaspartate , Oxygen , Reactive Oxygen Species , Xanthine OxidaseABSTRACT
In order to elucidate the mechanism of oxidative damage of cadimu(Cd) on culturedmouse preimplantation embyors.The embryotoxocity of Cd was examined after cultured mouse preimplantation embryoswere exposed to various concentrations of CdCl2. In addition, the protected effect of antioxidant,catalase against Cd-induced embryotoxicity was investigated.CdCl2 decreased the development of cultured mouse preimplantation embryos in dose andtime-dependent manners, and also oxidative damage was involoved in Cd-induced embryotoxicityin mouse preimplantation embryos by the prevention of catalase on Cd-induced toxicity.
Subject(s)
Animals , Mice , Blastocyst , Cadmium Chloride , Cadmium , Catalase , Embryonic StructuresABSTRACT
In order to elucidate the mechanism of oxidative damage of cadimu(Cd) on culturedmouse preimplantation embyors.The embryotoxocity of Cd was examined after cultured mouse preimplantation embryoswere exposed to various concentrations of CdCl2. In addition, the protected effect of antioxidant,catalase against Cd-induced embryotoxicity was investigated.CdCl2 decreased the development of cultured mouse preimplantation embryos in dose andtime-dependent manners, and also oxidative damage was involoved in Cd-induced embryotoxicityin mouse preimplantation embryos by the prevention of catalase on Cd-induced toxicity.
Subject(s)
Animals , Mice , Blastocyst , Cadmium Chloride , Cadmium , Catalase , Embryonic StructuresABSTRACT
In order to elucidate the cardiotoxicity of FeSO4 in cultured myocardial cells derived from neonatal rat, cardiotoxicity was measured by MTT assay when cultured cells were treated with various concentrations of FeSO4. In addition, the cardioprotective effect of antioxidants, glutathione and ascorbic acid was evaluated by MTT assay in these cultrures. Cell viability was remakably decreased in a dose -dependent manner after exposure of cultured rat myocardial cells to 20 microM FeSO4 for 48 hours. In the cardioprotective effect of antioxidants on FeSO4 -induced toxicity, glutathione blocked the cardiotoxicity induced by FeSO4, while ascorbic acid was not effective in blocking FeSO4 -induced cardiotoxicity in these cultures. These results suggest that FeSO4 is toxic in cultured myocardial cells from neonatal rat and selective antioxidants such as glutathione are effective in blocking the cardiotoxicity induced by FeSO4.
Subject(s)
Animals , Rats , Antioxidants , Ascorbic Acid , Cell Survival , Cells, Cultured , GlutathioneABSTRACT
BACKGROUND: In order to elucidate toxic mechanism of the oxygen radicals on cultured rat myocardial cells, cytotoxic effect of oxygen radicals was evaluated by MTT assay. In addition protective effect of glutathione(GSH) on oxidant-induced cardiotoxicity was investigated on these cultures. METHODS: Myocardial cells derived from neonatal rats were cultured for 12 hours in the medium containing various concentrations of glucose oxidase(GO). Cell viability was measured by MTT assay and morphological changes of the myocardial cells were observed by light microscope. RESULTS: GO-mediated oxygen radicals remarkably decreased cell viability of cultured myocardial cells in a dose-and time-dependent manner. And also, GSH blicked GO-induced cardiotoxicity in these cultures. CONCLUSION: These results suggest that the oxygen radicals are tixic and the selective antioxidants such as GSH are effective in blocking against the oxidant-induced cardiotoxicity in cultures of the myocardial cells of neonatsl rats.
Subject(s)
Animals , Rats , Antioxidants , Cell Survival , Glucose , Glutathione , Reactive Oxygen SpeciesABSTRACT
BACKGROUND: It is known that methylmercury poisoning, Minamata disease is very toxic to human body. But, cardiotoxic mechanism of methylmercury is left unknown, Recent study has been reported that the cleavage of methylmercury produce oxygen radicals as well as methyl radicals, and also these radicals induce the release of excitotoxic amino acids(EAAs). So, oxygen radicals and EAA are regarded as a causative factors in the various diseases such as heart disease induced by toxicity of methylmercury. We studied to know the cardiotoxic effect of methylmercury on cultured myocardial cells derived from neonatal rat in order to evaluate the toxic mechanism of methylmercury. METHODS: Myocardial cells of neonatal rat were incubated with various concentrations of methylmercuric chloride for 1-96 hours. MTT90 and MTT50 values were measured and cell viability was determined by MTT assay. In addition, morphological study was performed by light microscope after cultured myocardial cells that were exposed to methymercuric chloride. RESULTS: MTT90 and MTT50 values were 1microM and 15microM of methylmercuric chloride in cultured myocardial cells of neonatal rat respectively. Exposure of cultured rat myocardial cells to methylmercuric chloride resulted in a significant cell death in a time-dependent manner. In the observation of morphological changes, cultured cells treated with methlymercuric chloride showed decrease of cell number and disconnection between cultured myocardial cells. CONCLUSION: These observation suggest that methylmercury has a severe myocardiotoxicity on cultured myocardial cells derived from neonatal rat by the decrease of cell viability and morphological changes.
Subject(s)
Animals , Rats , Cell Count , Cell Death , Cell Survival , Cells, Cultured , Heart Diseases , Human Body , Mercury Poisoning, Nervous System , Poisoning , Reactive Oxygen SpeciesABSTRACT
To elucidate the neurotoxic mechanism of methylmercury on cultured bovine oligodendrocytes, neurotoxic effect was estimated by MTT assay after cultures were exposed to various concentrations of methylmercuric chloride (MMC). In addition, neuroprotective effect of antioxidant, allopurinol agonist MMC-induced neurotoxicity was examined on these cultures. Exposure of cultured bovine oligodendrocytes to MMC showed less than 50% of the cell viability 24 hours after treatment with 35µM of MMC. And also, allopurinol blocked the neurotoxicity induced by MMC on these cultures. These results suggest that oxygen radicals involve in MMC-mediated neurotoxicity, and also seletive antioxidants such as allopurinol are effective in blocking the neurotoxicity induced by MMC on cultured bovine oligodendrocytes.
Subject(s)
Allopurinol , Antioxidants , Cell Survival , Neuroprotective Agents , Oligodendroglia , Reactive Oxygen SpeciesABSTRACT
In order to examine the neurotoxic mechanism of oxygen radicals on cultured bovine oligodendrocytes, cytoxic effect of oxygen radicals was examined when cultures were treated with various concentrations of xanthine oxidase (XO) and hypoxanthine (HX) in culture medium. In addition, the neuroprotective effect of iron-chelators against the neurotoxicity induced by oxygen radicals was evaluated by MTT assay. Cell viability was remarkably decreased in a time-dependent manner after exposure of cultured bovine oligodendrocytes to 20mU/ml XO and 0.1mM HX for 4 hours. In the neuroprotective effect of iron-chelators on oxidant-induced neurotoxicity, tetrakis (2-pyridylmethyl)ethylenediamine (TPEN) blocked the neurotoxicity induced by oxygen radicals, while DFX was not effective in blocking oxidant-induced neurotoxicity in these cultures. These results suggest that oxygen radicals are toxic in cultured bovine oligodendrocytes, and also selective iron-chelators such as TPEN are effective in blocking the neurotoxicity induced by oxygen radicals.
Subject(s)
Allopurinol , Cell Survival , Hypoxanthine , Neuroprotective Agents , Oligodendroglia , Reactive Oxygen Species , Xanthine OxidaseABSTRACT
To evaluate the effect of midkine (MK), neurotrophic factor on cultured mouse spinal motor neuron, NSC-19 which was inhibited by glucose oxidase (GO)-induced oxygen radicals, MTT assay and neurofilament enzymeimmunoassay were carried out after NSC-19 cells were preincubated with various concentrations of midkine for 2 hours prior to exposure of glucose oxidase. The results were as follows : 1. MK increased the rate of cell viability and neurofilamental development in a dose-dependent manner on motoneurons inhibited by glucose oxidase-induced oxygen radicals. 2. MTT50 value was 25 mU/ml GO. 3. GO-induced oxygen radicals were toxic on cultured motor neurons in a time and dose-dependent manner. 4. GO-induced oxygen radicals induced the decrease of cells in number and the loss of neurites in cultured mouse spinal motor neurons. From above the results, it is concluded that oxygen radicals are toxic in cultured mouse spinal motor neurons, and selective neurotrophic factors such as MK enhance the viability of motor neurons inhibited by oxygen radicals.
Subject(s)
Animals , Mice , Cell Survival , Glucose , Glucose Oxidase , Intermediate Filaments , Motor Neurons , Nerve Growth Factor , Nerve Growth Factors , Neurites , Oxidative Stress , Reactive Oxygen SpeciesABSTRACT
In order to investigate the neurotoxic effect of methylmercury (MM) on cultured mouse spinal motoneuron cell line, NSC-19, neurotoxic effect of MM was evaluated by MTT assay after neurons were incubated with various concentrations of methylmercuric chloride (MMC) for 24 hours. In addition, neuroprotective effect of vitamin E against MMC-induced neurotoxicity was examined by MTT assay and neurofilament enzymeimmunoassay (EIA) in these cultures. The results were as follows : 1. MTT50 value was a concentration of 20µM methylmercuric chloride. 2. Methylmercuric chloride was toxic on cultured spinal motor neurons, NSC-19 cells in a time-and dose-dependent manner by severe decrease of cell viability. 3. Methylmercuric chloride induced the decrease of cell number and the loss of neuritis on these cultures. 4. Vitamin E remarkably increased the viabilily of cultured neurons damaged by methylmercury-induced neurotoxicity at a concentration of 250µM vitamin E. From above the results, it is suggested that methylmercury induces severe toxic effect on cultured mouse spinal motor neurons, NSC-19 cells, and the selective antioxidants such as vitamin E are effective in the neurotoxicity induced by methylmercury in these cultures.
Subject(s)
Animals , Mice , Antioxidants , Cell Count , Cell Culture Techniques , Cell Line , Cell Survival , Intermediate Filaments , Motor Neurons , Neuritis , Neurons , Neuroprotective Agents , Vitamin E , VitaminsABSTRACT
In order to elucidate the neurotoxicity of oxygen radicals, neurotoxic effect was investigated after cultured mouse spinal sensory ganglionic cells were exposed to oxygen radicals which were generated enzymatically by reaction of xanthine oxidase (XO) and hypoxanthine (HX) in culture medium. And also the neuroprotective effect of iron-chelators against oxidant-induced neurotoxicity was assessed by MTT assay and neurofilament enzymeimmuno assay (EIA). Cell viability was significantly decreased in a time-dependent planner after exposure of cultured neurons to 25mU/ml XO and 0.3mM HX for 3 hours. In the examination of neuroprotective effect of iron-chelators on oxidant-mediated neurotoxicity. TPEN was effective in blocking the neurotoxicity induced by oxygen radicals, while DFX did not showed any neuroprotective effect in these cultures. These results suggest that oxygen radicals are toxic in cultured mouse spinal sensory ganglionic cells, and also iron involves in oxidant-induced neurotoxicity. While, selective iron-chelators such as TPEN are effective in blocking the neurotoxicty induced by oxygen radicals.
Subject(s)
Animals , Mice , Cell Survival , Ganglia, Sensory , Hypoxanthine , Intermediate Filaments , Iron , Neurons , Neuroprotective Agents , Oxygen , Reactive Oxygen Species , Xanthine OxidaseABSTRACT
The gene for tyrosinase has been mapped to the long arm of chromosome 11 at 11q14-21. The gene is at least 50Kb in length and its coding region is divided into five exons. Until now several mutations of the tyrosinase gene have been identifed in patient with typical oculocutaneous albinism (OCA) who are responsible for tyrosinase negative OCA. It may be possible to determine the types of OCA by measuring the hairbulb tyrosinase activity. Hairbulb tyrosinase activity was examined in a Korean albino to determine the type of OCA. And also tyrosinase assay was carried out in normally pigmented individuals and all members of a Korean albino's family to examine the tyrosinase activities. Five exons of tyrosinase gene from a Korean albino were amplified by polymerase chain reaction. Each amplified exon segments were independently subcloned and DNA sequences of clones were determined. The results obtained were as follows : 1. A Korean albino had no measurable hairbulb tyrosinase activity and was identified as type IA (tyrosinase negative) oculocutaneous albinism. 2. Normally pigmented individuals had different ranges of hairbulb tyrosinase activity. 3. A Korean albino had two single base insertions within exon V (between 337bp and 338bp, 353bp and 354bp) of tyrosinase gene. These insertional mutations might disrupt tyrosinase function and were associated with a total lack of melanin biosynthesis.