Effect of humic acid on oxidative stress and neuroprotection in hypoxic-ischemic brain injury: part 1 (original) (raw)
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Humic Acid Induces Apoptosis in Human Endothelial Cells
Toxicology and Applied Pharmacology, 2002
Humic acid (HA) has been implicated as an etiologic factor in the vasculopathy of Blackfoot disease. In this study, the ability of HA to induce apoptosis was studied in cultured human umbilical vein endothelial cells. Treatment of endothelial cells with a variety of concentrations of HA (50-200 microg/ml) resulted in dose- and time-dependent sequences of events marked by apoptosis as shown by loss of cell viability, chromatin condensation, and internucleosomal DNA fragmentation. Antioxidants (superoxide dismutase, vitamin C, and vitamin E) and Ca(2+) chelator (BAPTA) effectively suppressed HA-induced DNA fragmentation (apoptosis). Further studies have shown that HA induced dramatic Ca(2+)-dependent caspase activation (2, 3, 6, 8, and 9). In contrast, negligible caspase-1 activation was observed. The increase in HA-induced apoptosis correlated with a reduction in Bcl-2, a potent cell death inhibitor, and an increase in Bax protein levels, which heterodimerizes with and thereby inhibits Bcl-2. Both of the antioxidants vitamin C and vitamin E prevented the dysregulation of Bcl-2 and Bax in HA-treated endothelial cells. Furthermore, the increase in p53 protein levels correlated with an increase in HA-induced apoptosis. We concluded that both Ca(2+) and oxidative stress were mediators of apoptosis caused by HA and the induction of apoptotic cell death on endothelial cells may be important to the etiology of HA-induced vascular disorder of Blackfoot disease.
Bratislavské lekárske listy, 2020
AIMS: Hypoxic ischemic encephalopathy is one of the main causes of neonatal deaths. The objective of this study was to evaluate the neuroprotective effect of antioxidant and anti-infl ammatory properties of sodium hydrosulfi de (NaHS) in neonatal rats with hypoxic ischemic encephalopathy, as well as its effect on neuronal apoptosis through histopathological and biochemical tests. METHODS: Forty-seven-day-old rats with induced hypoxia-ischemia (HI) were randomly separated into four groups. Half an hour after the induction of hypoxic-ischemia, serum physiological (SF), 50 μmol/kg NaHS, or 100 μmol/kg NaHS were intraperitoneally given to the rats. RESULTS: Apoptotic cells in the brain tissue of rats in HI + NaHS 50 μmol/kg, and HI + NaHS 100 μmol/kg groups decreased compared to HI group (p = 0.00). While HI + NaHS 50 μmol/kg and HI + NaHS 100 μmol/ kg groups yielded no difference in TNF-α, IL-6, and iNOS levels as compared to the HI group, an increase in NGF was detected in the 50 μmol/kg and 100 μmol/kg NaHS groups (p = 0.34, p = 0.24, p = 0.26, p = 0.026, p = 0.017). When TOS, TAS and OSI levels were compared, an increase in TAS and OSI and a decrease in TOS were observed in the treatment groups as compared to HI group. CONCLUSIONS: NaHS given to hypoxic-ischemic encephalopathy model signifi cantly decreased apoptosis in neurons and had a neuroprotective effi cacy with an increase in NGF levels (Tab.
Attenuation of Neuronal Damage by Gymnemic acid in Experimentally Induced Cerebral Ischemia in Rats
Journal of Applied Pharmaceutical Science, 2016
Gymnemic acid is obtained from the natural resource and has got antioxidant property, was investigated for the possible neuroprotective effect in experimentally induced cerebral ischemic rats. Carotid arteries clamped with the help of aneurysm clips to produce cerebral ischemia, the clips were removed from the arteries to allow the reflow of the blood through carotid arteries. It was observed that lipid peroxidation was increased significantly after bilateral common carotid artery occlusion. Brain endogenous antioxidant GSH and total protein levels were low. Administration of gymnemic acid in a dose of 250 mg/kg and 500 mg/kg b.w orally showed promising neuroprotective effect by reducing cerebral infarct size as well as improved all antioxidant levels showing activity against oxidative stress.
Free Radical Biology and Medicine, 2002
Humic acid (HA) has been implicated as an etiological factor in the peripheral vasculopathy of blackfoot disease (BFD). In this study, we examined the effects of HA upon the generation of nitric oxide (NO) during the process of lethal cell injury in cultured human umbilical vein endothelial cells (HUVECs). NO production was measured by the formation of nitrite (NO 2 Ϫ), the stable end-metabolite of NO. Cell death was assessed by measuring the release of intracellular lactate dehydrogenase (LDH). Treatment HUVECs with HA at a concentration of 50, 100, and 200 g/ml concentration-dependently increased nitrite levels, reaching a peak at 12 h subsequent to HA treatment, with a maximal response of approximately 400 pmole nitrite (from 1 ϫ 10 4 cells). HA-induced nitrite formation was blocked completely by N G-nitro-L-arginine methyl ester (L-NAME) and also by N G-methyl-L-arginine (L-NMA), both being specific inhibitors of NO synthase. The LDH released from endothelial cells was evoked at from 24 h after the addition of HA (50, 100, 200 g/ml) in a concentration-and time-dependent manner. The HA-induced LDH release was also reduced by the presence of both L-NAME and L-NMA. The addition of Ca 2ϩ chelator (BAPTA) inhibited both nitrite formation and LDH release by HA. Moreover, the antioxidants (superoxide dismutase, vitamin C, vitamin E) and protein kinase inhibitor (H7) effectively suppressed HA-induced nitrite formation. These results suggest that HA treatment of endothelial cells stimulates NO production, which can elicit cell injury via the stimulation of Ca 2ϩ-dependent NO synthase activity by increasing cytosolic Ca 2ϩ levels. Because the destruction of endothelial cells has been implicated in triggering the onset of BFD, the induction of excessive levels of NO and consequent endothelial-cell injury may be important to the etiology of HA-induced vascular disorders associated with BFD for humans.
Effects of humic acids in vitro
In Vitro Cellular & Developmental Biology - Animal, 2011
Humic acids are known for their overall positive health and productivity effects in animal feeding trials and, controversially, as an aetiological factor of cancer. We tried to assess the in vitro effect of humic acids from a selected source in Slovakia when used at recommended prophylactic dosage. We investigated antioxidant properties, enzymatic and non-enzymatic antioxidant defence system in liver mitochondria and cultured cancer cell lines in vitro. We observed a significant decrease in superoxide dismutase activity after humic acids treatment irrespective of dissolving in dimethyl sulphoxide or direct addition to mitochondria suspension in a respiration medium. Activities of other antioxidant enzymes measured, such as glutathione peroxidase and glutathione reductase, showed no significant differences from the control as well as the reduced glutathione content. Percentage of inhibition by humic acids of superoxide radical indicated lower efficacy compared with that of hydroxyl radical. Survival of six different cancer cells lines indicated that only the acute T lymphoblastic leukaemia cell line was sensitive to the tested humic acids. Despite relatively low solubility in aqueous solutions, humic acids from the selected source participated in redox regulation. By recapturing the radicals, humic acids reloaded the antioxidant defensive mechanism. Results from in vitro study conducted with humic acids from the natural source showed potential of these substances as promising immunity enhancing agents.
Time Course of Peripheral Oxidative Stress as Consequence of Global Ischaemic Brain Injury in Rats
Cellular and Molecular Neurobiology, 2008
Free radicals play an important role in the pathogenesis of brain injury. This study evaluates the potential relationship between ischaemia/reperfusion (I/R)-induced brain injury, peripheral oxidative stress (lymphocyte DNA damage), plasma antioxidant potential and uric acid levels. We observed that 15 min of ischaemia were sufficient to significantly increase lymphocyte DNA damage that remained elevated at the end of early (3 h) reperfusion and at later (72 h) reperfusion time; this parameter was not significantly increased, when compared to preoperated levels. In parallel, antioxidant potential was elevated after 15 min of ischaemia, remained high at early (3 h) reperfusion and decreased again with longer (72 h) reperfusion. A close association between the plasma antioxidant status and the uric acid content has been confirmed by findings that changes in TRAP values positively correlate with uric acid concentration in rat plasma after ischaemic injury. Moreover, results of in vitro experiments with extra uric acid addition to control plasma have shown that uric acid contributes to a greater part of TRAP values. These results indicate a similar time course of brain I/R-associated oxidative stress and peripheral antioxidant defence status and/or oxidative stress in animal experiments.
Humic acid induces G1 phase arrest and apoptosis in cultured vascular smooth muscle cells
Environmental Toxicology, 2009
Humic acid (HA) in well water used by the inhabitants for drinking is one of the possible etiological factors for Blackfoot disease (BFD). In this study, the ability of HA to inhibit cell cycle progression and induce apoptosis in cultured smooth muscle cells (SMCs; A7r5) was investigated. Treatment of the SMCs at various HA concentrations (25-200 lg/mL) resulted in sequences of events marked by apoptosis, as shown by loss of cell viability, morphology change, and internucleosomal DNA fragmentation. HAinduced apoptotic cell death that is associated with loss of mitochondrial membrane potential (DCm), cytochrome c translocation, caspase-3, -8, and -9 activation, poly ADP-ribose polymerase (PARP) degradation, dysregulation of Bcl-2 and Bax, and upregulation of p53 and phospholyrated p53 (p-p53) in SMCs. Flow cytometry analysis demonstrated that HA blocked cell cycle progress in the G1 phase in SMCs. This blockade of cell cycle was associated with reduced amounts of cyclin D1, CDK4, cyclin E, CDK2, and hyperphosphorylated retinoblastoma protein (pRb) in a time-dependent manner. Apparent DNA strand breaks (DNA damage) were also detected in a dose-dependent manner using Single-cell gel electrophoresis assay (comet assay). Furthermore, HA induced dose-dependent elevation of reactive oxygen species (ROS) level in SMCs, and antioxidant vitamin C and Trolox effectively suppressed HA-induced DNA damage and dysregulation of Bcl-2/Bax. Our findings suggest that HA-induced DNA damage, cell cycle arrest, and apoptosis in SMCs may be an underlying mechanisms for the atherosclerosis and thrombosis observed in the BFD endemic region. Wiley Periodicals, Inc. Environ Toxicol 24: 243-258, 2009
Turkish neurosurgery, 2008
HI (hypoxic-ischemic) brain injury is a major cause of neonatal mortality and longterm neurological morbidity. The aim of the present study was to investigate the effects of HPC (hypoxic preconditioning) on the oxidative-antioxidative status in the neonatal HI brain model. Fifty five 7-day-old rats were placed into; Control, HPC, HPC+HI insult, and HI insult groups. HPC, The HPC+HI insult groups were subjected to hypoxia (37 degrees C, 8%O2) and the control group to normoxia for 2.5 hrs. Twenty-four hours later, the rats in the HPC+HI insult and HI insult groups were exposed to cerebral HI produced by unilateral right common carotid artery (CCA) occlusion combined with 90 min hypoxia. Four hours after recovery, the malondialdehyde (MDA) level and the activities of superoxide dismutase (SOD), and glutathione peroxidase (GPx) were determined in the brain tissues of the rats. The findings of the present study suggest increased lipid peroxidation and/or decreased antioxidant activity in...
2008
Succinic semialdehyde dehydrogenase (SSADH) deficiency and tyrosinemia type II are characterized by predominant tissue and blood accumulation of γhydroxybutyric acid (GHB) and tyrosine, respectively. Patients with SSADH deficiency and tyrosinemia type II present neurological signs and symptoms. Although mechanisms of brain damage remain unclear, they are probably related to the accumulation of GHB or tyrosine leading to possible noxious effects on central nervous system (CNS) development in those patients. Considering that the damaging consequences of oxidative stress have been implicated in a variety of disorders of CNS, the effect of GHB and L-tyrosine were investigated on some oxidative stress parameters in cerebral cortex homogenates of young rats. The in vitro and in vivo effects of GHB, or its precursor 1,4-butanediol (1,4-BD), were similar. It was observed that GHB or 1,4-BD impairs non-enzymatic antioxidant defenses and induces lipid peroxidation. On the other hand, the in vitro and in vivo effects of Ltyrosine were different. Oxidative damage to DNA was promoted while nonenzymatic and enzymatic antioxidant defenses, and thiol-disulfide redox state (SH/SS ratio) were markedly diminished by L-tyrosine in vitro. In contrast, the acute administration of L-tyrosine causes lipid peroxidation and protein oxidation, decreases non-enzymatic antioxidant defenses, alters SH/SS ratio and stimulates glucose-6-phosphate dehydrogenase activity. Taken together, it may be presumed that GHB and L-tyrosine elicit oxidative stress in cerebral cortex of young rats. If these effects also occur in the brain of patients affected by SSADH deficiency or tyrosinemia type II, it is possible that oxidative stress may contribute, at least in part, to the neurological dysfunction characteristic of these diseases.
Journal of Neurochemistry, 2006
Oxidative stress is associated with the pathology of acute and chronic neurodegenerative disease. Cultured neuronal cells exposed to hypoxia-reoxygenation (H/R) injury, as a model for stroke, yield a burst of reactive oxygen species (ROS) as measured with electron paramagnetic resonance (EPR) spectroscopy in combination with spin trapping. Added superoxide dismutase inhibited spin-adduct formation verifying that superoxide radical anion was formed in neuronal cells following H/R injury. The intracellular ADP/ATP ratio increased rapidly over the first 5 h following injury and this was due primarily to the decreased cellular pools of ATP, consistent with the notion that H/R promotes mitochondrial dysfunction leading to decreased ATP reserve and increased ROS formation. As an early response to the enhanced oxidative stress, genes encoding for hypoxiainducible factor 1-a (HIF1-a), inducible haemoxygenase-1 (HO-1), and the oxygen-sensor neuroglobin increased significantly. Up-regulation of the HO-1 gene was paralleled by increased HO protein expression and activity. Despite this cellular response, apoptosis increased significantly following H/R injury indicating that the endogenous anti-oxidant defenses were unable to protect the cells. In contrast, addition of a phenolic anti-oxidant, bisphenol (BP), prior to H/R injury, inhibited ROS production and gene regulation and significantly decreased neuronal cell apoptosis. Added BP was converted stoichiometrically to the corresponding diphenoquinone indicating the synthetic anti-oxidant effectively decreased oxidative stress through a radical scavenging mechanism. Together, these data indicate that BP has the potential to act as a neuro-protective drug.