4-hydroxy-2-nonenal and Hypoxia-Ischemia--Brain

Recent clinical trials have demonstrated the efficacy and safety of therapeutic hypothermia for neonatal hypoxic ischemic encephalopathy (HIE). We previously reported that the levels of non-protein-bound iron and ascorbic acid (AA) are increased in the CSF of infants with HIE. In this study, we investigated the effect of hypothermia on the combined cytotoxicity of Fe and AA for differentiated PC12 cells. The optimal settings for hypothermic treatment were a temperature of 30-32 degrees C, rescue time window of less than 6 h, and minimum duration of at least 24 h. Hypothermia effectively prevented the loss of the mitochondrial transmembrane potential from 6 h to 72 h (end of the study period) and attenuated the release of apoptotic proteins (cytochrome c and apoptosis-inducing factor) at 6 h of exposure to Fe-AA. Activation of caspase-3 was also delayed until 24 h. Akt was transiently activated, although no influence of temperature was observed. Elevation of oxidative stress markers, including ortho-, meta-, and di-tyrosine (markers of protein oxidation) and 4-hydroxynonenal (lipid peroxidation) was significantly attenuated when the temperature was reduced by 5 degrees C. The half-cell reduction potential (Ehc) of GSSG/2GSH redox couple ranged from -220 to -180 mV in unstressed differentiated PC12 cells, and apoptosis was triggered when Ehc exceeded -180 mV. Hypothermia prevented Ehc from rising above -180 mV within 24 h of exposure to Fe-AA. In conclusion, hypothermia prevented cell death due to Fe-AA toxicity by inhibiting apoptotic pathways through maintenance of a reduced cellular environment, as well as by alleviating oxidative stress.

Topics: Aldehydes; Animals; Apoptosis; Apoptosis Regulatory Proteins; Ascorbic Acid; Biomarkers; Body Temperature; Drug Synergism; Glutathione; Hypothermia, Induced; Hypoxia-Ischemia, Brain; Iron; Membrane Potentials; Neurons; Neurotoxins; Oxidation-Reduction; Oxidative Stress; PC12 Cells; Proto-Oncogene Proteins c-akt; Rats; Temperature; Tyrosine

Maternal infection is associated with perinatal brain damage, but effects on the cerebellum are not known in detail. In this study, we examined the effects of placental inflammation induced by administering lipopolysaccharide into the uterine artery of pregnant sheep at 134-136 days gestation. The fetal brain was collected 72 h later and compared to brains collected from age-matched untreated fetuses. Placental lipopolysaccharide treatment had substantial effects on the fetal cerebellum, including increasing the number of cells undergoing apoptosis, widespread lipid peroxidation, and extravasation of plasma albumin, suggesting compromise of the cerebellar blood-brain barrier. These effects may account for some of the learning and motor deficits that emerge in neonates from pregnancies compromised by infection.

Topics: Aldehydes; Animals; Apoptosis; Biomarkers; Blood-Brain Barrier; Caspase 3; Cerebellar Diseases; Cerebellum; Cytokines; Disease Models, Animal; Female; Fetus; Gliosis; Hypoxia-Ischemia, Brain; Inflammation; Inflammation Mediators; Ki-67 Antigen; Lipid Peroxidation; Lipopolysaccharides; Oxidative Stress; Placenta; Pregnancy; Pregnancy Complications, Infectious; Sheep; Uterine Diseases; Uterus

Lipid membrane peroxidation is highly associated with neuronal death in various neurodegenerative diseases including cerebral stroke. Here, we report that simvastatin decreases oxygen and glucose deprivation (OGD)/reoxygenation-evoked neuronal death by inhibiting the production and cytoxicity of 4-hydroxy-2E-nonenal (HNE), the final product of lipid peroxidation. Simvastatin markedly decreased the OGD/reoxygenation-evoked death of cortical neurons. OGD/reoxygenation increased the intracellular HNE level mostly in neuronal cells, not glial cells. Simvastatin decreased the intracellular level of HNE in neuronal cells exposed to OGD/reoxygenation. We further found that HNE induced the cytotoxicity in neuronal cells and synergistically increased the N-methyl-D-aspartate (NMDA) receptor-mediated excitotoxicity. Simvastatin largely blocked the NMDA neurotoxicity potentiated by HNE. However, simvastatin did not alter the NMDA-evoked calcium influx in the absence or presence of HNE. HNE inhibited the activity of nuclear factor-kappa B (NF-kappaB), and the cytotoxicity of HNE was in good correlation with inactivation of NF-kappaB. Simvastatin reversed the inhibition of NF-kappaB activity induced by OGD/reoxygenation or HNE. The neuroprotection by simvastatin was significantly attenuated by various NF-kappaB inhibitors, implying that simvastatin inhibits the cytotoxicity of HNE at least in part by maintaining the activity of NF-kappaB. Further understanding of the neuroprotective mechanism of simvastatin may provide a therapeutic strategy for oxidative stress-related neurodegenerative diseases.

Topics: Aldehydes; Animals; Cell Death; Cells, Cultured; Cerebral Cortex; Cytoprotection; Enzyme Inhibitors; Hydroxymethylglutaryl-CoA Reductase Inhibitors; Hypoxia-Ischemia, Brain; Lipid Peroxidation; Nerve Degeneration; Neurons; Neuroprotective Agents; Neurotoxins; NF-kappa B; Oxidative Stress; Rats; Rats, Sprague-Dawley; Receptors, N-Methyl-D-Aspartate; Simvastatin

White matter of the neonatal brain is highly sensitive to hypoxic-ischemic insult. The susceptibility of premature oligodendrocytes (OLs) to free radicals (FRs) produced during hypoxia-ischemia (HI) has been proposed as one of the mechanisms involved. To test this hypothesis, and to further investigate if the FR scavenger alpha-phenyl-N-tert-butyl-nitrone (PBN) attenuates hypoxic-ischemic white matter damage (WMD), postnatal day 4 (P4) SD rats were subjected to bilateral common carotid artery ligation (BCAL), followed by 8% oxygen exposure for 20 min. Pathological changes were evaluated on P6 and P9, 2 and 5 days after the HI insult. HI caused severe WMD including rarefaction, necrosis and cavity formation in the corpus callosum, external and internal capsule areas. OL injury was evidenced by degeneration of O4 positive OLs on P6. Disrupted myelination was verified by decreased immunostaining of myelin basic protein (MBP) on P9. Axonal injury was demonstrated by increased amyloid precursor protein (APP) immunostaining on both P6 and P9. Two lipid peroxidation end products, malondialdehyde (MDA) and 4-hydroxynonenal (4-HNE), showed a one-fold elevation within 1-24 h following HI. 4-HNE immunostaining was found to specifically localize in the white matter area. Furthermore, pyknotic O4+ OLs were double-labeled with 4-HNE. These findings suggest that FRs are involved in the pathogenesis of neonatal WMD. PBN (100 mg/kg, i.p.) treatment alleviated the pathological changes of WMD following HI. It improved the survival of O4 positive OLs, attenuated hypomyelination and reduced axonal damage. PBN treatment also decreased the brain concentration of MDA/4-HNE and positive 4-HNE staining in the white matter area. These findings indicate that in the current WMD model, PBN protects both OLs and axons, the two main components in the white matter, from neonatal HI insult. FR scavenging appears to be the primary mechanism underlying its neuroprotective effect.

Topics: Age Factors; Aldehydes; Amyloid beta-Peptides; Analysis of Variance; Animals; Animals, Newborn; Antigens, Differentiation; Brain; Cell Count; Cell Survival; Cyclic N-Oxides; Free Radical Scavengers; Hypoxia-Ischemia, Brain; Immunohistochemistry; Infarction, Middle Cerebral Artery; Malondialdehyde; Myelin Basic Protein; Nitrogen Oxides; Oligodendroglia; Rats; Staining and Labeling; Time Factors

Free radicals induced by cerebral ischemia-reperfusion injury can trigger lipid peroxidation, leading to the production of malondialdehyde (MDA) and 4-hydroxy-2(E)-nonenal (4-HNE). Post-ischemia electroacupuncture (EA) therapy was able to reduce extent of lipid peroxidation. However, the effect of pre-ischemic EA therapy has not been reported. In this study, we aim to investigate the effectiveness of pre-ischemic EA therapy on lipid peroxidation in the rat ischemic injury model. Four groups of Sprague-Dawley rats were designed: Placebo group (without EA therapy), NA group (EA therapy on non-acupoint), GB20 group (EA therapy on Fengchi), and ST36 group (EA therapy on Zusanli). Half of each group (n = 6) received 30-minute EA therapy for 3 times and the other half group for 18 times before the occlusion of right middle cerebral artery. Right brains were taken for determination of concentration of MDA and the total of MDA plus 4-HNE. We found that multiple pre-ischemia EA therapy at either GB20 or ST36 can effectively reduce the amount of MDA produced after MCA occlusion. However, this reduction was not observed in the total amount of MDA and 4-HNE. In conclusion, pre-ischemia EA can partly regulate the lipid peroxidation in cerebral ischemia, where both GB20 and ST36 have a similar beneficial effectiveness.

Topics: Aldehydes; Animals; Brain; Brain Chemistry; Electroacupuncture; Hypoxia-Ischemia, Brain; Lipid Peroxidation; Male; Malondialdehyde; Medicine, Chinese Traditional; Rats; Rats, Sprague-Dawley; Reperfusion Injury