cytochrome-c-t and 8-hydroxyguanine

Brain injury represents a major health problem and may result in chronic inflammation and neurodegeneration. Due to antiinflammatory effects of gold, we have investigated the cerebral effects of metallic gold particles following a focal brain injury (freeze-lesion) in mice. Gold particles 20-45 microm in size or the vehicle (placebo) were implanted in the cortical tissue followed by a cortical freeze-lesioning. At 1-2 weeks post-injury, brains were analyzed by using immunohistochemistry and markers of inflammation, oxidative stress and apoptosis. This study shows that gold treatment significantly reduces the cerebral levels of tumor necrosis factor alpha (TNFalpha), oxidative DNA damage (as judged by 8-oxoguanine levels), and pro-apoptotic markers (cleaved caspase-3, cytochrome c leakage), when compared to those of controls. The data presented here points toward gold particles as a tool to modulate the cerebral response to injury.

Topics: Animals; Apoptosis; Biomarkers; Brain Injuries; Caspase 3; Cerebral Cortex; Cytochromes c; Disease Models, Animal; DNA Damage; Down-Regulation; Female; Gold; Guanine; Immunohistochemistry; Mice; Mice, Inbred C57BL; Neurons; Neuroprotective Agents; Oxidative Stress; Treatment Outcome; Tumor Necrosis Factor-alpha

Experimental laboratory investigation of the role and pathways of reactive oxygen species (ROS)-mediated motor neuron cell death in a mouse model of compression spinal cord injury.. To analyze ROS-mediated oxidative stress propagation and signal transduction leading to motor neuron apoptosis induced by compression spinal cord injury.. University of Louisville Health Science Center.. Adult C57BL/6J mice and transgenic mice overexpressing SOD1 were severely lesioned at the lumbar region by compression spinal cord injury approach. Fluorescent oxidation, oxidative response gene expression and oxidative stress damage markers were used to assay spinal cord injury-mediated ROS generation and oxidative stress propagation. Biochemical and immunohistochemical analyses were applied to define the ROS-mediated motor neuron apoptosis resulted from compression spinal cord injury.. ROS production was shown to be elevated in the lesioned spinal cord as detected by fluorescent oxidation assays. The early oxidative stress response markers, NF-kappaB transcriptional activation and c-Fos gene expression, were significantly increased after spinal cord injury. Lipid peroxidation and nucleic acid oxidation were also elevated in the lesioned spinal cord and motor neurons. Cytochrome c release, caspase-3 activation and apoptotic cell death were increased in the spinal cord motor neuron cells after spinal cord injury. On the other hand, transgenic mice overexpressing SOD1 showed lower levels of steady-state ROS production and reduction of motor neuron apoptosis compared to that of control mice after spinal cord injury.. These data together provide direct evidence to demonstrate that the increased production of ROS is an early and likely causal event that contributes to the spinal cord motor neuron death following spinal cord injury. Thus, antioxidants/antioxidant enzyme intervention combined with other therapy may provide an effective approach to alleviate spinal cord injury-induced motor neuron damage and motor dysfunction.

Topics: Animals; Apoptosis; Blotting, Western; Caspase 3; Caspases; Cell Count; Cytochromes c; Disease Models, Animal; DNA, Single-Stranded; Female; Guanine; Immunohistochemistry; In Situ Nick-End Labeling; Lac Operon; Lipid Peroxidation; Mice; Mice, Inbred C57BL; Mice, Transgenic; Models, Molecular; Motor Neurons; NF-kappa B; Peroxidases; Proto-Oncogene Proteins c-fos; Reactive Oxygen Species; Spinal Cord Injuries; Staining and Labeling; Superoxide Dismutase; Superoxide Dismutase-1; Time Factors

Although both bacillary and coccoid forms of Helicobacter pylori reside in human stomach, the pathophysiological significance of the two forms remains obscure. The present work describes the effect of oxygen tension on the transformation and reactive oxygen species (ROS) metabolism of this pathogen. Most H. pylori cultured under an optimum O2 concentration (7%) were the bacillary form, whereas about 80% of cells cultured under aerobic or anaerobic conditions were the coccoid form. The colony-forming unit of H. pylori decreased significantly under both aerobic and anaerobic culture conditions. The bacillary form of H. pylori generated predominantly superoxide radical, whereas the coccoid form generated preferentially hydroxyl radical. Specific activities of cellular respiration, urease, and superoxide dismatase decreased markedly after transformation of the bacillary form to the coccoid form, with concomitant generation of protein carbonyls and 8-hydroxyguanine. The frequency of mutation of cells increased significantly during culture under nonoptimum O2 conditions. These results indicate that ROS generated by H. pylori catalyze the oxidative modification of cellular DNA, thereby enhancing the transformation from the bacillary to the coccoid form. The enhanced generation of mutagenic hydroxyl radicals in the coccoid form might accelerate mutation and increase the genetic diversity of H. pylori.

Topics: Aerobiosis; Anaerobiosis; Bacterial Proteins; Ciprofloxacin; Cytochromes c; DNA; Drug Resistance; Guanine; Helicobacter pylori; Metronidazole; Mutation; Oxidative Stress; Oxygen; Reactive Oxygen Species; Rifampin; Superoxide Dismutase; Urease