title: The physiological behaviour of IMR-32 neuroblastoma cells is affected by a 12-h hypoxia/24-h reoxygenation period.
abstract: Nervous system cells are highly dependent on adequate tissue oxygenation and are very susceptible to hypoxia, which causes mitochondrial dysfunctions involved in apoptosis and necrosis. In this paper, we examine the effect of a 12-h incubation of differentiated IMR-32 neuroblastoma cells in a hypoxic environment (73% N(2): 2% O(2): 5% CO(2), v:v) by evaluating cell viability, modifications of NO, intracellular Ca(2+) concentration [Ca(2+)](i) and membrane potential, the production of phosphorylated ERK, desferoxamine-chelatable free iron and esterified F2-isoprostane levels. The same parameters were evaluated after a subsequent 24-h re-oxygenation period. The NO concentration increased significantly immediately after hypoxia and returned to values similar to those of controls after the reoxygenation period. At the same time, we observed a significant increase of [Ca(2+)](i) immediately after hypoxia. Phosphorylated ERK proteins increased significantly during the first 2 h of hypoxia, then decreased, and remained practically unmodified after 12 h hypoxia and the following reoxygenation period. Moreover, IMR-32 cell mitochondria were significantly depolarized after hypoxia, while membrane potential returned to normal after the reoxygenation period. Finally, desferoxamine-chelatable free iron and F2-isoprostane levels also increased significantly after hypoxia. Our results indicate that 2% O(2) hypoxia induces variations of NO and [Ca(2+)](i) with subsequent mitochondrial depolarization, and it is responsible for oxidative stress, represented by increased free iron and F2-isoprostane, protein carbonyls and 4 hydroxynonenal protein adducts levels.
authors.affiliation: Department of Physiology, University of Siena, Siena, Italy.
authors.forename: Carlo
authors.initials: C
authors.lastname: Aldinucci
authors.forename: Silvia Maria
authors.initials: SM
authors.lastname: Maiorca
authors.forename: Paola
authors.initials: P
authors.lastname: De Rosa
authors.forename: Mitri
authors.initials: M
authors.lastname: Palmi
authors.forename: Claudia
authors.initials: C
authors.lastname: Sticozzi
authors.forename: Lucia
authors.initials: L
authors.lastname: Ciccoli
authors.forename: Silvia
authors.initials: S
authors.lastname: Leoncini
authors.forename: Cinzia
authors.initials: C
authors.lastname: Signorini
authors.forename: Giuseppe
authors.initials: G
authors.lastname: Valacchi
authors.forename: Gian Paolo
authors.initials: GP
authors.lastname: Pessina
mesh_terms: D000255:Adenosine Triphosphate / Q000378:metabolism; D000447:Aldehydes / Q000378:metabolism; D002118:Calcium / Q000378:metabolism; D015687:Cell Hypoxia / Q000502:physiology*; D045744:Cell Line, Tumor; D002470:Cell Survival; D028441:F2-Isoprostanes / Q000378:metabolism; D006801:Humans; D007501:Iron / Q000378:metabolism; D053078:Membrane Potential, Mitochondrial / Q000187:drug effects; D019950:Mitogen-Activated Protein Kinase 1 / Q000378:metabolism; D048052:Mitogen-Activated Protein Kinase 3 / Q000378:metabolism; D009447:Neuroblastoma / Q000378:metabolism*; D009569:Nitric Oxide / Q000378:metabolism; D010100:Oxygen / Q000378:metabolism / Q000494:pharmacology*; D050050:Protein Carbonylation
chemical_list: D000447:Aldehydes; D028441:F2-Isoprostanes; D009569:Nitric Oxide; D000255:Adenosine Triphosphate; D007501:Iron; D019950:Mitogen-Activated Protein Kinase 1; D048052:Mitogen-Activated Protein Kinase 3; C027576:4-hydroxy-2-nonenal; D010100:Oxygen; D002118:Calcium