The effects of hypoxia/reoxygenation on the physiological behaviour of U373-MG astrocytes.
Nerve cells are very susceptible to hypoxia responsive for mitochondrial dysfunctions involved in the subsequent oxidative stress, apoptosis and necrosis. In this paper, we examined the effect of 12 h incubation of U-373 MG astrocytes in hypoxic environment (73% N(2): 2% O(2): 5% CO(2), v:v) by evaluating cell proliferation, modifications of NO and ATP production, intracellular Ca(2+) concentration [Ca(2+)](i), membrane potential, desferoxamine-chelatable free iron, esterified F2-isoprostanes levels and the production of phosphorylated ERK. The same parameters were evaluated also after a following re-oxygenation period of 24 h. Immediately after hypoxia the NO concentration increased significantly and returned to values similar to those of controls after the re-oxygenation period. At the same time, ATP levels remained similar to controls and the cell proliferation significantly decreased. This involved a significant increase of [Ca(2+)](i) immediately after hypoxia and the value remained significantly elevated after the following re-oxygenation period. Moreover, after hypoxia, astrocytes were slightly although not significantly depolarized. Indeed iron and F2-isoprostanes levels increased significantly after hypoxia. Finally ERK proteins increased slowly and not significantly after hypoxia and the same trend was observed after the re-oxygenation period. On the whole, our results indicate that 2% O(2) hypoxia induces a moderate oxidative stress, well tolerated by U-373 MG cells, remaining the ATP production, mitochondrial membrane potential and activated ERK proteins, similar to the values of controls.
Aldinucci
Carlo
C
Department of Physiology, University of Siena, 53100 Siena, Italy.
Maiorca
Silvia Maria
SM
De Rosa
Paola
P
Palmi
Mitri
M
Sticozzi
Claudia
C
Ciccoli
Lucia
L
Leoncini
Silvia
S
Signorini
Cinzia
C
Pessina
Gian Paolo
GP
D000255:Adenosine Triphosphate / Q000378:metabolism; D001253:Astrocytes / Q000166:cytology* / Q000201:enzymology / Q000378:metabolism; D015153:Blotting, Western; D002118:Calcium / Q000378:metabolism; D002460:Cell Line; D049109:Cell Proliferation; D003676:Deferoxamine / Q000378:metabolism; D048049:Extracellular Signal-Regulated MAP Kinases / Q000378:metabolism; D006801:Humans; D000860:Hypoxia / Q000473:pathology*; D007502:Iron Chelating Agents / Q000378:metabolism; D028421:Isoprostanes / Q000378:metabolism; D008564:Membrane Potentials; D010100:Oxygen / Q000008:administration & dosage*; D010766:Phosphorylation
D007502:Iron Chelating Agents; D028421:Isoprostanes; D000255:Adenosine Triphosphate; D048049:Extracellular Signal-Regulated MAP Kinases; D003676:Deferoxamine; D010100:Oxygen; D002118:Calcium