Hydrogen Peroxide Metabolism
in Alveolar Macrophages after Exposure to Hypoxia and Heat
E. M. LOBANOVA, A. D. TAHANOVICH
Department of Biochemistry, Belarusian State Medical University,
Minsk, Belarus
Received date September 19, 2005
Accepted date December 8, 2005
On-line available December 12, 2005
Summary
High temperature can change the effects of intra- and
intercellular regulators and therefore modify the cellular
response to hypoxia. We investigated H2O2 production by alveolar
macrophages, isolated from adult male rats, which were incubated
under conditions of oxygen deficiency and high temperature
(experiment in vitro). The incubation of these cells for 2 hours
at 10 % or 5 % oxygen led only to slight fluctuations in the
H2O2 level, while the rise of temperature from 37C up to 42C
significantly increased its generation. Level of thiobarbituric
acid-reactive substances (TBARS) underwent similar changes.
Under these conditions the accumulation of H2O2 was found to be
caused mainly by its decreased cleavage rather than its enhanced
production. This is indicated by decreased catalase and
glutathione peroxidase activity together with a parallel absence
of significant changes in superoxide dismutase (SOD) activity.
Slight fluctuation of reduced glutathione level and the
pronounced increase of glucose-6-phosphate dehydrogenase (G6PD)
activity were detected. Strong (5 %) but not moderate (10 %)
lack of oxygen led to a sharp increase in formation of cellular
nitrite ions by alveolar macrophages. In general, our data
showed that high temperature did not lead to any qualitative
shifts of defined hypoxia-derived changes in oxidant/antioxidant
balance in alveolar macrophages, but promoted sensitivity of
cells to oxygen shortage.
Key words
Alveolar macrophages • Hypoxia • Hyperthermia • Hydrogen
peroxide • Free radicals
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