Hyperoxia Attenuated Nitrotyrosine Concentration
in the Lung Tissue of
Rats with Experimental Pneumonia
B. Fišárková1, R. Vytášek3,
D. Miková2, M. Vízek1
1Institute
of Pathophysiology, 2Institute of Physiology and 3Institute
of Biochemistry, Second Faculty of Medicine, Charles University and Centre
for Experimental Cardiovascular Research, Prague, Czech Republic
Received June 3, 2003
Accepted July 15, 2003
Summary
Although nitrated proteins have been
repeatedly used as markers of lung injury, little is known about their
formation and metabolism under hyperoxia. We therefore measured
3-nitrotyrosine (3NTYR) concentrations in lung tissue and serum of rats
with carrageenan-induced pneumonia exposed to hyperoxia. Twenty-nine
Wistar male rats were assigned to one of 4 groups. Two experimental groups
were treated by intratracheal application of carrageenan (0.5 ml of 0.7 %
solution) and then one was exposed to hyperoxia for 7 days (FIO2
0.8), the other to air. Rats of two control groups breathed either
hyperoxic gas mixture or air for 7 days. At the end of exposure the
ventilation was determined in anesthetized, intubated animals in which
3NTYR concentrations were measured in the lung tissue and nitrites and
nitrates (NOx) were estimated in the serum. Carrageenan
instillation increased 3NTYR concentrations in lung tissue
(carrageenan-normoxic group 147±7
pmol/g protein, control 90±10
pmol/g protein) and NOx concentration in the serum
(carrageenan-normoxic group 126±13
ppb, control 78±9
ppb). Hyperoxia had no effect on lung tissue 3NTYR concentration in
controls (control-hyperoxic 100±14
pmol/g protein) but blocked the increase of lung tissue 3NTYR in
carrageenan-treated rats (carrageenan-hyperoxic 82±13
pmol/g protein), increased NOx in serum (control-hyperoxic 127±19
ppb) and decreased serum concentration of 3NTYR in both hyperoxic groups
(carrageenan-hyperoxic 51±5
pmol/g protein, control-hyperoxic 67±7
pmol/g protein, carrageenan-normoxic 82±9
pmol/g protein, control 91±7
pmol/g protein). The results suggest that hyperoxia affects nitration of
tyrosine residues, probably by increasing 3NTYR degradation.
Key words
Nitrotyrosine
·
Hyperoxia
·
Experimental pneumonia
·
Carrageenan ·
Nitrites and nitrates
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