V. Hockele et al., IN-VITRO EFFECTS OF NITROGEN-DIOXIDE ON THE RELEASE OF NITRIC-OXIDE BY BOVINE ALVEOLAR MACROPHAGES, Toxicology letters, 96-7, 1998, pp. 53-57
Bovine alveolar macrophages (BAM) were assessed for nitric oxide-produ
ction after exposure to synthetic air or NO2 [0.2 ppm] for 2 h and sub
sequent treatment with lipopolysaccharide (LPS) [1 mu g/ml]. Nitric ox
ide (NO) release, measured as nitrite in the supernatant, was quantifi
ed at different time points. LPS-stimulated BAM showed elevated nitrit
e levels after 24 h. Pre-treatment with NO2 resulted in higher nitrite
levels in comparison to air exposed BAM. Some of the BAM preparations
resulted in pre-activated macrophages that produce high amounts of NO
without LPS treatment. Within these cells LPS treatment reduced the n
itrite levels in comparison to untreated control incubations from the
same preparation. These pre-activated BAM exhibited no uniform effect
after NO2-exposure. In some experiments nitrite levels of pre-activate
d control BAM were decreased, while in others no influence could be ob
served. NO-production by pre-activated BAM or after I,PS-treatment cou
ld be inhibited by N-G-monomethyl-L-arginine (L-NMMA) [1 mM]. In order
to investigate, whether NO2-exposure alters inducible NO-synthase mRN
A expression, we now perform reverse transcription polymerase chain re
action (RT-PCR) of iNOS mRNA. This method will be a good tool to eluci
date whether NO2-exposure can modulate iNOS mRNA expression. (C) 1998
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