Changes in the expression of NO synthase isoforms after ozone: the effects of allergen exposure.
BACKGROUND
The functional role of nitric oxide (NO) and various nitric oxide synthase (NOS) isoforms in asthma remains unclear.


OBJECTIVE
This study investigated the effects of ozone and ovalbumin (OVA) exposure on NOS isoforms.


METHODS
The expression of inducible NOS (iNOS), neuronal NOS (nNOS), and endothelial NOS (eNOS) in lung tissue was measured. Enhanced pause (Penh) was measured as a marker of airway obstruction. Nitrate and nitrite in bronchoalveolar lavage (BAL) fluid were measured using a modified Griess reaction.


RESULTS
The nitrate concentration in BAL fluid from the OVA-sensitized/ozone-exposed/OVA-challenged group was greater than that of the OVA-sensitized/saline-challenged group. Methacholine-induced Penh was increased in the OVA-sensitized/ozone-exposed/OVA-challenged group, with a shift in the dose-response curve to the left, compared with the OVA-sensitized/saline-challenged group. The levels of nNOS and eNOS were increased significantly in the OVA-sensitized/ozone-exposed/OVA-challenged group and the iNOS levels were reduced compared with the OVA-sensitized/saline-challenged group.


CONCLUSIONS
In mice, ozone is associated with increases in lung eNOS and nNOS, and decreases in iNOS. None of these enzymes are further affected by allergens, suggesting that the NOS isoforms play different roles in airway inflammation after ozone exposure.
Jang
An-Soo
AS
Department of Internal Medicine, Soonchunhyang University Hospital, Bucheon, 1174, Jung-dong, Wonmi-gu, Bucheon-si, Gyeonggi-do, 420-767 Republic of Korea. jas877@schbc.ac.kr
Choi
Inseon-S
IS
Lee
Jong-Un
JU
Park
Sung-Woo
SW
Lee
June-Hyuk
JH
Park
Choon-Sik
CS
D000485:Allergens / Q000633:toxicity; D000818:Animals; D001249:Asthma / Q000139:chemically induced* / Q000201:enzymology*; D016084:Bronchoconstriction / Q000187:drug effects; D004781:Environmental Exposure / Q000009:adverse effects; D005260:Female; D008168:Lung / Q000187:drug effects* / Q000201:enzymology* / Q000473:pathology / Q000503:physiopathology; D051379:Mice; D008807:Mice, Inbred BALB C; D019001:Nitric Oxide Synthase / Q000378:metabolism*; D010047:Ovalbumin / Q000633:toxicity*; D010126:Ozone / Q000633:toxicity*; D020033:Protein Isoforms / Q000378:metabolism
D000485:Allergens; D020033:Protein Isoforms; D010126:Ozone; D010047:Ovalbumin; D019001:Nitric Oxide Synthase