Abstract: AIM: To investigate the levels of leukotrienes C4(LTC4),8-isoprostane,nitrite /nitrate(NO₂/NO₃) in exhaled breath condensate of patients with asthma and the effect of inflammatory factors after montelukast treatment. METHODS: 30 patients with asthma were enrolled. They were given 10 mg montelukast once each night for one month. Before starting therapy and one month later, the levels of LTC4, 8-isoprostane, NO₂/NO₃ in exhaled breath condensate were measured. RESULTS: The levels of LTC4(55±17) ng/mL,8-isoprostane (13±9) ng/mL,and NO₂/NO₃ (4.2±1.2) ng/mL were significantly higher in the asthma group than those in the control group (17±17) ,(7±6) ,(3.2±0.6) ng/mL(P<0.01). The levels of LTC4 (55±17) ng/mL in patients with asthma before treatment was significantly higer than those in patients after treatment (38±14) ng/mL(P<0.01). Before and after treatment,the levels of 8-isoprostane,NO₂/NO₃ were (13±9),(11±6),(4.2±1.2),(4.1±1.4) ng/mL;and there were no significant differences (P>0.05). CONCLUSION: Detecting the LTC4,8-isoprostane and NO₂/NO₃ in EBC can be used to monitor asthmatic airway inflammation,which are convenient,noninvasive and safe. Montelukast can decrease the level of LTC4, which is an effective anti-inflammatory agent.

Key words: Exhaled breath condensate, Leukotrienes C4, 8-isoprostane, Nitrite /Nitrate, Montelukast, Bronchial asthma