Abstract: AIM: To explore the clinical effect and mechanism of NAC on patients with chronic obstructive pulmonary disease (COPD).METHODS: 78 patients with COPD in stable phase were randomly divided into the treated grouPand the control group.Total and differential count of inflammatory cell in sputum,NF-kB,IL-8,TNF-α,and clinical symptom,FVC,FEV1,mPAPand the blood levels of malondialdchyde (MDA),superoxide dismutase (SOD),angiotensin-converting enzyme (ACE)and endothelins-1 (ET-1)were measured before and aftertreatment.RESULTS: 5 cases of the 78 patients dropped out.The rate of total marked effect and total effect were72.50 %,and 87.50 % respectively,in the treated group.All the indexes measured in patients before and aftertreatment were significantly different from those in healthy subjects (P<0.05).Differential count of polymorphonuclearneutrophil (PMN),the levels of IL-8 and TNF-α,the activity of NF-kB in sputum in the treated grouPdecreased aftertreatment (P<0.01),while the FEV1,FVC,mPAP,MDA,SOD,ACE,and ET-1 were ameliorated (P<0.05),and all were betterthan those in the control grouP(P<0.05).No obvious adverse effects were found.CONCLUSION: NAC used fortreating COPD is able to relive the clinical symptom and improve the lung function,with a fairly good safety,and can play a therapeutic role on patients with COPD by way of increasing anti-oxidative ability and reducing the airway inflammatory reaction.

Key words: chronic obstructive pulmonary disease(COPD), NAC, inflammatory Cells, IL-8, TNF-α, NFKb, anti-oxidative ability