ABSTRACT
Objective:To explore the role of matrix metalloproteinase 12 (MMP12) in airway macrophages and pulmonary neu-rogenic substance P ( SP ) in the pathogenesis of asthma by analyzing their relationship in different categories of asthmatic patients.Methods:Twenty patients of asthma remission phase ( remission asthma group ) , twenty ones of mild acute exacerbation asthma (mild asthma group) and twenty healthy adults (normal control group) were included,respectively.After lung function was measured,the numbers of macrophage in induced sputum were counted.The expression levels of MMP12 mRNA and protein in sputum macrophages were detected by quantitative reverse transcription polymerase chain reaction and Western blot.The concentration of sputum SP was assayed by enzyme immunometric assay.Results: ( 1 ) Compared with the subjects in normal control group, forced expiratory volume in 1 second%predicted ( FEV1 ) and forced expiratory flow rates at 50% of the forced vital capacity % predicted ( FEF50 ) were much lower and the numbers of sputum macrophages were much higher in the patients in different asthmatic groups.Compared with the patients in remission asthma group,FEV1 and FEF50 were much lower in the ones in mild asthma group.(2) MMP12 expressions in the macrophages and the concentrations of SP in sputum were significantly increased in the patients in different asthmatic groups compared with those in normal control group;Furthermore,MMP12 and SP in mild asthma group were much higher than in remission asthma.(3) In all patients from different asthmatic groups,mRNA expressions of MMP12 in the macrophages were positively correlated with the levels of sputum SP or the numbers of sputum macrophages,whereas negative correlations between mRNA expressions of MMP 12 and FEV 1 or FEF50 were observed.Conclusion: The regulatory imbalance of macrophages′MMP12 and pulmonary neurogic SP may participate in the pathogenesis of asthma and become the potential targets for asthma therapy.