ABSTRACT
<p><b>OBJECTIVE</b>To investigate the role and mechanism of matrix metalloproteinase 9 (MMP-9) and tumor necrosis factor α (TNF-α) in the pathogenesis of allergic rhinitis (AR) and asthma(AS).</p><p><b>METHODS</b>The rat models of AR and AS were made by injecting ovalbumin. The infiltration of eosinophils and mast cells were detected by hematoxylin-eosin (HE) staining and toluidine blue staining respectively, and the expression of MMP-9 and TNF-α in nasal mucosa and lung tissue were examined by immunohistochemical staining (SP method). The relationship of their expression with upper and lower respiratory tract inflammation was analyzed. SPSS 13.0 software was used to analyze the data.</p><p><b>RESULTS</b>The numbers of MMP-9 positive inflammatory cells in nasal mucosa and lung tissue of AR were (154.8 ± 12.0) and (124.0 ± 8.2), (43.2 ± 7.6) and (34.5 ± 5.0) in the control groups, the difference was significant (t value were 24.260, 29.525 respectively, all P < 0.05). The numbers of MMP-9 positive inflammatory cells in nasal mucosa and lung tissue of AS were (149.9 ± 11.7) and (120.1 ± 7.3), (48.6 ± 7.6) and (39.1 ± 5.2) in control groups, the difference was significant (t value were 22.929 and 28.530 respectively, all P < 0.05). The numbers of TNF-α positive inflammatory cells in nasal mucosa and lung tissue of AR were (188.8 ± 17.0), and (134.8 ± 7.9), (57.6 ± 23.3) and (40.3 ± 8.2) in control groups, the difference was significant (t value were 13.836 and 26.220, all P < 0.05). The numbers of TNF-α positive inflammatory cells in nasal mucosa and lung tissue of AS were (179.2 ± 15.4) and (153.5 ± 10.1), (70.5 ± 33.1) and (33.8 ± 14.0) in control groups, the difference was significant (t value were 9.412 and 21.858, all P < 0.05). There was a correlation between the expression of MMP-9 and TNF-α in nasal mucosa and lung tissue of AR (r values were 0.893 and 0.700 respectively, P values were 0.001 and 0.024, respectively) and AS (r values were 0.692 and 0.644 respectively, P values were 0.027 and 0.044 respectively) groups.</p><p><b>CONCLUSIONS</b>The inflammation is similar between AR and AS. The MMP-9 and TNF-α may play an important role in the pathogenesis of upper and lower respiratory tract inflammation.</p>