| Matrix Metalloproteinases (MMPs) is a large family of zinc - and calcium ?dependent endopeptidases, can degrade most components of the extracellular metrix(ECM) : collagen ,laminin,proteoglycan and e-lastin. Tissue inhibitors of metalloproteinases (TIMPs) can inhibit MMPs, and may involve in the deposition of ECM.Asthma is a chronic inflammatory disease of airway. Many in-flammatory cells are correlated with asthma. Inflammatory cells mi-grate to inflammatory foci through the basement membrane , the epithe-lial and endothelial layer, contribute to inflammation. But, inflamma-tion alone cannot explain all aspects of airway physiology in asthmat-ics. People found increased total airway smooth muscle and increased total airway wall thickness in postmortem from patients with severe asthma. These changes were referred to collectively as airway remode-ling. Now, people realized that airway inflammation and remodeling were two important features of asthma. Increased airway smooth mus-cle was one of the most important features of asthma. It can contribute to airway hyperresponsiveness , increase airway obstruction. Several studies showed that MMP - l,MMP -2 interfered with airway smooth muscle remodeling. But, MMP - 9, as one of the most important members of MMPs, and its inhibitor TIMP - 1, were not knownwhether interfered with asthmatic airway smooth muscle remodeling.In the present study, we remade the asthmatic quinea - pig mod-el, and examined the total cell number and eosinophil(EOS) percent-age; measured and calculated the airway smooth muscle area; and MMP - 9,TIMP - 1 expression. The aims of this study were to discuss the effects of MMP -9,TIMP - 1 on airway inflammation and airway smooth muscle remodeling.MaterialGuinea-pig; Ovalbumin; MMP -9,TTMP - 1 Histostain TM -Plus Kits. Universal 32R zentrifugen ; Metmorph/Cool Snalfx/Ax70 image analysis symtem.MethodTwenty guinea - pigs were divided into asthma group and control group. The animals were weighted 200 ?250g at the beginning of the test. The animals of asthmatic group were immunized by intraperitone-al (i. p. ) injection of 10% ( weight/volume, w/v) OVA on the first day of the study, and challenged with an aerosol of 1 % ( w/v) OVA after 1 week. The challenges were repeated 12 weeks. The animals of the control group received mock sensitization with i. p. injection of sterile normal salt solution (NS) and were challenged with an aerosol ofNS.The animals were anesthetized with 1% pentobarbital and per-formed bronchoaveolar lavage (BAL) of right lungs (5ml x 2) . The the right lungs were fixed with 4% paraformaldehyde via a trachealca-nnula and immersed in the fixative for 1 week at least. The lung tis-sues were embedded in paraffin and cut in 10μm sections. The BAL fluid (BALF) was filtered and centrifuged. Total cell numbers were counted. Differential counts of at least 100 cells were made. On the sections stained with hematoxylin and eosin ( HE) , the basement membrane perimeter and the airway smooth muscle area were meas-ured. Immunohistochemistry was performed to determine the BALF and airway smooth muscle expression of MMP -9,TIMP - 1. The col-or reaction was developed using DAB. The sections were counter-stained with hematoxylin. MMP - 9, TIMP - 1 Expression cells in BALF were counted using light microscope. MMP - 9, TIMP - 1 ex-pression in airway smooth muscle was measured by image quantitative analysis.Result1. The HE stained section of asthma group showed airway smooth muscle increasing, infiltration of inflammation cells, mainly EOS.2. The results of BALF: The total ceU number and EOS% of the asthmatic group [( 1140 ?165) x l0Vml, (39. 3 ?13. 89)% ] were higher than that of control group [ (394 ?133. 3) x l0Vml, (23. 3 ?4.13)%] (P<0.05). 3. The airway smooth muscle area ( Was/Pbm) of the asthmatic group [ (5. 90 ?2. 28) μm2 /μm] increased comparing with that of control group [(3. 33 ?.01) μLm2/μxm] (P<0.01).4. MMP -9,TIMP - 1 were expressed in BALF bo... |
PDF Full Text Request