Expression Of Matrix Metalloproteinases (MMP-2 And MMP-9) In Vocal Fold Polyps

Objective:The objective of this study was investigation and quantitative analysis of the expression of MMP-2 and MMP-9 in vocal fold polyps and normal tissue of vocal folds to probe the pathogeny of vocal fold polyp,understand the roles of MMP-2 and MMP-9 in the pathogenesis of vocal cord polyp and their mutual relations,and provide a theoretical basis for clinical prevention and treatment of vocal cord polyp.Materials and Methods:35 patients without other vocal cord lesions who were undergone polypectomy were enrolled in this study for the experimental group.The specimens of vocal cord polyps were diagnosed by pathologists. Specimens of normal vocal fold were obtained from 18 autopsy cases for the control group.All samples were stained with hematoxylin - eosin,and immunohistochemical staining of MMP-2 and MMP-9 were performed with monoclonal antibodies by MaxVision^TM method,and then the average value of Positive units that MMP-2 and MMP-9 had expressed in vocal fold polyps and normal tissue of vocal folds was analyzed by means of quantitative analysis of computer images.Negative controls were run without the primary antibody,which was replaced by PBS.Results:MMP-2 and MMP-9 expression was faint in the normal vocal fold.In the vocal cord polyp tissues,strong immunostaining for MMP-2 and MMP-9 was found in the epithelial cells,fibroblasts,inflammatory cells and vascular endothelial cells.The average value of MMP-2 positive units(30.5666±7.18438)in the vocal cord polyp group was higher than the normal vocal group(16.1361±4.32634),there was statistically significant difference(p＜0.05);The average value of MMP-9 positive units(42.9661±9.80116) in the vocal cord polyp group was higher than the normal vocal group (16.6147±8.48336),there was statistically significant difference(p＜0.05).It was statistically different that the average value of MMP-9 positive units compared with MMP-2 in the vocal cord polyp group(p＜0.05),and the mean of MMP-9 positive units(42.9661±9.80116) was higher than the mean of MMP-2 positive units (30.5666±7.18438).The average values of MMP-9 and MMP-2 positive units in the vocal cord polyp group were analyzed with scatter,the two variables were not linear trend shown that there was no correlation between them.conclusion:①vocal cord polyp is the result of many factors,various reasons lead to repeated injury of the vocal cords,which cause a sequence of Pathological changes such as:local hyperemia,edema,hemorrhage,epithelial degeneration,necrosis,loss or hyperplasia, inflammatory cell infiltration,vascular proliferation,expansion and increasing synthesis and secretion of MMP-2 and MMP-9.MMP-2 and MMP-9 break down extracellular matrix,which leads to subepithelial basement membrane thining or fracture,damage repair,structure remodeling,resulting in the formation of polyps.②In the long-term process of vocal cord injury,as a result of the common role of MMP-2,MMP-9 and other relevant inflammatory mediators lead to chronic inflammation,impaired vascular endothelial basement membrane,vessel wall permeability-increasing,so it could be easily that the materials within the vascular pass vessel wall into the space of organization,which causes the lamina propria mucosae of vocal cord especially Reinke's space edema,inflammatory cell infiltration,fibroblast proliferation,glassy degeneration,etc.At the same time,the connective tissue of lamina propria disordered,layered structure disappearing,above these result in the formation of vocal cord polyp.③In the development of vocal cord polyps,the increased expression of MMP-2 and MMP-9 promotes the formation of polyp Capillary,with rich blood supply,polyp constantly grows.