Distribution Of Fibronectin And Type Ⅲ Collagen In Nifedipine-induced Gingival Hyperplasia

PrefaceNifedipine, a calcium channel - blocking agent, is widely used for the treatment of hypertension, vasospastic angina and certain types of cardiac arrhythmias. Many clinical studies show it has important side - effects on the gingiva, but the pathogenesis of gingival overgrowth is uncertain. It has been demonstrated that the changes of extracellular matrix may be implicated the mechanism of nifedipine - induced gingival hyperplasia. Fibronectins are a class of high - molecular weight adhesive proteins, widely deposited in the extracellular matrix. Fibornectin has been implicated in a variety of cell functions, including adhesion, migration, growth. It has been shown to also play a role in cytoskeletal organization, phagocytosis and wound repair. The collagens are the most important components of extracellular matrix. They constitute a large proportion (60% ) of the total protein in human gingival stroma. The main types of collagen found are types I and III. Type III collagen is a kind of immature collagen which may have an important function in the elasticity of the tissues.Materials1. Study subjects: 25 patients of both sexes were classified in the following manner:A) Healthy control groupB) Simple gingivitis groupC) Adult periodontitis groupD) Puberty gingivitis groupE) Nifedipine - induced gingival hyperplasia groupEvery group has 5 patients. None of the patients had any other systemic disease or received any periodontal treatment or any drugs except nifedipine for at least 6 months.2. Instrument; Microtome, AX70 optical microscope, Cool-snapfx microimage instrument, Metamorph analysis software.3. Reagent.- Anti - human Fibronectin Antibodies;Anti - human Type III Collagen AntibodiesMethods1. Clinical examination;All patients underwent a periodontal probe examination at the first visit and their plaque index, gingival index, probing depth and clinical attachment level were recorded.2. Gingival biopsies:Biopsies were taken after local anesthesia, and always from the interproximal papilla of the examined teeth. The samples obtained were fixed in 10% buffered formalin at PH 7.2 and embedded in par-affin.3. Six sections of 5 fim in thickness were cut with microtome. Two of them were used in HE staining, the others for immunohisto-chemical studies.The microscopic slices were observed under a Coolsnapfx microscope , then analyzed using Metamorph software program. The program then calculated the area fraction occupied by fibronectin or type III collagen. The Kruskal - Wallis test of significance was used to evaluate differences between the groups for each component.Results1. HE - staining:Healthy group: Gingiva is covered by the stratified squamous epithelium. Rete ridges are long and thin along with abundant collagens, fibroblasts and few inflammatory cells in lamina propria.Inflamed gingival tissues: Epithelial downgrowth was along with different degree inflammatory infiltrating and vessels in the lamina propria.Nifedipine - induced gingival hyperplasia; The HE staining showed a hyperplastic, parakeratotic epithelium with extremely long and thin rete pegs which insert in very deep areas in the connective tissue. In the lamina propria we found numerous fibroblasts , dense collagen fibers, inflammatory cells and increasing numbers of vessels .2. Immunohistochemical staining FibronectinHealthy tissues; The extracelluar matrix of the healthy gingiva showed identical fibrillar and diffuse distribution of the glycoprotein fi-bronectin in the lamina propria.Inflamed gingival tissues; Fibronectin could be localized in the lamina propria in a fibrillar or mesh pattern of distribution. A parallel orientation of the fibers was also found in some areas. In the inflammatory cells infiltrating areas, we can also observe fibronection broken.Nifedipine - induced gingival hyperplasia: A brilliant staining in a fibrillar pattern of distribution and " cloud - like" arrangement in the fibe...