%0 Journal Article %T Histochemical Expression of Mast Cell Chymase in Chronic Periodontitis and Cyclosporine-Induced Gingival Overgrowth %A Tamilselvan Subramani %A Kamatchiammal Senthilkumar %A Soundararajan Periasamy %J Journal of Histology %D 2013 %R 10.1155/2013/812842 %X Mast cell (MC) mediators play a vital role in fibrosis. The purpose of this study was to investigate the MCs and their enzyme chymase in gingival tissues showing drug-induced gingival overgrowth (DIGO) and also to evaluate the correlation of MC counting and expression with the chronic periodontitis. In this study, 30 samples, including cyclosporine-induced gingival overgrowth, chronic periodontitis (10 for each), and ten normal gingival tissues, were collected. We analyzed the histochemical expression of MC chymase in all the collected tissues. In addition, the number of MCs was counted for each deparaffinized section stained with toluidine blue. Furthermore, total RNA was extracted from tissue samples, and RT-PCR was performed for MC chymase. The numbers of MCs were found to be increased in relative lesions compared to normal gingival tissues ( ). Moreover, chymase-containing MCs in DIGO tissues showed striking differences from those of control subjects and chronic periodontitis ( ). The RT-PCR analysis further revealed that MC chymase mRNA increased significantly in DIGO tissues. In conclusion, although the MCs were less numerous in numbers, the cells exhibited significant expression of chymase enzyme suggesting the involvement of MCs in DIGO. 1. Introduction Mast cells (MCs) are present in almost all human tissues and have been implicated in the pathogenesis of a variety of chronic inflammatory diseases. MCs contain various kinds of biochemical mediators: enzymes, such as histamine, heparin, tryptase, and chymase, and cytokines, including interleukin-(IL-) 4, IL-5, IL-6, and IL-8 in cytoplasmic granules [1, 2]. The release of these substances from MCs in inflammatory lesions is thought to play an important role in acceleration of the inflammatory process, angiogenesis, and fibrosis [2, 3]. According to their protease content, human MCs have been divided into two phenotypes: tryptase-positive and chymase-positive phenotypes, and both phenotypes are present in almost all human tissues. Drug-induced gingival overgrowth (DIGO) is an unwanted outcome of systemic medication and is limited to gingiva. Drugs associated with gingival enlargement are anticonvulsants (phenytoin), calcium channel blockers (nifedipine), and immunosuppressant such as cyclosporine-A [4, 5]. Although the pharmacological effects of these drugs are different and directed toward various primary target tissues, all of them seem to act similarly on a secondary target tissue, that is, the gingiva, causing almost similar clinical and histopathological findings. Although many theories are %U http://www.hindawi.com/journals/jh/2013/812842/