Epithelial to mesenchymal transition in Cyclosporine A-induced rat gingival overgrowth

Background and objective Epithelial-mesenchymal transition (EMT) has been proved to occur in drug-induced gingival overgrowth. However, the specific pathogenic mechanism remains uncertain. The aim of this study is to examine the expression of EMT markers in cyclosporine A (CsA)-induced gingival overgrowth in rat models. Material and methods Thirty-six rats were randomly divided into two groups. The experimental group received CsA therapy subcutaneously in a daily dose of 10 mg/kg, and the other group was used as a control. Six rats per group were sacrificed at 20, 40 and 60 days, and the gingivae were obtained. The expression of TGF-β1, E-Cadherin, ZEB1, ZEB2, and Snail1 were examined by quantitative real time PCR (qRT-PCR), western blotting, and immunohistochemistry. In addition, a group of microRNAs associated with EMT and fibrosis were also detected in gingival tissue by qRT-PCR. Results The mRNA and protein levels of TGF-β1, ZEB1, and ZEB2 in gingivae were significantly upregulated after 40 and 60 days of CsA administration. Conversely, the levels of E-cadherin were significantly downregulated in overgrowth sample at day 40 and 60. Intense immunohistochemmical staining for TGF-β1 were observed in the samples from CsA group at day 40 and 60. Concomitantly, the densities of E-cadherin were gradually decreased in the basal layers of epithelium with time. Three members of miR–200 s (miR-200a, miR-200b and miR-200c) were significantly downregulated in CsA-treated rats at 40 and 60 days, while miR-9, miR-23a and miR-155 were significantly upregulated when compared with those of the control group. Conclusions The process of EMT in CsA-induced rat gingival overgrowth is associated with increased expression of TGF-β1, ZEB1, and ZEB2, and decreased expression of E-cadherin.