Expression of TGF-β1 and PCNA in cyclosporin A-induced gingival overgrowth

PURPOSE: To investigate the expression of transforming growth factor-β1(TGF-β1) and proliferating cell nuclear of antigen(PCNA) in cyclosporin A(CsA)-induced gingival overgrowth(GO) tissues.METHODS: After extraction of half of the maxillary molars,20 male Sprague-Dawley rats were randomized into a CsA-injection group(10mg·kg-·d-1) or a normal saline control group.Ten rats per group were sacrificed at the fourth week after injection.The gingival width was measured under a stereo-microscope.After full demineralization of the mandible,gingival specimens were taken.The linear measurements and the immunohistochemistry analysis of TGF-β1 and PCNA were made using the software of Image Pro-plus 6.0.The data was analyzed with SAS6.12 software package.RESULTS: The percentage of cells positive staining for TGF-β1 and PCNA was significantly higher in the CsA rats than in the control rats(P0.05),but there was no significant difference between the edentulous and denti-gingiva in the same group(P0.05).CONCLUSIONS: The upregulation of TGF-β1 may have no direct relations with gingival inflammation in CsA-induced gingival overgrowth.In addition,TGF-β1 may be one of the key cytokines for CsA-induced gingival overgrowth.Increased epithelial proliferative activity may be the main cause of epithelial hyperplasia.