Local Inflammation Exacerbates Cyclosporine A-Induced Gingival Overgrowth in Rats

Gingival overgrowth (GO) is a common side effect of long-term cyclosporine A (CsA) treatment. The risk factors appraised include drug interactions with calcium channel blockers, age, cyclosporine dose, dental bacterial plaque, duration of treatment, and genetic predisposition. The relationship and mechanism between GO and local inflammation caused by dental bacterial plaque have not been clearly defined. This research was carried out to investigate the histomorphometrical alterations and serum levels of transforming growth factor beta 1 (TGF-beta 1) in CsA-induced GO with or without local inflammation. Thirty-four male Sprague-Dawley rats were divided into 4 groups: Group I (control); Group II (ligation); Group III (CsA); Group IV (ligation and CsA). After 9 weeks the rats were sacrificed. The morphological examination was made and the histological changes with hematoxylin and eosin (HE) staining were observed. TGF-beta 1 levels in serum were detected by Enzyme-linked immunosorbent assay (ELISA). We report here that obvious GO are found in Group III and Group IV after CsA treatment, especially those rats with existed gingivitis presented an aggravation of GO. TGF-beta 1 levels in CsA-exposed groups were significantly higher than untreated groups, but ligation did not affect TGF-beta 1 level. These findings suggest that CsA-induced GO can be exacerbated by local inflammation. TGF-beta 1 may be a key factor for the development of GO.