Stimulation of cells derived from nifedipine-induced gingival overgrowth with Porphyromonas gingivalis, lipopolysaccharide, and interleukin-1β

The purpose of this study was to clarify the main contributory factor of nifedipine-induced gingival overgrowth either by Porphyromonas gingivalis lipopolysaccharide (Pg-LPS) or interleukin-1beta (IL-1 beta). Human gingival fibroblasts from healthy tissues and nifedipine-induced gingival overgrowth tissues were stimulated with nifedipine, IL-1 beta, Escherichia coli lipopoly saccharide (Ec-LPS), and Pg-LPS, and the gene expressions were analyzed by RT-PCR. Analysis of the data showed no strong evidence of a synergistic effect of nifedipine and Pg-LPS on IL-6, connective tissue growth factor (CTGF), and type 1 collagen gene expression of either healthy cells or nifedipine-induced gingival overgrowth cells. Among the three stimulants - IL-1 beta, PgLPS, and Ec-LPS - androgen receptor and IL- 6 gene expressions in both the healthy and nifedipine-induced gingival overgrowth groups were strongly up-regulated by the presence of IL-1 beta only. Furthermore, the responses to IL-1 beta in the nifedipine-induced gingival overgrowth group were stronger than those of the healthy group. It can be concluded that IL-1 beta is an important mediator responsible for the higher IL-6 and androgen receptor expression of nifedipine-induced gingival overgrowth cells.