Abstract
BACKGROUND/PURPOSE: Peri-implantitis remains a substantial challenge. This study investigated the effect of titanium particles on human oral epithelial cells, focusing on the nucleotide-binding domain and leucine-rich repeat protein (NLRP) 3 inflammasome. MATERIALS AND METHODS: The Ca9-22 human gingival epithelial cell line was subjected to incubation with titanium particles. To evaluate cell viability, the MTT assay was employed. Total RNA was extracted, and messenger RNA (mRNA) expressions of COX2, TGF-β1, NLRP1, NLPR3, CASP1, and AIM2 were analyzed. The concentration of interleukin (IL)1β in cell supernatants was quantified through enzyme-linked immunosorbent assay. Intracellular reactive oxygen species (ROS) were visualized using an ROS assay Kit. RESULTS: Ca9-22 cells treated with titanium particles showed >75% cell viability across all concentrations tested, with consistent results. mRNA expressions of inflammation-related genes (COX2 and TGF-β1) significantly increased in a dose-dependent manner. The mRNA expression of NLRP3 and CASP1, as well as the secretion of IL1β, increased after 6-h incubation with titanium particles. Moreover, the ROS assay results showed increased production of ROS after treatment with titanium particles, whereas NLRP3 expression and IL1β secretion reduced after treatment with N-acetyl-l-cysteine (ROS scavenger). CONCLUSION: Our findings indicate that titanium particles possess a distinct ability to trigger the NLRP3 inflammasome, partly by producing ROS.