牙齦紫質單胞菌對不同細胞存活及細胞激素表現影響之評估

In this study, the effect of Porphyromonas gingivalis (P.gingivalis) on the survival and the expression of inflammatory cytokines and cell adhesion molecule which participate in the progression of stroke were focused. C6 rat glioma cells and bEnd.3 mouse brain endothelial cells were infected with heat-killed or live bacteria at different multiplicity of infection (MOI) levels for 24 hours. Results showed that live but not heat-killed P.gingivalis significantly induced the death of brain endothelial cells in a dose-dependent manner while P.gingivalis failed to induce cell death in glial cells. Moreover, DNA laddering after the incubation with P.gingivalis culture medium suggested that P.gingivalis and its released virulence factors led to apoptotic death in brain endothelial cells. Live P.gingivalis also caused significant expression of interleukin-1 beta (IL-1β) protein, and tumor necrosis factor alpha (TNF-α) protein in both cell models while heat-killed P.gingivalis failed to induce any inflammatory cytokines. Regarding adhesion molecule expression, no significant increase in platelet/endothelial cell adhesion molecule-1 (PECAM-1) expression was observed. Besides this, heat-killed P.gingivalis declined the adherence on host cells while live P.gingivalis increased the adherence on host cells as the MOIs increased. In conclusion, this study is the first study to establish the relationship between a main periodontal pathogen and stroke-related inflammatory response including the expression of cytokines and cell death via the adherence of bacteria on host cells in an in vitro study using glial cells and brain endothelial cells as cell models.