2024 Volume 22 Issue 4 Pages 178-186
The gram-negative bacterium Porphyromonas gingivalis（Pg）is implicated in periodontal disease. Lipopolysaccharide（LPS）, a component of the gram-negative bacterial cell wall, contributes to periodontal tissue destruction. The intra-gingival application of Pg-derived LPS（Pg-LPS）increases gingival TNF-alpha without affecting IL-6 in rats. Recognizing periodontal infection’s potential threat to health, we investigated the effects of intra-gingival Pg-LPS application on plasma TNF-alpha and IL-6 levels. For comparison, we analyzed the effects of LPS derived from Escherichia coli（Ec-LPS）.
Male Sprague-Dawley rats were employed, with each anaesthetised using urethane. The external jugular vein was cannulated for blood sampling and intravenous LPS administration. IL-6 and TNF-alpha levels were determined using enzyme-linked immunosorbent assay and bead-based Multi-Plex kits. Intra-gingival administration of Pg-LPS（1 µg）, but not Ec-LPS（1 µg）, increased TNF-alpha without affecting IL-6 in blood samples. Intravenous administration of a high dose of Ec-LPS（5 mg/kg）, but not the intra-gingivally applied dose（1 µg）of Ec- or Pg-LPS, increased blood TNF-alpha and IL-6 levels.
These findings suggest that intra-gingivally administered Pg-LPS increases blood TNF-alpha by binding to gingival Toll-like receptor subtypes, recognizing LPS and increasing TNF-alpha secretion. Alternatively, this increase may be mediated by translocation of TNF-alpha from the gingival extracellular space into the bloodstream.
