Interactions of periodontal pathogens with platelets in the gingival crevicular fluid of patients with periodontitis

Abstract Aim To explore the immunological defensive effects of platelets on periodontal pathogens in the gingival crevicular fluid (GCF). Materials and Methods GCF samples were collected from 20 patients with periodontitis and 10 healthy controls. Platelets in the GCF were detected by immunocytochemistry and immunofluorescence. Isolated platelets from healthy volunteers were co‐cultured with Porphyromonas gingivalis ( Pg ) and Fusobacterium nucleatum ( Fn ). The interactions between platelets and periodontal pathogens were observed by transmission and scanning electron microscopy. The isolated platelets plus neutrophils were co‐cultured with Pg or Fn , and the formation of neutrophil extracellular traps (NETs) was evaluated by staining with Sytox Green. Results The platelet level in the GCF was higher in patients with periodontitis than in healthy controls. Platelets interacted with bacteria and neutrophils in the GCF. In vitro, platelets recruited and engulfed periodontal pathogens. In response to periodontal pathogens, neutrophils released web chromatin, and platelets promoted the formation of intensive NETs. Conclusions Platelets, migrating to the gingival sulcus, may exert direct antibacterial effects or assist neutrophils.