An optimized method for establishing experimental rat periodontitis using "double-ligature" technique

Establishing stable and dependable animal models of experimental periodontitis is critical in advancing our understanding of the etiology, clinical diagnosis, and treatment of periodontitis. However, conventional silk ligation methods for inducing periodontitis in rats have limitations, with silk thread detachment being a major concern. In this study, we established a reliable rat periodontitis model using a novel "double-ligature" technique combining silk sutures with orthodontic wires, augmented by a high-sugar diet. Thirty rats were randomized into five groups: control, wire-only, silk-only, wire+silk, and wire+silk+sugar. After 2 weeks, the wire+silk+sugar group demonstrated significantly elevated clinical indices (sulcus bleeding index, probing depth, plaque index) versus controls (*p* < 0.05), alongside severe alveolar bone resorption quantified by micro-CT. Molecular analyses revealed upregulated inflammatory gene expression (e.g., TNF-α, IL-1β) in double-ligature groups. Histology confirmed extensive immune infiltration and periodontal ligament disruption. The combined approach induced robust periodontitis with 103% greater CEJ-ABC distance versus controls, while TRAP staining revealed 5-fold increased osteoclast activity. By this "double-ligature" technique, the pathogenesis of periodontitis can be studied on the one hand, and the therapeutic effect of biomaterials on the alveolar bone defects caused by periodontitis can be verified on the other hand. This reproducible method overcomes traditional silk ligature limitations (e.g., thread detachment) and provides a foundation for translational periodontitis research.