Biochemical And Biophysical Changes In Periodontitis Microenvironment

This study aimed to investigate the dynamic changes in biochemical factors (IL-1β, TGF-β1) and biophysical factors (matrix stiffness, integrin αvβ3) in the periodontal ligament microenvironment during the early and late stages of periodontitis, and their impact on osteogenic differentiation. A rat periodontitis model was established using Pg-LPS injections for 1 week (early stage) and 3 weeks (late stage). Micro-CT, nanoindentation, immunohistochemistry, and immunofluorescence were employed to analyze alveolar bone loss, periodontal ligament stiffness, and expression levels of IL-1β, TGF-β1, and integrin αvβ3. Bioinformatic analysis of human periodontal ligament gene data (GSE27993) was also performed. In early periodontitis, TGF-β1 was highly expressed, while IL-1β showed a slight increase. In late stages, TGF-β1 significantly decreased (11.34±2.91 vs. 20.41±2.64, P<0.01), whereas IL-1β increased (18.77±3.36 vs. 8.24±1.47, P<0.01). Periodontal ligament stiffness and integrin αvβ3 expression progressively declined, correlating with reduced osteogenic differentiation (RUNX2: 12.47±2.83 vs. 21.15±4.38, P<0.05). The study highlights that periodontitis alters the periodontal microenvironment, with TGF-β1 potentially maintaining tissue stability early, while IL-1β exacerbates inflammation and bone loss late. Mechanical degradation (reduced stiffness and integrin αvβ3) further impairs osteogenesis, suggesting combined biochemical and biophysical interventions may enhance periodontal regeneration.