Background: The present study aimed to evaluate whether chronic stress (CS) affects ligature-induced periodontal disease and to investigate the impact of CS on the mRNA levels of interleukin (IL)-1beta, -1 receptor antagonist, -6, and -10, interferon-gamma (IFN-gamma), receptor activator of nuclear factor-kappa B ligand (RANKL), and osteoprotegerin in the gingival tissues of rats.
Methods: Sixty male Wistar rats were assigned randomly to three groups: G1 (control; non-ligated sites), G2 (periodontal disease), and G3 (periodontal disease associated with restraint stress for 12 hours/day for the entire study). After 30 days, all animals were sacrificed by decapitation. Blood samples were taken, and the concentrations of corticosterone and catecholamines were measured as biomarkers of CS. Marginal tissues around ligated and non-ligated teeth were harvested, and gene expression was assessed by quantitative polymerase chain reaction. Moreover, the area of bone loss (ABL) was determined histometrically.
Results: Data analysis showed that CS increased serum levels of stress biomarkers (P <0.05), ligature placement resulted in a significant ABL compared to non-ligated sites, CS significantly increased the amount of ABL in inflamed sites (P <0.001), and CS significantly increased mRNA levels of proinflammatory (IL-1beta and -6 and IFN-gamma) and anti-inflammatory (IL-10) cytokines and proresorptive factor (RANKL) in ligated sites (P <0.05).
Conclusion: CS significantly increased bone loss resulting from ligature-induced periodontitis by a local increase in proinflammatory and proresorptive factors.