Orthodontic movement induces high numbers of cells expressing IFN-gamma atmRNA and protein levels

Cytokines are important signaling proteins that are liberated during immune challenges and exhibit many modulatory activities, However, their role in periodontal modeling during orthodontic tooth movement is not fully underst ood. The aim of this study was to analyze effects of mechanical force durin g orthodontic tooth movement, in the pressure zone, on the induction of int erferon-gamma (IFN-gamma) as a proinflammatory cytokine of Th1 type and int erleukin-4 (IL-4)/IL-10 as anti-inflammatory cytokines of Th2 type. In 12 W istar rats 40-45 days old, the maxillary first molar was moved mesially by means of a closed coil spring for 3, 7, and 10 days, The contralateral side served as a control. IFN-gamma, IL-4, and IL-10 mRNA were determined by in situ, hybridization, and protein levels of IFN-gamma was measured by immun ohistochemistry. Induction of IFN-gamma at both mRNA and protein levels was significantly higher on the experimental side than on the contralateral co ntrol side on day 3. The signal gradually became stronger on day 7 and rema ined high on day 10. Cytokines of the Th2 type (IL-4 and IL-10) were not de tected at all examined time points in both pressure and contralateral contr ol sides. Considering the potential immunoregulatory roles played by IFN-ga mma, our data suggest that IFN-gamma may be involved in periodontium remode ling during orthodontic tooth movement.