Interleukin-1 and tumor necrosis factor- expression on the compressed side of gingiva during orthodontic tooth movement

Objectives: The aim of this study was to investigate the effect of orthodontic loading on the expression of interleukin-1 (IL-1) and tumor necrosis factor- (TNF-) in compressed gingiva. Materials and Methods: Twenty-four male Wistar rats were used with four rats as controls at day 0. In ten rats, corticotomy was performed on either left or right side and the remaining side was served as control, and killed at 7 and 14 days. In the remaining ten rats, maxillary right and left first molars were moved orthodontically with a constant force of 20 g; appliance and appliance in conjunction with cortictomy (appliance-corticotomy) were sequentially alternated between left and right sides and euthanized at 7 and 14 days. Real time polymerase chain reactions of compressed gingiva excised from the euthanized rats was performed to measure mRNA expressions of IL-1 and TNF-. Results: There were no significant differences in the expression of IL-1 between all the groups. On the other hand, TNF- from the pressure side in the appliance group and the appliance in conjunction with corticotomy group showed significant increase on the 7th day compared to that of either control or corticotomy group. Conclusions: Orthodontic loading induced the elevation of TNF- in compressed gingiva.