Expression of TRAIL and its receptors DR5 and DcR2 in orthodontic tooth movement

Abstract

Background. TRAIL is a transmembrane protein that induces apoptosis in various tissues including alveolar bone. Its in vitro expression can be activated by several methods, such as RANKL administration and cell scraping. Expression of TRAIL and its receptors DR5 and DcR2 was examined in osteoclast-like cells to analyze their effects on cell lifespan and to explore their role in orthodontic tooth movement. Materials and Methods. Osteoclast-like cells were differentiated from a mouse hematopoietic cell line by stimulation with RANKL for 24 h (T1), 72 h (T2) or 5 days (T3); some cultures were then scraped. Immunostaining for TRAIL, DR5 and DcR2 was evaluated by immunocytochemistry and Western blot analysis in control and treated cells. Results. Significantly greater TRAIL expression was found in treated osteoclast-like cells at T1 and T3 both on immunocytochemistry and Western blotting. TRAIL expression peaked at T1 and T3 in correspondence with DcR2 and DR5 maxima, respectively. Conclusions. These data may contribute to a better understanding of the mechanisms regulating tooth movement and to improve the accuracy of orthodontic treatments.