An important pathway of apoptotic effect of nickel early released from orthodontic appliances – Preliminary data

Abstract Background Limited data demonstrate the effect of nickel released from orthodontic appliances. The mechanism of this action is not clear. The present study aimed to investigate the role of kynurenines, oxidative stress and caspase pathway in the mechanism of nickel action. Methods We studied the concentration of nickel, 3-hydroxykynurenine, total oxidative status in saliva and caspase-3 in epithelial cells in 10 subjects before and one week after orthodontic treatment. Results Orthodontic appliances significantly enhanced the concentration of nickel, 3-hydroxykynurenine, total oxidative status and augmented the expression of caspase-3 seven days after treatment in the oral cavity in respect to pre-treatment values. Conclusion Our data suggest that nickel released from orthodontic appliances activate tryptophan metabolism in oral cavity via the kynurenine pathway. The metal directly or through kynurenines enhancement activates oxidative stress and then via the caspase pathway induce apoptosis of buccal epithelial cells.