Effects of Tempol, a membrane-permeable radical scavenger, in a rodent model periodontitis

Background: Recent studies have demonstrated that Tempol (4-hydroxy-2,2,6,6-tetramethylpiperidine-N-oxyl), a cell membrane-permeable radical scavenger, exerts protective effects in various models of inflammation and shock. Reactive oxygen species (ROS) plays a pivotal role in the induction of genes involved in physiological processes as well as in the response to inflammation. Aim: We have investigated the effect of Tempol in a rat model of periodontitis. Materials and Methods: Periodontitis was induced in rats by placing a 2/0 braided silk ligature around the lower left first molar. At day 8, the gingivomucosal tissue encircling the mandibular first molar was removed for evaluation of neutrophils infiltration, tissue permeability, nitrotyrosine formation, poly-(ADP-ribose) polymerase (PARP) activation, radiography and histology. Results and conclusions: Legation significantly induced an increased neutrophil infiltration and a positive staining for nitrotyrosine formation and PARP activation. Ligation significantly increased Evans blue extravasation in gingivomucosal tissue and alveolar bone erosion as evaluated by radiography analysis. Intraperitonial injection of Tempol (10 mg/kg daily for 8 days) significantly decreased all of the parameters of inflammation as described above. This suggests that antioxidant therapies, which interfere with ROS, may be of benefit in the treatment of periodontitis.