Role of ferroptosis in periodontitis: An animal study in rats.

OBJECTIVE: This study aimed to investigate (1) the temporal pattern of ferroptosis, an iron-dependent cell death, in ligation-induced rat periodontitis and (2) the effect of ferrostatin-1, a ferroptosis inhibitor, on the model. BACKGROUND: Ferroptosis may contribute to various diseases. However, the role of ferroptosis in periodontitis is still fully understood. METHODS: In the first experiment, 25 rats with ligation-induced periodontitis were sacrificed on days 0, 1, 2, 7, and 10. Gingivae were obtained to determine tumor necrosis factor (TNF)-alpha, interleukin (IL)-1beta, and ferroptotic biomarkers, including solute carrier family 3 member 2 (SLC3A2) and solute carrier family 7 member 11 (SLC7A11) and glutathione peroxidase 4 (Gpx4), via immunoblotting. Using microcomputed tomography (muCT) and histology, the periodontal soft and hard tissue lesions, including dental alveolar bone crest level, bony characteristics of the surrounding alveolus, periodontal tissue inflammation, and periodontal tissue losses, were evaluated. In study two, 16 rats with induced periodontitis were grouped according to ferrostatin-1 treatment. The rats were intraperitoneally injected with solvent or ferrostatin-1 (1.5 mg/kg/day) 1 day before ligation and sacrificed on days 7 and 10. Gingival protein changes and periodontal tissue damage were also examined. RESULTS: In study one, SLC3A2/SLC7A11 and Gpx4 decreased since day 1; however, TNF-alpha/IL-1beta increased on days 7 and 10. Moreover, the muCT/histology revealed resorptive bony characteristics, inflamed gingival tissue, and periodontal attachment loss. In study two, ferrostatin-1-injected rats exhibited significantly increased SLC3A2/SLC7A11 and Gpx4 but decreased TNF-alpha/IL-1beta than vehicle rats. They also revealed lessened bone resorption, tissue inflammation, and attachment loss. CONCLUSION: This study highlights the role of ferroptosis, via the system Xc/Gpx4 pathway, in experimental periodontitis and may serve as a regulatory strategy.