Labo'Life Espana 1 article published in JoVE Immunology and Infection Induction of Periodontitis via a Combination of Ligature and Lipopolysaccharide Injection in a Rat Model Marta Munar-Bestard1,2, Oscar Villa1, Maria del Mar Ferrà-Cañellas1,2,3, Joana Maria Ramis1,2,4,5, Marta Monjo1,2,4,5 1Group of Cell Therapy and Tissue Engineering, Research Institute on Health Sciences (IUNICS), University of the Balearic Islands (UIB), 2Balearic Islands Health Research Institute (IdISBa), 3 In this study, a rat model of induction of periodontitis is presented via a combination of retentive ligature and repetitive injections of lipopolysaccharide derived from Porphyromonas gingivalis, over 14 days around the first maxillary molars. The ligation and LPS injection techniques were effective in inducing peridontitis, resulting in alveolar bone loss and inflammation.