Influence of obesity on experimental periodontitis in rats: histopathological, histometric and immunohistochemical study

Abstract

Objectives: This study assessed the influence of obesity on the progression of ligature-induced periodontitis in rats. Materials and methods: Forty-eight adult Wistar rats were randomly divided into two groups: the HL group (n = 24) was fed high-fat animal food to induce obesity, and the NL group (n = 24) was fed normolipidic animal food. Obesity was induced within a period of 120 days, and the induction of experimental periodontitis (EP) was subsequently performed for 30 days. The animals were euthanized after 7, 15, and 30 days, and the jaws were removed for histopathological, histometric, and immunohistochemical analyses. Tartrate-resistant acid phosphatase (TRAP), receptor activator of nuclear factor kappa beta ligand (RANKL), and osteoprotegerin (OPG) were analyzed via immunolabeling. Results: Histological findings indicated that the inflammation was more extensive and lasted longer in the HL⁄EP; however, advanced destruction also occurred in the NL/EP. Greater bone loss was verified in the HL/EP group (2.28 ± 0.35) in the period of 7 days than in the NL/EP group (1.2 ± 0.29). High immunolabeling was identified in the HL/EP group in the initial periods for RANKL and TRAP, whereas the NL⁄EP group presented with moderate immunolabeling for both factors. The HL/EP and NL/EP groups showed low immunolabeling for OPG. Conclusions: Obesity induced by a high-fat diet influenced alveolar bone metabolism when associated with experimental periodontitis and caused a more severe local inflammatory response and alveolar bone loss. Clinical relevance: Obesity is related to greater alveolar bone loss and an accentuated local inflammatory response, which may be reflected in the clinical severity of periodontitis and dental loss.