RESUMEN
INTRODUCTION: Inflammatory cytokines are associated with decreased insulin signal transduction. Moreover, local oral inflammation, such as that accompanying periodontal disease, is associated with insulin resistance and type 2 diabetes mellitus. The aim of this study was to evaluate the effect of periapical lesions (PLs) on insulin signaling and insulin sensitivity in rats. We hypothesized that PLs alter systemic insulin signaling and insulin sensitivity via elevated plasmatic tumor necrosis factor α (TNF-α). METHODS: Wistar rats were divided into control (CN) and PL groups. PLs were induced by exposing pulpal tissue to the oral environment. After 30 days, insulin sensitivity was measured using the insulin tolerance test. After euthanization, maxillae were processed for histopathology. Plasmatic concentrations of tumor necrosis factor α (TNF-α) were determined via the enzyme-linked immunosorbent assay. Insulin signal transduction was evaluated using insulin receptor substrate tyrosine phosphorylation status and serine phosphorylation status in periepididymal white adipose tissue via Western blotting. For insulin signaling and insulin tolerance tests, the analyses performed were analysis of variance followed by the Tukey post hoc test. For TNF-α analysis, the Student's t test was used. In all tests, P < .05 was considered significant. RESULTS: The rats with PLs showed higher plasmatic TNF-α, lower constant rate for glucose disappearance values, and reduced pp185 tyrosine phosphorylation status but no change in serine phosphorylation status in white adipose tissue after insulin stimulation. CONCLUSIONS: PLs can cause alterations to both insulin signaling and insulin sensitivity, probably because of elevation of plasmatic TNF-α. The results from this study emphasize the importance of the prevention of local inflammatory diseases, such as PLs, with regard to the prevention of insulin resistance.
Asunto(s)
Resistencia a la Insulina/fisiología , Insulina/fisiología , Enfermedades Periapicales/fisiopatología , Transducción de Señal/fisiología , Tejido Adiposo Blanco/patología , Animales , Exposición de la Pulpa Dental/complicaciones , Necrosis de la Pulpa Dental/complicaciones , Insulina/sangre , Proteínas Sustrato del Receptor de Insulina/análisis , Leucocitos Mononucleares/patología , Masculino , Neutrófilos/patología , Enfermedades Periapicales/sangre , Fosforilación , Ratas , Ratas Wistar , Receptor de Insulina/análisis , Serina/metabolismo , Factores de Tiempo , Factor de Necrosis Tumoral alfa/sangre , Tirosina/metabolismoRESUMEN
OBJECTIVES: The aim of this study was to evaluate triglyceride and cholesterol levels in diabetic rats and their relationship with pulpal and periodontal diseases. METHODS: Eighty male rats (Rattus norvegicus albinus, Wistar) were divided into the following eight groups comprising ten animals each: normal rats (G1), rats with pulpal diseases (G2), rats with periodontal diseases (G3), rats with both pulpal and periodontal diseases (G4), diabetic rats (G5), diabetic rats with pulpal diseases (G6), diabetic rats with periodontal diseases (G7), and diabetic rats with both periodontal and pulpal diseases (G8). Diabetes was induced by injecting streptozotocin, periapical lesions were induced by exposing pulpal tissue to the oral environment, and periodontal diseases were induced by periodontal ligature. The animals were killed after 30 days, and lipid profile was enzymatically measured using Trinder's method. The total assessed values were statistically analyzed by analysis of variance and Tukey test (p < 0.05). RESULTS: The triglyceride levels of diabetic rats with periodontal disease and of diabetic rats with both periodontal and pulpal diseases were significantly higher than those of normal rats and nondiabetic group rats, respectively. The differences in the cholesterol levels among the groups were not significant. CONCLUSIONS: We found that the association of pulpal and periodontal diseases with diabetes increased triglyceride levels in rats. CLINICAL SIGNIFICANCE: Changes in lipid profile may be related to the presence of oral infections and diabetes.