RESUMEN
OBJECTIVE: To ascertain the role of inducible nitric oxide synthase (iNOS) in the periodontitis response during diabetes. METHODS: Twenty-four male SD rats were randomly divided into four groups: control group (Control), diabetes mellitus group (D), diabetes mellitus plus periodontitis group (DP), and periodontitis group (P). Periodontitis and diabetes were established separately. Then the gingival tissue and alveolar bone were collected. A stereomicroscope was used to evaluate bone loss. The expression of iNOS, TNF-α, and NF-κB in the gingiva was detected by immunohistochemical staining, real-time PCR, and western blot analysis. RESULTS: Significant bone loss was observed in the DP and P groups and more extensive bone resorption was discovered in the DP group than in the P group (P < 0.05). The immunohistochemical staining analysis revealed enhanced expression of iNOS located in the gingiva of the three disease groups compared with the control group (P < 0.05). In particular, the level of iNOS was significantly higher in the DP group than in the P group (P < 0.05). This elevated trend of iNOS was further demonstrated by quantitative PCR and western blot analysis. Similarly, the mRNA and protein expression levels of NF-κB in the D, DP, and P groups were significantly higher than those of the control group, as was the level of TNF-α protein (P < 0.05). CONCLUSIONS: Our results proved diabetes exacerbated alveolar bone resorption in a periodontitis rat model. iNOS may be the inflammatory mediator in the course of periodontal injury promoted by diabetes.
Asunto(s)
Diabetes Mellitus/metabolismo , Encía/metabolismo , Óxido Nítrico Sintasa de Tipo II/metabolismo , Periodontitis/metabolismo , Pérdida de Hueso Alveolar , Animales , Encía/patología , Masculino , Ratas , Ratas Sprague-DawleyRESUMEN
Insulin-like growth factor-1 (IGF-1) promotes human dental pulp stem cell proliferation and osteogenic differentiation. However, the effects of IGF-1 on the proliferation, apoptosis and odontoblastic differentiation (mineralization) of dental pulp cells (DPCs) under high glucose (GLU) conditions remain unclear. In this study, isolated primary human DPCs were treated with various concentrations of high GLU. Cell proliferation and apoptosis were determined by Cell Counting Kit-8 and Annexin V-FITC/PI assays, respectively. The cells were cultured in odontoblastic induction medium containing various concentrations of high GLU. Odontoblastic differentiation was determined by alkaline phosphatase (ALP) activity assay. Mineralization formation was evaluated by von Kossa staining. The expression levels of IGF family members were measured by western blot analysis and RT-qPCR during proliferation and differentiation. The cells were then exposed to 25 mM GLU and various concentrations of IGF-1. Cell proliferation, apoptosis, ALP activity, mineralization formation and the levels of mineralization-related proteins were then evaluated. Our results revealed that high GLU significantly inhibited cell proliferation and promoted cell apoptosis. GLU (25 and 50 mM) markedly reduced ALP activity and mineralization on days 7 and 14 after differentiation. The levels of IGF family members were markedly decreased by high GLU during proliferation and differentiation. However, IGF-1 significantly reversed the effects of high GLU on cell proliferation and apoptosis. Additionally, IGF-1 markedly restored the reduction of ALP activity and mineralization induced by high GLU. Our findings thus indicate that IGF-1 attenuates the high GLU-induced inhibition of DPC proliferation, differentiation and mineralization.