Effects Of LPS On Reparative Dentine And Dental Pulp Cells In Periodontal Animal Model

Objective: To clarify the effects of LPS on reparative dentin and dental pulp cells by observing the change of pulp cells and the formation of reparative dentin in periodontal animal model established by injecting LPS.Methods:1、Choice of the concentrations of LPS for periodontitis animal model Six rats periodontal models were induced by repeated injection of LPS into the right maxillary labial and palatal gingival sulcus between the first and second upper molars for three times per week. The concentrations of LPS were 0.2、2、20 mg/mL. X-ray was taken to ensure the formation of periodontitis once a week.2、Established animal model of periodontitis. All rats periodontal models were induced by repeated injection of LPS into the right maxillary labial and palatal gingival sulcus between the first and second upper molars for three times per week. X-ray was taken to ensure the formation of periodontitis once a week. The rats were killed after the formation of periodontitis in the third and the fifth week, then the right maxillary including the first and second upper molars were separated and fixed. The alveolar bone loss was recorded and the section was stained with HE. Then the data were analyzed using the SPSS software package.3-. The effects of LPS on the pulp cells and the reparative dentin Pulp cells and the formation of reparative dentin were also studied histologically.Results:1、Choice of the concentrations of LPS for periodontitis animal model It was appropriate to establish the periodontal models by 2 mg/mL LPS, because it was similar to human periodontitis such as speed and so on. The formation of periodontitis induced by repeated injection of LPS with 0.2 mg/mL were slowly. In the first week periodontitis animal models were formed by 20 mg/mL LPS injected. It was’t similar to the formation of human periodontitis.2、Established animal model of periodontitis. Periodontitis model were formed in the third week after LPS infection, the slight alveolar bone resorption was found. In the fifth week, alveolar bone absorption was more than 1/3 root length, but not more than the 1/2 root length. Osteoclasts were also found. The loss of the the right alveolar bone in the third week was less than that in the fifth week, and it had statistical significance; while the bone loss in the left had no statistical significance. The loss of the alveolar bone had statistical significance between the control side and experiment side at third week and fifth. In the fifth week, the alveolar bone loss in the first molar was more than in the second molar, and it had statistical significance while the alveolar bone loss in the third molar hadn’t been found.3、The effect of LPS on the pulp cells and the reparative dentin The rats were killed after the formation of periodontitis, odontoblasts arranged disorderly. Vacuolar degeneration of the odontoblastic layer was observed. Inflammatory cells and the formation of reparative dentin were also showed.Conclusion:1、It is the good study for periodontitis animal model by repeated injection of 2mg/mL LPS.2、LPS can stimulate the formation of reparative dentin.