| Objective:To explore the effect of severe periodontitis on learning and memory function of streptozotocin induced alzheimer's disease?AD?model rats.Methods:Sixty male SD rats were randomly divided into three groups:blank group,model control group,and experimental group,with 20 rats in each group.Rat models of sporadic senile dementia?SAD?were prepared in a model control group and an experimental group of rats by repeated injection of streptozotocin?STZ?solution?6 mg/kg?into bilateral lateral ventricles.After the completion of the model,rats in the experimental group were treated with bilateral maxillary second molar 0.2 mm metal ligature and silk ligature plus+10%high glucose diet to prepare a severe periodontitis animal model.After completion of the modeling,Morris water maze was used to detect the behavioral learning and memory of rats on the 30th and 60th day respectively for 4 consecutive days and on the 5th day for space exploration detection.At the same time,after the completion of modeling,the rats'blood glucose at the tail vein was dynamically monitored once a week until they were taken.The rats were sacrificed and then sacrificed in batches and brain tissue and bilateral maxillary bones were obtained.Pathological sections of the brain tissue were sectioned and stained with hematoxylin-eosin to observe the neuronal density in the hippocampus of rats with severe periodontitis under light microscope.The effect of morphology.Elisa was used to detect the expression of A?1-40,IL-1,IL-6,TNF-?and CRP in hippocampus and cortex of rats.Level.The rat bilateral alveolar bone tissue was made on one side and pathological sections of the periodontal tissue were made.Hematoxylin-eosin staining was used for histological examination.The other side of the alveolar bone was stained with methylene blue to observe the alveolar bone resorption.Results:?1?HE staining of periodontal tissue slices showed that severe periodontitis appeared in the experimental group compared with the model control group and the blank group,that is,periodontal soft tissue retraction occurred in the model area,a large number of inflammatory cells infiltrated,and the alveolar dome was reduced.In the epithelium of the furrows,ulceration occurred,combined with epithelial growth to the root side,periodontal ligament fiber bundles disrupted and ruptured,and tissue necrosis and sequestrum formation appeared in the bifurcation area.Osteoclasts were seen in some bone tissues.The alveolar bone of the maxillary second molars was heavily absorbed,reaching the middle and lower thirds of the roots,while the model control group and the blank group had no obvious abnormal changes.?2?The dynamic randomized blood glucose measurement in the rat tail vein showed no significant differences between the experimental group,the model control group,and the blank group,and all were within the range of normal blood glucose values.?3?In behavioral experiments,the Morris water maze test showed that the escape latency of rats in the 30-day experimental group and the model control group was significantly higher than that in the blank group on the 2nd day,but the rats in the experimental group The escape latency was not significantly different from the model control group;the escape latency of the 60-day experimental group and the model control group was significantly higher than that of the blank group on the second day.The escape latency of the experimental group was greater than that of the model control group.The trend was elevated but the difference was not statistically significant.?4?HE staining showed that the number of neurons in the CA3 region of the hippocampus in the experimental group and model control group was significantly lower than that in the blank group.The arrangement of the cells was disordered,and some cells showed nuclear condensation.A 30-day experiment was performed.The number of cells with nuclear pyknosis was higher in the group than in the model control group.The number of neurons in the CA3 region of the hippocampus in the 60-day experimental group was significantly reduced,the arrangement of the cells was more irregular,and the nucleus was more pyknosis.?5?Expression of A?1-40,IL-1,IL-6,TNF-?,and CRP in the hippocampus of the experimental group and the model control group at the 30-day and 60-day modeling were lower than those in the blank group.Significantly higher,the experimental group increased more significantly than the model control group.The expression levels of A?1-40,IL-1,IL-6,TNF-?and CRP in the cortex of the experimental group and the model control group were significantly higher than those of the control group at 30 days and 60 days after model establishment.Significant.There was no significant difference in the content of each factor in the hippocampus and cortex of the blank group compared with the 30 days after the modeling.The model control group had 60 days of modeling compared with 3 models of30 days.There was no significant difference in the contents of IL-1 and IL-6 in the hippocampus.The contents of CRP,TNF-?,and A?1-40-40 were 60 days compared to the model 30 days.Decreased,and the difference was statistically significant;there was no significant difference in the content of CRP in the cortex.The contents of IL-1,IL-6,TNF-?,and A?1-40-40 were reduced 60 days after modeling compared with 30 days after modeling,and the differences were statistically significant.Meaning.The content of IL-1,IL-6,and A?1-40-40 in the hippocampus was not significantly different between the experimental group and the 60-day model-building group.The contents of CRP and TNF-?were reduced 60 days compared with the 30-day model building period.The difference was statistically significant;there was no significant difference in the content of CRP,TNF-?,and A?1-40-40 in the cortex,and the difference was not statistically significant.The contents of IL-1 and IL-6 were reduced by 60 days compared with the 30 days after modeling.Small,and the difference was statistically significant.Conclusion:Under the experimental conditions,severe periodontitis aggravated STZ-induced neuronal injury in rats by aggravating the inflammatory reaction,but there was no significant difference in STZ-induced learning and memory impairment in rats. |
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