| Traumatic occlussion is one of most common diseases in oral, It could cause the injure of the periodontal tissue due to occlusal normal or bite force not harmonious, serious occlusal traumatism can lead to alveolar bone absorption. Alveolar bone absorption is a complex biological process, involving the osteoblast, osteoclast, thousands of cytokines and the cell signaling network consist of the cytokines. The mechanism of bone absorption caused by occlusal traumation is currently one of the hot spots in oral medicine field, the exact molecular biology mechanism is unclear, needing further study. The purpose of the present study was to observe absorption of alveolar bone of rats due to occlusal traumation during different time through the establishment of the rat occlusal traumation animal model,and investigate the early responses of alveolar bone to occlusal trauma through genome-wide microarray.Experiments one The influence of occlusal trauma to rats’ periodontal tissuePurpose:To observe the effection of occlusal traumation to periodontal tissue of rats during different times through the establishment of the rat occlusal traumation animal model.Methods:The occlusal surface of the upper left first molar of rat was raised by placing a stainless steel wire to induce occlusal trauma in the lower left first molar. Extracted the alveolar bone tissue of the first molars after0h,24h,3d,7d and14d respectively, Took X-ray, HE dyeing,and immunohistochemistry dyeing were used to observe the expression of MMP-9, the single factor analysis of variance immune to histological dyeing results in statistical analysis.Results:The results of X-ray showed that:the bone trabeculae of control group were clear, lamina dura were continuous and complete, did not see obvious bone absorption. The width of the periodontal membrane in1day group,3days group had not seen obviously increased, the periodontal membrane had seen widened obviously.HE dyeing results show that:as occlusal trauma time increased, the destruction of periodontal tissues are more and more remarkable.Immunohistochemical shows that:in all the occlusal trauma group,MMP-9positive dyeing cells could be found in the periodontal tissue, and the number of positive cells increase gradually along with the time of occlusal trauma. Compared with control group,the percentage of the number of positve cells at24h of occlusal trauma group the differences were not significant in statistically and the differences of other groups were significant.Conclusion:The results of X-ray, HE dyed and immunohistochemical staining found that occlusal trauma could cause the destruction of rats’periodontal tissue,and the destruction enhanced with time.Experiment two The primary study on the gene expression profiles of alveolar bone with traumatic occlusion in early stage in ratsPurpose:To investigate the early responses of alveolar bone to occlusal trauma through genome-wide microarray, and investigate the molecular biology mechanism of occlusal trauma to alveolar bone absorption further.Methods: Established rats occlusal trauma animal model.After24hours, extracted the alveolar bone tissue of the first molars at the both sides of rats’ lower jaws under anesthesia, the different expressive genes were shown by genome-wide microarray, which comprises about27,000genes and analyzed the different expressive genes with Pathway and GO analysis, finally the results of the microarray were examined by RT-PCR.Results:In the results of the study,586different expressions were found, of which the expressions of166genes increased and420genes decreased.106different pathway were involved with Pathway analysis and270different functional classification related to GO analysis,and the results of the microarray and RT-PCR are consistent。Conclusion:The balance of the lower alveolar bone was destroyed after24hours of traumatic occlusion. At early phase of the occlusal trauma, osteogenesis and bone formation in rat’s alveolar bone were inhibited, yet osteoclastogenesis and bone resorption were not significant. |
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