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BACKGROUND: Connexin 43 (Cx43) plays an important role in occurrence and development of osteoarthritis. However, the specific mechanisms involved remain unclear. OBJECTIVE: To verify the possibility of the dominant position of Cx43 in connexin family in osteoarthritis by detecting the expression of Cx43 in articular cartilage and chondrocyte cell line, and to construct shRNA lentivirus vector of Cx43 gene and establish a stable transfer cell line of chondrocyte (SW1353). METHODS: Animal models of osteoarthritis were established in six C57BL/6 mice by anterior cruciate ligament transection. The differences of Cx43 expression between osteoarthritic and normal knees were investigated by immunohistochemistry. Expression of Cx43 mRNA in chondrocyte (SW1353) was detected by RT-PCR, and the expression levels of Cx37, Cx40, Cx45 and Cx46 in SW1353 cells were detected as control. Cx43 were connected to the lentiviral vector carrying the EGFP gene, to reconstruct the lentiviral vector plasmid. The viral particles were generated by co-transfection of 293T cells with Cx43-shRNA. After transfection of Cx43-shRNA lentiviral vector into chondrocytes (SW1353), the expression level of Cx43 was detected by western blot assay and RT-PCR. The study protocol was approved by the Ethics Committee of State Key Laboratory of Oral Diseases, approved No. SKLODLL2013A172. RESULTS AND CONCLUSION: The expression level of Cx43 was significantly increased in the articular cartilage of osteoarthritic knees. The expression level of Cx43 mRNA was significantly higher than that of Cx37, Cx40, Cx45 and Cx46 in chondrocytes (SW1353). In SW1353 cells, Cx43 occupied the dominant position in connexin family. Cx43 shRNA lentiviral vector could inhibit the expression of Cx43 mRNA in SW1353 cells. The stably transfected SW1353 cell line was screened, laying a foundation for verifying the role of Cx43 in osteoarthritis.
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BACKGROUND:Peridental membrane distraction osteogenesis exerts the functions at peridental membrane and leads to tooth movement. Alveolar bone distraction osteogenesis produces tooth movement through the displacement of the whole bone plate. OBJECTIVE:To establish three-dimensional finite element model of upper and lower jaw of healthy adults under three different conditions, and to compare the stress distribution and distal movement of the models using three-dimensional finite element analysis method. METHODS:Model 1:three-dimensional finite element model of the canine under normal conditions using a variety of software;Model 2:three-dimensional finite element model of the canine after distracting osteggenesis of the periodontal ligament;Model 3, three-dimensional finite element model of the canine after reducing resistance and distracting osteggenesis of the alveolar bone. The force loadings were stimulated among these models. RESULTS AND CONCLUSION:The biggest displacements on those three models occurred in canine crown on 1/3, and the displacement quantity on canine was model 2>model 3>model 1. The biggest equivalent stress concentrated in distal alveolar crest, and the equivalent stress was model 2
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Objective To establish a three-dimensional finite element model of rapid canine tooth movement by reducing resistance and distracting procedures,and to discuss canine distal movement and force distribution of periodontium,and to provide theory basis for its clinical application.Methods Through 64-slice spiral scanning,temporomandibular joint (TMJ),the mandible,lower jaw denture section phantom DICOM data were obtained.Mimics software,Geomagic Studio 8.0 software,Unigraphics NX software,and Ansys11.0 software were mixed,and the three-dimensional finite element model were established under the conventional condition to move the canine (model 1 ),rapid canine movement through distracting osteggenesis of the periodontal ligament (model 2),rapid canine movement tooth movement through reducing resistance and distracting method (model 3),the strength were carried on three kind of models and the canine,the pericementum,the tooth socket bone stress distribution were observed.Results The biggest displacements on those three models occured in canine crown on 1/3,biggest displacement quantity:model 3 ＞model 2 ＞model 1,and the canine crown displacement reduced gradually from crown to the root point; in the model 1 most greatly equivalent stress mainly concentrated in the middle of distal alveolar crest,but in the models 2 and 3 most greatly equivalent stress centralism area shifted liguodistal alveolar crest.Conclusions In the process of canine distal movement,reducing bone resistance,can accelerate the tooth moving speed effectively and simultaneously,the canine has distal motion tendency.While under the action of force,the canine tends to move ligually with the canine distal movement,and thus appropriate measures should be taken to prevent canine lingual rotation in clinical work.