| Actinobacillus actinomycetemcomitans is one of the known periodontal pathogens, producing a variety of virulence factors can cause alveolar bone destruction. Studies have proved that oral self-cleaning function was reduced because of the fixed Appliance. In the initial 2 months, A.a detection rate increased significantly. any movement of the teeth ,during orthodontic, affects the surrounding bone tissue centainly,brings a series of changes,such as bone resorption,bone formation. The reconstruction of bone,a series of comPlicated procedure involve in bone resorption and bone formation,which need the cooperation of osteoblast,osteoclast,and osteocytes.The cooperation of the cells depends on intercellular transmission.The tranmission is accomplished via the gap junction of the cells. Cell gap junction is a cellular connection ,presented in animal tissues, in addition to blood cells, tumor cells and skeletal muscle cells . Gap junction,composed by connexin(Cx) Protein,Permit the exchange of regulating molceules between contact cells which play a very impontant role in embryogenesis,cell proliferation and differetiation.The recent study discovered that the bone reconstruction has relationshio with the gene expression of the gap junctional connexin;the alteration of mechanism of signal transduction and the adjustment of gap junctional intercellular conmmunication. Meanwhile,the gap junctional connexin was regulated by some growth factors,neurotransm-itters,hormone.These factors influence connexin,then adjust the amount of cells in bone tissue,affect the metabolism of cells,result in the corresponding alternation of bone tissue.The recent study discovered that the bone reconstruction has relationshio with the gene expression of the gap junctional connexin;the alteration of mechanism of signal transduction and the adjustment of gap junctional intercellular conmmunication. Meanwhile,the gap junctional connexin was regulated by some growth factors,neurotransm-itters,hormone.These factors influence connexin,then adjust the amount of cells in bone tissue,affect the metabolism of cells,result in the corresponding alternation of bone tissue.To investigate the effect of Actinobacillus actinomycetemcomitans on differentiation and gap junctional intercellular communication in osteoblasts.In this study,We use rat Osteoblast MC3T3-E1,maintained in BHI growth medium mixed with A.a culture supernatants,learned the Cx43 gene expression,and their gap junctional intercellular communication.the results and conclusions are as followed:1.Osteoblastic cell was maintained in BHI growth medium mixed with A.a culture supernatants.Used neutral red to test cellular activity.Until concentration to 20% there was no changing on the viability of Osteoblastic cells compare to BHI sample as control.2.The quantitative RT-PCR assay for differentiation markers .mRNA expression of ALP,BSP,OCN was difference from control and decreased.3.The change of gap junctional intercellular communication were detected by SLDT.The diffusion distance of fluorescent dye in cells cultured with A.a culture supernatants was shorter than those of control.4.The change of Connexin43 expressions in the Osteoblastic were detected by Western blot.The protein expression of Cx43 in sample treated with A.a culture supernatants was remarkable deficiency than in sample treated with BHI.The results showed,A.a inhibit the differentiation and gap junctional intercellular communication in osteoblasts. |
