The Study Of The Effects Of Silencing Girdinin Human Periodontal Ligament Fibroblasts Cells Under Distraction Force

[Objective] To culture the human Periodontal ligament fibroblasts (hPDLFs) in vitro. To investigate the effects on the signal pathway of Girdin/Akt in hPDLFs caused by distraction stress in vitro. The aim of this study is to further investigate the biomechanical process with in the tissue remodeling during orthodontic tooth movement.[Methods] The hPDLFs were cultured using the method of improved tissue adhering and were identified by their morphological and using immunochemistry. Dynamic mechanical tensile stress were applied in vitro to the hPDLFs and human osteoblastic MG63cells with the use of a forcel four-point bending system with5000μ strain, at a frequency of0.5Hz. And the changes of cell ultrastructure were observed on with transmission electron microscopic. To investigate the inhibitory effect of small interfering RNA (siRNA) on the expression of Girdin,and to observe the effects of down regulated Girdin on the expression of Girdin, p-Girdin,Akt and p-Akt in human osteoblastie MG63cells and to observe the changes of cell ultrastructure with transmission electron microscopic.[Results]1.Using the method of improved tissue adhering, we have successfully cultured and subcultured the human periodontal ligament cells.2.The observation of transmission electron microscopic:Compared with the control group, periodontal fibroblasts in experimental group in a spindle-shaped, much prominence and long, vacuole-like structures of varying sizes, some vacuoles containing collagen fragments, cell volume increases in apparent intensity active functional State, cytoplasmic organelles unusually rich, developed rough endoplasmic reticulum, mitochondria, present different degrees of expansion, swelling; Compared with the control group, MG63cell volume increased in the experimental group were active functional State, cytoplasmic organelles unusually rich, developed rough endoplasmic reticulum, mitochondria, present different degrees of expansion, swelling.3. The results of western blot test:Compared with the blank control group,the expression of Girdin, P-Girdin, Akt, p-Akt was markedly down-regulated by siRNA of human Girdin. With Dynamic mechanical tensile stress, the expression of Girdin, P-Girdin, Akt, p-Akt was down-regulated by siRNA of human Girdin again.[Conclusion]1.We have successfully cultured the hPDLFs using the method of improved tissue adhering.2. Superb mechanical stress can contribute to normal periodontal tissue reconstruction.3. Girdin/Akt signaling pathway involved in the regulation of proliferation and apoptosis of osteoblasts, and down-regulation of Girdin induced apoptosis in osteoblastic cells.