Studies On The Effects Of Enamel Matrix Proteins To Periodontal Ligament Cells And The Periodontal Tissue Regeneration

Ever since Slavkin in 1975 found that enamel matrix proteins (EMP5) which originated from Hertwig epithelium sheath can promote the formation of accellular cementum, EMP5 have been tried experimentally more and more. Periodontal ligament(PDL) cells are not oniy the key component of periodontal tissue but also play a fundamental role in the regeneration of periodontal tissue. The purpose of the present study was to explore the effects of EMP5 on the biological activities of PDL cells through cell culture technique and on the periodontal tissue regeneration through animal experiment in order to investigate the possible mechanism why EMP5 could induce periodontal tissue regeneration. 1 .The biological effects of EMP5 on PDL cells. (1 )The establishment of human PDL cells experimental model in vitro. To study the different reactivities of PDL cells to EMP5 we established the PDL cells culture model by tissue explant in vitro. The cells were typical fibroblast-like, and with the positive immunocytochemical reaction for vimentin protein and negative for keratin proteift, which verified that they were of mesodermal origin. Their doubling time was 48.24 hours. (2) The effects of EMP5 on proliferation of PDL cells MTT assays showed that EMP5 significantly increased optical density(OD) of PDL cells in a dose-dependent manner: EMP5 of 25梚 OOmgIL ?? could statistically promote the proliferation of PDL cells and SOmg/L was the most optimal concentration. Adding EMIP5 of SOmg/L for 3-~-7 days caused a significant PDL cells replication and the optimal time was 5 days. The data suggested that EMP5 had the capacity to accelerate PDL cells multiplication. (3) The effects of EMP5 ALPase activity of PDL cells. A kinetic method was applied to measure the ALPase activity of PDL cells .Exposed to EMP5 of 25條OOmg/L ALPase activity of PDL cells didn抰 change significantly .However EMPs of 200mgIL could raise PDL cells?ALPase activity statistically .The results indicated that EMPs was involved in regulating the differentiation of PDL cells. 2.Animal experiment studies on the effects of EMPs in guided tissue regeneration. (1 )After 1 month postsurgically, compared with controlled group, both EMPs + e-PTFE membrane group and e-PTFE membrane group had more newly formed cementum and alveolar bone and most of the furcation defects had been filled with newly formed alveolar bone, cementum, periodontal ligament and connective tissue; After 3 months, the two experimental groups had almost been filled with newly formed tissues. The amount of the new tissues between two experimental groups had no statistical difference; however, the types varied significantly: both upper and lower sections of neoformed cementum in e-PTFE membrane group were cellular cementum; in EMPs + e-PTFE membrane group, the upper section of neofonned cementum was cellular cementum while the lower one was accellular cementum. The above results revealed that the combining application of EMPs and e-PTFE membrane could significantly promote the treatment of furcation defects. Furthermore EMPs played an important role in accelerating ?? the regeneration of periodontal tissue, especially accellular cementum. (2)After...