The Response To Recombinant Human Bone Morphogenetic Protein-2 In Cementoblasts In Vitro

Root resorption is one of the most common side effects in orthodontic treatment. It occurs when the balance of the resorption and regeneration is disturbed. After orthodontic force is removed, orthodontics-associated root resorption will soon cease and new cementum deposition as well as new periodontal attachment could be detected in the lacuna on the resorpted root surface. Despite possible complex mechanisms, it is the cementoblasts that are of central importance in root repair. Cementoblasts locate in periodontal ligament, lining on the root surface. It can not only prevent the cementoclast from attaching, but also form new cementum-like tissue to repair the resorpted root surface. But the mechanism of cementoblasts repairing resorpted root is still unclear, and therefore, relative researches seem quite essential. Bone morphogenetic protein-2(BMP-2), belonging to transforming growth factor-β(TGF-β), is known to enhance mineralization in many tissues,especially to be able to stimulate periodontal ligament cells to express mineral associated gene, and hence plays an important role in periodontal treatment. In the regard, this study is aimed to examine the effects of BMP-2 on murine cementoblasts OCCM-30 in vitro. Methods: In this study, immortalized murine cementoblast cell line, OCCM-30, were exposed to recombinant human bone morphogenetic protein-2(rhBMP-2), and MTT method for cell proliferation, IFCC reference method for ALP and Real-time PCR for expression of mineral-associated markers Cbfα1 and OCN mRNA were used to determine whether cementoblasts would respond to rhBMP-2 in a dose-(50ng/ml and 100ng/ml) and time-depentent manner.Results:1. Both doses of rhBMP-2 could promote the cell proliferation, and the effect was more significant at a dose of 50ng/ml.2. Cementoblasts have an activity of ALP, and at the point of 48h after exposure to rhBMP-2(50ng/ml and 100ng/ml), the ALP activity in cementoblasts didn't have evident change.3. rhBMP-2 at the dose of 50ng/ml could incipiently and transiently up-regulate the expression of Cbfα1 and OCN mRNA, while only an enhancement trend induced by rhBMP-2 at 100ng/ml was detected. This suggests that rhBMP-2 at 50ng/ml may optimally influence the function of cementoblasts.Based on these findigs, this study identified BMP-2 as a trigger factor for stimulating the response of cementoblasts, and provided a premise for effective prevention and treatment of orthodontic root resorption.