The Experimental Study On SCPA Turning Into Dental Pulp-dentine Under Different Concentration Of TNF-α

Objectives: By using tissue engineering method, to discuss the possibility of the rat stem cells from the apical papilla turning into dental pulp-dentin in differe nt concentrations of tumor necrosis factor-α. Methods: Isolating rat root nipple tis sue, obtaining rat stem cells from the apical papilla by enzyme digestion and tissu e explant method, identifying the origin of the cells, and detecting stem cells fro m the apical papilla proliferation in vitro and mineralization of tooth bone after in terveneng in different concentrations of tumor necrosis factor-α; Meanwhile, transpl anting different groups the cells were combined with hydroxyapatite(cell + hydro xyapatite, 10ng/ml tumor necrosis factor-α cells + hydroxyapatite, hydroxyapatite b lank control, cells blank control) into rat subcutaneous to observe new tissue form ation for 8/12 weeks. Results: MTT assay shows that different concentrations of t umor necrosis factor-α can stimulate the proliferation of rat stem cells from the a pical papilla in vitro, tumor necrosis factor-α in experimental group 10 and 50ng/ml can significantly promote the proliferation of rat stem cells from the apical pa pilla(P<0.05), the difference was statistically significant. Alizarin red staining sh ows that com-pared with the control group(0ng/ml tumor necrosis factor-α), the e xperimental group(5, 10, 50ng/ml tumor necrosis factor-α) stains lighter and mine ralized nodule formation are smaller; the control group contains larger scale of red nodules and shows as dark orange control. Immunohistochemical staining showed that the expression of dentin sialoprotein and bone sialoprotein are in the rat ste m cells from the apical papilla cytoplasm. In the experimental group, the cytoplas m of some cells stain lightly as brown, showed as positive expression; the control group(0ng/ml tumor necrosis factor-α) cells the cytoplasm completely dark brow n colored, being strong positive expression. The dentin pulp alike structure formati on is visible in the graft in 0ng/ml tumor necrosis factor-α Group as well as 10ng/ml tumor necrosis factor-α group, and dentin sialoprotein/bone sialoprotein are b oth expressed as positive, no mineralized tissue is formatted in blank control grou p. Conclusion: rat stem cells from the apical papilla has high proliferation and os teogenic differentiation capacity, can regenerate dentin pulp complex. The growth and proliferateion of tumor necrosis factor-α on rat stem cells from the apical pap illa have role in promoting, but to some extent, can also inhibit rat stem cells fro m the apical papilla’s mineralization and tooth osteogenic.