Study on dental pulp stem cells from patients with hypophosphatasia / 北京大学学报(医学版)

ABSTRACT

Objective:To find out whether the dentin formation of hypophosphatasia children is affec-ted;to study the biological difference of cultured human dental pulp cells from deciduous teeth between hypophosphatasia and normal healthy children.Methods: Anterior deciduous teeth were collected from hypophosphatasia(experiment group)and normal healthy children(control group)respectively.Grounding sections of the affected and healthy deciduous teeth were made to observe their roots;the den-tal pulp cells were separated and cultured.The characteristics of cell proliferation,differentiation and calcification were studied and compared between the two groups of children.MTT assay was performed to study the growth curves of the cells;RT-PCR was performed to evaluate the expression of tissue nonspecific alkaline phosphatase(TNSALP)at different stages;von Kosssa staining was used to test formed calcification nodules after 3 weeks of induction.Results: From the grounding sections,the root surface of the experiment group was not smooth with absorbed areas,cementum was absent.For proliferation activity and the expression of TNSALP,the dental pulp cells from experiment group was obviously lower than control group.Calcified nodules could be seen in both groups,but the nodules were less and the sizes were smaller in experiment group than in control group.Conclusion: In hypophosphatasia patients,not only the cementum but also the dentin were affected.The proliferation,TNSALP expression and calcification capability of the dental pulp cells were influenced in hypophosphatasia patients,and this may be related to the tooth calcification defect.