Objective To study the effect of hypoxia on the mRNA expression of osteoprotegerin(OPG) and receptor activa‐tor for nuclear factor‐κB ligand(RANKL) in human periodontal ligament cells(hPDLCs) and to explore the role of hypoxia in the orthodontic bone resorption in pressure side .Methods The primary hPDLCs were cultivated with enzyme digestion assay and tis‐sue cultivation .The 3-5 generations of hPDLCs were respectively cultured 3 ,6 ,12 and 24 h in normoxia condition (20% O2 ) or in hypoxia condition (2% O2 ) .The mRNA expression of OPG and RANKL were detected with RT‐PCR .The experimental data was analyzed by one way ANOVA using SPSS15 .0 .Results After cultivated in hypoxia condition for 3 h or 6 h ,the mRNA expression of OPG and RANKL in hPDLCs didn′t change significant(P> 0 .05) .After cultivated in hypoxia condition for 12 h or 24 h ,the mRNA expression of OPG in hPDLCs decreased while the RANKL increased .Thus the ratio of RANKL/OPG increased and the difference was significant(P<0 .05) .Conclusion Hypoxia can regulate the mRNA expression of OPG and RANKL in hPDLCs and will promote the orthodontic bone resorption in pressure side .

OBJECTIVEPeriodontal tissue remodeling includes remodeling of alveolar bone, periodontal ligament, and cementum. Cementoblast plays a main role in repairing root resorption. Canonical Wnt/β-catenin signaling can promote the odontogenic differentiation in osteoblast. However, the mechanism on how the orthodontic force influences the function of cementoblast and the relationship between the canonical Wnt/β-catenin signaling and Runx2 of cementoblast are not yet known. The aim of this study is focus on this relationship.

METHODSOCCM30 cementoblasts were subjected to mechanical strain by four-point bending system with tension stress for 0, 3, 6, and 12 h. They were pretreated with different concentrations of Dikkopf-1 (DKK1) for 48 h. Western blot analysis was performed to detect the β-catenin levels in the nucleus. Runx2 mRNA was observed by real-time quantitative polymerase chain reaction (RT-PCR). OCCM30 cementoblasts were then pretreated with 150 ng · mL(-1) DKK1 for 48 h and subjected to mechanical strain by FX4000T system with tension stress for 12 h. Western blot analysis was conducted to detect the β-catenin levels in the nucleus, and Runx2 mRNA was observed by RT-PCR.

RESULTSOCCM30 cementoblasts had significantly higher Runx2 mRNA and β-catenin levels after being loaded with mechanical stress. The amount of Runx2 mRNA in OCCM30 cementoblasts was significantly decreased by DKK1. When OCCM30 cemento-blasts were pretreated with DKK1 without stress, their β-catenin level was significantly decreased by DKK1 and Wnt signaling was blocked. When they were not pretreated with stress, the β-catenin level with DKK1 was lower than that without DKK1. Without DKK1, the β-catenin level in OCCM30 cemento- blasts increased afterbeing loaded with mechanical stress. With DKK1, the β-catenin level in OCCM30 cementoblasts, which were loaded with mechanical stress, was higher than that without mechanical stress.

CONCLUSIONCementoblasts had higher Runx2 mRNA expression under mechanical stress because of the Wnt/β-catenin signaling pathway effect.

Cell Differentiation ; Dental Cementum ; Humans ; In Vitro Techniques ; Osteoblasts ; Signal Transduction ; Stress, Mechanical ; Wnt Proteins ; beta Catenin

Objective To explore the effect of problem-based learning(PBL)in x-ray cephalometric teaching.Method Forty students were divided into two groups:the conventional teaching group(A)and the PBL group(B),each team twenty students.The teaching effectiveness was evaluated by subjective questionnaire and objective test.Resulte The evalution shows that group B was significantly superior to group A.Conclusions Problem-based learning can im-prove the students' understanding of the significance of cephalometric and deserve to be popu-larized in experiment teaching.

Objective:To study the influence of Cm-Sn-Ls and Li-Sm-Pg angle change on facial 3D aesthetics and to compare the aesthetic evaluation difference between orthodontic professionals and non-professionals.Methods:Facial photographs of a skeletal class Ⅱ and a class Ⅲ subject were respectively obtained and 3D head inodels were created by 3DMAX.Then 16 head models were obtained for each subject by changing Cm-Sn-Ls and Li-Sm-Pg angles.30 othodontic professionals and 60 non-professionals were chosen to score the models by NRS.Results:For class Ⅱ subject,the 2 groups gave lowest score to original profile,Cm-Sn-Ls and Li-Sm-Pg angle change of + 15°,-15°;the professionals gave highest score to(+ 10°,0)、(+ 15°,0),while non-professionals gave highest score to (+ 5 °,-5 °) and (+ 5°,-10°).For class Ⅲ subject,the 2 groups selected original profile,(0,+ 15 °) and (0,+ 10°) for lowest score,and professionals selected (-5°,+ 15°) 、(-10°,+ 15°) for highest score,while non-professionals choose (-10°,+5°) 、(-15°,0) for highest score (between groups,P ＜ 0.05).Conclusion:Both orthodontic professionals and non-professionals like the profile with appropriate compensation for skeletal class Ⅱ and class Ⅲ patients,but there is some aesthetic difference about the amount of compensation between the two groups.

OBJECTIVEThis study investigated the effects of salvianolic acid B (Sal B), a major bioactive component of the Chinese medicine salvia miltiorrhiza, on osteogenic differentiation of human periodontal ligament cells (hPDLCs).

METHODSThird passage PDLCs were used in this experiment. Methyl thiazolyl tetrazolium (MTT) method was employed to observe the effects of different Sal B concentrations on proliferation activity of hPDLCs. Alkaline phosphatase (ALP) activity and mineralization capability were measured, and mRNA expression of osteocalcin (OCN) was detected to investigate the effects of Sal B on osteogenesis of hPDLCs.

RESULTSSal B did not influence the viability of hPDLCs. The ALP activity and OCN mRNA expression levels of hPDLCs were both significantly improved (P<0.05) under treatment with different Sal B concentrations (0.5, 1, and 5 μmol·L⁻¹) compared with those in OIM group. Moreover, the number of mineralized nodules formed by hPDLCs were considerably higher under treatment with different Sal B concentrations (0.5, 1, and 5 μmol·L⁻¹) than that in the OIM group.

CONCLUSIONSAppropriate Sal B concentration can improve the osteogenic differentiation of hPDLCs.

Benzofurans ; Cell Differentiation ; Cells, Cultured ; Humans ; Osteocalcin ; Osteogenesis ; Periodontal Ligament

OBJECTIVES: Human periodontal ligament cells (hPDLCs) are important source of periodontal tissue reconstruction. Under chronic inflammation, the multi-directional differentiation potential and chemotaxis in hPDLCs are decreased. Therefore, inhibiting inflammatory microenvironment and improving the functional characteristics of stem cells can better promote periodontal tissue reconstruction. This study was to investigate the effect of astaxanthin (AST) on lipopolysaccharide (LPS)-induced inflammation in hPDLCs and the underlying mechanisms. METHODS: hPDLCs were isolated and cultured in vitro, and vimentin and keratin immunocytochemical staining were used to identify hPDLCs. CCK-8 assay was used to measure the effects of AST (1, 5, 10, 20, 50, 100, and 200 μmol/L) on proliferation of hPDLCs. Quantitative RT-PCR (RT-qPCR) and ELISA were used to measure the mRNA and protein expression of inflammatory factors (IL-6, IL-1β, and TNF-α) in the control (Con) group, the LPS group, and the LPS+AST (5, 10, 20, and 50 μmol/L) group. Western blotting was used to detect the protein expression of IKBα, phosphorylated IKBα (p-IKBα), and p65 in the Con group, the LPS group, the AST (20 μmol/L) group, and the LPS+AST (20 μmol/L) group. After 10 μmol/L PDTC treatment, the mRNA and protein expressions of IL-6, IL-1β, and TNF-α were detected by RT-qPCR and ELISA. RESULTS: Cell morphology and immunocytochemical staining showed that the cells were in line with the characteristics of hPDLCs. Treatment with AST could promote the proliferation of hPDLCs, which reached the peak at 20 μmol/L. The mRNA and protein expressions of IL-6, IL-1β, and TNF-α in the LPS group were higher than those in the Con group (all CONCLUSIONS AST promotes the proliferation of hPDLCs, which is related to suppression of LPS-induced the secretion of inflammatory factors via inhibiting the activation of NF-κB signaling pathway.
Cells, Cultured ; Humans ; Inflammation/chemically induced* ; Lipopolysaccharides ; NF-kappa B ; Periodontal Ligament ; Tumor Necrosis Factor-alpha/genetics* ; Xanthophylls

OBJECTIVE: This study aims to investigate the effect of neurotrophin 3 (NT-3) on the osteogenic differentiation of human dental follicle cells (hDFCs). METHODS: hDFCs were isolated and cultured in vitro. Immunocytochemical staining was used to identify the origin of hDFCs. The effects of different NT-3 concentrations on hDFCs proliferation were detected by using CCK-8 assay. The alkaline phosphatase (ALP) activities and mRNA expression levels of bone morphogenetic protein-2 (BMP-2) and osteocalcin (OCN) were determined to investigate the effects of NT-3 on hDFCs osteogenesis. The difference in the number of mineralized nodules was detected using alizarin red staining. RESULTS: Vimentin and cytokeratin staining results showed that hDFCs originated from the mesenchymal cells. NT-3 exerted no evident effect on hDFCs proliferation. The ALP activity and the BMP-2 and OCN mRNA expression levels of hDFCs were significantly improved under treatment with different NT-3 concentrations (25, 50, and 100 ng·mL ⁻¹) compared with those in the control group. BMP-2 and OCN mRNA relative expression levels of hDFCs reached the highest when the NT-3 concentration was 100 ng·mL ⁻¹. The number of mineralized nodules reached the maximum when the hDFCs were treated with 50 and 100 ng·mL ⁻¹ NT-3. CONCLUSIONS Appropriate mass concentration of NT-3 can promote the osteogenic differentiation of hDFCs.
Alkaline Phosphatase ; Bone Morphogenetic Protein 2 ; metabolism ; Cell Differentiation ; Cells, Cultured ; Dental Sac ; Humans ; Mesenchymal Stem Cells ; Neurotrophin 3 ; pharmacology ; Osteocalcin ; metabolism ; Osteogenesis