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Zeng Y.,Chongqing Medical University | Zeng Y.,Chongqing key Laboratory of Oral Diseases and Biomedical science | Zeng Y.,Chongqing Municipal Key Laboratory of Oral Biomedical Engineering of Higher Education | Pei X.,University of Sichuan | And 7 more authors.
Surface and Coatings Technology | Year: 2016

As novel nanomaterials, graphene and its derivations have been applied into hydroxyapatite as reinforcements for biomedical applications. However, graphene/hydroxyapatite composites serving as implant coating have rarely been studied. In this study, graphene oxide (GO)/hydroxyapatite (HA) composite coatings have been firstly fabricated by electrochemical deposition technique on titanium (Ti) substrate. Then, the microstructure, phase constituents, bonding strength and in vitro cellular responses of composite coatings were researched. Raman spectroscopy and transmission electron microscopy corroborated that graphene oxide was successfully incorporated into the composite coatings. Results revealed that addition of GO have enhanced both the crystallinity of deposited apatite particles and the bonding strength of the as-synthesized composite coatings. Moreover, in vitro cell culture assessment showed better biocompatibility of composite coatings compared with the pure HA coating and pure Ti substrate. These results suggested that GO/HA composite coatings might be a promising candidate in the field of biomaterials, especially for implant coatings. © 2015 Elsevier B.V. Source

Zhang H.,Chongqing Medical University | Li L.,Chongqing Medical University | Dong Q.,Chongqing Medical University | Wang Y.,Chongqing Medical University | And 6 more authors.
Cellular Physiology and Biochemistry | Year: 2015

Background/Aims: BMP9 is highly capable of promoting osteogenic differentiation of mesenchymal stem cells (MSCs) although the molecular mechanism involved is largely unknown. Here, we explored the detail role of PKA/CREB signaling in BMP9-induced osteogenic differentiation. Methods: Activation status of PKA/CREB signaling is assessed by nonradioactive assay and Western blot. Using PKA inhibitors and a dominant negative protein of CREB (A-CREB), we investigated the effect of PKA/CREB signaling on BMP9-induced osteogenic differentiation. Results: We found that BMP9 promotes PKA activity and enhances CREB phosphorylation in MSCs. BMP9 is shown to down-regulate protein kinase A inhibitor γ (PKIγ) expression. We demonstrated that PKA inhibitors suppress BMP9-induced early osteogenic marker alkaline phosphatase (ALP) activity in MSCs as well as late osteogenic markers osteopontin (OPN), osteocalcin (OCN) and matrix mineralization. We found that PKA inhibitor reduces BMP9-induced Runx2 activation and p38 phosphorylation in MSCs. Lastly, interference of CREB function by A-CREB decreased BMP9-induced osteogenic differentiation as well. Conclusion: Our results revealed that BMP9 may activate PKA/CREB signaling in MSCs through suppression of PKIγ expression. It is noteworthy that inhibition of PKA/CREB signaling may impair BMP9-induced osteogenic differentiation of MSCs, implying that activation of PKA/CREB signaling is required for BMP9 osteoinductive activity. © 2015 S. Karger AG, Basel. Source

Wang Q.,Chongqing Medical University | Wang Q.,Chongqing key Laboratory of Oral Diseases and Biomedical science | Wang Q.,Chongqing Municipal Key Laboratory of Oral Biomedical Engineering of Higher Education | Ao Y.,Chongqing Medical University | And 3 more authors.
Oncology Reports | Year: 2016

Previous studies have shown that the aberrant expression of period circadian clock 2 (Per2) is closely related to the occurrence and development of cancers,but the specific mechanism remains unclear. In the present study,we used shRNA to downregulate Per2 in oral squamous cell carcinoma (OSCC) Tca8113 cells,and then detected the alterations in cell cycle,cell proliferation and apoptosis by flow cytometric analysis and mRNA expression alterations in all the important genes in the cyclin/cyclin-dependent protein kinase (CDK)/cyclin-dependent kinase inhibitor (CKI) cell cycle network by RT-qPCR. We found that in the Tca8113 cells,after Per2 downregulation,the mRNA expression levels of cyclin A2,B1 and D1,CDK4,CDK6 and E2F1 were significantly increased (P<0.05),the mRNA expression levels of p53,p16 and p21 were significantly decreased (P<0.05),cell proliferation was significantly higher (P<0.05),apoptosis was significantly lower (P<0.05) and the number of cells in the G1/G0 phase was significantly decreased (P<0.05). The present study proves that in OSCC,clock gene Per2 plays an important role in cell cycle progression and the balance of cell proliferation and apoptosis by regulation of the cyclin/CDK/CKI cell cycle network. Further research on Per2 may provide a new effective molecular target for cancer treatments. Source

Xu X.,Chongqing Medical University | Xu X.,Chongqing key Laboratory of Oral Diseases and Biomedical science | Zhou J.,Chongqing Medical University | Zhou J.,Chongqing key Laboratory of Oral Diseases and Biomedical science | And 4 more authors.
PLoS ONE | Year: 2016

Objective: To observe dynamic changes in root resorption repair, tooth movement relapse and alveolar bone microstructure following the application of orthodontic force. Materials and Methods: Forces of 20 g, 50 g or 100 g were delivered to the left maxillary firstmolars of fifteen 10- week-old rats for 14 days. Each rat was subjected tomicro-computed tomography scanning at 0, 3, 7, 10, 14, 28 and 42 days after force removal. The root resorption crater volume, tooth movement relapse and alveolar bone microarchitecture were measured at each time point. Results: From day 3 to day 14, the root resorption volume decreased significantly in each group. In the 20-g force group, the root resorption volume gradually stabilized after 14 days, whereas in the 50-g and 100-g force groups, it stabilized after 28 days. In all groups, toothmovement relapsed significantly from day 0 to day 14 and then remained stable. From day 3 to day 10, the 20-g group exhibited faster relapse than the 50-g and 100-g groups. In all groups, the structure model index and trabecular separation decreased slowly from day 0 to day 10 and eventually stabilized. Trabecular number increased slowly from day 0 to day 7 and then stabilized. Conclusions: The initial stage of root resorption repair did not change significantly and was followed by a dramatic repair period before stabilizing. The most serious tooth movement relapse occurred immediately after the appliance was removed, and then the tooth completely returned to the original position. © 2016 Xu et al.This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited. Source

Wang C.,Chongqing Medical University | Wang C.,Chongqing key Laboratory of Oral Diseases and Biomedical science | Zhang W.,Lanzhou Hospital of Stomatology | Ajmera D.H.,Chongqing Medical University | And 5 more authors.
Biomechanics and Modeling in Mechanobiology | Year: 2015

Dental implants have to be placed with the long axis in different angulations due to the change in bone morphology. The objective of this study was to investigate the different bone remodeling response induced by the tilted dental implants and to assess whether it could lead to bone loss and implant failure. In this study, bone remodeling due to palato-labially inclined dental implants placed in the anterior maxillary incisor region was simulated. CT-based finite element models of a maxillary bone with dental implants were created herein. Five dental implants were placed at (Formula presented.), (Formula presented.), (Formula presented.), (Formula presented.) and (Formula presented.), respectively. The remodeling progression was recorded and compared. Model (Formula presented.) (palatal side) shows the highest bone density values, but the inclined implant at (Formula presented.) (labial side) leads to significant bone loss. From a biomechanical perspective, it is speculated that a palatally inclined implant is more likely to enhance the bone density in the maxillary anterior region, but labial inclination of implant could jeopardize its stability. © 2015 Springer-Verlag Berlin Heidelberg Source

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