Type I collagen (Col I) is a main component of extracellular matrix (ECM). Its safety, biocompatibility, hydrophilicity and pyrogen immunogenicity make it suitable for tissues engineering applications. Mg2+ also control a myriad of cellular processes, including the bone development by enhancing the attachment and differentiation of osteoblasts and accelerating mineralization to enhance bone healing. In our studies, Mg2+ bind collagen to promote the proliferation and differentiation of osteoblasts through the expression of integrins and downstream signaling pathways. In order to clarify the biological behavior effect of 10 mM Mg2+/Col I coating, we performed 3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT), alkaline phosphatase (ALP), 4′6-diamidino-2-phenylindole (DAPI), Alizarin red staining and Rhodamine B-isothiocyanate (RITC)-labeled phalloidin experiments and found that 10 mM Mg2+ group, Col I-coating group, 10 mM Mg2+/Col I-coating group, respectively, promoted the proliferation and differentiation of osteoblasts, especially 10 mM Mg2+/Col I-coating group. We detected the mRNA expression of osteogenic-related genes (Runx2, ALP and OCN, OPN and BMP-2) and the protein expression of signaling pathway (integrin α2, integrin β1, FAK and ERK1/2), these results indicated that 10 mM Mg2+/Col I coating play an critical role in up-regulating the MC3T3-E1 cells activity. The potential mechanisms of this specific performance may be through activating via integrin α2β1-FAK-ERK1/2 protein-coupled receptor pathway.

In this study, we composited mineralized collagen and magnesium-calcium alloy by freeze-drying, followed by dip-coating PMMA bone cement to enhance the composite of mineralized collagen and magnesium-calcium alloy. In vitro degradation test was performed to observe the pH and weight loss of the material. The contact angle test was used to detect the hydrophilicity of the material. Subsequently, MC3T3-E1 were used to assess cell biocompatibility In vitro by cell adhesion, cytotoxicity, alkaline phosphatase, alizarin red staining, and cytoskeleton. The results showed that the pH changes of the PMMA/NHAC/Mg–Ca was slower than that of the Mg–Ca , and the weight loss rate at 7 d and 14 d were lower than that of the Mg–Ca (P < 0.05) in degradation test. Wettability experiment showed that PMMA/NHAC/Mg–Ca was a hydrophilic material and Mg–Ca was a hydrophobic material (P < 0.05). In vitro cell experiments, the PMMA/NHAC/Mg–Ca had more cell adhesion than Mg–Ca and more synapses were connected to others. In the cytotoxicity experiment, the cell proliferation lever of PMMA/NHAC/Mg–Ca was higher than that of Mg–Ca at each time point (P < 0.05). In the 7 d alkaline phosphatase experiment, the PMMA/NHAC/Mg–Ca showed higher ALP activity than the Mg–Ca (P < 0.05), and in the alizarin red experiment at 14 d and 28 d, there were more obvious calcified nodules and mineralized area. After 1 day of culture in the PMMA/NHAC/Mg–Ca extract, the cells showed a clearer and more complete cytoskeletal structure and better cell morphology. In conclusion, PMMA/NHAC/Mg–Ca orthopedic implants had a better hydrophilicity, cytotoxicity and osteogenic ability, besides with a slower rate of degradation, and could be implanted in animals for further research, which were expected to be used for the repair of clinical bone defects.

To discuss the feasibility of the application of porous Mg–Sr alloy combined with Mg–Sr alloy membrane in the repair of mandibular defects in dogs. The second and third mandibular premolars on both sides were extracted from six dogs. The model of mandible buccal fenestration bone defects were prepared after the sockets healed. Twelve bone defects were randomly divided into groups A and B, then Mg–Sr alloy was implanted in bone defects of group A and covered by Mg–Sr alloy membrane while Mg–Sr alloy was implanted in bone defects of group B and covered by mineralized collagen membrane. Bone defects observed on cone beam computed tomographic images and comparing the gray value of the two groups after 4, 8 and 12 weeks. After 12 weeks, the healing of bone defects were evaluated by gross observation, X-ray microscopes and histological observation of hard tissue. Bone defects in each group were repaired. At 8 and 12 weeks, the gray value of group A was higher than that of group B (P &lt; 0.05). At 12 weeks, the bone volume fraction of group A was higher than that of group B (P &lt; 0.05). The newly woven bone in group A is thick and arranged staggered, which was better than that of group B. Porous Mg–Sr alloy combined with Mg–Sr alloy membrane could further promote the repair of mandibular defects, and obtain good osteogenic effect.

Data from several case-control studies on the relation between the Cyclin D1 (CCND1) G870A polymorphism and oral cancer susceptibility implicated conflicting conclusions. Thus, a meta-analysis was performed to derive a more precise evaluation of the association. We searched PubMed and Embase for related studies that had been published in English and eight available studies were finally included in the meta-analysis. Odd ratios (ORs) and 95 % confidence intervals (CIs) were calculated for each study. Our meta-analysis suggested that CCND1 G870A polymorphism was not associated with oral cancer risk (OR AA vs. GG = 1.08, 95 % CI = 0.90-1.30, P heterogeneity = 0.175; OR AA + GA vs. GG = 1.02, 95 % CI = 0.91-1.14, P heterogeneity = 0.781; OR AA vs. GA + GG = 1.16, 95 % CI = 0.98-1.36, P heterogeneity = 0.107; OR A vs. G = 1.05 95 % CI = 0.96-1.15, P heterogeneity = 0.211; OR GA vs. GG = 0.94, 95 % CI = 0.82-1.08, P heterogeneity = 0.935). However, in the subgroup analysis by ethnicity, possible significance among Asian groups was indicated in two genetic models (OR AA vs. GA + GG = 1.27, 95 % CI = 1.05-1.54, P heterogeneity = 0.572; OR allele A vs. allele G = 1.11, 95 % CI = 1.00-1.24, P heterogeneity = 0.211). Taken together, the meta-analysis revealed that CCND1 G870A polymorphism might be correlated with the susceptibility of oral cancer in Asians.

Magnesium (Mg) alloy with good mechanical properties and biodegradability is considered as one of the ideal bone repair materials. However, the rapid corrosion of Mg-based metals can pose harm to the function of an implant in clinical applications. In this study, micro-arc oxidation coating was prepared on the surface of the Mg–Ca matrix, then the chitosan and mineralized collagen (nano-hydroxyapatite/collagen; nHAC) were immobilized on the surface of the MAO/Mg–Ca matrix to construct the CS-nHAC/Mg–Ca composites of different component proportions (the ratio of CS to nHAC is 2:1, 1:1, and 1:2, respectively). The corrosion resistance, osteogenic activity, and angiogenic ability were extensively investigated. The results indicated that the CS-nHAC reinforcement materials can improve the corrosion resistance of the Mg matrix significantly and promote the proliferation and adhesion of mouse embryo osteoblast precursor cells (MC3T3-E1) and human umbilical vein endothelial cells (HUVECs). In addition, the CS-nHAC/Mg–Ca composites can not only promote the alkaline phosphatase (ALP) activity and extracellular matrix mineralization of MC3T3-E1 cells but also enhance the migration motility and vascular endothelial growth factor (VEGF) expression of HUVECs. Meanwhile, the 2CS-1nHAC/Mg–Ca composite exhibited the optimum function characteristics compared with other samples. Therefore, considering the improvement of corrosion resistance and biocompatibility, the CS-nHAC/Mg–Ca composites are expected to be a promising orthopedic implant.