Dental pulp-dentin complex defects remain a major unresolved problem in oral medicines. Clinical therapeutic methods including root canal therapy and vital pulp therapy are both considered as conservative strategies, which are incapable of repairing the pulp-dentin complex defects. Although biomaterial-based strategies show remarkable progress in antibacterial, anti-inflammatory, and pulp regeneration, the important modulatory effects of nerves within pulp cavity have been greatly overlooked, making it challenging to achieve functional pulp-dentin complex regeneration. In this study, we propose an injectable bioceramics-containing composite hydrogel in combination of Li-Ca-Si (LCS) bioceramics and gelatin methacrylate matrix with photo-crosslinking properties. Due to the sustained release of bioactive Li, Ca and Si ions from LCS, the composite hydrogels possess multiple functions of promoting the neurogenic differentiation of Schwann cells, odontogenic differentiation of dental pulp stem cells, and neurogenesis-odontogenesis couples in vitro. In addition, the in vivo results showed that LCS-containing composite hydrogel can significantly promote the pulp-dentin complex repair. More importantly, LCS bioceramics-containing composite hydrogel can induce the growth of nerve fibers, leading to the re-innervation of pulp tissues. Taken together, the study suggests that LCS bioceramics can induce the innervation of pulp-dentin complex repair, offering a referable strategy of designing multifunctional filling materials for functional periodontal tissue regeneration.
Dental Pulp/drug effects* ; Hydrogels/pharmacology* ; Animals ; Ceramics/pharmacology* ; Dentin/drug effects* ; Biocompatible Materials/pharmacology* ; Rats ; Gelatin ; Regeneration/drug effects* ; Cell Differentiation/drug effects* ; Injections ; Humans ; Odontogenesis/drug effects*

OBJECTIVES: The mechanism of the odontogenic differentiation of apical papillary cells (APCs) stimulated by bioactive glass 45S5 is still unclear. This study aims to investigate the effect of autophagy on the odontogenic differentiation of APCs stimulated by bioactive glass 45S5. METHODS: APCs were isolated and cultured in vitro, and the cell origin was identified by flow cytometry. The culture medium was prepared with 1 mg/mL 45S5, and its pH and ion concentration were determined. The experiments were divided into control, 45S5, and 3-methyladenine (3-MA) 45S5 groups. In the 45S5 group, APCs were induced to culture with 1 mg/mL 45S5. In the 3-MA 45S5 group, the autophagy inhibitor 3-MA was added to 1 mg/mL 45S5. Protein immunoblotting assay (Western blot) was used to detect the expression of autophagy-associated proteins of microtubule-associated protein 1 light-chain 3β (LC3B) and P62 after 24 h of induction culture in each group. Real-time quantitative polymerase chain reaction (RT-qPCR) was used to detect the expression of bone sialoprotein (BSP), Runt-related transcription factor 2 (Runx2), dentin sialophosphoprotein (DSPP), and dentin matrix protein-1 (DMP-1) after 7 d of induction culture. Cellular alkaline phosphatase (ALP) staining analyzed cellular ALP activity at 7 d of induction, and alizarin red staining evaluated the formation of mineralized nodules at 21 d of induction. RESULTS: The pH of the 45S5 extract culture medium was 8.65±0.01, which was not significantly different from that of the control group (P>0.05). The silicon ion concentration of the 45S5 induction culture medium was (1.56±0.07) mmol/L, which was higher than that of the control group (0.08±0.01) mmol/L (P<0.05). The calcium ion concentration of the 45S5 induction culture was (1.57±0.15) mmol/L, which was not significantly different from that of the control group (P>0.05). Western blot results showed that LC3B-Ⅱ/Ⅰ ratio increased and P62 expression decreased in the 45S5 group compared with those in the control group (P<0.05). By contrast, the ratio decreased and the expression increased in the 3-MA 45S5 group compared with those in the 45S5 group (P<0.05). RT-qPCR results showed that the expression of BSP, Runx2, DMP-1, and DSPP enhanced in the 45S5 group compared with that in the control group (P<0.05), but the expression decreased in the 3-MA 45S5 group compared with that in the 45S5 group (P<0.05). Semi-quantitative analysis of ALP staining and alizarin red staining showed that the ALP activity was enhanced, and the formation mineralized nodule increased in the 45S5 group compared with those in the control group. The ALP activity weakened, and the formation mineralized nodules were reduced in the 3-MA 45S5 group compared with that those in the 45S5 group. CONCLUSIONS Cell autophagy participates in the odontogenic differentiation of APCs induced by 1 mg/mL 45S5 in vitro.
Autophagy/drug effects* ; Cell Differentiation/drug effects* ; Odontogenesis/drug effects* ; Dental Papilla/cytology* ; Humans ; Microtubule-Associated Proteins/metabolism* ; Glass/chemistry* ; Cells, Cultured ; Core Binding Factor Alpha 1 Subunit/metabolism* ; Extracellular Matrix Proteins/metabolism* ; Ceramics/pharmacology* ; Adenine/pharmacology* ; Sialoglycoproteins/metabolism* ; Phosphoproteins/metabolism* ; Integrin-Binding Sialoprotein/metabolism* ; Alkaline Phosphatase/metabolism* ; RNA-Binding Proteins

Tooth bleaching agents may weaken the tooth structure. Therefore, it is important to minimize any risks of tooth hard tissue damage caused by bleaching agents. The aim of this study was to evaluate the effects of applying 45S5 bioglass (BG) before, after, and during 35% hydrogen peroxide (HP) bleaching on whitening efficacy, physicochemical properties and microstructures of bovine enamel. Seventy-two bovine enamel blocks were prepared and randomly divided into six groups: distilled deionized water (DDW), BG, HP, BG before HP, BG after HP and BG during HP. Colorimetric and microhardness tests were performed before and after the treatment procedure. Representative specimens from each group were selected for morphology investigation after the final tests. A significant color change was observed in group HP, BG before HP, BG after HP and BG during HP. The microhardness loss was in the following order: group HP>BG before HP, BG after HP>BG during HP>DDW, BG. The most obvious morphological alteration of was observed on enamel surfaces in group HP, and a slight morphological alteration was also detected in group BG before HP and BG after HP. Our findings suggest that the combination use of BG and HP could not impede the tooth whitening efficacy. Using BG during HP brought better protective effect than pre/post-bleaching use of BG, as it could more effectively reduce the mineral loss as well as retain the surface integrity of enamel. BG may serve as a promising biomimetic adjunct for bleaching therapy to prevent/restore the enamel damage induced by bleaching agents.
Animals ; Biomimetic Materials ; analysis ; therapeutic use ; Cattle ; Ceramics ; analysis ; chemistry ; Chemical Phenomena ; Color ; Colorimetry ; Dental Enamel ; drug effects ; ultrastructure ; Electron Probe Microanalysis ; Glass ; analysis ; chemistry ; Hardness ; Hydrogen Peroxide ; pharmacology ; Hydrogen-Ion Concentration ; Microscopy, Electron, Scanning ; Protective Agents ; analysis ; therapeutic use ; Random Allocation ; Solubility ; Spectroscopy, Fourier Transform Infrared ; Time Factors ; Tooth Bleaching ; methods ; Tooth Bleaching Agents ; pharmacology ; Water ; chemistry ; X-Ray Diffraction

OBJECTIVETo investigate the role of p38 mitogen-activated protein kinases (MAPKs) in the apoptosis of human bronchial epithelial cells (BEAS-2B) induced by refractory ceramic fibers (RCFs).

METHODSBEAS-2B cells were exposed to 10, 20, 40, 80, and 160 µg/cm(2) RCF1, RCF2, and RCF3 for 24 h, and the cell viability was measured by CCK-8 assay. BEAS-2B cells were exposed to 20, 40, and 100 µg/cm(2) RCF1, RCF2, and RCF3 for 24 h, and the cell apoptosis rate was measured by flow cytometry. BEAS-2B cells were exposed to 40 µg/cm(2) RCF1, RCF2, and RCF3, and the expression levels of phospho-p38 MAPK and caspase-3 were measured by Western blot. In each of the above treatments, the BEAS-2B cells were divided into positive control, p38 inhibitor SB203580 intervention, and normal groups.

RESULTSAs the concentration of RCFs rose, the RCF exposure groups showed decreased cell viability and increased cell apoptosis rate. After SB203580 intervention, the intervention groups (all concentrations of asbestos + SB, 20, 40, 80, and 160 µg/cm(2)RCF1+SB, and 40, 80, and 160 µg/cm(2) RCF2 and RCF3+SB) had significantly increased cell viabilities (P < 0.05), and the intervention groups (asbestos + SB and 20, 40, and 100 µg/cm(2) RCF1, RCF2, and RCF3 + SB) had significantly decreased cell apoptosis rates (P < 0.05). Compared with the normal group, the RCF (40 µg/cm(2)) exposure and positive control groups had significantly increased expression of phospho-p38 MAPK (P < 0.05), and the RCF (40 µg/cm(2)) exposure group had significantly increased expression of caspase-3 (P < 0.05). The intervention groups (asbestos + SB and 40 µg/cm(2) RCF1, RCF2, and RCF3 + SB) had significantly decreased expression of caspase-3 after SB203580 intervention.

CONCLUSIONp38 MAPKs play an important role in RCF-induced apoptosis of BEAS-2B cells.

Apoptosis ; drug effects ; Bronchi ; cytology ; Caspase 3 ; metabolism ; Cell Line ; Ceramics ; toxicity ; Epithelial Cells ; drug effects ; metabolism ; pathology ; Humans ; Imidazoles ; pharmacology ; Pyridines ; pharmacology ; p38 Mitogen-Activated Protein Kinases ; metabolism

Animals ; Cell Cycle ; drug effects ; Cell Proliferation ; drug effects ; Cells, Cultured ; Ceramics ; pharmacology ; Gene Expression Regulation ; drug effects ; Glass ; Humans ; Osteoblasts ; drug effects ; metabolism ; Osteogenesis ; drug effects

BACKGROUNDBiphasic calcium phosphate (BCP) ceramics has a potential advantage as an osteoconductive matrix and has an optimal resorption rate for bone formation. Using BCP ceramics as a bone graft during spinal fusion requires osteogenesis within the material and subsequent bridging between adjacent vertebrae to provide long-term support. Bisphosphonates have been reported to prolong the process of bone healing. The influence of bisphosphonate treatment on bone formation within BCP ceramics in spinal fusion remains unknown. The aim of this study was to evaluate the influence of alendronate on BCP osteogenesis in posterolateral spinal fusion.

METHODSPosterolateral spinal fusion with pedicle screw fixation was performed at the lumbar spine in twenty-two pigs. BCP ceramics were applied as a bone graft to obtain bone fusion between adjacent transverse processes. Eleven pigs in the treatment group received oral alendronate 10 mg/d for three months postoperatively. Eleven pigs in the control group did not receive treatment with alendronate. All animals underwent posterolateral spinal fusion with BCP ceramics. The fusion rate was evaluated three months after the operation.

RESULTSThe fusion rates evaluated by X-ray were 27.3% in the treatment group and 20% in the control group. The fusion rates using histological evaluation were 18.2% in the treatment group and 20% in the control group. The mean volumes of fusion mass were (3.64 +/- 0.86) cm(3) in the treatment group and (4.26 +/- 0.63) cm(3) in the control group. No significant differences were found in either trabecular bone volume or residual BCP volume between treatment and control groups using histological evaluation. The new bone formation within BCP ceramics was greater in the area adjacent to transverse process (P < 0.01).

CONCLUSIONOral alendronate with a dose of 10 mg daily do not inhibit bone formation within BCP ceramics or affect the fusion rate in posterolateral spinal fusion from porcine models.

Alendronate ; pharmacology ; Animals ; Calcium Phosphates ; chemistry ; Ceramics ; chemistry ; Female ; Osteogenesis ; drug effects ; Spinal Fusion ; Swine

OBJECTIVETo determine the osteogenic capacity of autologous bone marrow mesenchymal stem cells (BMSCs)-calcium phosphate ceramic composites in vitro and implanted as a bone graft substitute for lumbar anterior interbody fusion in rhesus monkeys.

METHODSFrom March 2003 to April 2005, 9 adult rhesus monkeys underwent lumbar L(3 - 4) and L(5 - 6) discectomy and interbody fusion via an anterior retroperitoneal approach. Two fusion sites in each animal were randomly assigned to two of three treatments: autogenous tricortical iliac crest bone graft (autograft group, n = 6) or cell-free ceramic graft (ceramic group, n = 6) or BMSCs-ceramic composite graft (BMSCs group, n = 6). Autologous BMSCs were culture-expanded and stimulated with osteogenic supplement. The cell-ceramic composites were constructed in a rotary dynamic cell culture system. The spinal fusion segments were evaluated by radiography, biomechanical testing, histologic analysis and histomorphometric analysis at 3 months post-surgery.

RESULTSBiomechanical testing showed that spinal segments from the autograft group and the BMSCs-ceramic group were statistically and significantly stiffer than the cell-free ceramic group. The BMSCs-ceramic group and the autograft group showed equivalent biomechanical stiffness by statistical analysis. Histologically, both the autograft group and the BMSCs-ceramic group achieved osseous union, but the cell-free ceramic group had a fibrous union. Quantitative histologic analysis showed that the amount of bone formation was significantly greater in the autograft group and the BMSCs-ceramic group compared with the cell-free ceramic group. However, the amount of ceramic residue was significantly greater in the cell-free ceramic group versus the BMSCs-ceramic group.

CONCLUSIONSThe results indicate that BMSC-ceramic composites can enhance bone regeneration and achieve osseous spinal fusion 3 months after the implantation in rhesus monkey interbody fusion model. Cell-free ceramics has an unsatisfactory efficacy in spinal fusion due to its tense fibrous fusion.

Animals ; Bone Regeneration ; drug effects ; Bone Substitutes ; pharmacology ; Calcium Phosphates ; Ceramics ; Female ; Macaca mulatta ; Male ; Mesenchymal Stromal Cells ; cytology ; Spinal Fusion ; methods ; Tissue Engineering

OBJECTIVETo investigate the nitrifying characteristics of both suspended- and attached-biomass in a hybrid bioreactor.

METHODSThe hybrid biological reactor was developed by introducing porous ceramic particles into the reactor to provide the surface for biomass attachment. Microorganisms immobilized on the ceramics were observed using scanning electron microscopy (SEM). All chemical analyses were performed in accordance with standard methods.

RESULTSThe suspended- and attached-biomass had approximately the same nitrification activity. The nitrifying kinetic was independent of the initial biomass concentration, and the attached-biomass had a stronger ability to resist the nitrification inhibitor.

CONCLUSIONThe attached biomass is superior to suspended-biomass for nitrifying wastewater, especially that containing toxic organic compounds. The hybrid biological reactor consisting of suspended- and attached-biomass is advantageous in such cases.

Biomass ; Bioreactors ; Cells, Immobilized ; Ceramics ; Microscopy, Electron, Scanning ; Nitrogen ; metabolism ; Phenol ; pharmacology ; Sewage ; Waste Disposal, Fluid ; instrumentation

OBJECTIVETo observe the heterotopic osteogenesis of autogenous marrow stromal cells loading on porous calcium phosphate ceramic scaffolds with rhBMP2 gene transfection in a Sprague-Dawley rat model.

METHODSAutogenous marrow stromal cells were obtained from left femurs and tibias of 20 male adult SD rats under general anesthesia and sterile condition and cultured in alpha-Minimal Essential Medium supplemented with 15% fetal bovine serum. RhBMP2 gene was transfected into stromal cells by means of LipofectAMINE 2000 reagent five days after primary culture. The stably gene expressive cells were selected with G-418 for 14 days and mixed with stromal cells without transfection. The mixture cells were seeded and subcultured for another 10 days in porous calcium phosphate bioceramic that had been subjected to surface-modification via soaking in human plasma fibronectin. The cell-ceramic compound was implanted subcutaneously and intramuscularly in the corresponding rat. Lab animals were sacrificed at two-week intervals till twenty weeks postoperatively and the involved samples were removed.

RESULTSMorphologic and histological study demonstrated that cell-ceramic compound had an ability of heterotopic osteogenesis, which was similar to that of autogenous osteoblasts in previous study.

CONCLUSIONIt seems that autogenous stromal cells with rhBMP2 transfection acts as a bioreactor promoting proliferation and differentiation of stem cells when they are replanted into the corresponding animals.

Animals ; Bone Marrow Cells ; cytology ; physiology ; Bone Morphogenetic Protein 2 ; Bone Morphogenetic Proteins ; biosynthesis ; genetics ; Calcium Phosphates ; pharmacology ; Ceramics ; pharmacology ; Male ; Osteogenesis ; drug effects ; Rats ; Rats, Sprague-Dawley ; Recombinant Proteins ; biosynthesis ; genetics ; Stromal Cells ; cytology ; physiology ; Transfection ; Transforming Growth Factor beta

New bone formation in long-term intramuscle implant of Ca-P biomaterial was investigated in this experiment. After implanting into dog dorsal muscle for 15 months, a thin fibrous membrane that wrapped HA/TCP implant was still observed obviously. Three types of tissues, i.e. mesenchymal tissue, bone and bone marrow, regularly distributed in different pores of implant. Nearly all the pores of implants were occupied by bone. Bone in the pores located in the central region of implant was matured lamellar bone characterized by obvious lacuna and rich bone marrow. However, bone in the peripheral pores was immature woven bone without bone marrow formation. Furthermore, mesenchymal tissues only exist in the peripheral pores and usually were connected with immature woven bone. It was demonstrated that porous HA/TCP has bone inductivity and it could induce new bone formation at non-osseous site. Well-regulated distribution of mesenchymal tissue, bone and bone marrow in the pores suggest bone morphogenesis in the implant must obey a specific space-time program.
Animals ; Biocompatible Materials ; Bone Substitutes ; pharmacology ; Ceramics ; pharmacology ; Dogs ; Hydroxyapatites ; pharmacology ; Implants, Experimental ; Materials Testing ; Osteogenesis ; drug effects