OBJECTIVE: To review the research progress of strontium (Sr) modified β-tricalcium phosphate composite biomaterials (SrTCP) promoting osteogenesis through immune regulation, and provides reference and theoretical support for the further development and research of SrTCP bone repair materials in bone tissue engineering in the future. METHODS: The literature about SrTCP promoting osteogenesis through immune regulation at home and abroad in recent years was extensively reviewed, and the preparation methods, immune mechanism and application of promoting osteogenesis were summarized and analyzed. RESULTS: The preparation methods of SrTCP include solid-state reaction sintering method, solution combustion quenching method, direct doping method, ion substitution method, etc. SrTCP has immune regulatory effects, which can play an immune regulatory role in inducing macrophage polarization, inducing angiogenesis and anti oxidative stress to promote osteogenesis. CONCLUSION At present, studies have shown that SrTCP can promote bone defect repair through immune regulation. Subsequent studies can start from the control of the optimal repair concentration and release rate of Sr, and further clarify the specific mechanism of SrTCP in promoting angiogenesis and anti oxidative stress, which is helpful to develop new materials for bone defect repair.
Calcium Phosphates/pharmacology* ; Strontium/pharmacology* ; Biocompatible Materials/pharmacology* ; Humans ; Osteogenesis/drug effects* ; Tissue Engineering/methods* ; Bone Substitutes/pharmacology* ; Bone Regeneration/drug effects* ; Animals ; Tissue Scaffolds/chemistry* ; Neovascularization, Physiologic/drug effects* ; Macrophages/immunology*

OBJECTIVE: To investigate the antioxidant and osteogenic induction capabilities of calcium phosphate nanoflowers (hereinafter referred to as nanoflowers) in vitro at different concentrations. METHODS: Nanoflowers were prepared using gelatin, tripolyphosphate, and calcium chloride. Their morphology, microstructure, elemental composition and distribution, diameter, and molecular constitution were characterized using scanning electron microscopy, transmission electron microscopy, Fourier transform infrared spectroscopy, and energy-dispersive spectroscopy. Femurs and tibias were harvested from twelve 4-week-old Sprague Dawley rats, and bone marrow mesenchymal stem cells (BMSCs) were isolated and cultured using the whole bone marrow adherent method, followed by passaging. The third passage cells were identified as stem cells by flow cytometry and then co-cultured with nanoflowers at concentrations of 0, 0.4, 0.8, 1.2, 1.6, 2.0, 2.4, 2.8, 3.2, and 3.6 mg/mL. Cell counting kit 8 (CCK-8) assay was performed to screen for the optimal concentration that demonstrated the best cell viability, which was subsequently used as the experimental concentration for further studies. After co-culturing BMSCs with the screened concentration of nanoflowers, the biocompatibility of the nanoflowers was verified through live/dead cell staining, scratch assay, and cytoskeleton staining. The antioxidant capacity was assessed by using reactive oxygen species (ROS) fluorescence staining. The in vitro osteoinductive ability was evaluated via alkaline phosphatase (ALP) staining, alizarin red staining, and immunofluorescence staining of osteocalcin (OCN) and Runt-related transcription factor 2 (RUNX2). All the above indicators were compared with the control group of normally cultured BMSCs without the addition of nanoflowers. RESULTS: Scanning electron microscopy revealed that the prepared nanoflowers exhibited a flower-like structure; transmission electron microscopy scans discovered that the nanoflowers possessed a multi-layered structure, and high-magnification images displayed continuous atomic arrangements, with the nanoflower diameter measuring (2.00±0.25) μm; energy-dispersive spectroscopy indicated that the nanoflowers contained elements such as C, N, O, P, and Ca, which were uniformly distributed across the flower region; Fourier transform infrared spectroscopy analyzed the absorption peaks of each component, demonstrating the successful preparation of the nanoflowers. Through CCK-8 screening, the concentrations of 0.8, 1.2, and 1.6 mg/mL were selected for subsequent experiments. The live/dead cell staining showed that nanoflowers at different concentrations exhibited good cell compatibility, with the 1.2 mg/mL concentration being the best (P<0.05). The scratch assay results indicated that the cell migration ability in the 1.2 mg/mL group was superior to the other groups (P<0.05). The cytoskeleton staining revealed that the cell morphology was well-extended in all concentration groups, with no significant difference compared to the control group. The ROS fluorescence staining demonstrated that the ROS fluorescence in all concentration groups decreased compared to the control group after lipopolysaccharide induction (P<0.05), with the 1.2 mg/mL group showing the weakest fluorescence. The ALP staining showed blue-purple nodular deposits around the cells in all groups, with the 1.2 mg/mL group being significantly more prominent. The alizarin red staining displayed orange-red mineralized nodules around the cells in all groups, with the 1.2 mg/mL group having more and denser nodules. The immunofluorescence staining revealed that the expressions of RUNX2 and OCN proteins in all concentration groups increased compared to the control group, with the 1.2 mg/mL group showing the strongest protein expression (P<0.05). CONCLUSION The study successfully prepares nanoflowers, among which the 1.2 mg/mL nanoflowers exhibits excellent cell compatibility, antioxidant properties, and osteogenic induction capability, demonstrating their potential as an artificial bone substitute material.
Animals ; Osteogenesis/drug effects* ; Mesenchymal Stem Cells/drug effects* ; Calcium Phosphates/pharmacology* ; Rats, Sprague-Dawley ; Rats ; Antioxidants/chemistry* ; Cells, Cultured ; Cell Differentiation/drug effects* ; Nanostructures/chemistry* ; Tissue Engineering/methods* ; Bone Marrow Cells/cytology* ; Coculture Techniques ; Tissue Scaffolds/chemistry* ; Male ; Biocompatible Materials/chemistry* ; Cell Survival ; Core Binding Factor Alpha 1 Subunit/metabolism* ; Cell Proliferation

OBJECTIVE: To investigate the protective effects of procyanidin on periprosthetic osteolysis caused by tricalcium phosphate (TCP) wear particles in the mouse calvaria and its mechanism. METHODS: Forty-eight male ICR mice were randomly divided into sham group, TCP group, and procyanidin (0.2 mg/kg, 1 mg/kg, 5 mg/kg)-treated group (n=12). A periprosthetic osteolysis model in the mouse calvaria was established by implanting 30 mg of TCP wear particles onto the surface of bilateral parietal bones following removal of the periosteum. On the 2 day post-operation, procyanidin (1 mg/kg, 5 mg/kg) was locally injected to the calvaria under the periosteum every other day. After 2 weeks, all the mice were sacrificed to collect the blood samples and the calvaria. Periprosthetic osteolysis and osteoclastogenesis in the mouse calvaria were observed by tartrate resistant acid phosphatase (TRAP) staining and HE staining. mRNA levels of TRAP, capthesin K, c-Fos and NFATc1 in the periprosthestic bone tissue were examined by real-time fluorescence quantitative PCR. Serum contents of total anti-oxidation capacity (T-AOC) and MDA, and superoxide dismutase (SOD) activity were determined by chemical colorimetry. Protein expressions of autophagic biomarkers such as Beclin-1 and LC-3 in periprosthetic bone tissue of the calvaria were examined by Western blot. RESULTS: Compared with sham group, periprosthetic osteolysis, osteoclastogenesis, mRNA levels of TRAP, capthesin K, c-Fos and NFATc1, and serum MDA content were increased significantly in the TCP group (P＜0.05), whereas serum T-AOC level and SOD activity were decreased. The protein expressions of Beclin-1 and LC-3, and the conversion of LC3-II from LC3-I were both up-regulated markedly in the mouse calvaria of TCP group (P＜0.05). Compared with TCP group, osteolysis, osteoclastogenesis, mRNA levels of TRAP, capthesin K, c-Fos and NFATc1 and serum MDA content were decreased obviously in the procyanidine group (P＜0.05), serum T-AOC level and SOD activity were increased, the expressions of Beclin-1 and LC-3, and the conversion of LC3-II from LC3-I were down-regulated obviously in the mouse calvaria of procyanidin group (P＜0.05). CONCLUSION Procyanidin has a protective effect of periprosthetic osteolysis caused by TCP wear particles in the mouse calvaia, its mechanism may be mediated by inhibition of oxidative stress and autophagy.
Animals ; Autophagy ; Biflavonoids ; pharmacology ; Calcium Phosphates ; adverse effects ; Catechin ; pharmacology ; Male ; Mice ; Mice, Inbred ICR ; Osteolysis ; Oxidative Stress ; Proanthocyanidins ; pharmacology ; Prostheses and Implants ; adverse effects ; Random Allocation ; Skull

Tooth decay is prevalent, and secondary caries causes restoration failures, both of which are related to demineralization. There is an urgent need to develop new therapeutic materials with remineralization functions. This article represents the first review on the cutting edge research of poly(amido amine) (PAMAM) in combination with nanoparticles of amorphous calcium phosphate (NACP). PAMAM was excellent nucleation template, and could absorb calcium (Ca) and phosphate (P) ions via its functional groups to activate remineralization. NACP composite and adhesive showed acid-neutralization and Ca and P ion release capabilities. PAMAM+NACP together showed synergistic effects and produced triple benefits: excellent nucleation templates, superior acid-neutralization, and ions release. Therefore, the PAMAM+NACP strategy possessed much greater remineralization capacity than using PAMAM or NACP alone. PAMAM+NACP achieved dentin remineralization even in an acidic solution without any initial Ca and P ions. Besides, the long-term remineralization capability of PAMAM+NACP was established. After prolonged fluid challenge, the immersed PAMAM with the recharged NACP still induced effective dentin mineral regeneration. Furthermore, the hardness of pre-demineralized dentin was increased back to that of healthy dentin, indicating a complete remineralization. Therefore, the novel PAMAM+NACP approach is promising to provide long-term therapeutic effects including tooth remineralization, hardness increase, and caries-inhibition capabilities.
Amines ; pharmacology ; Calcium ; Calcium Phosphates ; chemistry ; pharmacology ; Dentin ; chemistry ; Humans ; Nanocomposites ; chemistry ; Nanoparticles ; Tooth Remineralization ; methods

Bone mass is important for dental implant success and is regulated by mechanoresponsive osteocytes. We aimed to investigate the relationship between the levels and orientation of tensile strain and morphology and orientation of osteocytes at different dental implant positions in the maxillary bone. Bone biopsies were retrieved from eight patients who underwent maxillary sinus-floor elevation with β-tricalcium phosphate prior to implant placement. Gap versus free-ending locations were compared using 1) a three-dimensional finite-element model of the maxilla to predict the tensile strain magnitude and direction and 2) histology and histomorphometric analyses. The finite-element model predicted larger, differently directed tensile strains in the gap versus free-ending locations. The mean percentage of mineralised residual native-tissue volume, osteocyte number (mean ± standard deviations: 97 ± 40/region-of-interest), and osteocyte shape (~90% elongated, ~10% round) were similar for both locations. However, the osteocyte surface area was 1.5-times larger in the gap than in the free-ending locations, and the elongated osteocytes in these locations were more cranially caudally oriented. In conclusion, significant differences in the osteocyte surface area and orientation seem to exist locally in the maxillary bone, which may be related to the tensile strain magnitude and orientation. This might reflect local differences in the osteocyte mechanosensitivity and bone quality, suggesting differences in dental implant success based on the location in the maxilla.
Biopsy ; Bone-Implant Interface ; Calcium Phosphates ; pharmacology ; Dental Implants ; Finite Element Analysis ; Humans ; Maxilla ; surgery ; Osteocytes ; physiology ; Radiography, Panoramic ; Sinus Floor Augmentation ; Tensile Strength

Objective: To analysis the biomechanical and biocompatible properties of calcium phosphate cement (CPC) enhanced by chitosan short nanofibers(CSNF) and Arg-Gly-Asp (RGD). Methods: Chitosan nanofibers were prepared by electrospinning, and cut into short fibers by high speed dispersion. CPC with calcium phosphorus ratio of 1.5:1 was prepared by Biocement D method. The composition and structure of CPC, CSNF, RGD modified CSNF (CSNF-RGD), CSNF enhanced CPC (CPC-CSNF), RGD modified CPC-CSNF (CPC-CSNF-RGD) were observed by infrared spectrum, X-ray diffraction (XRD) and scan electron microscopy (SEM). The mechanical properties were measured by universal mechanical testing instrument. The adhesion and proliferation of MC3T3 cells were assessed using immunofluorescence staining and MTT method. Results: The distribution of CSNF in the scaffold was homogeneous, and the porous structure between the nanofibers was observed by SEM. The infrared spectrum showed the characteristic peaks at 1633 nm and 1585 nm, indicating that RGD was successfully grafted on chitosan nanofibers. The XRD pattern showed that the bone cement had a certain curability. The stain-stress test showed that break strengths were (17.74±0.54) MPa for CPC-CSNF and (16.67±0.56) MPa for CPCP-CSNF-RGD, both were higher than that of CPC(all P<0.05). The immunofluorescence staining and MTT results indicated that MC3T3 cells grew better on CPC-CSNF-RGD after 240 min of culture(all P<0.05). Conclusion: CSNF-RGD can improve the biomechanical property and biocompatibility of CPC, indicating its potential application in bone tissue repair.
3T3 Cells ; Animals ; Biocompatible Materials ; Bone Cements ; chemistry ; metabolism ; pharmacology ; Calcium Phosphates ; metabolism ; Cell Proliferation ; drug effects ; Chitosan ; chemistry ; pharmacology ; Mice ; Nanofibers ; chemistry ; Oligopeptides ; chemistry

OBJECTIVETo observe the effect of a new biomaterial in promoting the bone regeneration for repairing critical-size cranial defects in SD rats.

METHODSCritical-size cranial defects were induced in 3-month-old male Sprague-Dawley rats and repaired with the implants of calcium phosphate from growth factor enhanced matrix 21 (CaPfromGEM21, control), CaPfromGEM21 preloaded with 10 ng bone morphogenetic protein-2 (BMP-2), CaPfromGEM21 preloaded with 100 ng BMP-2, CaPfromGEM21 preloaded with 0.3 µg platelet-derived growth factor-BB (PDGF-BB), or CaPfromGEM21 preloaded with 3 µg PDGF-BB. The defects were examined 6 weeks after the surgery with X-ray, micro-CT, HE staining and quantitative assessments.

RESULTSX-ray showed defect repair in all the groups. The fracture line became obscure, and the defects were almost fully repaired by the regenerated bone tissues in PDGF-BB group. Micro-CT demonstarted new bone formation in the defects. The new bone volume was significantly greater in PDGF-BB groups than in BMP-2 groups (P<0.05). HE staining revealed the presence of new bones in the defects and new vessels in and around the new bones without inflammatory cells. The new bone area fraction was significantly greater in 10 ng BMP-2 group and 0.3 µg PDGF-BB group than in the control group (P<0.05), and the new vessel density was similar in the all the 4 cytokine-preloaded groups and all significantly greater than that in the blank and CaPfromGEM21 control group (P<0.05).

CONCLUSIONCaPfromGem21 combined with BMP-2 or PDGF-BB has good biocompatibility and can better promote bone regeneration for repairing bone defects.

Animals ; Biocompatible Materials ; Bone Morphogenetic Protein 2 ; pharmacology ; Bone Regeneration ; drug effects ; Calcium Phosphates ; pharmacology ; Male ; Prostheses and Implants ; Proto-Oncogene Proteins c-sis ; pharmacology ; Rats ; Rats, Sprague-Dawley ; Skull ; pathology ; Wound Healing

OBJECTIVETo evaluate the effect of 2-methacryloyloxyethyl phosphorylcholine (MPC) and nanoparticles of amorphous calcium phosphate (NACP) on the protein-repellent property of dental adhesive.

METHODSMPC and NACP were incorporated into SBMP as the test group. Scotchbond Multi-Purpose (SBMP) was used as control group. Human dentin shear bond strengths were measured. Protein adsorption onto samples was determined by micro bicinchoninic acid (BCA) method. A dental plaque microcosm biofilm model with human saliva as inoculum was used to investigate biofilm viability.

RESULTSThe dentin bond strength of modified group was (28.7±2.2) MPa, which was not significantly different from that of the SBMP control group. The amount of protein adsorption in the modified group and the SBMP control group were (0.21±0.02) µg/cm(2) and (4.17±0.45) µg/cm(2) respectively. Lactic acid production of biofilms in modified group and SBMP control were (7.71 ± 1.01) mmol/L and (19.18 ± 2.34) mmol/L repectively.

CONCLUSIONSMPC-NACP based dental adhesive greatly reduce the protein adsorption and bacterial adhesion, without compromising dentin shear bond strength. This novel bonding agent may have wide application.

Adsorption ; Biofilms ; drug effects ; growth & development ; Calcium Phosphates ; pharmacology ; Dental Cements ; pharmacology ; Dental Plaque ; Dentin ; chemistry ; Humans ; Lactic Acid ; biosynthesis ; Methacrylates ; pharmacology ; Nanoparticles ; Phosphorylcholine ; analogs & derivatives ; pharmacology ; Resin Cements ; pharmacology ; Saliva ; Tensile Strength

BACKGROUNDA practical problem impeding clinical translation is the limited bone formation seen in artificial bone grafts. Low-pressure/vacuum seeding and dynamic culturing in bioreactors have led to a greater penetration into the scaffolds, enhanced production of bone marrow cells, and improved tissue-engineered bone formation. The goal of this study was to promote more extensive bone formation in the composites of porous ceramics and bone marrow stromal cells (BMSCs).

METHODSBMSCs/β-tricalcium phosphate (β-TCP) composites were subcultured for 2 weeks and then subcutaneously implanted into syngeneic rats that were split into a low-intensity pulsed ultrasound (LIPUS) treatment group and a control group. These implants were harvested at 5, 10, 25, and 50 days after implantation. The samples were then biomechanically tested and analyzed for alkaline phosphate (ALP) activity and osteocalcin (OCN) content and were also observed by light microscopy.

RESULTSThe levels of ALP activity and OCN content in the composites were significantly higher in the LIPUS group than in the control group. Histomorphometric analysis revealed a greater degree of soft tissue repair, increased blood flow, better angiogenesis, and more extensive bone formation in the LIPUS groups than in the controls. No significant difference in the compressive strength was found between the two groups.

CONCLUSIONLIPUS treatment appears to enhance bone formation and angiogenesis in the BMSCs/β-TCP composites.

Animals ; Bone Marrow Cells ; physiology ; Bone Transplantation ; Calcium Phosphates ; pharmacology ; Male ; Osteogenesis ; physiology ; Rats ; Stromal Cells ; Tissue Engineering ; methods ; Transplantation, Isogeneic ; Ultrasonics ; methods

OBJECTIVETo study the effects of administration or local application of epimedium on the fracture healing in osteoporosis rats.

METHODSEighty-two 4-month old clean female rats, 210-250 g, were randomly divided into the experimental group (n = 75) and the control group (n = 7). The bilateral ovaries were resected in the experimental group, while only little fat tissue around the ovary was resected in the control group. Ten weeks after operation the osteoporosis model was successfully established verified by bone densitometry and scanning electron microscopy (SEM). The femur fracture models were established in the rest 72 rats of the experimental group. They were randomly divided into 3 groups, 24 in each group, i.e., the calcium phosphate cement (CPC) group (Group A), the CPC-epimedium group (Group B), and the epimedium administration group (Group C). The serum alkaline phosphatase (ALP) levels of the 3 groups were determined 2, 4, 8, and 12 weeks after surgery. The vitodynamical test and observation of the histological section were performed.

RESULTSThe serum ALP levels increased to some extent in the 3 groups 2, 4, and 8 weeks after bone fracture surgery. But the increase was more obvious in Group B with statistical difference shown when compared with Group A and C (P < 0.05). The ALP level in Group B decreased to the normal range till the 12th week. The bone fracture had not completely healed in Group C and A. Their ALP levels decreased to some extent, but were still maintained to a comparatively higher level, showing statistical difference when compared with that of Group B (P < 0.05). These results were agreeable with the results of the histological observation. Better bone activity promoting results were shown in Group B. The vitodynamical test results of the femur of Group B were all higher than those of Group A and C at each time point (P < 0.05).

CONCLUSIONSLocal application of epimedium could accelerate the fracture healing in osteoporosis rats. It showed better effects when compared with oral administration at the same dose.

Alkaline Phosphatase ; blood ; Animals ; Bone Cements ; therapeutic use ; Calcium Phosphates ; therapeutic use ; Drugs, Chinese Herbal ; administration & dosage ; pharmacology ; therapeutic use ; Epimedium ; Female ; Fracture Healing ; drug effects ; Fractures, Bone ; drug therapy ; etiology ; Osteoporosis ; complications ; drug therapy ; Ovariectomy ; Rats