OBJECTIVETo assess the experimental and clinical data regarding the effects of electromagnetic fields (EMFs) on fracture non-union.

DATA SOURCESThe English language literature regarding EMFs on fracture non-union were searched using MEDLINE, Web of Science and Embase, for the period January 2006 to June 2011. The search terms were electromagnetic fields and non-union/bone marrow stem cells (BMSCs)/bone.

STUDY SELECTIONArticles were included in the review if they were related to the use of EMFs on BMSCs or bone tissue. Papers without full manuscripts available were excluded.

RESULTSThe basic and clinical research in this field, while somewhat limited, supports the insightful application of EMFs to ameliorate disability due to fracture non-union.

CONCLUSIONSFurther basic and clinical research to validate the use of EMFs in facilitating function and bone reparative processes in fracture non-union is required.

Animals ; Bone Regeneration ; physiology ; Electromagnetic Fields ; Humans

Distraction osteogenesis (DO) is widely used for bone tissue engineering technology. Immune regulations play important roles in the process of DO like other bone regeneration mechanisms. Compared with others, the immune regulation processes of DO have their distinct features. In this review, we summarized the immune-related events including changes in and effects of immune cells, immune-related cytokines, and signaling pathways at different periods in the process of DO. We aim to elucidated our understanding and unknowns about the immunomodulatory role of DO. The goal of this is to use the known knowledge to further modify existing methods of DO, and to develop novel DO strategies in our unknown areas through more detailed studies of the work we have done.
Bone Regeneration/physiology* ; Bone and Bones ; Osteogenesis/physiology* ; Osteogenesis, Distraction/methods* ; Tissue Engineering

BACKGROUNDRegenerative techniques help promote the formation of new attachment and bone filling in periodontal defects. However, the dimensions of intraosseous defects are a key determinant of periodontal regeneration outcomes. In this study, we evaluated the efficacy of use of anorganic bovine bone (ABB) graft in combination with collagen membrane (CM), to facilitate healing of noncontained (1-wall) and contained (3-wall) critical size periodontal defects.

METHODSThe study began on March 2013, and was completed on May 2014. One-wall (7 mm × 4 mm) and 3-wall (5 mm × 4 mm) intrabony periodontal defects were surgically created bilaterally in the mandibular third premolars and first molars in eight beagles. The defects were treated with ABB in combination with CM (ABB + CM group) or open flap debridement (OFD group). The animals were euthanized at 8-week postsurgery for histological analysis. Two independent Student's t-tests (1-wall [ABB + CM] vs. 1-wall [OFD] and 3-wall [ABB + CM] vs. 3-wall [OFD]) were used to assess between-group differences.

RESULTSThe mean new bone height in both 1- and 3-wall intrabony defects in the ABB + CM group was significantly greater than that in the OFD group (1-wall: 4.99 ± 0.70 mm vs. 3.01 ± 0.37 mm, P < 0.05; 3-wall: 3.11 ± 0.59 mm vs. 2.08 ± 0.24 mm, P < 0.05). The mean new cementum in 1-wall intrabony defects in the ABB + CM group was significantly greater than that in their counterparts in the OFD group (5.08 ± 0.68 mm vs. 1.16 ± 0.38 mm; P < 0.05). Likewise, only the 1-wall intrabony defect model showed a significant difference with respect to junctional epithelium between ABB + CM and OFD groups (0.67 ± 0.23 mm vs. 1.12 ± 0.28 mm, P < 0.05).

CONCLUSIONSOne-wall intrabony defects treated with ABB and CM did not show less periodontal regeneration than that in 3-wall intrabony defect. The noncontained 1-wall intrabony defect might be a more discriminative defect model for further research into periodontal regeneration.

Alveolar Bone Loss ; surgery ; Animals ; Biocompatible Materials ; therapeutic use ; Bone Regeneration ; physiology ; Bone Substitutes ; therapeutic use ; Cattle ; Dogs ; Guided Tissue Regeneration, Periodontal ; methods ; Male ; Wound Healing ; physiology

OBJECTIVETo explore the feasibility of bovine pericardium used as a material for guiding bone regeneration.

METHODS1 cm x 1 cm x 0.5 cm defects were created on both buccal sides of the mandibles of 11 dogs. One side was covered with Glutaraldehyde (GA) cross-linking bovine pericardium; no membrane covered side was used as control. The animals were sacrificed in 2 weeks, 4 weeks, 8 weeks and 16 weeks after operation to observe the repair of the bone defects.

RESULTS(1) Wounds healed well in 10 dogs. Meanwhile, wounds in dogs of 16 weeks group healed badly and severe inflammatory response was found in bovine pericardium treated area. (2) The pericardium can be maintained in vivo for 16 weeks without absorption, there were only mild inflammatory cells invading. (3) The bone defects covered with bovine pericardium repaired better than control groups significantly.

CONCLUSION(1) GA bovine pericardium have the effect on guiding bone regeneration in the repair of dog experimental bone defects and it is possible that the bovine pericardium will be used as a new kind of GBR material; (2) GA bovine pericardium has good biocompatibility.

Animals ; Biocompatible Materials ; Bone Regeneration ; physiology ; Cattle ; Dogs ; Feasibility Studies ; Male ; Mandibular Injuries ; surgery ; Pericardium ; physiology

OBJECTIVETo explore suitable scaffold material for big segmental long bone defect by studying the properties of the prepared deproteinized bone.

METHODSCancellated bone were made as 30 mm x mm x 3 mm bone blocks from inferior extremity of pig femur along bone trabecula. The deproteinized bone was prepared with an improved method. Their morphological features, components, cell compatibility, mechanical and immunological properties were investigated respectively.

RESULTSDeproteinized bone maintained natural reticular pore system. The main organic material is collagen I and inorganic composition is hydroxyapatite. It has good mechanical properties, cell adhesion rate and histocompatibility.

CONCLUSIONThis deproteinized bone can be applicable as scaffold for reparation of big segmental defect in long bone.

Animals ; Bone Regeneration ; physiology ; Bone Transplantation ; methods ; Collagen ; Hydroxyapatites ; Swine ; Tissue Engineering ; methods ; Tissue Scaffolds

OBJECTIVETo explore the effect of electroporation mediated gene therapy on bone mineral density and strength of new-formed bone in mandibular distraction gap, so as to enhance the osteogenesis and shorten the distraction term.

METHODSNew-Zealand rabbits were employed. The distraction began after 3 days of latency period at the rate of 0. 8 mm per day for 7 days. After distraction, the rabbits were randomly divided into 5 groups to receive injection in the distraction gap with recombinant plasmid 2 microg (0.1 microg/microl) pIRES-hVEGF165-hBMP2 in group A, with recombinant plasmid pIRES-hBMP2 in group B, with recombinant plasmid pIRES-hVEGF165 in group C, with pIRES in group D, and with normal saline (NS) in group E. After injection, electroporation was performed in all the groups. After 1 week, 2 weeks, 4 weeks and 8 weeks of consolidation, all the animals underwent X-ray and quantitative computed tomography (QCT). The new-formed bone in distraction gap was selected as regions of interest (ROI) to measure the bone mineral density(BMD). Then the rabbits were sacrificed and the new-formed bone samples were harvested to detect 3-point crushing strength.

RESULTSBMD of newly formed bone in group A, B and C was markedly higher than that in group D and E (P < 0.01). After 2 weeks of consolidation, BMD in group A was much higher than that in the other groups, but there was no difference between group B and C. After 4 weeks of consolidation, BMD in group A and B was markedly higher than that in group C, D and E (P < 0.01). After 8 weeks of consolidation, BMD in group A was markedly higher than that in the other groups. While the BMD was not significantly different between group B and C, but the BMD in group B and C was higher than that in group D and E (P < 0.01). After 4 weeks of consolidation, the 3-point crushing strength of newly formed bone in group A was markedly higher than that in group B,C, D and E (P < 0.01), which was still the same after 8 weeks of consolidation. And the crushing strength in group B was higher than that in group C, D and E (P < 0. 05).

CONCLUSIONSElectroporation-mediated transfection of recombinant plasmid pIRES-hVEGF165-hBMP2 could greatly enhance osteogenesis and calcification. A combination of VEGF and BMP may promote osteogenesis and angiogenesis simultaneously, so as to magnify the effect of each growth factor, resulting a synergetic effect.

Animals ; Bone Density ; Bone Regeneration ; Electroporation ; Genetic Therapy ; Mandible ; physiology ; surgery ; Osteogenesis, Distraction ; Rabbits

OBJECTIVETo evaluate the quality of the alveolar ridge augmented by Ti-Ni shape memory alloy (Ti-Ni SMA) distractor.

METHODSAll of the mandibular premolars and the first molars were extracted from 12 adult mongrel canines. One month later, box-shaped osteotomy was carried out in the left mandibles and Ti-Ni SMA distractors were imbedded. The right sides served as blank control. The canines were killed 3 or 6 months later and specimens were taken from corresponding area of the experiment sides and the control. Bone mineral density and biomechanical function were measured.

RESULTSBone mineral density, ultimate compressive strength and Young's Modules of the augmented ridge were lower than the blank control three months after distraction. But the indexes increased and showed no significant difference with the control six months after distraction.

CONCLUSIONSThe canines mandibular posterior alveolar ridge could be augmented by distraction osteogenesis using Ti-Ni SMA distractor, and the new bone is strong enough for implant placement.

Alveolar Ridge Augmentation ; methods ; Animals ; Bone Density ; Bone Regeneration ; physiology ; Compressive Strength ; Dogs ; Male ; Mandible ; physiology ; Nickel ; Osteogenesis, Distraction ; Titanium

OBJECTIVETo investigate the effect on intramuscular connective tissue and passive range of joint motion by the stress produced in limb lengthening.

METHODSAn animal model of limb lengthening was established in the tibia of rabbits. Distraction was initiated at a rate of 1 mm/d and 2 mm/d in two steps respectively, and both proceeded until 10% and 20% of the tibia length was achieved. Muscle samples were harvested at the time when distraction ended and at the 4th week of consolidation after the distraction. Scanning electron microscope was applied to observe the morphological changes of the perimysium. The goniometer, which we made for this study, was used to measure the passive range of joint motion.

RESULTSThe collagen fibers were partitioned in bundles, crimped and interconnected closely and orderly. In the regime of 1 mm/d distraction with 10% lengthening, no apparent changes of the collagen fiber and passive range of joint motion was demonstrated. When tibia was increased to 20%, the crimped fibers showed a tendency of being straightened while the passive range of joint motion was reduced. The findings remained the same at the 4th week of consolidation. In the regime of 2 mm/d distraction with 10% lengthening, the crimped structure of the collagen fibers in the perimysium disappeared and the fibers were almost straightened. Additionally, the interconnection of the collagen fibers became loosened and interstice was presented among the fibers. At the 4th week of consolidation, the restoration to the original crimped structure was not completed. When the lengthening ratio was increased to 20%, the collagen fibers were straightened completely. This condition remained unchanged throughout all 4 weeks. The passive range of joint motion was reduced dramatically in the regime of 2 mm/d distraction.

CONCLUSIONThe ultrastructure of perimysium and the passive range of joint motion in the regime of 1mm/d lengthening shows the condition closest to the normal ones. The regime of 2 mm/d lengthening may cause an apparent change in the ultrastructure of perimysium and passive range of joint motion.

Animals ; Bone Lengthening ; Collagen ; ultrastructure ; Connective Tissue ; injuries ; physiology ; ultrastructure ; Male ; Osteogenesis, Distraction ; Rabbits ; Range of Motion, Articular ; physiology ; Regeneration ; physiology

Bone maintenance theory considers that the external load is the direct stimulating source of the bone remodeling. In this article, the method of experimental observation of self-repairing process of the bone defect and related results are introduced. Firstly, a hole was drilled in the rabbit thighbone so that the continuity of the bone was changed. Then bone defect model was established, and the thighbone data were obtained by using CT scanning, and the self-repairing process of bone defects caused by growth factor were observed and analyzed by MIMICS software. Finally, the relationship between volume changes of sclerotin was established, and scientific bases were provided for introducing the bionic topology optimization method to the remodeling process. The experimental results showed that the self-repairing of the each layer sclerotin of the young rabbits was faster than that of the adult ones under the same condition. In addition, the volume always changes contrarily between the spongy bone and enamel bone during the self-repairing process of bone defect.
Animals ; Bone Regeneration ; physiology ; Female ; Femoral Fractures ; physiopathology ; Femur ; injuries ; Fracture Healing ; physiology ; Male ; Osteogenesis ; physiology ; Rabbits

After the articular cartilage injury, the metabolic level is increased during the progressive degeneration, the chondrocytes secrete a variety of inflammatory factors, and the original cell phenotype is gradually changed. For a long time, a large number of researchers have done a lot of researches to promote anabolism of chondrocytes and to maintain the stability of chondrocyte phenotype. There are many molecular signaling pathways involved in the process of promoting cartilage repair. This review focuses on the key signaling molecules in articular cartilage repair, such as transforming growth factor-beta and bone morphogenetic protein, and reveals their roles in the process of cartilage injury and repair, so that researchers in related fields can understand the molecular mechanism of cartilage injury and repair widely and deeply. Based on this, they may find promising targets and biological methods for the treatment of cartilage injury.
Bone Morphogenetic Proteins ; physiology ; Cartilage, Articular ; growth & development ; injuries ; Chondrocytes ; physiology ; Humans ; Regeneration ; Signal Transduction ; Transforming Growth Factor beta ; physiology