Bone Defects In Group Research Articles

Characterization of the Angiogenic and Proteomic Features of Circulating Exosomes in a Canine Mandibular Model of Distraction Osteogenesis.

Distraction osteogenesis (DO) represents a highly effective method for addressing significant bone defects; however, it necessitates a long treatment period. Exosomes are key mediators of intercellular communication. To investigate their role in the angiogenesis and osteogenesis of DO, we established a canine mandibular DO model with a bone defect (BD) group as the control. Higher levels of angiogenesis were observed in the regenerating tissue from the DO group compared to those from the BD group, accompanied by earlier osteogenesis. Proteomic analysis was performed on circulating exosomes at different phases of the DO using a data-independent acquisition method. Data are available via ProteomeXchange with the identifier PXD050531. The results indicated specific alterations in circulating exosome proteins at different phases of DO, reflecting the regenerative activities in the corresponding tissues. Notably, fibronectin 1 (FN1), thrombospondin 1 (THBS1), and transferrin receptor (TFRC) emerged as potential candidate proteins related to the angiogenic response in DO. Further cellular experiments validated the potential of DO-associated circulating exosomes to promote angiogenesis in endothelial cells. Collectively, these data reveal previously unknown mechanisms that may underlie the efficacy of DO and suggest that exosome-derived proteins may be useful as therapeutic targets for strategies designed to improve DO-related angiogenesis and bone regeneration.

Experimental study on the causes of spontaneous osteogenesis of Masquelet technique induced membrane

To investigate the causes of spontaneous osteogenesis of Masquelet technique induced membrane. Forty-two male Sprague-Dawley rats aged 7-9 weeks were selected to establish a critical-sized bone defect of the right middle femur model. Then the rats were randomly divided into 4 groups, with 12 rats in groups A-C and 6 rats in group D. The bone defects in groups A-C were filled with vancomycin-loaded polymethyl methacrylate bone cement spacers. Then the Kirschner wires were used for intramedullary fixation in groups A and B, and the bone cement was used to connect the bone cement spacers and the bone ends in group B. The steel plate was used to fixation in group C. The bone defect in group D was only fixed with steel plate as a blank control group. The general condition was observed after operation. At 5 weeks after operation, 6 rats in groups A-C were selected for STRO-1 immunohistochemical staining to observe the content of mesenchyme stem cells (MSCs) in the induced membrane (STRO-1 + cells). At 12 weeks after operation, the remaining rats in groups A-D were taken for X-ray observation, gross observation, and histological observation (HE, safranin O-green staining) to observe the spontaneous osteogenesis of the membrane. All rats in the 4 groups survived until the completion of the experiment. At 5 weeks after operation, the immunohistochemical staining showed that group B was negative, while the contents of MSCs in the induced membrane in groups A and C were 14.20%±1.92% and 5.00%±0.71%, respectively, with a significant difference ( P<0.05). At 12 weeks after operation, group A showed that the new bone formed at the osteotomy site and growth towards the center of the bone defect, with an average length of 3.1 mm on one side; and the presence of bone, cartilage lesions, fibers, and a small amount of neovascularization were observed in the induced membrane. Group C only had a small amount of new bone at the osteotomy site, and a small amount of neovascularization in the induced membrane. Groups B and D did not have any new bone, but bone resorption or atrophy at the osteotomy site. Although the Masquelet technique induced membrane has osteogenesis, the key factor for the spontaneous osteogenesis is the bone marrow overflow from the bone marrow cavity providing MSCs. The spontaneous osteogenesis of the induced membrane belongs to endochondral ossification.

Influence of zoledronic acid and low-intensity laser on collagen fibers during the bone repair process.

To evaluate collagen fibers during the bone repair process in critical defects created in the tibias of rats, treated with zoledronic acid (AZ) associated with low-level laser therapy (LLLT). Ten rats were distributed according to treatment: group 1) saline solution; group 2) LLLT; group 3) AZ; group 4) AZ and LLLT. AZ was administered at the dose of 0.035 mg/kg at fortnightly intervals over eight weeks. Next, 2-mm bone defects were created in the tibias of all animals. The bone defects in groups 2 and 4 were irradiated LLLT in the immediate postoperative period. After periods 14 and 28 of application, the animals were euthanized, and birefringence analysis was performed. Approximately 90% of the total area was occupied by collagen fibers within the red color spectrum, this area being statistically larger in relation to the area occupied by collagen fibers within the green and yellow spectrum, in the four groups. Over the 14-day period, there was no statistically significant difference between the groups. In the 28-day period, group 2 (14.02 ± 15.9%) was superior in quantifying green birefringent fibers compared to group 1 (3.06 ± 3.24%), with p = 0.009. LLLT associated with ZA is effective in stimulating the neoformation of collagen fibers. The LLLT group without the association with ZA showed a greater amount of immature and less organized matrix over a period of 28 days.

Superparamagnetic Iron Oxide Nanoparticles Activate Mitogen-Activated Protein Kinase Pathway and Promote Bone Marrow Derived Mesenchymal Stem Cells Homing to Repair Bone Defects in Rats with Osteosarcoma

Superparamagnetic iron oxide nanoparticles exert its action on repairing bone defects. Whether they have the same repair effect on osteosarcoma bone defects and the mechanism is worth studying. The bone defect model of osteosarcoma rats was constructed and divided into bone defect group, positive control group, low-dose nano-group, medium-dose nano-group, high-dose nano-group, and blocker group followed by analysis of new bone formation, bone marrow derived mesenchymal stem cells (BMSC) homing, bone morphogenetic protein-2 (BMP-2), Collagen I, and Phosphorylated 44/42 mitogen-activated protein kinase (p44/42) protein expression. The proportion of new bone formation in positive control group and different dose groups was higher than bone defect group and blocker group (P &lt;0.05). The positive control group had rich collagen fibers at repair site, which were more cellulose and neatly arranged. Low-dose group was more collagenous than positive control group. There was no new bone formation in the bone defect group and the blocking agent group and no Y chromosome positive cells were found in the blood vessel wall. New bone formation was seen in the positive control group and the nano-group and the number of blood vessels was abundant and rich in Y chromosome positive cells. Compared with the other two groups, positive control group and nano-group had higher BMP-2, Collagen I expression (P &lt;0.05), and lower p44/42 expression (P &lt;0.05). The p-mitogen-activated protein kinase (MAPK) levels were the lowest in bone defect group, blocker group, and positive control group, while nano-group was opposite. Superparamagnetic iron oxide nanoparticles can repair bone defects in osteosarcoma rats, and the mechanism of action is mainly related to the activation of the MAPK pathway.

Evaluating the Effect of Jointly Administering Synthetic Graft and Ankaferd Blood Stopper for Bone Recovery in Created Bone Deformities in Diabetic Rats

Objective: In the present paper, it was purposed to examine the late impacts of bone tissue recoveries in combination with synthetic grafts and Ankaferd Blood Stopper (ABS), which are effective in bone wound healing in diabetic rats.&#x0D; Methods: A total of 64 Wistar albino male rats with diabetes were studied. A bone deformity was generated in the calvarium of diabetic rats. These diabetic rats are divided into 4 different groups. Only saline was applied to the bone defect in group 1, Beta-tricalcium phosphate (β-TCP) graft was administered to Group 2, ABS solution to Group 3, (β-TCP+ABS) were administered to group 4. Eight rats from each group were sacrificed on the 28th day and another 8 rats on the 56th day. Immunohistochemical, histopathological, and Dual Energy X-ray Absorptiometry (DEXA) analyzes of the obtained samples were made.&#x0D; Results: In histopathological measurements, osteoblastic activity and bone regeneration were considerably higher in the group treated with group 2 and group 4 when compared to the control group on the 28th and 56th day (p˂ .05). Western blotting findings showed that the osteopontin (OP) and osteonectin (ON) expression at 28th day increased dramatically in the treated with group 4. DEXA analyzes revealed that BMC values in groups treated with group 2, group 3 and group 4 on 28th day were considerably higher than the control group (p˂ .05).&#x0D; Conclusion: We can believe and conclude that ABS in combination with a β-TCP bone graft will produce more successful outcomes on wound&#x0D; healing and formation of new bone in diabetic rats.

The optimization of ligature/bone defect-induced periodontitis model in rats.

The destruction of alveolar bone is a crucial manifestation of severe chronic periodontitis, which stem cell-based bioengineered therapies are expected to cure. Therefore, a cost-effective, reproducible, quantifiability and easier to administrate animal model that mimics human periodontitis is of great importance for further endeavor. In this study, we created periodontitis rat models in silk ligation group, bone defect group and bone defect/silk ligation group, respectively. Obvious periodontal inflammation but slight alveolar bone resorption was observed in the ligation group, while surgical trauma was not robust enough to continually worsen the constructed bone defect area in the bone defect group. In the bone defect/ligature group, significant and stable periodontal inflammation was the most enduring with similar evolving pathological patterns of human periodontitis. It also exhibited enhanced clinical similarity and confirmed its superiority in quantitativeness. The present rat model is the first study to reproduce a pathological process similar to human periodontitis with reliable stability and repeatability, manifesting a priority to previous methods. Day 9-12 is the best time for reproducing severe periodontitis syndromes with vertical bone resorption in this model.

Effects of different intensities of intermittent pneumatic soft-tissue compression on bone defect repair

BackgroundTo estimate the effects of different intensities of intermittent pneumatic soft-tissue compression on bone defect repair in an animal model.MethodsFive mm radial bone defect in length was made in 64 mature New Zealand rabbits and all animals randomly assigned into four groups: Group A (control group without compression), Group B (5–7 kPa intensity), Group C (8–10 kPa intensity) and Group D (11–13 kPa intensity). On the fourth day after surgery, their legs were intermittently pneumatic compressed for 4 weeks. The stimulation lasted 30 min every day and the frequency of compression was 15 Hz. New bone formation in 4 groups was evaluated by gross observation, X-ray, Micro-CT, and histological staining at 2 and 4 weeks after surgery.ResultThere was more new bony callus in the bone defect in group C than in other groups by gross observation and X-ray radiography at 2 and 4 weeks. The Micro-CT results showed more new bony callus, bone trabecula and higher bone mineral density in group C. Fluorescent labeling results showed the speed of new bone formation in Group C was faster than that in other groups, among which the control group had the slowest speed of new bone formation. The result of histology had shown that the trabeculae in bone callus in group C had a regular form, the trabeculae were wide and had a more become osteoblast around them.ConclusionThe intermittent pneumatic soft-tissue compression can accelerate new bone formation of bone defects and the optimal intensity is 8–10 kPa for repairing the rabbit radial bone defect.

COMBINED USE OF HYALURONIC ACID WITH NANO-BIOACTIVE GLASS ENHANCED BIOCEMENT BASED SILICATE STIMULATED BONE REGENERATIVE CAPACITY IN TIBIAL BONE DEFECTS OF RABBITS: IN-VIVO STUDY

An ideal biomaterial for bone regeneration is a longstanding quest nowadays. This study aimed to evaluate the osteogenic potentiality of nano-bioactive glass enhanced biocement based silicate with or without hyaluronic acid seeded in rabbits’ tibial bone defects. For this, 24 male rabbits with two 5 mm defects (1 defect per tibia) were divided into three equal groups. Among the predefined three groups, for the rabbits of group 1(control) bone defects were left untreated while for the members of group 2 defects received nano-bioactive glass enhanced biocement based silicate cement, and group 3 defects received nano-bioactive glass cement mixed with hyaluronic acid. Animals of each group were divided equally for euthanization after 3 and 6 weeks. Bone specimens were processed and examined histologically with histomorphometrically analysis of new bone area percentage. The bone defects in group 3 showed significantly improved osseous healing histologically as compared to the group 1&amp;2. The morphometric analysis also revealed a significant increase in the new bone area percentage in group 3 as compared to the group 1 and 2 (P &lt; 0.05). The results of the present study can be concluded that bone defects could be treated with nano-bioactive glass and hyaluronic acid cement. Although, nano-bioactive glass alone was capable of bone regeneration the combination of both had significant regenerative capacity.

Bone healing in critically sized defects in rat calvaria, transplanted with chitosan alone, or associated with collagen and / or chondroitin sulfate:histological and histomorphometric pilot study

Background: Chitosan is a natural biopolymer that has gained a special interest in bone regeneration in recent years. Objective: The objective of this study is to show the bone formation obtained following a transplantation of sponges of chitosan alone, chitosan combined with chondroitin sulfate or chitosan combined with chondroitin sulfate and collagen, in rat critical calvarial bone defects. Material and Methods: 12 Wistar rats were divided into 4 groups of 3 rats each. Critically sized bone defects were made in calvaria, and grafted by sponges of:collagen / chitosan / chondroitin (group 1), chitosan (group 2), chitosan / chondroitin sulfate (group3). Bone defects of group 4 remained empty for control. The animals were sacrificed 12 weeks after the surgery. Results: Histological analysis showed the formation of lamellar bone in the chitosan group. In the chitosan / chondroitin sulfate group, formation of a less mature bone than that of the chitosan group was also observed. However, the least bone formation was observed in the collagen / chitosan / chondroitin sulfate group. Histological sections showed the presence of fibrous tissue. The results for this group are similar to the control group. In groups 2 and 3, the materials appear completely resorbed while in group 1 the resorption of the matrix was incomplete. Conclusion: Despite the size of the sample, this study has shown that chitosan alone or in combination with chondroitin sulfate promotes bone formation. On the other hand, the combination chitosan / chondroitin sulfate / collagen showed a negative result.

In Vitro Efficacy of Three Different Nonsurgical Implant Surface Decontamination Methods in Three Different Defect Configurations.

Assessment of in vitro efficacy of three different nonsurgical implant surface decontamination methods in three peri-implant bone defect simulation models. A total of 180 implants were allocated to differently angulated (30, 60, and 90 degrees) peri-implant bone defect resin models, each covered by a mucosa mask. All implants were stained with indelible red color and assigned to one of the three defect models. In each simulated bone defect group, 20 implants were decontaminated for 2 minutes with a curette (CUR), sonic scaler (SOSC), or air-powder abrasion device (APA) with glycine powder. Photos were taken from both sides of each implant to measure the percentage of uncleaned implant surface area. Scanning electron microscopy (SEM) was used to assess the implant surface for morphologic damage. Among the three defect angulations, a significantly different cleaning efficacy (P < .001) for each treatment method was found (30 degrees: CUR [67.33%], SOSC [62.70%], APA [39.33%]; 60 degrees: CUR [61.59%], SOSC [54.31%], APA [23.91%]; 90 degrees: CUR [66.82%], SOSC [55.77%], APA [28.03%]). SEM did not show any considerable surface damage after APA treatment in comparison with after CUR or SOSC. Air-powder abrasion proved to be the most efficient nonsurgical treatment device for each type of defect in this in vitro model with the least noticeable surface change. No decontamination method resulted in complete cleaning of the color remnants on the implant surface.

Optimizing the Fracture Repair Mouse Model by Using Different Sizes of Femoral Defects

Although mouse models are crucial in orthopedic studies, no study has explored the bone healing process in mice through continuous imaging. Thus, we optimized a mouse model for femoral defect by continually monitoring the bone healing process of different‐sized femoral defects. We observe bone healing images and quantify the trabecular bone value up to 1 month after surgery. In the 0.3‐mm group, significant bone bridge formation and spongy bone trabeculae were found on the day 14 after the defect operation. The bone healed on day 21 with the formation of external callus and internal callus structures and transformed to a remodeled compact bone on day 28. In the 1‐mm group, bone bridge formation occurred on day 21 after surgery. Moreover, bone healing was observed on day 28 with the formation of external callus and internal callus structures. Mice in the 1.5‐mm group were prone to fracture during feeding after bone defect surgery. The fluorescent staining results of osterix and cathepsin K also revealed that the bone formation process in the 0.3‐mm group was faster than that in the 1‐mm group. This study optimized a bone healing mouse model that can be applied for developing new strategies for accelerating bone healing.Support or Funding InformationDuring the study period, the authors received funding support from the Ministry of Science and Technology, Taiwan (grant numbers MOST 107‐2314‐B‐182A‐036‐MY3 and MOST 108‐2320‐B‐182A‐020 ‐MY3), and the Chang Gung Memorial Hospital (grant numbers CRRPG3H1311, CRRPG3H1312, CRRPG3H1313, CMRPG3F2011, CMRPG3F2012, CMRPG3F2013). The funders had no role in study design, data collection, data interpretation and analysis, decision to publish, or preparation of the manuscript.Continuous observation of the bone healing process in the 0.3‐mm bone defect group of the mouse femoral bone.Images of 3D micro‐computed tomography (CT) angiography as well as hematoxylin and eosin (H&amp;E)‐stained and Safranin O (SFO)‐stained histopathological slides. Immunofluorescence staining of osterix and cathepsin K indicates osteoblast and osteoclast signals, respectively.Figure 1

Study on repairing canine mandibular defect with porous Mg-Sr alloy combined with Mg-Sr alloy membrane.

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 < 0.05). At 12 weeks, the bone volume fraction of group A was higher than that of group B (P < 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.

LncRNA Urothelial Carcinoma-Associated 1 (UCA1) Regulates Rat Bone Marrow Mesenchymal Stem Cell Differentiation and Promotes Repair of Bone Defects

Bone marrow mesenchymal stem cells (BMSCs) have characteristics of self-renewal and multidirectional differentiation. LncRNA UCA1 regulates BMSCs differentiation. Whether LncRNA UCA1 plays a role in bone defects remains unclear. BMSCs were randomly divided into control group, radiation group (6Gy), radiation + UCA1 group followed by analysis of the expression of LncRNA UCA1, RUNX2 and OPN by real time PCR, BMSCs proliferation by MTT assay as well as ALP activity. Healthy Sprague-Dawley rats were randomly divided into control group; bone defect group; UCA1 group, in which UCA1-transfected BMSCs were infused into bone defect rats followed by analysis of bone mineral density, ALP activity as well as the formation of type II collagen by ELISA. LncRNA UCA1 expression was significantly decreased in BMSCs of irradiated group, with decreased BMSCs proliferation, reduced expression of RUNX2 and OPN as well as decreased ALP activity (P &lt; 0.05). Transfection of UCA1 significantly up-regulated LncRNA UCA1 expression in BMSCs, promoted BMSCs proliferation, increased the expression of RUNX2 and OPN, and the activity of ALP (P &lt; 0.05). In addition, UCA1 promoted bone mineral density, increased ALP activity and type II collagen formation in rats with bone defect. LncRNA UCA1 promotes osteogenic differentiation of BMSCs, and targeting it might be a novel approach to promote bone remodeling at the bone defect site.

Acceleration of Bone Fracture Healing through the Use of Natural Bovine Hydroxyapatite Implant on Bone Defect Animal Model

Bone is an important organ for supports the body that stores reserve of calcium, phosphorus, and other minerals. In fracture conditions where bleeding, soft tissue edema, nerve damage, and blood vessels around the bone damage happen, they can cause the mobilization of these minerals in the surrounding tissue. One of the efforts made in the treatment of these fractures is reconnection, in which it works by filling of bone defect with a matrix and administration of anti-infection. Biomaterial filling in defective bone is thought to accelerate the healing process of bone fracture and prevent osteomyelitis. For this reason, this study evaluates the acceleration of bone fracture healing using natural hydroxyapatite (NHA) bone filler in rabbits with bone defect model. Fracture modeling was performed by surgical technique and drilling of bones with a 4.2 mm diameter to form a defect in the rabbit femur. Bone implant contained bovine hydroxyapatite-gelatin-glutaraldehyde (BHA implant) or bovine hydroxyapatite-gelatin-glutaraldehyde-gentamicin (BHA-GEN implant) that was inserted in bone defects. 27 rabbits were divided into 3 groups: the control group who had bone defect, the bone defect group was given BHA implant and the bone defect group was given BHA-GEN implant. Observation of osteoclast, osteoblast, osteocyte, BALP level, and bone morphological integrity was carried out on the 14th, 28th, and 42nd days after surgery. Histological observation of rabbit femur showed a significant difference on the number of osteoclast, osteoblast and osteocyte in all three groups. The BALP level also showed a significant difference in the group given the natural BHA bone implant compared to the control group on day 14 (p = 0.0361). Based on the result of the X-ray, there was also a better integration of rabbit femur bone in groups with the use of BHA or BHA-GEN bone implant. Thus, it can be concluded that the use of a natural BHA implant can accelerate the process of bone repair in the fracture of rabbit femur. In addition, BHA implants were compatible as a matrix for supporting the bone cell growth.

P17. Effect of bone marrow mesenchymal stem cell combined with concentrate growth factor (CGF) on postmenopausal bone defects

BACKGROUND CONTEXT Concentrate growth factor (CGF) is a third-generation platelet concentrate that releases a variety of bioactive substances and plays a good role in promoting tissue healing. Bone marrow mesenchymal stem cell (BMSCs) transplantation has been used to treat osteoporosis. However, effect of bone marrow mesenchymal stem cell combined with concentrate growth factor (CGF) on postmenopausal bone defects remains elusive. PURPOSE To observe the effect of BMSCs combined with concentrate growth factor (CGF) on postmenopausal bone defects and to explore related mechanisms. METHODS A total of 50 Sprague-Dawley rats were randomly divided into A (SHAM), B (model), C (CGF), D (BMSCs) and E (CGF + BMSCs) group. Group A did not remove ovaries and L6 vertebral body was created a 3mm × 3mm × 3mm large bone defect. The B, C, D, E groups experimented ovariectomy and then L6 vertebral body created a 3mm × 3mm × 3mm large bone defect model. C and E groups were filled with a suitable concentrate growth factor (CGF). D and E groups were injected Brdu-labeled BMSCs through tail vein. After 4 and 8 weeks of treatment, the vertebral body of the bone defect was taken for micro-CT and the parameters such as TV/BV, Tb.N, Tb.Th, Tb.Sp and vBMD. HE staining of vertebral bodies were to observe the morphology of bone tissue. Brdu immunohistochemistry and Brdu immunofluorescence were used to detect stem cell homing. Immunofluorescence was used to detect the expression of VEGF, BMP2 and NF-KB. Runx2, CTSK and VEGF NF-KB were detected by PCR and Western-bolt. RESULTS The Brdu labeling rate of BMSCs was up to 95.43%. After 4 and 8 weeks of intervention, bone formation in bone defects of groups C, D and E were significantly higher than that of group B. TV/BV, Tb.N, Tb.h and vBMD of C, D group were significantly higher than the model group, and the Tb.Sp of group B was higher than that of group C, D and E. The morphology of bone tissue in groups C, D and E was better than that in model group. The CGF combined BMSCs group showed a good synergistic effect, and their bone micro-structure and bone histomorphology were better than that of CGF or BMSCs alone. In the D and E groups, Brdu immunofluorescence and immunohistochemistry were detected in the bone defect. Compared with the model group, the expression of VEGF, BMP2 and NF-KB was more obvious in the bone defects of group C, D and E. Compared with the SHAM group, the expression of CTSK mRNA and protein in the model group was significantly up-regulated (P CONCLUSIONS BMSCs combined with CGF can effectively treat postmenopausal bone defects, which may promote bone defect repair by regulating inflammation, bone formation and angiogenesis. FDA DEVICE/DRUG STATUS This abstract does not discuss or include any applicable devices or drugs.

Repair of rabbit segmental radial defect by a compound of adipose-derived stem cells with the ink-jet all-core structure composite scaffold

Objective To repair segmental radial defect by adipose-derived stem cells (ADSCs) combined with a porous wrapped-core structure composite scaffold composed of poly(lactic-co-glycolic acid)/β-tricalciumphosphate (PLGA/β-TCP) skeleton ink-jet wrapped with Type I collagen. Methods 1.5 cm segmental radial defects were created in 36 rabbits, then the combination of ADSCs and ink-jet all-core structure composite scaffold (group A) and the combination of ADSCs and PLGA/β-TCP skeleton (group B) were transplanted into the untreated radial defect as blank control group (group C). 12, 24, 48 weeks after implantation, animals were sacrificed and the constructs were harvested and analyzed. Results Imaging, gross observation and histological examination showed that the bone defect in group A was completely repaired, which was significantly superior to the partial repair in group B and not in group C. In group A, synosteosis was formed between the two ends of the critical-size bone defect 12 weeks postoperation; bone integrity was almost finished and bone marrow started a trend of recanalization 24 weeks postoperation; bone defect repair was completely repaired and bone marrow was recanalized 48 weeks later. As compared with group C at 12, 24, and 48 h [(0.58±1.00), (0.58±1.00) and (0.58±1.00) points], Lane-Sandhu indicated that the new bone forming in group B [(1.22±0.59), (4.89±0.8), and (6.18±0.71) points was significantly increased (t=13.500, P<0.05); As compared with group B, the new bone forming in group A [(5.11±0.70), (8.31±0.48), and (12.98±0.60) points] was significantly increased (t=18.000, P<0.05). Conclusion The combination of ADSCs and ink-jet all-core structure composite scaffold exhibits a favorable osteogenesis, biocompatibility and biodegradability during the repair of autologous segmental radial defect model, which clearly demonstrates promise for the treatment of bone defects through tissue engineering. Key words: Ink-jet all-core structure composite scaffold; Adipose-derived stem cells; Tissue engineering; Bone repair

Effect of low-level laser therapy and zoledronic acid on bone repair process.

This study aimed to evaluate, through histomorphometric analysis, the bone repair process in the tibia of rats treated with zoledronic acid and submitted to 808-nm low-level laser therapy (LLLT) by using arsenide aluminum gallium laser. For this purpose, 20 rats were used and distributed according to treatment: group 1-saline administration; group 2-treated with LLLT; group 3-treated with zoledronic acid; and group 4-treated with zoledronic acid and LLLT. The zoledronic acid was administered at a dose of 0.035mg/kg every 2weeks for 8weeks. Subsequently, bone defects of 2mm were prepared in the tibias of all groups. The bone defects in groups 2 and 4 were irradiated with LLLT in the immediate post-operative period. After 14 and 28days of application, the animals were submitted and euthanized for histomorphometric analysis. The results were submitted to statistical analysis (α = 5%), and the intragroup comparison was performed using the t test. On the other hand, for intergroup comparison, the ANOVA test was performed, and to the groups presenting statistically significant difference, the Student-Newman-Keuls test was used. In intergroup comparison, group 1 (mean ± SD= 45.2 ± 18.56%) showed a lower bone formation compared with groups 2 (64.13 ± 3.51%) (p = 0.358) and 4 (15.2 ± 78.22%) (p = 0.049), at the 14-day period. Group 3 (20.99 ± 7.42%) also presented a lower amount of neoformed bone tissue, with statistically significant difference when compared with groups 1 (p = 0.002), 2, and 4 (p ≤ 0,001). After 28days, group 1 presented a lower amount of neoformed bone tissue compared with the other groups, with p = 0.020. Thus, it was concluded that LLLT associated with zoledronic acid is effective for stimulating bone formation in surgically created defects in rats, at the periods studied.

Study on the bone regeneration induced by advanced-platelet-rich fibrin and β- tricalcium phosphate composite

To explore the osteogenesis effect of advanced-platelet-rich fibrin (A-PRF) and β-tricalcium phosphate (β-TCP) composite. Thirty-two healthy female New Zealand rabbits were randomly selected. A-PRF was prepared by collecting blood from middle auricular artery. Rabbits were randomly divided into 6 groups: groups A, B, C, D, and E (6 rabbits in each group) and group F (2 rabbits). Bone defects (6 mm in diameter, 8 mm in depth) were drilled into femur condyle of each rabbit's both back legs. Then A-PRF and β-TCP composites manufactured by different proportion were planted into bone defects of group A (1∶1), group B (2∶1), group C (4∶1), group D (1∶2) and group E (1∶4) ( V/ V). The bone defect was not repaired in group F. The specimens were collected at 8 and at 12 weeks after operation. Then gross observation, X-ray examination, Micro-CT examination, and biomechanical test were performed. The bone volume/total volume (BV/TV), trabecular number (Tb.N), trabecular thickness (Tb.Th), and trabecular spacing (Tb.Sp), compressive strength, and modulus of elasticity were calculated. The gross observation and X-ray examination showed that the osteogenesis effect at 12 weeks was better than that at 8 weeks. At the same time point, the repair of bone defect and the formation of new bone in group B were better than those in other groups. Micro-CT examination showed that the trabeculae of new bone in group B were the most and the trabeculae arranged closely at 8 and 12 weeks. Besides there were significant differences in BV/TV, Tb.N, and Tb.Sp between group B and the other groups ( P<0.05). There were significant differences in Tb.N and Tb.Th in group B, BV/TV and Tb.Sp in group C, Tb.Sp in group D between 8 weeks and 12 weeks ( P<0.05). Biomechanical tests showed that the compression strength and elastic modulus of group B were the highest, and the compression strength and elastic modulus of group C were the lowest at 8 and at 12 weeks, showing significant differences ( P<0.05). There were significant differences in compression strength and elastic modulus of each group between 8 weeks and 12 weeks ( P<0.05). The A-PRF and β-TCP composite can repair femoral condylar defects in rabbits, and the osteogenesis is better in proportion of 2∶1.

Short-term results of the management of severe bone defects in primary TKA with cement and K-wires

ObjectiveThe aim of this study was to evaluate the results of cement and kirschner wire augmentation in the management of bone defects in primary TKA. MethodsTwenty-four patients (10 male, 14 female; mean age: 66 years) with uncontained unilateral medial tibial articular bone defect who underwent TKA between 2010 and 2014 were included in this study. The average follow up time was 33.7 months. Patients were divided to two groups according to the size of the bone defect (Group 1: <20 mm, Group 2: >20 mm). The tibial defect was reconstructed by using cement and K-wires. We used posterior stabilized prosthesis with no tibial stem extension. ResultsThe preoperative and postoperative lower extremity mechanical axis in Group I was in a mean varus of 15° and mean varus of 3°, respectively (p < 0.001). The preoperative and postoperative lower extremity mechanical axis in Group 2 was in a mean varus of 20° and mean varus of 3° respectively in Group II (p < 0.001). None of the patients neither suffered from failure of K-wires nor loosening. ConclusionThe use of cement and K-wires augmentation appears to be a simple and cost-effective treatment option for the tibial bone defects in primary TKA. Level of evidenceLevel IV, Therapeutic study.

Evaluation of poly(lactide-co-glycolide)/hydroxyapatite nanofibres for reconstruction of critical-sized segmental bone defects in a canine model

The treatment of segmental bone defects is a challenging problem for both human and veterinary medicine. Various biomaterials have successfully been used to treat these defects. Numerous recent in vitro studies have shown the potential of treating bone tissues using poly(lactide-co-glycolide)/hydroxyapatite (PLGA/HAp) nanofibres, which are fabricated using electrospinning. The purpose of this study was to evaluate the possibility of using a bone scaffold of PLGA/HAp nanofibres to repair critical-sized segmental bone defects in a canine model. The experimental bone defects were created in a 15 mm-long region of the radius. The area of the defect in each of 10 Beagle dogs was treated with a transplant of PLGA/HAp nanofibres in gelatin. The control group consisted of five Beagle dogs with similar defect sites that were not treated. Radiological and histological examinations were used to monitor the response of PLGA/HAp nanofibre-treated canine bone. Micro-computed tomography (micro-CT) was used to evaluate bone mass parameters 18 weeks after treatment in the experimental bone defect group. Our radiological and histological results showed that the PLGA/HAp nanofibre is biodegradable in the defect sites and replaces new bone tissue. Micro-CT showed that bone mass parameters were significantly (P &amp;lt; 0.05) increased in the critical-sized segmental bone defects of PLGA/HAp nanofibre-treated animals as compared to those of untreated animals. Based on these results, we conclude that PLGA/HAp nanofibres may be used as a bone scaffold biomaterial in canines.