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Objective. To study the effect of hyaluronic acid (HA) on local anaesthetic chondrotoxicity in vitro. Methods. Chondrocytes were harvested from bovine femoral condyle cartilage and isolated using collagenase-containing media. At 24 hours after seeding 15 000 cells per well onto a 96-well plate, chondrocytes were treated with media (DMEM/F12 + ITS), PBS, 1:1 lidocaine (2%):PBS, 1:1 bupivacaine (0.5%):PBS, 1:1 lidocaine (2%):HA, 1:1 bupivacaine (0. 5%):HA, or 1:1 HA:PBS for one hour. Following treatment, groups had conditions removed and 24-hour incubation. Cell viability was assessed using PrestoBlue and confirmed visually using fluorescence microscopy. Results. Media-treated groups had a mean of 1.55×10. 4. cells/well (. sem. 783). All treated cells showed statistically significant reduced viability when compared with media alone (all p < 0.003). Cells treated with bupivacaine + HA (6.70×10. 3. cells/well (. sem. 1.10×10. 3. )) survived significantly more than bupivacaine (2.44×10. 3. cells/well (. sem . 830)) (p < 0.001). Lidocaine + HA (1.45×10. 3. cells/well (. sem. 596)) was not significantly more cytotoxic than lidocaine (2.24×10. 3. cells/well (. sem. 341)) (p = 0.999). There was no statistical difference between the chondrotoxicities of PBS (8.49×10. 3. cells/well (. sem. 730) cells/well) and HA (4.75×10. 3. cells/well (. sem. 886)) (p = 0.294). Conclusions. HA co-administration reduced anaesthetic cytotoxicity with bupivacaine but not lidocaine, suggesting different mechanisms of injury between the two. Co-administered intra-articular injections of HA with bupivacaine, but not lidocaine, may protect articular chondrocytes from local anaesthetic-associated death. Cite this article: Bone Joint Res 2013;2:270–5


Bone & Joint Research
Vol. 5, Issue 10 | Pages 500 - 511
1 Oct 2016
Raina DB Gupta A Petersen MM Hettwer W McNally M Tägil M Zheng M Kumar A Lidgren L

Objectives. We have observed clinical cases where bone is formed in the overlaying muscle covering surgically created bone defects treated with a hydroxyapatite/calcium sulphate biomaterial. Our objective was to investigate the osteoinductive potential of the biomaterial and to determine if growth factors secreted from local bone cells induce osteoblastic differentiation of muscle cells. Materials and Methods. We seeded mouse skeletal muscle cells C2C12 on the hydroxyapatite/calcium sulphate biomaterial and the phenotype of the cells was analysed. To mimic surgical conditions with leakage of extra cellular matrix (ECM) proteins and growth factors, we cultured rat bone cells ROS 17/2.8 in a bioreactor and harvested the secreted proteins. The secretome was added to rat muscle cells L6. The phenotype of the muscle cells after treatment with the media was assessed using immunostaining and light microscopy. Results. C2C12 cells differentiated into osteoblast-like cells expressing prominent bone markers after seeding on the biomaterial. The conditioned media of the ROS 17/2.8 contained bone morphogenetic protein-2 (BMP-2 8.4 ng/mg, standard deviation (. sd. ) 0.8) and BMP-7 (50.6 ng/mg, . sd. 2.2). In vitro, this secretome induced differentiation of skeletal muscle cells L6 towards an osteogenic lineage. Conclusion. Extra cellular matrix proteins and growth factors leaking from a bone cavity, along with a ceramic biomaterial, can synergistically enhance the process of ectopic ossification. The overlaying muscle acts as an osteoinductive niche, and provides the required cells for bone formation. Cite this article: D. B. Raina, A. Gupta, M. M. Petersen, W. Hettwer, M. McNally, M. Tägil, M-H. Zheng, A. Kumar, L. Lidgren. Muscle as an osteoinductive niche for local bone formation with the use of a biphasic calcium sulphate/hydroxyapatite biomaterial. Bone Joint Res 2016;5:500–511. DOI: 10.1302/2046-3758.510.BJR-2016-0133.R1


Bone & Joint Research
Vol. 8, Issue 2 | Pages 41 - 48
1 Feb 2019
Busse P Vater C Stiehler M Nowotny J Kasten P Bretschneider H Goodman SB Gelinsky M Zwingenberger S

Objectives. Intra-articular injections of local anaesthetics (LA), glucocorticoids (GC), or hyaluronic acid (HA) are used to treat osteoarthritis (OA). Contrast agents (CA) are needed to prove successful intra-articular injection or aspiration, or to visualize articular structures dynamically during fluoroscopy. Tranexamic acid (TA) is used to control haemostasis and prevent excessive intra-articular bleeding. Despite their common usage, little is known about the cytotoxicity of common drugs injected into joints. Thus, the aim of our study was to investigate the effects of LA, GC, HA, CA, and TA on the viability of primary human chondrocytes and tenocytes in vitro. Methods. Human chondrocytes and tenocytes were cultured in a medium with three different drug dilutions (1:2; 1:10; 1:100). The following drugs were used to investigate cytotoxicity: lidocaine hydrochloride 1%; bupivacaine 0.5%; triamcinolone acetonide; dexamethasone 21-palmitate; TA; iodine contrast media; HA; and distilled water. Normal saline served as a control. After an incubation period of 24 hours, cell numbers and morphology were assessed. Results. Using LA or GC, especially triamcinolone acetonide, a dilution of 1:100 resulted in only a moderate reduction of viability, while a dilution of 1:10 showed significantly fewer cell counts. TA and CA reduced viability significantly at a dilution of 1:2. Higher dilutions did not affect viability. Notably, HA showed no effects of cytotoxicity in all drug dilutions. Conclusion. The toxicity of common intra-articular injectable drugs, assessed by cell viability, is mainly dependent on the dilution of the drug being tested. LA are particularly toxic, whereas HA did not affect cell viability. Cite this article: P. Busse, C. Vater, M. Stiehler, J. Nowotny, P. Kasten, H. Bretschneider, S. B. Goodman, M. Gelinsky, S. Zwingenberger. Cytotoxicity of drugs injected into joints in orthopaedics. Bone Joint Res 2019;8:41–48. DOI: 10.1302/2046-3758.82.BJR-2018-0099.R1


Aims

This study intended to investigate the effect of vericiguat (VIT) on titanium rod osseointegration in aged rats with iron overload, and also explore the role of VIT in osteoblast and osteoclast differentiation.

Methods

In this study, 60 rats were included in a titanium rod implantation model and underwent subsequent guanylate cyclase treatment. Imaging, histology, and biomechanics were used to evaluate the osseointegration of rats in each group. First, the impact of VIT on bone integration in aged rats with iron overload was investigated. Subsequently, VIT was employed to modulate the differentiation of MC3T3-E1 cells and RAW264.7 cells under conditions of iron overload.


Bone & Joint Research
Vol. 5, Issue 12 | Pages 602 - 609
1 Dec 2016
Muto T Kokubu T Mifune Y Inui A Sakata R Harada Y Takase F Kurosaka M

Objectives. Triamcinolone acetonide (TA) is widely used for the treatment of rotator cuff injury because of its anti-inflammatory properties. However, TA can also produce deleterious effects such as tendon degeneration or rupture. These harmful effects could be prevented by the addition of platelet-rich plasma (PRP), however, the anti-inflammatory and anti-degenerative effects of the combined use of TA and PRP have not yet been made clear. The objective of this study was to determine how the combination of TA and PRP might influence the inflammation and degeneration of the rotator cuff by examining rotator cuff-derived cells induced by interleukin (IL)-1ß. Methods. Rotator cuff-derived cells were seeded under inflammatory stimulation conditions (with serum-free medium with 1 ng/ml IL-1ß for three hours), and then cultured in different media: serum-free (control group), serum-free + TA (0.1mg/ml) (TA group), serum-free + 10% PRP (PRP group), and serum-free + TA (0.1mg/ml) + 10% PRP (TA+PRP group). Cell morphology, cell viability, and expression of inflammatory and degenerative mediators were assessed. Results. Exposure to TA significantly decreased cell viability and changed the cell morphology; these effects were prevented by the simultaneous administration of PRP. Compared with the control group, expression levels of inflammatory genes and reactive oxygen species production were reduced in the TA, PRP, and TA+PRP groups. PRP significantly decreased the expression levels of degenerative marker genes. Conclusions. The combination of TA plus PRP exerts anti-inflammatory and anti-degenerative effects on rotator cuff-derived cells stimulated by IL-1ß. This combination has the potential to relieve the symptoms of rotator cuff injury. Cite this article: T. Muto, T. Kokubu, Y. Mifune, A. Inui, R. Sakata, Y. Harada, F. Takase, M. Kurosaka. Effects of platelet-rich plasma and triamcinolone acetonide on interleukin-1ß-stimulated human rotator cuff-derived cells. Bone Joint Res 2016;5:602–609. DOI: 10.1302/2046-3758.512.2000582


Bone & Joint Research
Vol. 1, Issue 1 | Pages 1 - 7
1 Jan 2012
Rosenberg N Rosenberg O

Objectives. The need for bone tissue supplementation exists in a wide range of clinical conditions involving surgical reconstruction in limbs, the spine and skull. The bone supplementation materials currently used include autografts, allografts and inorganic matrix components; but these pose potentially serious side-effects. In particular the availability of the autografts is usually limited and their harvesting causes surgical morbidity. Therefore for the purpose of supplementation of autologous bone graft, we have developed a method for autologous extracorporeal bone generation. Methods. Human osteoblast-like cells were seeded on porous granules of tricalcium phosphate and incubated in osteogenic media while exposed to mechanical stimulation by vibration in the infrasonic range of frequencies. The generated tissue was examined microscopically following haematoxylin eosin, trichrome and immunohistochemical staining. Results. Following 14 days of incubation the generated tissue showed histological characteristics of bone-like material due to the characteristic eosinophilic staining, a positive staining for collagen trichrome and a positive specific staining for osteocalcin and collagen 1. Macroscopically, this tissue appeared in aggregates of between 0.5 cm and 2 cm. . Conclusions. We present evidence that the interaction of the cellular, inorganic and mechanical components in vitro can rapidly generate three-dimensional bone-like tissue that might be used as an autologous bone graft


Bone & Joint Research
Vol. 3, Issue 12 | Pages 328 - 334
1 Dec 2014
Harada Y Kokubu T Mifune Y Inui A Sakata R Muto T Takase F Kurosaka M

Objectives. To investigate the appropriate dose and interval for the administration of triamcinolone acetonide (TA) in treating tendinopathy to avoid adverse effects such as tendon degeneration and rupture. Methods. Human rotator cuff-derived cells were cultured using three media: regular medium (control), regular medium with 0.1 mg/mL of TA (low TA group), and with 1.0 mg/mL of TA (high TA group). The cell morphology, apoptosis, and viability were assessed at designated time points. Results. In the low TA group, the cells became flattened and polygonal at seven days then returned to normal at 21 days. The cell apoptosis ratio and messenger ribonucleic acid expression of caspase-3, 7, 8, and 9 increased, and viability was reduced in the low and high groups at seven days. In the low TA group, apoptosis and viability returned to normal at 21 days, however, in the high TA group, the cell morphology, apoptosis ratio, caspase-3, 7, 8, and 9 and viability did not return by day 21. Re-administration was performed in the low TA group at 7-, 14-, and 21-day intervals, and cell viability did not return to the control level at the 7- and 14-day intervals. Conclusion. A 0.1 mg/mL dose of TA temporarily decreased cell viability and increased cell apoptosis, which was recovered at 21 days, however, 1 mg/mL of TA caused irreversible damage to cell morphology and viability. An interval > three weeks was needed to safely re-administer TA. These findings may help determine the appropriate dose and interval for TA injection therapy. Cite this article: Bone Joint Res 2014;3:328–34


Bone & Joint Research
Vol. 6, Issue 2 | Pages 73 - 81
1 Feb 2017
Ishihara K Okazaki K Akiyama T Akasaki Y Nakashima Y

Objectives. Osteophytes are products of active endochondral and intramembranous ossification, and therefore could theoretically provide significant efficacy as bone grafts. In this study, we compared the bone mineralisation effectiveness of osteophytes and cancellous bone, including their effects on secretion of growth factors and anabolic effects on osteoblasts. Methods. Osteophytes and cancellous bone obtained from human patients were transplanted onto the calvaria of severe combined immunodeficient mice, with Calcein administered intra-peritoneally for fluorescent labelling of bone mineralisation. Conditioned media were prepared using osteophytes and cancellous bone, and growth factor concentration and effects of each graft on proliferation, differentiation and migration of osteoblastic cells were assessed using enzyme-linked immunosorbent assays, MTS ((3-(4,5-dimethylthiazol-2-yl)-5-(3-carboxymethoxyphenyl)-2-(4-sulfophenyl)-2H-tetrazolium)) assays, quantitative real-time polymerase chain reaction, and migration assays. Results. After six weeks, the area of mineralisation was significantly higher for the transplanted osteophytes than for the cancellous bone (43803 μm. 2. , . sd. 14660 versus 9421 μm. 2. , . sd. 5032, p = 0.0184, one-way analysis of variance). Compared with cancellous bone, the conditioned medium prepared using osteophytes contained a significantly higher amounts of transforming growth factor (TGF)-β1 (471 pg/ml versus 333 pg/ml, p = 0.0001, Wilcoxon rank sum test), bone morphogenetic protein (BMP)-2 (47.75 pg/ml versus 32 pg/ml, p = 0.0214, Wilcoxon rank sum test) and insulin-like growth factor (IGF)-1 (314.5 pg/ml versus 191 pg/ml, p = 0.0418, Wilcoxon rank sum test). The stronger effects of osteophytes towards osteoblasts in terms of a higher proliferation rate, upregulation of gene expression of differentiation markers such as alpha-1 type-1 collagen and alkaline phosphate, and higher migration, compared with cancellous bone, was confirmed. Conclusion. We provide evidence of favourable features of osteophytes for bone mineralisation through a direct effect on osteoblasts. The acceleration in metabolic activity of the osteophyte provides justification for future studies evaluating the clinical use of osteophytes as autologous bone grafts. Cite this article: K. Ishihara, K. Okazaki, T. Akiyama, Y. Akasaki, Y. Nakashima. Characterisation of osteophytes as an autologous bone graft source: An experimental study in vivo and in vitro. Bone Joint Res 2017;6:73–81. DOI: 10.1302/2046-3758.62.BJR-2016-0199.R1


Bone & Joint Research
Vol. 8, Issue 1 | Pages 32 - 40
1 Jan 2019
Berger DR Centeno CJ Steinmetz NJ

Objectives

Platelet-rich plasma (PRP) is being used increasingly often in the clinical setting to treat tendon-related pathologies. Yet the optimal PRP preparations to promote tendon healing in different patient populations are poorly defined. Here, we sought to determine whether increasing the concentration of platelet-derived proteins within a derivative of PRP, platelet lysate (PL), enhances tenocyte proliferation and migration in vitro, and whether the mitogenic properties of PL change with donor age.

Methods

Concentrated PLs from both young (< 50 years) and aged (> 50 years) donors were prepared by exposing pooled PRP to a series of freeze-thaw cycles followed by dilution in plasma, and the levels of several platelet-derived proteins were measured using multiplex immunoassay technology. Human tenocytes were cultured with PLs to simulate a clinically relevant PRP treatment range, and cell growth and migration were assessed using DNA quantitation and gap closure assays, respectively.


Objectives

Platelet-rich fibrin matrix (PRFM) has been proved to enhance tenocyte proliferation but has mixed results when used during rotator cuff repair. The optimal PRFM preparation protocol should be determined before clinical application. To screen the best PRFM to each individual’s tenocytes effectively, small-diameter culture wells should be used to increase variables. The gelling effect of PRFM will occur when small-diameter culture wells are used. A co-culture device should be designed to avoid this effect.

Methods

Tenocytes harvested during rotator cuff repair and blood from a healthy volunteer were used. Tenocytes were seeded in 96-, 24-, 12-, and six-well plates and co-culture devices. Appropriate volumes of PRFM, according to the surface area of each culture well, were treated with tenocytes for seven days. The co-culture device was designed to avoid the gelling effect that occurred in the small-diameter culture well. Cell proliferation was analyzed by water soluble tetrazolium-1 (WST-1) bioassay.


Bone & Joint Research
Vol. 5, Issue 12 | Pages 610 - 618
1 Dec 2016
Abubakar AA Noordin MM Azmi TI Kaka U Loqman MY

In vivo animal experimentation has been one of the cornerstones of biological and biomedical research, particularly in the field of clinical medicine and pharmaceuticals. The conventional in vivo model system is invariably associated with high production costs and strict ethical considerations. These limitations led to the evolution of an ex vivo model system which partially or completely surmounted some of the constraints faced in an in vivo model system. The ex vivo rodent bone culture system has been used to elucidate the understanding of skeletal physiology and pathophysiology for more than 90 years. This review attempts to provide a brief summary of the historical evolution of the rodent bone culture system with emphasis on the strengths and limitations of the model. It encompasses the frequency of use of rats and mice for ex vivo bone studies, nutritional requirements in ex vivo bone growth and emerging developments and technologies. This compilation of information could assist researchers in the field of regenerative medicine and bone tissue engineering towards a better understanding of skeletal growth and development for application in general clinical medicine.

Cite this article: A. A. Abubakar, M. M. Noordin, T. I. Azmi, U. Kaka, M. Y. Loqman. The use of rats and mice as animal models in ex vivo bone growth and development studies. Bone Joint Res 2016;5:610–618. DOI: 10.1302/2046-3758.512.BJR-2016-0102.R2.


Bone & Joint Research
Vol. 6, Issue 6 | Pages 358 - 365
1 Jun 2017
Sanghani-Kerai A Coathup M Samazideh S Kalia P Silvio LD Idowu B Blunn G

Objectives

Cellular movement and relocalisation are important for many physiologic properties. Local mesenchymal stem cells (MSCs) from injured tissues and circulating MSCs aid in fracture healing. Cytokines and chemokines such as Stromal cell-derived factor 1(SDF-1) and its receptor chemokine receptor type 4 (CXCR4) play important roles in maintaining mobilisation, trafficking and homing of stem cells from bone marrow to the site of injury. We investigated the differences in migration of MSCs from the femurs of young, adult and ovariectomised (OVX) rats and the effect of CXCR4 over-expression on their migration.

Methods

MSCs from young, adult and OVX rats were put in a Boyden chamber to establish their migration towards SDF-1. This was compared with MSCs transfected with CXCR4, as well as MSCs differentiated to osteoblasts.


Bone & Joint Research
Vol. 6, Issue 3 | Pages 123 - 131
1 Mar 2017
Sasaki T Akagi R Akatsu Y Fukawa T Hoshi H Yamamoto Y Enomoto T Sato Y Nakagawa R Takahashi K Yamaguchi S Sasho T

Objectives

The aim of this study was to investigate the effect of granulocyte-colony stimulating factor (G-CSF) on mesenchymal stem cell (MSC) proliferation in vitro and to determine whether pre-microfracture systemic administration of G-CSF (a bone marrow stimulant) could improve the quality of repaired tissue of a full-thickness cartilage defect in a rabbit model.

Methods

MSCs from rabbits were cultured in a control medium and medium with G-CSF (low-dose: 4 μg, high-dose: 40 μg). At one, three, and five days after culturing, cells were counted. Differential potential of cultured cells were examined by stimulating them with a osteogenic, adipogenic and chondrogenic medium.

A total of 30 rabbits were divided into three groups. The low-dose group (n = 10) received 10 μg/kg of G-CSF daily, the high-dose group (n = 10) received 50 μg/kg daily by subcutaneous injection for three days prior to creating cartilage defects. The control group (n = 10) was administered saline for three days. At 48 hours after the first injection, a 5.2 mm diameter cylindrical osteochondral defect was created in the femoral trochlea. At four and 12 weeks post-operatively, repaired tissue was evaluated macroscopically and microscopically.


Bone & Joint Research
Vol. 7, Issue 2 | Pages 157 - 165
1 Feb 2018
Sun Y Kiraly AJ Sun AR Cox M Mauerhan DR Hanley EN

Objectives

The objectives of this study were: 1) to examine osteophyte formation, subchondral bone advance, and bone marrow lesions (BMLs) in osteoarthritis (OA)-prone Hartley guinea pigs; and 2) to assess the disease-modifying activity of an orally administered phosphocitrate ‘analogue’, Carolinas Molecule-01 (CM-01).

Methods

Young Hartley guinea pigs were divided into two groups. The first group (n = 12) had drinking water and the second group (n = 9) had drinking water containing CM-01. Three guinea pigs in each group were euthanized at age six, 12, and 18 months, respectively. Three guinea pigs in the first group were euthanized aged three months as baseline control. Radiological, histological, and immunochemical examinations were performed to assess cartilage degeneration, osteophyte formation, subchondral bone advance, BMLs, and the levels of matrix metalloproteinse-13 (MMP13) protein expression in the knee joints of hind limbs.


Bone & Joint Research
Vol. 6, Issue 12 | Pages 649 - 655
1 Dec 2017
Liu Y Zhu H Hong H Wang W Liu F

Objectives

Recently, high failure rates of metal-on-metal (MOM) hip implants have raised concerns of cobalt toxicity. Adverse reactions occur to cobalt nanoparticles (CoNPs) and cobalt ions (Co2+) during wear of MOM hip implants, but the toxic mechanism is not clear.

Methods

To evaluate the protective effect of zinc ions (Zn2+), Balb/3T3 mouse fibroblast cells were pretreated with 50 μM Zn2+ for four hours. The cells were then exposed to different concentrations of CoNPs and Co2+ for four hours, 24 hours and 48 hours. The cell viabilities, reactive oxygen species (ROS) levels, and inflammatory cytokines were measured.


Bone & Joint Research
Vol. 5, Issue 10 | Pages 523 - 530
1 Oct 2016
Yuan Y Zhang GQ Chai W Ni M Xu C Chen JY

Objectives

Osteoarthritis (OA) is characterised by articular cartilage degradation. MicroRNAs (miRNAs) have been identified in the development of OA. The purpose of our study was to explore the functional role and underlying mechanism of miR-138-5p in interleukin-1 beta (IL-1β)-induced extracellular matrix (ECM) degradation of OA cartilage.

Materials and Methods

Human articular cartilage was obtained from patients with and without OA, and chondrocytes were isolated and stimulated by IL-1β. The expression levels of miR-138-5p in cartilage and chondrocytes were both determined. After transfection with miR-138-5p mimics, allele-specific oligonucleotide (ASO)-miR-138-5p, or their negative controls, the messenger RNA (mRNA) levels of aggrecan (ACAN), collagen type II and alpha 1 (COL2A1), the protein levels of glycosaminoglycans (GAGs), and both the mRNA and protein levels of matrix metalloproteinase (MMP)-13 were evaluated. Luciferase reporter assay, quantitative real-time polymerase chain reaction (qRT-PCR), and Western blot were performed to explore whether Forkhead Box C1 (FOCX1) was a target of miR-138-5p. Further, we co-transfected OA chondrocytes with miR-138-5p mimics and pcDNA3.1 (+)-FOXC1 and then stimulated with IL-1β to determine whether miR-138-5p-mediated IL-1β-induced cartilage matrix degradation resulted from targeting FOXC1.


Bone & Joint Research
Vol. 6, Issue 5 | Pages 315 - 322
1 May 2017
Martinez-Perez M Perez-Jorge C Lozano D Portal-Nuñez S Perez-Tanoira R Conde A Arenas MA Hernandez-Lopez JM de Damborenea JJ Gomez-Barrena E Esbrit P Esteban J

Objectives

Implant-related infection is one of the most devastating complications in orthopaedic surgery. Many surface and/or material modifications have been developed in order to minimise this problem; however, most of the in vitro studies did not evaluate bacterial adhesion in the presence of eukaryotic cells, as stated by the ‘race for the surface’ theory. Moreover, the adherence of numerous clinical strains with different initial concentrations has not been studied.

Methods

We describe a method for the study of bacterial adherence in the presence of preosteoblastic cells. For this purpose we mixed different concentrations of bacterial cells from collection and clinical strains of staphylococci isolated from implant-related infections with preosteoblastic cells, and analysed the minimal concentration of bacteria able to colonise the surface of the material with image analysis.


Bone & Joint Research
Vol. 6, Issue 2 | Pages 90 - 97
1 Feb 2017
Rajfer RA Kilic A Neviaser AS Schulte LM Hlaing SM Landeros J Ferrini MG Ebramzadeh E Park S

Objectives

We investigated the effects on fracture healing of two up-regulators of inducible nitric oxide synthase (iNOS) in a rat model of an open femoral osteotomy: tadalafil, a phosphodiesterase inhibitor, and the recently reported nutraceutical, COMB-4 (consisting of L-citrulline, Paullinia cupana, ginger and muira puama), given orally for either 14 or 42 days.

Materials and Methods

Unilateral femoral osteotomies were created in 58 male rats and fixed with an intramedullary compression nail. Rats were treated daily either with vehicle, tadalafil or COMB-4. Biomechanical testing of the healed fracture was performed on day 42. The volume, mineral content and bone density of the callus were measured by quantitative CT on days 14 and 42. Expression of iNOS was measured by immunohistochemistry.


Bone & Joint Research
Vol. 5, Issue 11 | Pages 569 - 576
1 Nov 2016
Akahane M Shimizu T Kira T Onishi T Uchihara Y Imamura T Tanaka Y

Objectives

To assess the structure and extracellular matrix molecule expression of osteogenic cell sheets created via culture in medium with both dexamethasone (Dex) and ascorbic acid phosphate (AscP) compared either Dex or AscP alone.

Methods

Osteogenic cell sheets were prepared by culturing rat bone marrow stromal cells in a minimal essential medium (MEM), MEM with AscP, MEM with Dex, and MEM with Dex and AscP (Dex/AscP). The cell number and messenger (m)RNA expression were assessed in vitro, and the appearance of the cell sheets was observed after mechanical retrieval using a scraper. β-tricalcium phosphate (β-TCP) was then wrapped with the cell sheets from the four different groups and subcutaneously implanted into rats.


Bone & Joint Research
Vol. 5, Issue 10 | Pages 492 - 499
1 Oct 2016
Li X Li M Lu J Hu Y Cui L Zhang D Yang Y

Objectives

To elucidate the effects of age on the expression levels of the receptor activator of the nuclear factor-κB ligand (RANKL) and osteoclasts in the periodontal ligament during orthodontic mechanical loading and post-orthodontic retention.

Materials and Methods

The study included 20 male Sprague-Dawley rats, ten in the young group (aged four to five weeks) and ten in the adult group (aged 18 to 20 weeks). In each rat, the upper-left first molar was subjected to a seven-day orthodontic force loading followed by a seven-day retention period. The upper-right first molar served as a control. The amount of orthodontic tooth movement was measured after seven-day force application and seven-day post-orthodontic retention. The expression levels of RANKL and the tartrate-resistant acid phosphatase (TRAP)-positive osteoclasts were evaluated on day 7 (end of mechanical force loading) and day 14 (after seven days of post-orthodontic retention). Statistical analysis was performed using the t-test, and significance was set at p < 0.05.