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Bone & Joint Research
Vol. 12, Issue 4 | Pages 259 - 273
6 Apr 2023
Lu R Wang Y Qu Y Wang S Peng C You H Zhu W Chen A

Aims

Osteoarthritis (OA) is a prevalent joint disorder with inflammatory response and cartilage deterioration as its main features. Dihydrocaffeic acid (DHCA), a bioactive component extracted from natural plant (gynura bicolor), has demonstrated anti-inflammatory properties in various diseases. We aimed to explore the chondroprotective effect of DHCA on OA and its potential mechanism.

Methods

In vitro, interleukin-1 beta (IL-1β) was used to establish the mice OA chondrocytes. Cell counting kit-8 evaluated chondrocyte viability. Western blotting analyzed the expression levels of collagen II, aggrecan, SOX9, inducible nitric oxide synthase (iNOS), IL-6, matrix metalloproteinases (MMPs: MMP1, MMP3, and MMP13), and signalling molecules associated with nuclear factor-kappa B (NF-κB) and mitogen-activated protein kinase (MAPK) pathways. Immunofluorescence analysis assessed the expression of aggrecan, collagen II, MMP13, and p-P65. In vivo, a destabilized medial meniscus (DMM) surgery was used to induce mice OA knee joints. After injection of DHCA or a vehicle into the injured joints, histological staining gauged the severity of cartilage damage.


Orthopaedic Proceedings
Vol. 101-B, Issue SUPP_5 | Pages 116 - 116
1 Apr 2019
Bock R Pezzotti G Zhu W Marin E Rondinella A Boschetto F McEntire B Bal BS
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Introduction

Support of appositional bone ingrowth and resistance to bacterial adhesion and biofilm formation are preferred properties for biomaterials used in spinal fusion surgery. Although polyetheretherketone (PEEK) is a widely used interbody spacer material, it exhibits poor osteoconductive and bacteriostatic properties. In contrast, monolithic silicon nitride (Si3N4) has shown enhanced osteogenic and antimicrobial behavior. Therefore, it was hypothesized that incorporation of Si3N4 into a PEEK matrix might improve upon PEEK's inherently poor ability to bond with bone and also impart resistance to biofilm formation.

Methods

A PEEK polymer was melted and compounded with three different silicon nitride powders at 15% (by volume, vol.%), including: (i) α-Si3N4; (ii) a liquid phase sintered (LPS) ß-Si3N4; and (iii) a melt-derived SiYAlON mixture. These three ceramic powders exhibited different solubilities, polymorphic structures, and/or chemical compositions. Osteoconductivity was assessed by seeding specimens with 5 × 105/ml of SaOS-2 osteosarcoma cells within an osteogenic media for 7 days. Antibacterial behavior was determined by inoculating samples with 1 × 107 CFU/ml of Staphylococcus epidermidis (S. epi.) in a 1 × 108/ml brain heart infusion (BHI) agar culture for 24 h. After staining with PureBlu™ Hoechst 33342 or with DAPI and CFDA for SaOS-2 cell adhesion or bacterial presence, respectively, samples were examined with a confocal fluorescence microscope using a 488 nm Krypton/Argon laser source. Images were also acquired using a FEG-SEM in secondary and backscattered modes on gold sputter-coated specimens (∼20–30Å). Hydroxyapatite (HAp) deposition was measured using a laser microscope. Raman spectra were collected for samples in backscattering mode using a triple monochromator using a 532 nm excitation source (Nd:YVO4 diode-pumped solid-state laser).


Orthopaedic Proceedings
Vol. 99-B, Issue SUPP_3 | Pages 25 - 25
1 Feb 2017
McEntire B Zhu W Pezzotti G Marin E Sugano N Bal B
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Introduction

Femoral heads made from zirconia-toughened alumina (ZTA) are the most advanced bioceramic available for total hip arthroplasty. ZTA's superior mechanical properties result from the polymorphic transformation of its zirconia (ZrO2) phase in the presence of a propagating crack. In vitro derived activation energies predict that several human lifetimes are needed to reach a state of significant transformation;1 but in vivo confirmation of material stability is still lacking. This investigation determined if transition metal ions might be responsible for triggering the tetragonal to monoclinic (t®m-ZrO2) phase transformation in this bioceramic.

Materials and Methods

BIOLOX®delta femoral heads (CeramTec GmbH, Plochingen, Germany) were acquired and characterized for their surface monoclinic content, Vm, using Raman spectroscopy. Then they were physiologically scratched with different metals (i.e., Ti, CoCr, and Fe, n=3 each) to simulate in vivo staining as a result of acetabular shell impingement due to subluxation or dislocation. They were subsequently hydrothermally aged for up to 100 h in an autoclave at 98∼132°C and 1 bar pressure. Raman maps, each consisting of 120 spectra, were compiled and monoclinic contents, Vm, calculated for zones adjacent to and away from the metal stains.2 Activation energies for the t®m transformation in stained and non-stained zones were derived and compared to retrieved heads having service lives of between ∼45 days and ∼8 years.


Orthopaedic Proceedings
Vol. 99-B, Issue SUPP_3 | Pages 47 - 47
1 Feb 2017
McEntire B Pezzotti G Bock R Zhu W Marin E Adachi T Bal B
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Introduction

Due to its remarkable stoichiometric flexibility and surface chemistry, hydroxyapatite (HAp) is the fundamental structural material in all vertebrates. Natural HAp's properties inspired an investigation into silicon nitride (Si3N4) to see if similar functionality could be engineered into this bioceramic. Biological and in situ spectroscopic analyses were used to monitor the response of osteosarcoma cells (SaOS-2) to surface-modulated Si3N4 and a titanium alloy after long-term in vitro exposure.

Materials and Methods

Four groups of Si3N4 discs, Ø12.7×1.0mm, (Amedica Corporation, Salt Lake City, UT USA) were subjected to surface treatments: (i) “As-fired;” (ii) HF-etched (5% HF solution for 45 s); (iii) Oxidized (1070°C for 7 h); and (iv) Nitrogen-annealed (1400°C for 30 min, 1.1 bar N2 gas).1 Titanium alloy discs (Ti6Al4V, ASTM F136) were used as a control group. SaOS-2 cells cultured for 24 h at 37°C were deposited (5×105 cells/ml) and incubated on the UV sterilized discs in an osteogenic medium for 7 days at 37°C. Cell proliferation was monitored using scanning electron and laser microscopy. The Receptor Activator of NF-kB Ligand (sRANKL) and the insulin growth factor 1 (IGF-1) were used to evaluate osteoclast formation and cell proliferation efficiency, respectively. In situ Raman spectroscopy was employed to monitor metabolic cell activity. Statistics (n≥3) were analyzed using the Student's t-test or one-way Analysis of Variance with p<0.05 considered significant.