Immature bovine cartilage wear by fatigue failure and delamination.
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ABSTRACT:
SUBMITTER: Durney KM
PROVIDER: S-EPMC7809915 | biostudies-literature |
REPOSITORIES: biostudies-literature
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Project description:INTRODUCTION: The zone of calcified cartilage (ZCC) anchors articular cartilage (AC) to subchondral bone through a layer of intermediate stiffness. The regulation and functional consequences of cartilage calcification may vary with depth from the articular surface. The hypothesis of this study was that the in vitro calcification of immature AC occurs selectively in the deep region and is associated with a local increase in stiffness. METHODS: AC and growth plate cartilage (GPC) from calves were incubated in DMEM, 1% FBS, 100?g/mL ascorbate, and ±10mM ß-glycerophosphate (ßGP) for up to 3 weeks. To assess the time course and effects of cell viability and ßGP, full-depth strips of AC and GPC were analyzed by histology, indentation, and (45)Ca(++) uptake. To assess the effect of tissue zone, disks harvested from surface and deep zone AC and from reserve and hypertrophic zone of GPC were incubated independently and analyzed by compression and for (45)Ca(++) uptake and biochemical components. RESULTS: The deep ~20% of immature AC calcified within 3 weeks, with calcification dependent on cell viability and ßGP. Mineral was deposited continuously around cells in AC but only between cell columns in GPC. The deep zone of AC exhibited a compressive modulus of 0.53 MPa after ßGP-induced calcification, ~4-fold stiffer than AC incubated without ßGP. CONCLUSIONS: Cartilage explants exhibit inherent zone-specific calcification processes, resulting in an increase in stiffness associated with cartilage calcification. Such properties may be useful for engineering a biomimetic ZCC tissue to integrate cartilaginous tissue to bone, thereby forming a mechanically functional osteochondral unit.
| S-EPMC3382981 | biostudies-literature
Project description:Tearing of the parasagittal bridging veins (BVs) is thought to be a source of extra-axial hemorrhage (EAH) associated with abusive traumatic brain injuries (TBIs) in children. However, the pediatric BV mechanical properties are unknown. We subjected porcine adult, porcine newborn, and human infant BVs to either a low rate pull to failure, a high rate pull to failure, or 30 s of cyclic loading followed by a pull to failure. An additional subset of human infant BVs was examined for viscoelastic recovery between two cycling episodes. We found that human infant BVs are stronger than porcine BVs, and BV mechanical properties are rate dependent, but not age dependent. Successive cyclic loading to a uniform level of stretch softened BVs with decaying peak stresses, and shifted their stress-stretch relationship. These data are critical in understanding BV tissue behavior in accidental and abusive trauma scenarios, which in turn may clarify circumstances that may be injurious to young children.
| S-EPMC5529232 | biostudies-literature
Project description:This paper aims to characterize the wear behavior of hydrogel constructs designed for human articular cartilage replacement. To this purpose, poly (ethylene glycol) diacrylate (PEGDA) 10% w/v and gellan gum (GG) 1.5% w/v were used to reproduce the superior (SUP) cartilage layer and PEGDA 15% w/v and GG 1.5% w/v were used to reproduce the deep (DEEP) cartilage layer, with or without graphene oxide (GO). These materials (SUP and DEEP) were analyzed alone and in combination to mimic the zonal architecture of human articular cartilage. The developed constructs were tested using a four-station displacement control knee joint simulator under bovine calf serum. Roughness and micro-computer tomography (µ-CT) measurements evidenced that the hydrogels with 10% w/v of PEGDA showed a worse behavior both in terms of roughness increase and loss of uniformly distributed density than 15% w/v of PEGDA. The simultaneous presence of GO and 15% w/v PEGDA contributed to keeping the hydrogel construct's characteristics. The Raman spectra of the control samples showed the presence of unreacted C=C bonds in all the hydrogels. The degree of crosslinking increased along the series SUP < DEEP + SUP < DEEP without GO. The Raman spectra of the tested hydrogels showed the loss of diacrylate groups in all the samples, due to the washout of unreacted PEGDA in bovine calf serum aqueous environment. The loss decreased along the series SUP > DEEP + SUP > DEEP, further confirming that the degree of photo-crosslinking of the starting materials plays a key role in determining their wear behavior. μ-CT and Raman spectroscopy proved to be suitable techniques to characterize the structure and composition of hydrogels.
| S-EPMC7830039 | biostudies-literature
Project description:Enamel wear, which is inevitable due to the process of mastication, is a process in which the microcracking of enamel occurs due to the surface contacting very small hard particles. When these particles slide on enamel, a combined process of microcutting and microcracking in the surface and subsurface of the enamel takes place. The aim of this study was to detect microscopic differences in the microcrack behavior by subjecting enamel specimens derived from different age groups (immature open-apex premolars, mature closed-apex premolars, and deciduous molars) to cycles of simulated impact and sliding wear testing under controlled conditions. Our findings indicated that the characteristics of the microcracks, including the length, depth, count, orientation, and relation to microstructures differed among the study groups. The differences between the surface and subsurface microcrack characteristics were most notable in the enamel of deciduous molars followed by immature premolars and mature premolars whereby deciduous enamel suffered numerous, extensive, and branched microcracks. Within the limitations of this study, it was concluded that enamel surface and subsurface microcracks characteristics are dependent on the posteruptive age with deciduous enamel being the least resistant to wear based on the microcrack behavior as compared to permanent enamel.
| S-EPMC5926526 | biostudies-literature
Project description:Objective. Identify novel genes and pathways specific to superficial (SZ), middle (MZ) and deep zones (DZ) of normal articular cartilage. Methods. Articular cartilage was obtained from knees of 4 normal human donors. The cartilage zones were dissected on a microtome. RNA was analyzed on human genome arrays. Data obtained with human tissue were compared to bovine cartilage zone specific DNA arrays. Genes differentially expressed between zones were evaluated using direct annotation for structural or functional features, and by enrichment analysis for integrated pathways or functions. Results. The greatest differences were observed between SZ and DZ in both human and bovine cartilage. The MZ was transitional between the SZ and DZ and thereby shared some of the same pathways as well as structural/functional features of the adjacent zones. Cellular functions and biological processes enriched in the SZ relative to the DZ, include most prominently ECM receptor interactions, cell adhesion molecules, regulation of actin cytoskeleton, ribosome-related functions and signaling aspects such as Interferon gamma, IL4, CDC42Rac and Jak-Stat. Two pathways were enriched in the DZ relative to the SZ, including PPARG and EGFR_SMRTE. Conclusion. These differences in cartilage zonal gene expression identify new markers and pathways that govern the unique differentiation status of chondrocyte subpopulations.
2012-08-01 | GSE39796 | GEO
Project description:Though changes in normal joint motions and loads (e.g., following anterior cruciate ligament injury) contribute to the development of knee osteoarthritis, the precise mechanism by which these changes induce osteoarthritis remains unknown. As a first step toward identifying this mechanism, this study evaluates computational wear simulations of a patellofemoral joint specimen wear tested on a knee simulator machine. A multibody dynamic model of the specimen mounted in the simulator machine was constructed in commercial computer-aided engineering software. A custom elastic foundation contact model was used to calculate contact pressures and wear on the femoral and patellar articular surfaces using geometry created from laser scan and MR data. Two different wear simulation approaches were investigated--one that wore the surface geometries gradually over a sequence of 10 one-cycle dynamic simulations (termed the "progressive" approach), and one that wore the surface geometries abruptly using results from a single one-cycle dynamic simulation (termed the "non-progressive" approach). The progressive approach with laser scan geometry reproduced the experimentally measured wear depths and areas for both the femur and patella. The less costly non-progressive approach predicted deeper wear depths, especially on the patella, but had little influence on predicted wear areas. Use of MR data for creating the articular and subchondral bone geometry altered wear depth and area predictions by at most 13%. These results suggest that MR-derived geometry may be sufficient for simulating articular cartilage wear in vivo and that a progressive simulation approach may be needed for the patella and tibia since both remain in continuous contact with the femur.
| S-EPMC3119794 | biostudies-literature
Project description:Objective. Identify novel genes and pathways specific to superficial (SZ), middle (MZ) and deep zones (DZ) of normal articular cartilage. Methods. Articular cartilage was obtained from knees of 4 normal human donors. The cartilage zones were dissected on a microtome. RNA was analyzed on human genome arrays. Data obtained with human tissue were compared to bovine cartilage zone specific DNA arrays. Genes differentially expressed between zones were evaluated using direct annotation for structural or functional features, and by enrichment analysis for integrated pathways or functions. Results. The greatest differences were observed between SZ and DZ in both human and bovine cartilage. The MZ was transitional between the SZ and DZ and thereby shared some of the same pathways as well as structural/functional features of the adjacent zones. Cellular functions and biological processes enriched in the SZ relative to the DZ, include most prominently ECM receptor interactions, cell adhesion molecules, regulation of actin cytoskeleton, ribosome-related functions and signaling aspects such as Interferon gamma, IL4, CDC42Rac and Jak-Stat. Two pathways were enriched in the DZ relative to the SZ, including PPARG and EGFR_SMRTE. Conclusion. These differences in cartilage zonal gene expression identify new markers and pathways that govern the unique differentiation status of chondrocyte subpopulations. 6 samples, 2 bovine donors, 3 conditions each donor (SZ, MZ and DZ), 0 donor replicates, comparisons made between SZ, MZ and DZ to identify differentially expressed genes.
2012-07-31 | E-GEOD-39796 | biostudies-arrayexpress
Project description:Failure diagnosis invariably involves consideration of both associated material condition and the results of a mechanical analysis of prior operating history. This Review focuses on these aspects with particular reference to creep-fatigue failure diagnosis. Creep-fatigue cracking can be due to a spectrum of loading conditions ranging from pure cyclic to mainly steady loading with infrequent off-load transients. These require a range of mechanical analysis approaches, a number of which are reviewed. The microstructural information revealing material condition can vary with alloy class. In practice, the detail of the consequent cracking mechanism(s) can be camouflaged by oxidation at high temperatures, although the presence of oxide on fracture surfaces can be used to date events leading to failure. Routine laboratory specimen post-test examination is strongly recommended to characterise the detail of deformation and damage accumulation under known and well-controlled loading conditions to improve the effectiveness and efficiency of failure diagnosis.
| S-EPMC5458918 | biostudies-other
Project description:Many material properties of articular cartilage are anisotropic, particularly in the superficial zone where collagen fibers have a preferential direction. However, the anisotropy of cartilage wear had not been previously investigated. The objective of this study was to evaluate the anisotropy of cartilage material behavior in an in vitro wear test. The wear and coefficient of friction of bovine condylar cartilage were measured with loading in directions parallel (longitudinal) and orthogonal (transverse) to the collagen fiber orientation at the articular surface. An accelerated cartilage wear test was performed against a T316 stainless-steel plate in a solution of phosphate buffered saline with protease inhibitors. A constant load of 160 N was maintained for 14000 cycles of reciprocal sliding motion at 4 mm/s velocity and a travel distance of 18 mm in each direction. The contact pressure during the wear test was approximately 2 MPa, which is in the range of that reported in the human knee and hip joint. Wear was measured by biochemically quantifying the glycosaminoglycans (GAGs) and collagen that was released from the tissue during the wear test. Collagen damage was evaluated with collagen hybridizing peptide (CHP), while visualization of the tissue composition after the wear test was provided with histologic analysis. Results demonstrated that wear in the transverse direction released about twice as many GAGs than in the longitudinal direction, but that no significant differences were seen in the amount of collagen released from the specimens. Specimens worn in the transverse direction had a higher intensity of CHP stain than those worn in the longitudinal direction, suggesting more collagen damage from wear in the transverse direction. No anisotropy in friction was detected at any point in the wear test. Histologic and CHP images demonstrate that the GAG loss and collagen damage extended through much of the depth of the cartilage tissue, particularly for wear in the transverse direction. These results highlight distinct differences between cartilage wear and the wear of traditional engineering materials, and suggest that further study on cartilage wear is warranted. A potential clinical implication of these results is that orienting osteochondral grafts such that the direction of wear is aligned with the primary fiber direction at the articular surface may optimize the life of the graft.
| S-EPMC7306004 | biostudies-literature
Project description:Cartilage wear particles are released into the synovial fluid by mechanical and chemical degradation of the articular surfaces during osteoarthritis and attach to the synovial membrane. Accumulation of wear particles could alter key tissue-level mechanical properties of the synovium, hindering its characteristically low-friction interactions with underlying articular surfaces in the synovial joint. The present study employs a custom loading device to further the characterization of native synovium friction properties, while investigating the hypothesis that attachment of cartilage wear particles increases friction coefficient. Juvenile bovine synovium demonstrated characteristically low friction coefficients in sliding contact with glass, in agreement with historical measurements. Friction coefficient increased with higher normal load in saline, while lubrication with native synovial fluid maintained low friction coefficients at higher loads. Cartilage wear particles generated from juvenile bovine cartilage attached directly to synovium explants in static culture, with incorporation onto the tissue denoted by cell migration onto the particle surface. In dilute synovial fluid mimicking the decreased lubricating properties during osteoarthritis, wear particle attachment significantly increased friction coefficient against glass, and native cartilage and synovium. In addition to providing a novel characterization of synovial joint tribology this work highlights a potential mechanism for cartilage wear particles to perpetuate the degradative environment of osteoarthritis by modulating tissue-level properties of the synovium that could impact macroscopic wear as well as mechanical stimuli transmitted to resident cells.
| S-EPMC8492547 | biostudies-literature