scholarly journals The Mechanical Consequence of Removing the Superficial Zone of Articular Cartilage

2011 ◽  
Author(s):  
S. M. Hosseini ◽  
Y. Wu ◽  
C. C. van Donkelaar ◽  
K. Ito
Keyword(s):  
Articular Cartilage ◽  
Articular Surface ◽  
Dry Weight ◽  
Collagen Fibers ◽  
Matrix Composition ◽  
Middle Zone ◽  
Deep Zone ◽  
Superficial Zone ◽  
Diarthrodial Joints ◽  
Fluid Fraction

Articular cartilage (AC) functions as a load-bearing, low friction, and wear resistant material in diarthrodial joints. The distribution of AC matrix composition is highly depth-dependent. The fluid fraction in AC is 80% and decreases from surface to the depth of the tissue [1]. Collagen constitutes 70% of the tissue dry weight, and is highest in the superficial and deep zones and lowest in the middle zone [2]. Proteoglycans (PG’s) constitute 20–30% of the tissue dry weight. PG’s are lowest in the superficial zone, and highest in the middle zone. Although the PG content is lower in the deep zone than in the middle zone, the fixed charge density (FCD) is highest in the deep zone [3]. Apart from AC composition, its structure is also depth-dependent. In the superficial zone collagen fibers are densely packed, and are arranged parallel to the articular surface. In the middle zone collagen fibers are more randomly arranged. In the deep zone, the collagen fibers have their largest diameters and are arranged perpendicular to the subchondral bone (Fig. 1) [4].

A Review of the Collagen Orientation in the Articular Cartilage

Cartilage ◽  
2021 ◽  
pp. 194760352098877
Author(s):  
Roy D. Bloebaum ◽  
Andrew S. Wilson ◽  
William N. Martin
Keyword(s):  
Surface Layer ◽  
Articular Cartilage ◽  
Fiber Orientation ◽  
Collagen Fiber ◽  
Articular Surface ◽  
Imaging Techniques ◽  
Collagen Fibers ◽  
Deep Zone ◽  
Collagen Fiber Orientation ◽  
Critical Point Drying

Objective There has been a debate as to the alignment of the collagen fibers. Using a hand lens, Sir William Hunter demonstrated that the collagen fibers ran perpendicular and later aspects were supported by Benninghoff. Despite these 2 historical studies, modern technology has conflicting data on the collagen alignment. Design Ten mature New Zealand rabbits were used to obtain 40 condyle specimens. The specimens were passed through ascending grades of alcohol, subjected to critical point drying (CPD), and viewed in the scanning electron microscope. Specimens revealed splits from the dehydration process. When observing the fibers exposed within the opening of the splits, parallel fibers were observed to run in a radial direction, normal to the surface of the articular cartilage, radiating from the deep zone and arcading as they approach the surface layer. After these observations, the same samples were mechanically fractured and damaged by scalpel. Results The splits in the articular surface created deep fissures, exposing parallel bundles of collagen fibers, radiating from the deep zone and arcading as they approach the surface layer. On higher magnification, individual fibers were observed to run parallel to one another, traversing radially toward the surface of the articular cartilage and arcading. Mechanical fracturing and scalpel damage induced on the same specimens with the splits showed randomly oriented fibers. Conclusion Collagen fiber orientation corroborates aspects of Hunter’s findings and compliments Benninghoff. Investigators must be aware of the limits of their processing and imaging techniques in order to interpret collagen fiber orientation in cartilage.

Depth Dependent Diffusivity Profile in Bovine Articular Cartilage: Comparing Transverse and Axial Diffusivities

2007 ◽  
Author(s):  
Onyi N. Irrechukwu ◽  
Marc E. Levenston
Keyword(s):  
Extracellular Matrix ◽  
Articular Cartilage ◽  
Articular Surface ◽  
Deep Zone ◽  
Superficial Zone ◽  
Transport Pathway ◽  
Bovine Articular Cartilage ◽  
Extracellular Matrix Components ◽  
Matrix Components ◽  
Oriented Parallel

As articular cartilage is avascular, diffusion at a tissue length scale is the primary mode of solute and nutrient transport to its cells. The major extracellular matrix components are water (70–80%), chondrocytes, collagen (10–20%) and proteoglycans (5–10%) bearing sulfated glycosaminoglycans (GAG) [1]. Electron microscopy studies have shown that articular cartilage can be regarded as having three separate structural zones — superficial, middle and deep. The proportions of the various matrix components vary from the surface to the deep zone in any given joint and the greatest variations in content occur in the GAG content [2]. In addition the collagen fiber alignment varies, with fibers oriented parallel to the articular surface in the superficial zone, randomly oriented in the middle zone and oriented perpendicular to the surface in the deep zone. To a large extent, it is the spatially inhomogeneous composition of articular cartilage and microstructural orientation of its extracellular matrix components that determines the tortuosity of the transport pathway [3]. We therefore hypothesized that the diffusivity profile of a solute through the cartilage depth is inversely related to the GAG content and that the ratio between the axial and lateral diffusivities within each cartilage zone is related to the degree of anisotropy within the zone.

A Fibril Reinforced Poroelastic Model of Articular Cartilage Including Depth Dependent Material Properties

1999 ◽  
Author(s):  
L. P. Li ◽  
M. D. Buschmann ◽  
A. Shirazi-Adl
Keyword(s):  
Articular Cartilage ◽  
Regional Differences ◽  
Articular Surface ◽  
Collagen Fibrils ◽  
Superficial Zone ◽  
Cartilage Surface ◽  
Poroelastic Model ◽  
Oriented Parallel ◽  
Strain Dependent ◽  
Very High

Abstract Articular cartilage is a highly nonhomogeneous, anisotropic and multiphase biomaterial consisting of mainly collagen fibrils, proteoglycans and water. Noncalcified cartilage is morphologically divided into three zones along the depth, i.e. superficial, transitional and radial zones. The thickness, density and alignment of collagen fibrils vary from the superficial zone, where fibrils are oriented parallel to the articular surface, to the radial zone where fibrils are perpendicular to the boundary between bone, and cartilage. The concentration of proteoglycans increases with the depth from the cartilage surface. These regional differences have significant implications to the mechanical function of joints, which is to be explored theoretically in the present work by considering inhomogeneity along the cartilage depth. A nonlinear fibril reinforced poroelastic model is employed as per Li et al. (1999) in which the collagen fibrils were modeled as a distinct constituent whose tensile stiffness was taken to be very high and be strain dependent but whose compressive stiffness was neglected.

scholarly journals Localization of hyaluronic acid in human articular cartilage.

1994 ◽  
Vol 42 (4) ◽  
pp. 513-522 ◽  
Author(s):  
A Asari ◽  
S Miyauchi ◽  
S Kuriyama ◽  
A Machida ◽  
K Kohno ◽  
...  
Keyword(s):  
Extracellular Matrix ◽  
Hyaluronic Acid ◽  
Articular Cartilage ◽  
Dermatan Sulfate ◽  
Keratan Sulfate ◽  
Human Articular Cartilage ◽  
Middle Zone ◽  
Deep Zone ◽  
Weak Staining ◽  
Pre Treatment

To demonstrate localization of hyaluronic acid (HA) in articular cartilage of the human femur, biotinylated HA-binding region, which specifically binds HA molecules, was applied to the tissue. In sections fixed by 2% paraformaldehyde-2% glutaraldehyde, HA staining was detected in lamina splendens and chondrocytes in the middle zone. By pretreatment with trypsin, intense HA staining appeared in the extracellular matrix of the deep zone and weak staining in the superficial and middle zones. Moreover, pre-treatment with chondroitinase ABC (CHase ABC) intensely enhanced the stainability for HA in the superficial and middle zones and weakly in the deeper zone. Combined pre-treatment of trypsin with CHase ABC abolished intra- and extracellular staining for HA in all zones. By microbiochemical study, the concentrations of HA and dermatan sulfate were high in the middle zone, whereas those of chondroitin sulfate and keratan sulfate were high in the deep zone. These results suggest that HA is abundantly synthesized in and secreted from the chondrocytes, particularly in the middle zone, whereas it is largely masked by proteoglycan constituents in the extracellular matrix.

scholarly journals Mechanical loading of in situ chondrocytes in lapine retropatellar cartilage after anterior cruciate ligament transection

2009 ◽  
Vol 7 (47) ◽  
pp. 895-903 ◽  
Author(s):  
Sang-Kuy Han ◽  
Ruth Seerattan ◽  
Walter Herzog
Keyword(s):  
Anterior Cruciate Ligament ◽  
Articular Cartilage ◽  
Normal Control ◽  
Structural Integrity ◽  
Articular Surface ◽  
Cruciate Ligament ◽  
Superficial Zone ◽  
Native Bone ◽  
Anterior Cruciate ◽  
Early Oa

The aims of this study were (i) to quantify chondrocyte mechanics in fully intact articular cartilage attached to its native bone and (ii) to compare the chondrocyte mechanics for cells in healthy and early osteoarthritis (OA) tissue. We hypothesized that cells in the healthy tissue would deform less for given articular surface pressures than cells in the early OA tissue because of a loss of matrix integrity in early OA and the associated loss of structural integrity that is thought to protect chondrocytes. Chondrocyte dynamics were quantified by measuring the deformation response of the cells to controlled loading of fully intact cartilage using a custom-designed confocal indentation system. Early OA was achieved nine weeks following transection of the anterior cruciate ligament (ACL) in rabbit knees. Experiments were performed on the retropatellar cartilage of early OA rabbit knees (four joints and 48 cells), the corresponding intact contralateral control knees (four joints and 48 cells) and knees from normal control rabbits (four joints and 48 cells). Nine weeks following ACL transection, articular cartilage of the experimental joints showed substantial increases in thickness, and progression towards OA as assessed using histological grading. Local matrix strains in the superficial zone were greater for the experimental (38 ± 4%) compared with the contralateral (27 ± 5%) and normal (28 ± 4%) joints ( p = 0.04). Chondrocyte deformations in the axial and depth directions were similar during indentation loading for all experimental groups. However, cell width increased more for the experimental cartilage chondrocytes (12 ± 1%) than the contralateral (6 ± 1%) and normal control chondrocytes (6 ± 1%; p < 0.001). On average, chondrocyte volume increased with indentation loading in the early OA cartilage (8 ± 3%, p = 0.001), while it decreased for the two control groups (−8 ± 2%, p = 0.002 for contralateral and −8 ± 1%, p = 0.004 for normal controls). We conclude from these results that our hypothesis of cell deformations in the early OA tissue was only partially supported: specifically, changes in chondrocyte mechanics in early OA were direction-specific with the primary axial deformations remaining unaffected despite vastly increased average axial matrix deformations. Surprisingly, chondrocyte deformations increased in early OA in specific transverse directions which have received little attention to date but might be crucial to chondrocyte signalling in early OA.

Fibre Reinforcement and Mechanical Stability in Articular Cartilage

1984 ◽  
Vol 13 (3) ◽  
pp. 153-156 ◽  
Author(s):  
D W L Hukins ◽  
R M Aspden ◽  
Y E Yarker
Keyword(s):  
Articular Cartilage ◽  
Tensile Stress ◽  
Articular Surface ◽  
Applied Pressure ◽  
Swelling Pressure ◽  
Collagen Fibrils ◽  
Torsional Stiffness ◽  
Surface Zone ◽  
Fibre Reinforcement ◽  
Deep Zone

The gel phase of articular cartilage is reinforced by collagen fibrils. These fibrils have low flexural and torsional stiffness, but are able to provide reinforcement if deformation of the tissue increases their tensile stress. An estimate suggests that the lengths of collagen fibrils in articular cartilage are at least of the same order as their critical length so that tensile stress in the tissue will increase the stress in the fibrils rather than simply pull them out of the gel. In the surface zone the collagen fibrils are oriented so that the efficiency of reinforcement, η, is about 0.6 tangential to the surface; tension in the fibrils is thus able to withstand swelling pressure within the tissue whose condition for stability resembles that of a pressure vessel. Swelling pressure allows the tissue to support applied pressure. An intermediate zone has a roughly isotropic η value of about 0.2, while in the deep zone collagen fibrils appear to tie the cartilage to the subchondral bone; in this deep zone η has a value of about 0.6 perpendicular to the surface direction. There is also some preferred orientation of collagen fibrils in the plane of the articular surface within the surface zone; in patellar cartilage the preferred orientations can be related to the direction of stress which could be generated by movement of the joint.

scholarly journals Localization of proteoglycan monomer and link protein in the matrix of bovine articular cartilage: An immunohistochemical study.

1980 ◽  
Vol 28 (7) ◽  
pp. 621-635 ◽  
Author(s):  
A R Poole ◽  
I Pidoux ◽  
A Reiner ◽  
L H Tang ◽  
H Choi ◽  
...  
Keyword(s):  
Articular Cartilage ◽  
Articular Surface ◽  
Guanidine Hydrochloride ◽  
Cartilage Matrix ◽  
Binding Studies ◽  
Superficial Zone ◽  
Surface Culture ◽  
Bovine Articular Cartilage ◽  
Link Protein ◽  
The Matrix

Using monospecific antisera and immunofluorescence microscopy, proteoglycan monomer (PG), and link proteins were demonstrated throughout the extracellular matrix of bovine articular cartilage. A narrow band of strong pericellular staining was usually observed for both molecules, indicating a pericellular concentration of proteoglycan monomer: this conclusion was supported by dye-binding studies. Whereas PG was evenly distributed throughout the remaining matrix, more link protein was detectable in interterritorial sites in middle and deep zones. Well-defined zones of weaker territorial staining for link protein stained strongest for chondroitin sulfate. Trypsin treatment of cartilage resulted in a loss of most of the PG staining, but some selective retention of link protein, particularly around chondrocytes in the superficial zone at and near the articular surface. This residual staining was largely removed if sections were fixed after chondroitinase treatment. After extraction of cartilage with 4M guanidine hydrochloride, only PG remained and this was concentrated in the superficial zone. These observations are shown to support the concept of aggregation of PG and link protein with hyaluronic acid (HA) in cartilage matrix, and the binding of PG and link protein to HA, which is attached to the chondrocyte surface. Culture of cartilage depleted of PG and link protein by trypsin demonstrated that individual chondrocytes can secrete both PG and link proteins and that the organization of cartilage matrix can be regenerated in part over a period of 4 days.

scholarly journals Genipin crosslinked chitosan/PEO nanofibrous scaffolds exhibiting an improved microenvironment for the regeneration of articular cartilage

2021 ◽  
pp. 088532822110020
Author(s):  
Kuan Yong Ching ◽  
Orestis Andriotis ◽  
Bram Sengers ◽  
Martin Stolz
Keyword(s):  
Extracellular Matrix ◽  
Articular Cartilage ◽  
Articular Chondrocytes ◽  
Immunohistochemical Analysis ◽  
Chitosan Solution ◽  
Deep Zone ◽  
Superficial Zone ◽  
Fibril Structure ◽  
Nanofibrous Scaffolds ◽  
Poly Ethylene

Towards optimizing the growth of extracellular matrix to produce repair cartilage for healing articular cartilage (AC) defects in joints, scaffold-based tissue engineering approaches have recently become a focus of clinical research. Scaffold-based approaches by electrospinning aim to support the differentiation of chondrocytes by providing an ultrastructure similar to the fibrillar meshwork in native cartilage. In a first step, we demonstrate how the blending of chitosan with poly(ethylene oxide) (PEO) allows concentrated chitosan solution to become electrospinnable. The chitosan-based scaffolds share the chemical structure and characteristics of glycosaminoglycans, which are important structural components of the cartilage extracellular matrix. Electrospinning produced nanofibrils of ∼100 nm thickness that are closely mimicking the size of collagen fibrils in human AC. The polymer scaffolds were stabilized in physiological conditions and their stiffness was tuned by introducing the biocompatible natural crosslinker genipin. We produced scaffolds that were crosslinked with 1.0% genipin to obtain values of stiffness that were in between the stiffness of the superficial zone human AC of 600 ± 150 kPa and deep zone AC of 1854 ± 483 kPa, whereas the stiffness of 1.5% genipin crosslinked scaffold was similar to the stiffness of deep zone AC. The scaffolds were degradable, which was indicated by changes in the fibril structure and a decrease in the scaffold stiffness after seven months. Histological and immunohistochemical analysis after three weeks of culture with human articular chondrocytes (HACs) showed a cell viability of over 90% on the scaffolds and new extracellular matrix deposited on the scaffolds.

ASSESSMENT OF THREE-DIMENSIONAL ARCHITECTURE OF COLLAGEN FIBERS IN THE SUPERFICIAL ZONE OF BOVINE ARTICULAR CARTILAGE

2004 ◽  
Vol 08 (04) ◽  
pp. 167-179 ◽  
Author(s):  
J. P. Wu ◽  
T. B. Kirk ◽  
M. H. Zheng
Keyword(s):  
Articular Cartilage ◽  
Laser Scanning ◽  
3D Visualization ◽  
Articular Surface ◽  
3D Structure ◽  
Collagen Matrix ◽  
Laser Scanning Confocal Microscopy ◽  
Collagen Fibres ◽  
Superficial Zone ◽  
Bovine Articular Cartilage

The aim of this study is to investigate the structure and the collagen matrix of the superficial zone of articular cartilage using a 3D imaging technique. The split line thought to represent the orientation of the collagen fibres in the superficial zone was found using Hultkrantz's method. A semitransparent membrane was physically peeled off from the most superficial surface of bovine articular cartilage. Using fibre optic laser scanning confocal microscopy, the collagen matrix in normal cartilage, the membrane and the cartilage with the membrane peeled off were studied. The superficial zone was found to contain a more sophisticated 3D collagenous matrix than previously reported. The collagen matrix in the membrane consists of interwoven long collagen bundles, and the collagen fibres immediately subjacent to it align spatially in a predominantly oblique direction to the articular surface. The split line does not represent the orientation of the collagen in the membrane. This study presents a 3D visualization technique for a minimal-invasive examination of the 3D architecture of the collagen fibres in the superficial zone of articular cartilage, and offers a new insight into the 3D structure of the collagen matrix in the superficial zone of native cartilage.

Quantitative description of collagen structure in the articular cartilage of the young and adult equine distal metacarpus

2008 ◽  
Vol 58 (4) ◽  
pp. 353-370 ◽  
Author(s):  
Henk Schipper ◽  
Sander Kranenbarg ◽  
Johan van Leeuwen ◽  
Merel Gijsen ◽  
Monique Haazelager ◽  
...  
Keyword(s):  
Articular Cartilage ◽  
Adult Animal ◽  
Articular Surface ◽  
Young Animal ◽  
Quantitative Description ◽  
Collagen Structure ◽  
Collagen Network ◽  
Diarthrodial Joints ◽  
Sem Study ◽  
Predominant Orientation

AbstractThe orientation and organisation of collagen fibrils play an important role in the mechanical functioning of the articular cartilage (AC) that covers the surfaces in the diarthrodial joints. In the adult animal, typically an arcade like 'Benninghoff structure' is found. Because the remodelling capacity of the collagen network in the adult animal is limited, this Benninghoff structure needs to develop before the animal reaches maturity, and it needs to develop correctly. The aim of this study is to use quantitative polarised light microscopy (qPLM) and scanning electron microscopy (SEM) techniques to investigate if this Benninghoff structure is already present in the young animal, and to quantitatively investigate possible differences in collagen structure in the equine distal metacarpus of the young and adult animal. In total, 21 forelimbs of 13 horses are used. In animals of age 10 months and older, we find an arcade like Benninghoff structure for the collagen fibril network in both the qPLM and SEM study. The qPLM study shows that the collagen's predominant orientation is parallel to the articular surface throughout the entire cartilage depth in two animals directly after birth. These findings are supported by SEM results on a foal. We conclude that structural remodelling of the collagen network in AC occurs in the first months after birth. Because animals start with collagen parallel to the articular surface and need to remodel this structure to a Benninghoff architecture, and because collagen structure is an important parameter for AC mechanics and mechanobiology, these results suggest implications for AC epigenetics.

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