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PubMedDate not supplied

Mono-iodoacetate-induced histologic changes in subchondral bone and articular cartilage of rat femorotibial joints: an animal model of osteoarthritis.

Osteoarthritis (OA) is a degenerative joint disease characterized by joint pain and a progressive loss of articular cartilage. Studies to elucidate the pathophysiology of OA have been hampered by the lack of a rapid, reproducible animal model that mimics both the histopathology and symptoms associated with the disease. Injection of mono-iodoacetate (MIA), an inhibitor of glycolysis, into the femorotibial joint of rodents promotes loss of articular cartilage similar to that noted in human OA. Here, we describe the histopathology in the subchondral bone and cartilage of rat (Wistar) knee joints treated with a single intra articular injection of MIA (1 mg) and sacrificed at 1, 3, 5, 7, 14, 28, and 56 days postinjection. Histologically, the early time points (days 1-7) were characterized by areas of chondrocyte degeneration/necrosis sometimes involving the entire thickness of the articular cartilage in the tibial plateaus and femoral condyles. Changes to the subchondral bone, as evidenced by increased numbers of osteoclasts and osteoblasts, were noted at by day 7. By 28 days, there was focal fragmentation and collapse of bony trabeculae with fibrosis and increased osteoclastic activity. By 56 days there were large areas of bone remodeling evidenced by osteoclastic bone resorption and newly formed trabeculae with loss of marrow hematopoietic cells. Subchondral cysts and subchondral sclerosis were present in some rats. In conclusion, intra-articular injection of MIA induces loss of articular cartilage with progression of subchondral bone lesions that mimic those of OA. This model offers a rapid and minimally invasive method to reproduce OA-like lesions in a rodent species.

Animals↗
PubMed2006

Radiographic findings of osteoarthritis versus arthroscopic findings of articular cartilage degeneration in the tibiofemoral joint.

PURPOSE: To retrospectively correlate radiographic findings of osteoarthritis of the tibiofemoral joint with arthroscopic findings of articular cartilage degeneration within the tibiofemoral joint in patients with chronic knee pain. MATERIALS AND METHODS: The study was performed in compliance with HIPAA regulations. Approval from an institutional review board and a waiver of informed consent were obtained. The study group consisted of 125 patients with osteoarthritis of the tibiofemoral joint (66 men, 59 women; age range, 35-77 years; average age, 52 years) and 25 patients of similar age (14 men, 11 women; age range, 36-69 years; average age, 50 years) with no osteoarthritis of the tibiofemoral joint. All patients underwent standing anteroposterior radiography of the knee prior to arthroscopic knee surgery. Each articular surface of the tibiofemoral joint was graded at arthroscopy. Two radiologists retrospectively reviewed the knee radiographs to determine the presence of marginal osteophytes, joint space narrowing, subchondral sclerosis, and subchondral cysts. The sensitivity and specificity of the radiographic features of osteoarthritis for the detection of articular cartilage degeneration within the medial and lateral compartments of the tibiofemoral joint were determined. RESULTS: The sensitivity of marginal osteophytes, joint space narrowing, subchondral sclerosis, and subchondral cysts for the detection of articular cartilage degeneration was 67%, 46%, 16%, and 10%, respectively, for the medial compartment and 49%, 7%, 6%, and 3%, respectively, for the lateral compartment. The specificity of marginal osteophytes, joint space narrowing, subchondral sclerosis, and subchondral cysts for the detection of articular cartilage degeneration was 73%, 95%, 100%, and 100%, respectively, for the medial compartment and 81%, 100%, 100%, and 100%, respectively, for the lateral compartment. CONCLUSION: Marginal osteophytes were the most sensitive radiographic feature for the detection of osteoarthritis of the tibiofemoral joint. Joint space narrowing, subchondral sclerosis, and subchondral cysts were less sensitive radiographic features of osteoarthritis and rarely occurred in the absence of associated osteophyte formation.

Adult↗
PubMedDate not supplied

Arthroscopic microscopy of articular cartilage using optical coherence tomography.

BACKGROUND: Optical coherence tomography is an echograph of infrared light that can yield microscopic cross-sectional images of articular cartilage without removing or damaging the tissue. HYPOTHESIS: To determine whether optical coherence tomography images of human cartilage can be acquired arthroscopically and whether the resulting images have high correlation with histopathology. METHODS: Optical coherence tomography was configured into an arthroscope and used to image 2 human cadaver knees and 45 cores harvested from 9 osteoarthritic knees. The imaged cartilage was then processed for histological analysis. Optical coherence tomography images and histology were graded using a modified Mankin structural score. Agreement was determined using weighted kappa statistics. Morphometric analysis performed on optical coherence tomography images was correlated with histomorphometric analysis using linear regression. RESULTS: Imaging of the medial and lateral femoral condyles and trochlea was readily accomplished using the optical coherence tomography arthroscope. Modified Mankin surface scores for specimens with the earliest structural changes (grades 0-3) had high agreement with scores assigned to histology (kappa= 0.87). Fibrillation indices calculated from optical coherence tomography had near-perfect correlation to that of histology (R = 0.98) CLINICAL RELEVANCE: Arthroscopic optical coherence tomography may be clinically useful for early detection of articular cartilage injury and nondestructive assessment of articular cartilage repair.

Arthroscopy↗
PubMed2004

Effect of low-power helium-neon laser irradiation on 13-week immobilized articular cartilage of rabbits.

Influence of low-power (632.8 nm, Helium-Neon, 13 J/cm2, three times a week) laser on 13-week immobilized articular cartilage was examined with rabbits knee model. Number of chondrocytes and depth of articular cartilage of experimental group were significantly higher than those of sham irradiated group. Surface morphology of sham-irradiated group had rough prominences, fibrillation and lacunae but surface morphology of experimental group had more similarities to control group than to sham irradiated group. There were marked differences between ultrastructure features of control group and experimental group in comparison with sham irradiated group. Low-power Helium-Neon laser irradiation on 13-week immobilized knee joints of rabbits neutrilized adverse effects of immobilization on articular cartilage.

Animals↗
PubMed2004

The cellular responses of articular cartilage to sharp and blunt trauma.

OBJECTIVE: To determine the response of immature articular cartilage to both sharp and blunt trauma in terms of cell death, cell proliferation and matrix synthesis. DESIGN: Blunt wounds were made with a trephine in full depth immature bovine articular cartilage explants which were cut in half through the center of the trephine wound with a sharp scalpel to produce blunt and sharp trauma on the same explant. Explants were maintained in culture for up to 10 days. Prior to fixation at days 2, 5 and 10, medium was supplemented with 10 microCi ml-1 35S-sulphate, [3H]-proline or [3H]-thymidine for 24h to assess matrix synthesis and cell proliferation. Cell death was assessed using a Live/Dead label. RESULTS: In the case of blunt wounds, a band of cell death was observed adjacent to the lesion edge. Microautoradiography demonstrated little radiolabel incorporation and, therefore, no new matrix synthesis or cell proliferation within this region. In contrast, wounds made with a sharp scalpel showed restricted cell death, with radiolabel incorporation adjacent to the lesion edge at all time points. This demonstrated not only chondrocyte proliferation and new matrix synthesis at the wound margin, but also an up-regulation of matrix synthesis adjacent to the lesion edge. CONCLUSIONS: In terms of clinical relevance, the use of sharp precise instruments during the surgical management of cartilage defects may be necessary to reduce cell death and promote matrix elaboration at the lesion edge in order to facilitate successful integration.

Animals↗
PubMed1995

Articular cartilage. Part I. The normal joint.

Articular hyaline cartilage is of interest to both the clinician and the basic scientist because of its unique physical and chemical properties which are a consequence of its biochemical composition. Although it is a tissue which is hypocellular, avascular, and also lacks nerves and lymphatics, it is active in synthesis and degradation. Articular cartilage responds to the forces to which it is subjected and, in this way, maintains its integrity as long as those forces do not exceed the tissue's capacity for repair or permanently change the biologic response of the cells.

Animals↗
PubMed2000

Functional adaptation of equine articular cartilage: the formation of regional biochemical characteristics up to age one year.

Biochemical heterogeneity of cartilage within a joint is well known in mature individuals. It has recently been reported that heterogeneity for proteoglycan content and chondrocyte metabolism in sheep develops postnatally under the influence of loading. No data exist on the collagen network in general or on the specific situation in the horse. The objective of this study was to investigate the alterations in equine articular cartilage biochemistry that occur from birth up to age one year, testing the hypothesis that the molecular composition of equine cartilage matrix is uniform at birth and biochemical heterogeneity is formed postnatally. Water content, DNA content, glycosaminoglycan content (GAG) and biochemical characteristics of the collagen network (collagen content, hydroxylysine content and hydroxylysylpyridinoline [HP] crosslinks) were measured in immature articular cartilage of neonatal (n = 16), 5-month-old foals (n = 16) and yearlings (n = 16) at 2 predefined differently loaded sites within the metacarpophalangeal joint. Statistical differences between sites were analysed by ANOVA (P<0.01), and age correlation was tested by Pearson's product moment correlation analysis (P<0.01). In neonatal cartilage no significant site differences were found for any of the measured biochemical parameters. This revealed that the horse has a biochemically uniform joint (i.e. the cartilage) at birth. In the 5-month-old foals and yearlings, significant site differences, comparable to those in the mature horse, were found for DNA, GAG, collagen content and hydroxylysine content. This indicates that functional adaptation of articular cartilage to weight bearing for these biochemical parameters takes place during the first months postpartum. Water content and HP crosslinks showed no difference between the 2 sites from neonatal horses, 5-month-old animals and yearlings. At both sites water, DNA and GAG decreased during maturation while collagen content, hydroxylysine content and HP crosslinks increased. We propose that a foal is born with a uniform biochemical composition of cartilage in which the functional adaptation to weight bearing takes place early in life. This adaptation results in biochemical and therefore biomechanical heterogeneity and is thought to be essential to resist the different loading conditions to which articular cartilage is subjected during later life. As collagen turnover is extremely low at mature age, an undisturbed functional adaptation of the collagen network of articular cartilage at a young age may be of significant importance for future strength and resistance to injury.

Age Factors↗
PubMed2001

The effect of dynamic compression on the response of articular cartilage to insulin-like growth factor-I.

Articular cartilage is routinely subjected to mechanical forces and to cell-regulatory molecules. Previous studies have shown that mechanical stimuli can influence articular chondrocyte metabolic activity, and biochemical studies have shown that growth factors and cytokines control many of the same cell functions. Little is known, however, of the relationships or interplay, if any, between these two key components of the articular environment. This study investigated the comparative and interactive effects of low amplitude, sinusoidal, dynamic compression and insulin-like growth factor-I (IGF-I), a polypeptide in synovial fluid that is anabolic for cartilage. In bovine patellofemoral cartilage explants, IGF-I increased protein and proteoglycan synthesis 90% and 120%, respectively while dynamic compression increased protein and proteoglycan synthesis 40% and 90%, respectively. Stimulation by IGF-I was significantly greater than by dynamic compression for both protein and proteoglycan synthesis. When applied together, the two stimuli enhanced protein and proteoglycan synthesis by 180% and 290%, respectively, a degree greater than that achieved by either stimulus alone. IGF-I augmented protein synthesis with a time constant of 12.2 h. Dynamic compression increased protein synthesis with a time constant of 2.9 h, a rate significantly faster than that of IGF-I, suggesting that these signals act via distinct cell activation pathways. When used together, dynamic compression and IGF-I acted with a time constant of 5.6 h. Thus, dynamic compression accelerated the biosynthetic response to IGF-I and increased transport of IGF-I into the articular cartilage matrix, suggesting that, in addition to independently stimulating articular chondrocytes, cyclic compression may improve the access of soluble growth factors to these relatively isolated cells.

Animals↗
PubMed1993

Viscoelastic shear properties of articular cartilage and the effects of glycosidase treatments.

The objectives of this study were to determine the viscoelastic shear properties of articular cartilage and to investigate the effects of the alteration of proteoglycan structure on these shear properties. Glycosidase treatments (chondroitinase ABC and Streptomyces hyaluronidase) were used to alter the proteoglycan structure and content of the tissue. The dynamic viscoelastic shear properties of control and treated tissues were measured and statistically compared. Specifically, cylindrical bovine cartilage specimens were subjected to oscillatory shear deformation of small amplitude (gamma degrees = 0.001 radian) over a physiological range of frequencies (0.01-20 Hz) and at various compressive strains (5, 9, 12, and 16%). The dynamic complex shear modulus was calculated from the measurements. The experimental results show that the solid matrix of normal articular cartilage exhibits intrinsic viscoelastic properties in shear over the range of frequencies tested. These viscoelastic shear properties were found to be dependent on compressive strains. Our data also provide significant insights into the structure-function relationships for articular cartilage. Significant correlations were found between the material properties (the magnitude of dynamic shear modulus, the phase shift angle, and the equilibrium compressive modulus), and the biochemical compositions of the cartilage (collagen, proteoglycan, and water contents). The shear modulus was greatly reduced when the proteoglycans were degraded by either chondroitinase ABC or Streptomyces hyaluronidase. The results suggest that the ability of collagen to resist tension elastically provides the stiffness of the cartilage matrix in shear and its elastic energy storage capability. Proteoglycans enmeshed in the collagen matrix inflate the collagen network and induce a tensile prestress in the collagen fibrils. This interaction of the collagen and proteoglycan within the cartilage matrix provides the complex mechanism that allows the tissue to resist shear deformation.

Animals↗
PubMed1992

Local stimulation of proteoglycan synthesis in articular cartilage explants by dynamic compression in vitro.

Cultured bovine articular cartilage was subjected to 50 ms, 0.5-1.0 MPa compressions repeated at intervals of 2-60 s for 1.5 h and simultaneously labeled with 35SO4. The compression was delivered with a 4-mm-diameter nonporous loading head on an 8-mm-diameter cartilage explant. This method created directly compressed (central) and uncompressed (border) areas within the tissue. Analysis of the whole explant under a 0.5 MPa load showed significantly increased 35SO4 incorporation by compression repeated at 2- and 4-s but not at 20- and 60-s intervals. When the incorporation was studied separately in the border and central areas, a statistically significant stimulation was noticed in the central area with a 4-s cycle, while the border area was stimulated with a 2-s cycle. Autoradiography of the central area showed that the stimulation with 0.5 MPa and a 4-s cycle occurred through the whole depth of the cartilage, while raising the pressure to 1 MPa or the frequency to 2 s reduced the stimulation, particularly in the superficial cartilage. In the border area the stimulation with 0.5 MPa and a 2-s cycle was noted in the superficial zone only. The stimulation of proteoglycan synthesis is thus limited to certain loading frequencies and pressures and occurs in specific areas under and around the loaded site. Its rapid appearance suggests enhanced glycosylation or sulfation of core proteins or enhanced speed of posttranslational processing.

Animals↗
PubMed2000

Delamination rates of tissue flaps used in articular cartilage repair.

A popular strategy in the treatment of articular cartilage lesions involves the introduction of cell suspensions into the defect void and its closure with a periosteal flap (autologous chondrocyte transplantation technique). We applied this methodology in goats and discovered that all sutured flaps (n = 6 animals) became detached from nonimmobilized joints during the recovery period. The purpose of this study was to ascertain whether postoperative restriction of joint movement could prevent the delamination of flaps. Partial-thickness defects were created in the knee joint cartilage of 27 goats. These defects were then filled with a fibrin matrix and covered with periosteal (n = 6) or fascial (n = 21) flaps, which were sutured with simple, interrupted stitches to the surrounding tissue. The joints were immobilized by means of a modified Robert Jones bandage for periods of 2-6 weeks, after which time they were inspected for the absence or presence of flaps. In four animals, joint immobilization for 3 weeks was followed by free movement for a similar period. Four of the six periosteal flaps and two of the 21 fascial ones became delaminated after the period of immobilization. In the four goats permitted 3 weeks of free joint movement following a similar period of joint immobilization, all flaps (which had been retained up to the end of the immobilization period) became detached. These findings indicate that joint immobilization hinders the delamination of flaps but that this restriction of movement must be sustained for an undefined period of time. The nature of the tissue used for flaps also influences their rate of retention by immobilized joints.

Animals↗
PubMed1997

The use of active shape models for making thickness measurements of articular cartilage from MR images.

Previously reported studied to quantify articular cartilage have used labor-intensive manual or semi-automatic data-driven techniques, demonstrating high accuracy and precision. However, none has been able to automate the segmentation process. This paper describes a fast, automatic, model-based approach to segmentation and thickness measurement of the femoral cartilage in 3D T1-weighted images using active shape models (ASMs). Systematic experiments were performed to assess the accuracy and precision of the technique with in vivo images of both normal and abnormal knees. Segmentation accuracy was determined by comparing the results of the segmentation with the boundaries delineated by a radiologist. The mean error in locating the boundary was 0.57 pixels. To assess the precision of the measurement technique, the mean thickness of the femoral cartilage was calculated for repeated scans of five healthy volunteers. A mean coefficient of variation (CV) of 2.8% was obtained for the thickness measurements.

Cartilage, Articular↗
PubMed1971

Heterogeneity of protein-polysaccharides of porcine articular cartilage. The chondroitin sulphate proteins associaterd with collagen.

Pig articular cartilage, from which protein-polysaccharides soluble in iso-osmotic sodium acetate had been removed, was extracted in three further stages with 8m-urea in 2m-sodium acetate and with tris-HCl buffer after bacterial collagenase digestion, followed by the same urea-sodium acetate solution, thus leaving only 2% of the original uronic acid in the tissue. The histological appearance of the cartilage was unaltered until after collagenase digestion. The collagenase used did not affect the viscosity or molecular size of a protein-polysaccharide preparation obtained previously. The protein-polysaccharides in each extract differed in size, amino acid composition and protein content, but protein and keratan sulphate contents were not related to hydrodynamic size, in contrast with protein-polysaccharides extracted previously before collagenase digestion. Hydroxyproline could not be removed from those obtained by the first urea-sodium acetate extraction until degraded by heat. The galactosamine/pentose molar ratio agreed closely with the galactosamine/serine molar ratio that was destroyed on treatment with 0.5m-sodium hydroxide, showing that chondroitin sulphate was attached only to serine residues. From these molar ratios the chondroitin sulphate chains were calculated to be of the same average length in protein-polysaccharides in all three extracts although somewhat shorter than in protein-polysaccharides extracted previously. Some threonine residues were also destroyed on alkali treatment suggesting that keratan sulphate may be attached to threonine. These findings together with previous results show that differences in size, composition and physical state extend to all the protein-polysaccharides in cartilage.

Acetates↗
PubMed1981

Extractable proteoglycan from human femoral-head articular cartilage.

Proteoglycans were prepared from human femoral-head articular cartilage by using either guanidinium hydrochloride or MgCl2 as extractant, followed by density-gradient centrifugation. The proteoglycan subunit had a particle weight of 2.6 x 10(6), with a radius of gyration, RG, of 68.5 nm in 150 mM-NaCl/20 mM-sodium phosphate buffer, pH 7.0. The proteoglycan aggregate had a particle weight of 3.7 x 10(6) (RG 84 nm) for guanidinium hydrochloride extracts and 8.7 x 10(6) (RG 118 nm) for MgCl2 extracts in the same buffer. The addition of excess of high-molecular-weight hyaluronate did not significantly alter the particle size of the aggregate. The small increase in size probably reflects a rapid equilibrium between hyaluronate and proteoglycan monomers, and is not due to proteolytic cleavage producing non-aggregating units. Experiments that support the rapid-interaction hypothesis include analytical ultracentrifugation and column chromatography. This interaction does not appear to be pressure-sensitive at 20 degrees C, but is sensitive to temperature variation near the physiological range.

Adolescent↗
PubMed1983

Age-related changes in the structure of proteoglycan link proteins present in normal human articular cartilage.

Link proteins were identified immunologically in human articular-cartilage protein preparations from various individuals. Irrespective of age, all cartilages contained three link proteins of mol.wts. 48000, 44000 and 41000. However, with increasing age, multiple additional components of mol.wts. 26000-30000 were commonly observed under conditions where disulphide bonds were reduced.

Aging↗
PubMed1984

Extracts of human articular cartilage contain an inhibitor of tissue metalloproteinases.

When human articular cartilage is extracted with 2M-guanidinium hydrochloride at pH 7.5, an inhibitor is obtained that blocks the activity of three metalloproteinases, including collagenase. Molecular-sieve chromatography of the inhibitor gives an Mr value for the inhibitor of 28 500. The inhibitor is stable to heat (60 degrees C, 1h) and acid (pH2, 24 degrees C, 10 min). It is destroyed by trypsin and by reduction and alkylation. It is slowly inactivated by aminophenylmercuric acetate. It binds to concanavalin A-Sepharose and is eluted with alpha-D-1-O-methyl glucopyranoside. Complexes of enzyme and inhibitor are not re-activated by aminophenylmercuric acetate and only partially so by high levels of trypsin. These properties indicate that this inhibitor is a member of the TIMP (tissue inhibitor of metalloproteinases) class. Such an inhibitor, previously found in tissue culture and amniotic fluid, is now shown to be directly extractable from tissue.

Alkylation↗
PubMed1986

Control of proteoglycan biosynthesis. Further studies on the effect of serum on cultured bovine articular cartilage.

Proteoglycan synthesis in explant cultures of adult bovine articular cartilage is stimulated in a dose-dependent manner when the tissue is cultured in the presence of foetal-calf serum. The stimulation of proteoglycan synthesis is paralleled by a similar increase in DNA synthesis; however, when DNA synthesis is inhibited by hydroxyurea the stimulation of proteoglycan synthesis by serum remains essentially the same. The apparent half-life of the pool of proteoglycan core protein precursor was measured in freshly isolated tissue as well as in tissue cultured for 7 days in the presence and in the absence of foetal-calf serum; under all conditions the half-life was the same, suggesting that this value is independent of the net rate of proteoglycan synthesis. In the presence of actinomycin D, an inhibitor of RNA synthesis, there was a difference in the apparent half-life of the available pool of mRNA coding for proteoglycan core protein: 8.5 h for tissue maintained in the presence of serum and 3.8 h for tissue cultured in the absence of serum. It is suggested that proteoglycan synthesis is stimulated by serum factors at the level of DNA-dependent RNA synthesis. Concomitant with an increase in the rate of proteoglycan synthesis induced by the presence of serum in the culture medium, an increase in the concentrations of several glycosyltransferases involved in chondroitin sulphate synthesis was also observed.

Animals↗
PubMed1979

Single cilia in the articular cartilage of the cat.

Single cilia (SC) in the articular cartilage of the cat are described with regard to structure, frequency and intracellular location. Comparison is made with their occurrence in the cartilage of other species or in other tissues; special consideration is given to their developmental stages. In the 1-year-old cat examined, about 20% of the cells showed SC with a predominantly intracellular course and some of them did not reach the extracellular space at all. Cross-sections of the proximal region of SC reveal the familiary 9+0 pattern; towards the distal end, the number of doublets and the diameter of the shaft are decreasing. It is concluded that most of the SC encountered are undergoing involution.

Animals↗