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At least 109 records · Page 6Linked to original sources
PubMed2005

Cartilage glycosaminoglycan loss in the acute phase after an anterior cruciate ligament injury: delayed gadolinium-enhanced magnetic resonance imaging of cartilage and synovial fluid analysis.

OBJECTIVE: To examine the glycosaminoglycan (GAG) content in cartilage and that in synovial fluid and determine whether they are associated, in patients with an acute anterior cruciate ligament (ACL) injury. METHODS: Twenty-four patients (14 of whom were male) with a mean age of 27 years (range 17-40 years) were assessed with delayed gadolinium-enhanced magnetic resonance imaging (MRI) of cartilage an average of 3 weeks after an ACL rupture and compared with 24 healthy volunteers. Two hours after an intravenous injection of Gd-DTPA(2-) (0.3 mmoles/kg body weight), quantitative measurements of the T1 relaxation time (T1(Gd) [T1 relaxation time in the presence of Gd-DTPA]) were made in lateral and medial femoral weight-bearing cartilage. In the patients, synovial fluid was aspirated immediately before the MRI, and GAG was analyzed using dye precipitation with Alcian blue. RESULTS: Fifteen of the 24 patients had an isolated bone bruise in the lateral femoral condyle, where the cartilage T1(Gd) was shorter than that in the controls (mean +/- SD 385 +/- 83 msec and 445 +/- 41 msec, respectively; P = 0.004), consistent with decreased GAG content. However, the T1(Gd) was also decreased in the medial femoral cartilage, where bone bruises were rare (376 +/- 76 msec in patients versus 428 +/- 38 msec in controls; P = 0.006). The mean +/- SD synovial fluid GAG concentration in patients was 157 +/- 86 mug/ml and showed a positive correlation with the T1(Gd) (r = 0.49, P = 0.02). CONCLUSION: This study indicates that an ACL injury causes posttraumatic edema of the lateral femoral cartilage but initializes a generalized biochemical change within the knee that leads to GAG loss from both lateral and medial femoral cartilage. In cartilage with a high GAG content (long T1(Gd)), more GAG is released into the synovial fluid, suggesting that cartilage quality is a factor to consider when interpreting cartilage biomarkers of metabolism.

Adolescent↗
PubMed2004

Investigations into growth and differentiation in the cartilage of the condylar process in the domestic pig. A quantitative study of endochondral cartilage growth and cell distribution.

AIM: The aim of this study was to examine the extent to which the ratio of the endochondral growth components cell volume increase to matrix production was subject to age-dependent and animal-specific changes per cell in the condylar cartilage of the domestic pig. In addition, it was to be investigated whether the cell distribution in the condylar cartilage and thus the tissue differentiation changes as one aspect of the aging process and whether the differentiation differs from that of primary hyaline cartilage. MATERIAL AND METHODS: The tissue specimens available were hematoxylin/eosin-stained section series from the cartilage of the condylar process of six domestic pigs (0-24 months) of the genus Suis scrofa. Using a special squared measuring grid in the optical path of a microscope, the following histomorphometric primary parameters were ascertained in the cartilage zones under investigation: the average section area of the cartilage cells and the number of cut cells per unit area. From these figures, the cell volume and the extracellular matrix volume per cell were calculated using the stereological calculation algorithm for ellipsoids of revolution in accordance with Weibel and Gomez. Quantitative analysis of the cell distribution pattern was based on two methods used in stochastic geometry: calculation of the dispersion index DI, and performance of the chi(2) adaptation test. RESULTS: It was shown that, in this species of experimental animal, the relative proportion of cell volume increase in the complete process of endochondral growth is predominant until the juvenile stage at 11 months. In late puberty, volume gain as a result of matrix synthesis then exceeds cell volume increase. Comparisons with other stereological growth studies show that the investigated ratio in the condylar cartilage of the domestic pig has a similar aging behavior to that in the rat. By contrast, the matrix synthesis is predominant in the monkey. The cell clustering typical of mature hyaline cartilage in other joints was not observed at any stage in the development of the condylar cartilage. This suggests that the differentiation process is adapted in a special way to the stress-strain relationship in the temporomandibular joint. CONCLUSION: The methods used successfully in the present study for measuring and evaluating uninfluenced cartilage growth in the condylar process of the domestic pig is suitable for more extensive basic studies into the influence of orthodontic treatment on joint development.

Aging↗
PubMed1998

Magnetic resonance imaging of articular cartilage: ex vivo study on normal cartilage correlated with magnetic resonance microscopy.

The aims of this study were (a) to compare the MR appearance of normal articular cartilage in ex vivo MR imaging (MRI) and MR microscopy (MRM) images of disarticulated human femoral heads, (b) to evaluate by MRM the topographic variations in articular cartilage of disarticulated human femoral heads, and subsequently, (c) to compare MRM images with histology. Ten disarticulated femoral heads were examined. Magnetic resonance images were obtained using spin-echo (SE) and gradient-echo (GE) sequences. Microimages were acquired on cartilage-bone cylindrical plugs excised from four regions (superior, inferior, anterior, posterior) of one femoral head, using a modified SE sequence. Both MRI and MRM images were obtained before and after a 90 degrees rotation of the specimen, around the axis perpendicular to the examined cartilage surface. Finally, MRM images were correlated with histology. A trilaminar appearance of articular cartilage was observed with MRI and with a greater detail with MRM. A good correlation between MRI and MRM features was demonstrated. Both MRI and MRM showed a loss of the trilaminar cartilage appearance after specimen rotation, with greater evidence on MRM images. Cartilage excised from the four regions of the femoral head showed a different thickness, being thickest in the samples excised from the superior site. The MRM technique confirms the trilaminar MRI appearance of human articular cartilage, showing good correlation with histology. The loss of the trilaminar appearance of articular cartilage induced by specimen rotation suggests that this feature is partially related to the collagen-fiber orientation within the different layers. The MRM technique also shows topographic variations in thickness of human articular cartilage.

Aged↗
PubMed2006

Treatment of articular cartilage defects in horses with polymer-based cartilage tissue engineering grafts.

The objective of our study was to evaluate the integration of autologous cartilage tissue engineering transplants based on resorbable polyglactin/polydioxanone scaffolds into full-thickness cartilage defects of horses. Cartilage biopsies were taken from the non-load-bearing area of the lateral talus of the left tibiotarsal joint of eight healthy Haflinger horses. Tissue engineering cartilage transplants were generated by three-dimensional arrangement of autologous chondrocytes in biocompatible and resorbable polymer scaffolds. Full-thickness cartilage defects of 8 mm in diameter were created in the tubular bone condyle of the fetlock joint and cartilage grafts were fixed using an anchor system, while defects without grafting served as controls. After 6 and 12 months the repair tissue was evaluated histologically and showed formation of a cartilaginous tissue and good integration into the surrounding host tissue with firm bonding of the graft to the adjacent cartilage and the underlying subchondral bone. Biochemical analysis demonstrated that the content of glycosaminoglycans and hydroxyproline is comparable in repair tissue derived from treated and control defects. The use of three-dimensional autologous cartilage transplants based on resorbable polymer scaffolds ensures secure fixation, good integration of the graft into cartilage lesions, and is therefore suggested as a promising therapeutic option for the treatment of cartilage defects.

Animals↗
PubMed2005

Novel ultrasonic evaluation of tissue-engineered cartilage for large osteochondral defects--non-invasive judgment of tissue-engineered cartilage.

Although numerous methods for regenerating articular cartilage have been investigated, the regenerated tissue showed various histological findings from hyaline-like cartilage to fibrous tissue. Without biopsy, we are unable to know whether the cartilage regeneration method was histologically successful or not. We developed a new ultrasonic evaluation system for articular cartilage using the maximum magnitude (MM) from ultrasonic analysis. The purpose of this study was to investigate the usefulness of ultrasonic judgment of the cartilage regeneration procedure. Using our system we quantitatively evaluated tissue-engineered cartilage in rabbit cartilage defects. The specimens were retrospectively divided into two groups on the basis of histological findings and investigated whether significant differences in ultrasonic analysis could be found between the two (group H: hyaline-like cartilage group, successful; group F: fibrous tissue group, failure). In the ultrasonic findings, the MM was 1.11+/-0.32 in group H and 0.65+/-0.18 in group F and these differences were significant (P=0.00061). Our results suggest that the ultrasonic evaluation system used in the present study is capable of judging the success or failure of cartilage regeneration procedures, and therefore, it could be a valuable tool arthroscopic diagnosis of cartilage regeneration.

Animals↗
PubMed2000

Tracheal reconstruction using alcohol-stored homologous cartilage and autologous cartilage in the rabbit model.

OBJECTIVE: Reconstruction of laryngotracheal stenosis continues to pose a significant challenge. Cartilage grafts have been in use for almost a century, but despite good clinical results, many questions concerning the survival and growth of implanted cartilage persist. To reduce donor site morbidity, the use of homologous cartilage has been investigated. This study compared alcohol-stored homologous auricular cartilage with autologous auricular cartilage for anterior graft laryngotracheal reconstruction in a rabbit model. METHODS: Autologous and alcohol preserved homologous auricular cartilage was transplanted to the resected anterior tracheal wall of the twenty New Zealand rabbits. Rabbits were sacrificed 6 weeks after surgery and histologic analysis was performed on the implanted cartilage grafts. RESULTS: The autografts were significantly more likely than the homografts to demonstrate viable cells (95% vs. 30%, P<0.05) and less likely to exhibit significant resorption, fibrosis or necrosis (P<0.05). Resorption and necrosis were most common in areas of trauma to the graft. Complete epithelialization occurred in all of the autografts but in only 65% of the homografts (P<0.05). New cartilage formation and integration of the implanted grafts was poor with both types of grafts. CONCLUSION: Autologous cartilage appears to have better survival than alcohol preserved homologous cartilage when used for anterior graft laryngotracheal reconstruction in a rabbit model.

Animals↗
PubMed2004

Restoration of arthritic cartilage defects using autologous chondrocytes transplantation is superior to cartilage-paste graft in rabbits.

This study compared the articular cartilage repair potential of cultured chondrocytes transplantation with bone-cartilage paste-graft in the resurfacing of full-thickness defects without breaching of the subchondral bone plate in rabbit knees. A 5 x 5-mm articular cartilage defect was created in the patellar groove of the femur. Three months following creation, the defect was filled with cultured autologous chondrocytes (group 1) or bone-cartilage paste (group 2). A control group of untreated defects was followed for 1 year. The reparative tissue was analyzed macroscopically, histologically, and by immunohistochemistry 3-12 months post-transplantation. The surfaces of the reparative tissue in group 1 were smooth, and the defects were filled with reparative tissue that resembled hyaline cartilage. The composition of the repair tissue more closely resembled cartilage, as demonstrated by cartilage-specific stains. In contrast, the reparative tissue in group 2 was fibrous and exhibited markers of mesenchymal stem cells and bone formation. Transplantation of cultured chondrocytes into a full-thickness defect in the rabbit generates a biologic substitute tissue that resembles native articular cartilage with living cells capable of synthesizing the surrounding cartilage matrix. In contrast, analysis of the healing response to the paste-graft technique failed to show cartilage-like characteristics. This information may be clinically applicable to direct the use of these treatments in chondral injuries.

Animals↗
PubMed2002

Cartilage-specific matrix protein, chondromodulin-I (ChM-I), is a strong angio-inhibitor in endochondral ossification of human neonatal vertebral tissues in vivo: relationship with angiogenic factors in the cartilage.

Although cartilage contains many angiogenic factors during endochondral ossification, it is an avascular tissue. The cartilage-specific non-collagenous matrix protein chondromodulin-I (ChM-I) has been shown to be a strong angio-inhibitor. To elucidate whether ChM-I plays an essential role in angio-inhibition during endochondral ossification in man, we investigated the expression and localization of ChM-I in comparison with those of angiogenic factors and the endothelial cell marker CD34 in human neonatal vertebral tissues. Although invasion of CD34-positive endothelial cells was observed in primary subchondral spongiosa, expression of the marker of endothelial cells, CD34, was not found in neonatal vertebral cartilage matrix. Type II collagen was deposited in all matrices during endochondral ossification, whereas aggrecan was deposited in the matrix of hypertrophic cartilage, especially around lacunae. Vascular endothelial growth factor (VEGF), which is known to be a strong angiogenic factor, was localized in chondrocytes in mature to hypertrophic cartilage and also in bone marrow. Fibroblast growth factor-2 (FGF-2; basic fibroblast growth factor), which is also known to be a strong angiogenic factor, was localized in the cytoplasm of chondrocytes of mature cartilage in human vertebral cartilage tissues. Transforming growth factor (TGF)-beta has been reported to have many functions including angiogenesis, and TGF-beta1 was also localized in mature chondrocytes in endochondral tissues undergoing ossification. On the other hand, the novel cartilage-specific matrix protein ChM-I was localized in interterritorial regions of the matrix in mature to hypertrophic cartilage, especially around lacunae. In conclusion, these observations indicate that ChM-I may serve as a barrier against the angiogenic properties of VEGF, FGF-2 and TGF-beta1 during endochondral ossification, and this matrix molecule may play an essential role in determining the avascular nature of cartilage in vivo.

Angiogenesis Inducing Agents↗
PubMed2003

Articular cartilage restoration with costal cartilage previously fused with bone.

A novel procedure was developed for restoration of an articular cartilage defect using an autologous costal cartilage prepared with iliac bone, and the durability in vivo of this biologic construct was examined. First, an osteochondral complex was prepared (successful preparation, 67 of 80). Cancellous bone blocks isolated from the ilium of male Japanese White rabbits aged 5 months were implanted onto the surface of the costal cartilage before being tied by a pair of 3-0 silk thread sutures that were looped around the costal cartilage from behind. Second, 3 months later, the bone-attached costal cartilage was harvested and implanted into a full-thickness cartilage defect induced in a trochlear groove of the femur. All of the grafts were fixed to the recipient, maintaining its cartilage structure until 6 months (n = 28) and 12 months (n = 12) after implantation. However, when the costal cartilage without any bony portion was implanted into a similarly induced defect, 42% (10 of 24) were detached from the recipient before 12 months after implantation. The nontreated defect did not heal spontaneously to a satisfactory level (n = 12). These findings suggest that an osteochondral fragment, prepared by grafting cancellous bone onto costal cartilage, can be used for articular cartilage restoration.

Animals↗
PubMed2004

Hyaline cartilage engineered by chondrocytes in pellet culture: histological, immunohistochemical and ultrastructural analysis in comparison with cartilage explants.

Cartilage engineering is a strategic experimental goal for the treatment of multiple joint diseases. Based on the process of embryonic chondrogenesis, we hypothesized that cartilage could be engineered by condensing chondrocytes in pellet culture and, in the present study, examined the quality of regenerated cartilage in direct comparison with native cartilage. Chondrocytes isolated from the sterna of chick embryos were cultured in pellets (4 x 10(6) cells per pellet) for 2 weeks. Cartilage explants from the same source were cultured as controls. After 2 weeks, the regenerated cartilage from pellet culture had a disc shape and was on average 9 mm at the longest diameter. The chondrocyte phenotype was stabilized in pellet culture as shown by the synthesis of type II collagen and aggrecan, which was the same intensity as in the explant after 7 days in culture. During culture, chondrocytes also continuously synthesized type IX collagen. Type X collagen was negatively stained in both pellets and explants. Except for fibril orientation, collagen fibril diameter and density in the engineered cartilage were comparable with the native cartilage. In conclusion, hyaline cartilage engineered by chondrocytes in pellet culture, without the transformation of cell phenotypes and scaffold materials, shares similarities with native cartilage in cellular distribution, matrix composition and density, and ultrastructure.

Aggrecans↗
PubMed2004

Gender-specific distribution of glycosaminoglycans during cartilage mineralization of human thyroid cartilage.

The role of glycosaminoglycans (GAG) in the process of cartilage mineralization, especially in the hypertrophic zone of growth plates, is not yet fully understood. Human thyroid cartilage can serve as a model to observe matrix changes associated with cartilage mineralization because the processes follow a distinct route, progress very slowly and show sexual differences. Histochemical staining for low sulphated GAG (chondroitin-4- and -6-sulphates) was decreased in the interterritorial matrix of thyroid cartilage starting at the beginning of the fifth decade, but not in the pericellular or territorial matrix of chondrocytes. Because cartilage mineralization progressed in the interterritorial matrix it seems likely that a decreasing content of chondroitin-4- and -6-sulphates is involved in the mineralization process. This hypothesis is supported by the observation that immunostaining for chondroitin-4- and -6-sulphates was weaker in mineralized cartilage areas than in unmineralized areas, whereas there was no difference in staining for keratan sulphate. In all life decades, female thyroid cartilages contained more chondrocytes with a territorial rim of chondroitin-4- and -6-sulphates probably preventing cartilage mineralization compared with age-matched male specimens. Taken together, the characteristic distribution pattern of chondroitin-4- and -6-sulphates being more concentrated in female than in male thyroid cartilages provided evidence that these macromolecules decrease in cartilage mineralization.

Adolescent↗
PubMed1998

Articular cartilage superficial zone collagen birefringence reduced and cartilage thickness increased before surface fibrillation in experimental osteoarthritis.

OBJECTIVES: To investigate articular cartilage collagen network, thickness of birefringent cartilage zones, and glycosaminoglycan concentration in macroscopically normal looking knee joint cartilage of young beagles subjected to experimental slowly progressive osteoarthritis (OA). METHODS: OA was induced by a tibial 30 degree valgus osteotomy in 15 female beagles at the age of 3 months. Fifteen sisters were controls. Cartilage specimens were collected seven (Group 1) and 18 months (Group 2) postoperatively. Collagen induced optical path difference and cartilage zone thickness measurements were determined from histological sections of articular cartilage with smooth and intact surface by computer assisted quantitative polarised light microscopy. Volume density of cartilage collagen fibrils was determined by image analysis from transmission electron micrographs and content of glycosaminoglycans by quantitative digital densitometry from histological sections. RESULTS: In the superficial zone of the lateral tibial and femoral cartilage, the collagen induced optical path difference (birefringence) decreased by 19 to 71% (p < 0.05) seven months postoperatively. This suggests that severe superficial collagen fibril network deterioration took place, as 18 months postoperatively, macroscopic and microscopic OA was present in many cartilage areas. Thickness of the uncalcified cartilage increased while the superficial zone became thinner in the same sites. In operated dogs, glycosaminoglycan content first increased (Group 1) in the lateral tibial condyle and then decreased (Group 2) (p < 0.05). CONCLUSION: In this OA model, derangement of the superficial zone collagen network was the probable reason for birefringence reduction. This change occurred well before macroscopic OA.

Animals↗
PubMed2005

Arthroscopic cartilage indentation and cartilage lesions of anterior cruciate ligament-deficient knees.

BACKGROUND: The anterior cruciate ligament-deficient knee is prone to osteoarthritis and meniscus lesions. Very little, however, is known about the biomechanical properties of articular cartilage in anterior cruciate ligament-deficient knees. PURPOSE: To evaluate biomechanical and macroscopical cartilage changes in the knee joint with respect to the time after anterior cruciate ligament rupture. HYPOTHESIS: Chronic anterior cruciate ligament deficiency induces cartilage softening. STUDY DESIGN: Cross-sectional study; Level of evidence, 3. METHODS: Cartilage stiffness of 50 patients undergoing anterior cruciate ligament reconstructive surgery because of symptomatic knee instability after chronic anterior cruciate ligament rupture was measured with an arthroscopic indenter device, and the number and size of cartilage lesions were evaluated. RESULTS: The cartilage stiffness did not correlate with time from trauma to surgery (r = 0.002, P = .99), but the number of cartilage lesions in the knee increased when the time from the initial trauma to reconstructive surgery increased (r = 0.356, P = .011). Indentation values measured on healthy-looking cartilage on damaged joint surfaces were lower than the values measured on healthy joint surfaces (P < .01 on lateral femoral condyle and on tibial plateaus). CONCLUSIONS: The number of cartilage lesions increases with increased time after initial trauma. The arthroscopic indenter device is able to detect cartilage softening as the early mechanical sign of degradation not yet visible to the eye.

Adolescent↗
PubMed1985

Chondrolysis associated with cartilage canals of the epiphyseal cartilage of the distal humerus of growing pigs.

The articular-epiphyseal (A-E) cartilage of the distal humeri of 7 pigs weighing 13.1 to 18.2 kg and of 3 pigs weighing 36.4 to 40.9 kg was studied. Frozen samples of A-E cartilage were stained for the presence of reduced nicotinamide adenine dinucleotide dehydrogenase, lactate dehydrogenase, isocitrate dehydrogenase, and uridine diphosphate galactose-4-epimerase. Additional frozen sections and paraffin-processed sections were stained using the Alcian blue-critical electrolyte concentration method, safranin O-fast green, and hematoxylin and eosin. An area of grossly visible, opaque A-E cartilage of the medial condyle corresponded to regions of chondrolysis of the epiphyseal cartilage. The chondrolytic regions contained chondrocytes that did not stain for enzymes, had reduced staining for proteoglycans in the matrix, and were located at the site where the A-E cartilage increased in thickness. Cartilage canals were associated with the chondrolytic areas. Cartilage canals in both groups of pigs were commonly in various stages of chondrification, some of which were associated with degenerative cartilage. The regions of chondrolysis may indicate sites of biomechanical weakness in the A-E cartilage during the transformation of the epiphyseal cartilage into bone.

Animals↗
PubMed1994

Effect of interleukin 1 on articular cartilage from young and aged horses and comparison with metabolism of osteoarthritic cartilage.

The effect of interleukin 1 (IL-1) on equine articular cartilage was investigated, using a cartilage explant culture system. Measurement of [35S]O4 incorporation revealed synthesis of matrix proteoglycan by cartilage to be decreased 45, 59.7, and 37.5% after 1, 3, and 5 days, respectively, in culture in the presence of 5 U of IL-1/ml. There was no change in proteoglycan degradation as determined by measurement of [35S]O4 release into the culture medium. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis of cartilage-conditioned medium indicated that exposure of cartilage to IL-1 caused a decrease in total protein synthesis by 45, 68, and 87% after 1, 3, and 5 days, respectively, in culture while selectively inducing synthesis of the 57-kd neutral metalloproteinase stromelysin (matrix metalloproteinase-3) in young and adult horses. Identification of stromelysin was confirmed by functional characterization and immunoprecipitation. Baseline total protein synthesis, as well as specific synthesis of stromelysin in cartilage from adult and aged horses, was markedly less than that of young horses. The IL-1-induced reduction in total protein synthesis may not be a characteristic of equine articular cartilage from affected joints of horses with naturally acquired osteoarthritis as indicated by an overall increase in protein synthesis by osteoarthritic explants. Introduction of IL-1 into an equine articular cartilage explant culture system resulted in decrease of matrix component synthesis and increase in specific degradative enzyme synthesis and activity. Articular cartilage from aged horses had markedly less overall metabolic activity, compared with cartilage from young horses.(ABSTRACT TRUNCATED AT 250 WORDS)

Aging↗
PubMed1989

Involvement of nonarticular cartilage, as demonstrated by release of a cartilage-specific protein, in rheumatoid arthritis.

Analysis of human cartilage extracts by radioimmunoassay showed that the noncollagenous 148-kd cartilage matrix protein was present in extracts of tracheal cartilage but was undetectable in normal or arthritic joint cartilage, corroborating previous results with bovine cartilage samples. Concentrations of the protein in the circulation, as studied by radioimmunoassay, were greatly elevated in patients with rheumatoid arthritis and polyarticular juvenile rheumatoid arthritis. In contrast, patients with reactive arthritis and oligoarticular juvenile rheumatoid arthritis, as well as rheumatoid arthritis patients treated with low-dose glucocorticoids, had levels similar to those in healthy controls. The serum concentrations were not related to age. A patient with polychondritis and tracheal involvement had a high serum concentration of the protein, which decreased during plasma exchange and cyclophosphamide treatment. Studies of the release of this cartilage matrix protein, which is present in nonarticular cartilage but not in articular cartilage, should aid in the understanding of the mechanisms of cartilage involvement in disease, and the protein may become a clinically useful marker.

Aged↗
PubMed1998

Epiphyseal and physeal cartilage vascularization: a light microscopic and tritiated thymidine autoradiographic study of cartilage canals in newborn and young postnatal rabbit bone.

The vascular pattern of newborn and early postnatal epiphyseal and physeal cartilage is integral to long bone development and differs from later postnatal patterns. In the present study, we supplement light microscopic histology with tritiated thymidine autoradiography to help assess the position of cartilage canals and the dynamics of cartilage vascularity in relation to growth. Tritiated thymidine labeling studies to assess cell proliferation activity were done by using 2 microc/g body weight intraperitoneal injections into newborn and 3-, 4-, and 7-day-old New Zealand white rabbits that were killed 1 hr after the injection. Proximal humeral, distal femoral, and third metatarsal epiphyses were assessed by routine histology and serial section autoradiography. Cartilage canals were seen in each epiphysis. Transphyseal vessels were seen in each epiphysis continuous from the epiphysis to the metaphysis or were present within the physis traversing the proliferating and hypertrophic cell zones. Histologic sections showed vessels from the perichondrium continuous with those of the epiphyseal cartilage canals at proximal humeral, distal femoral, and metatarsal epiphyses. Serial sections showed vascular buds and connective tissue cells lying in indentations at the periphery of and present within the epiphyseal cartilage. Autoradiographic studies showed extensive labeling of vessel wall cells and surrounding connective tissue cells of the cartilage canals (a) within the epiphyseal cartilage, (b) traversing the physis, and (c) within the epiphyseal cartilage but continuous with the perichondrial vessels. The labeling was always far more extensive than in the surrounding chondrocytes and was always present throughout the entire extent of the canals. In conclusion, the cell labeling activity strongly supports an active dynamic phenomenon underlying the vascularization of epiphyseal and physeal cartilage.

Age Factors↗
PubMed2003

1H magnetic resonance spectroscopy of nanomelic chicken cartilage: effect of aggrecan depletion on cartilage T2.

OBJECTIVE: To determine the effect of proteoglycan depletion on cartilage proton magnetic resonance (MR) spectroscopy T2 using nanomelic chicken cartilage, a genetic mutant that completely lacks aggrecan. DESIGN: Proton MR spectroscopic T2 measurements of normal embryonic and nanomelic femoral epiphyseal cartilage were obtained using a 96-echo pulse sequence with inter-echo delay times increased logarithmically over the TE period of 60 micros to 1.7 s. The relative intensity and distribution of cartilage T2 components were determined by fitting signal decay curves to a multi-exponential function. The number of T2 components in the signal decay curves was determined by the degree of freedom limited r2 of the fit. RESULTS: For normal fetal chicken cartilage, 97.6 +/- 0.2% (mean +/- 95% confidence interval) of the total signal comprises a long T2 component (179.1 +/- 1.3 ms) with a relatively small short T2 component (0.5 +/- 0.4 ms). The T2 distribution for nanomelic cartilage is more heterogeneous with four components identified: two short T2 components (0.5 +/- 0.02 and 7.3 +/- 0.6 ms), a large intermediate component (56.4 +/- 5.6 ms), and a broadly distributed long component (137.5 +/- 16.6 ms). In nanomelic cartilage there is greater heterogeneity of cartilage T2 indicating greater variation in water proton mobility and exchange of water with the extracellular matrix. CONCLUSION: Absence of aggrecan in the extracellular cartilage matrix produces greater heterogeneity in cartilage T2, but will not increase T2 as has been previously reported with degenerative change of the collagen matrix.

Aggrecans↗