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PubMed2001

Use of an antineoepitope antibody for identification of type-II collagen degradation in equine articular cartilage.

OBJECTIVE: To develop an antibody that specifically recognizes collagenase-cleaved type-II collagen in equine articular cartilage. SAMPLE POPULATION: Cartilage specimens from horses euthanatized for problems unrelated to the musculoskeletal system. PROCEDURE: A peptide was synthesized representing the carboxy- (C-) terminus (neoepitope) of the equine type-II collagen fragment created by mammalian collagenases. This peptide was used to produce a polyclonal antibody, characterized by western analysis for reactivity to native and collagenase-cleaved equine collagens. The antibody was evaluated as an antineoepitope antibody by ELISA, using peptides +/- an amino acid at the C-terminus of the immunizing peptide. Collagen cleavage was assayed from equine articular cartilage cultured with interleukin-1 (IL-1), +/- a synthetic MMP inhibitor, BAY 12-9566. Cartilage specimens from osteoarthritic and nonarthritic joints were compared for antibody staining. RESULTS: An antibody, 234CEQ, recognized only collagenase-generated 3/4-length fragments of equine type-II collagen. This was a true antineoepitope antibody, as altering the C-terminus of the immunizing peptide significantly decreased competition for binding in an inhibition ELISA. The IL-1-induced release of type-II collagen fragments from articular cartilage was prevented with the MMP inhibitor. Cartilage from an osteoarthritic joint of a horse had increased staining with the 234CEQ antibody, compared with normal articular cartilage. CONCLUSIONS AND CLINICAL RELEVANCE: We generated an antineoepitope antibody recognizing collagenase-cleaved type-II collagen of horses. This antibody detects increases in type-II collagen cleavage in diseased equine articular cartilage. The 234CEQ antibody has the potential to aid in the early diagnosis of arthritis and to monitor treatment responses.

Animals↗
PubMed2005

Effects of sodium hyaluronate and methylprednisolone acetate on proteoglycan synthesis in equine articular cartilage explants.

OBJECTIVE: To determine effects of sodium hyaluronate (HA) on corticosteroid-induced cartilage matrix catabolism in equine articular cartilage explants. SAMPLE POPULATION: 30 articular cartilage explants from fetlock joints of 5 adult horses without joint disease. PROCEDURE: Articular cartilage explants were treated with control medium or medium containing methylprednisolone acetate (MPA; 0.05, 0.5, or 5.0 mg/mL), HA (0.1, 1.0, or 1.5 mg/mL), or both. Proteoglycan (PG) synthesis was measured by incorporation of sulfur 35-labeled sodium sulphate into PGs, and PG degradation was measured by release of radiolabeled PGs into the medium. Total glycosaminoglycan (GAG) content in media and explants and total explant DNA were determined. RESULTS: Methylprednisolone acetate caused a decrease in PG synthesis, whereas HA had no effect. Only the combination of MPA at a concentration of 0.05 mg/mL and HA at a concentration of 1.0 mg/mL increased PG synthesis, compared with control explants. Methylprednisolone acetate increased degradation of newly synthesized PGs into the medium, compared with control explants, and HA alone had no effect. Hyaluronate had no effect on MPA-induced PG degradation and release into media. Neither MPA alone nor HA alone had an effect on total cartilage GAG content. Methylprednisolone acetate caused an increase in release of GAG into the medium at 48 and 72 hours after treatment. In combination, HA had no protective effect on MPA-induced GAG release into the medium. Total cartilage DNA content was not affected by treatments. CONCLUSIONS AND CLINICAL RELEVANCE: Our results indicate that HA addition has little effect on corticosteroid-induced cartilage matrix PG catabolism in articular cartilage explants.

Animals↗
PubMed2006

Assessment of the use of RNA quality metrics for the screening of articular cartilage specimens from clinically normal dogs and dogs with osteoarthritis.

OBJECTIVE: To assess 2 methods of RNA purification by use of different quality metrics and identify the most useful metric for quality assessment of RNA extracted from articular cartilage from dogs with osteoarthritis. SAMPLE POPULATION: 40 articular cartilage specimens from the femoral heads of 3 clinically normal dogs and 37 dogs with osteoarthritis. PROCEDURES: RNA was extracted from articular cartilage by 2 purification methods. Quality metrics of each sample were determined and recorded by use of a UV spectrophotometer (Spec I; to determine the 260 to 280 nm absorbance ratio [A(260):A(280) ratio]), a second UV spectrophotometer (Spec II; to determine A(260):A(280) and A(260):A(230) absorbance ratios), and a microfluidic capillary electrophoresis analyzer (to determine the ribosomal peak ratio [RR], degradation factor [DF], and RNA integrity number [RIN]). The RNA was extracted from affected (osteoarthritic) articular cartilage and assessed with the same quality metrics. Metric results were compared with visual analysis of the electropherogram to determine the most useful RNA quality metric. RESULTS: No differences in methods of RNA purification were determined by use of quality metrics. The RNA extracted from unaffected (normal) cartilage was of higher quality than that extracted from affected (osteoarthritic) cartilage, as determined by the RIN and Spec II A(260):A(230) ratio. The RIN and RR were the most sensitive metrics for determining RNA quality, whereas the DF was most specific. A significant proportion (32%) of RNA extracted from osteoarthritic articular cartilage specimens was determined as being of low quality. CONCLUSIONS AND CLINICAL RELEVANCE: No single metric provided a completely sensitive and specific assessment of the quality of RNA recovered from articular cartilage.

Animals↗
PubMed1998

Rehabilitation following surgical procedures to address articular cartilage lesions in the knee.

Knowledge of the structure and function of articular cartilage is important when considering rehabilitation following surgical procedures for articular cartilage lesions of the knee. Articular cartilage is avascular and derives its nutrition primarily from synovial fluid, resulting in a limited potential for regeneration. Basic science evidence has demonstrated that compressive loading may have a positive impact on articular cartilage healing; however, excessive shear loading may be detrimental. Rehabilitation following surgical procedures for articular cartilage lesions should include controlled range of motion exercises. Exercises to enhance muscle function must be done in a manner which minimizes shear loading of the joint surfaces in the area of the lesion. A period of protected weight bearing is often necessary and should be followed by progressive loading of the joint. This article will: 1) provide a brief review of the structure and function of articular cartilage lesions as it relates to rehabilitation; 2) describe common surgical procedures to address articular cartilage lesions; and 3) provide guidelines for rehabilitation following surgical management of articular cartilage lesions.

Animals↗
PubMed2000

Spontaneous production of nitric oxide (NO), prostaglandin (PGE2) and neutral metalloproteinases (NMPs) in media of explant cultures of equine synovial membrane and articular cartilage from normal and osteoarthritic joints.

Nitric oxide (NO), prostaglandin E2 (PGE2), and the activity of neutral metalloproteinases (NMPs) were measured in conditioned media of equine synovial membrane and articular cartilage explant cultures from horses with normal joints (n = 7) and from horses affected with moderate (n = 7) or severe osteoarthritis (n = 14) as judged by macroscopic appearance. Normal articular cartilage appeared glossy and bluish-white, was of normal thickness and showed no evidence of discolouration, fibrillation or other cartilage discontinuity. Slight discolouration and fibrillation or minor clefts of the cartilage were considered as moderate OA, whereas erosions of articular cartilage down to the subchondral bone were considered as cases of severe OA. Explant cultures of equine synovial membrane and articular cartilage released the local mediators, NO and PGE2, as well as detectable levels of NMP activity into culture media. Concentrations of NO were higher in articular cartilage explants compared to synovial membrane explants, whereas concentrations of PGE2 were higher in synovial membrane explants. The NMPs with collagenolytic activities were similar in both explant cultures, whereas gelatinolytic activities were higher in synovial membrane explant cultures and caseinolytic activities were generally higher in articular cartilage explant cultures. Furthermore it was shown that concentrations or enzyme activities increased according to the severity of disease of the joints. Concentrations for NO, collagenolytic and gelatinolytic NMPs were relatively stable, whereas PGE2 and caseinolytic NMP concentrations increased over time in culture.

Animals↗
PubMed2004

Clinical significance of ossification of the cartilages of the front feet based on nuclear bone scintigraphy, radiography and lameness examinations in 21 Finnhorses.

REASONS FOR PERFORMING STUDY: Research on the clinical significance of ossification of the cartilages of the foot has been limited, despite the common nature of the condition and conflicting reports in previous literature. HYPOTHESIS: Some radiographic features in the ossification of the cartilages, such as incomplete fusion lines between separate centres of ossification and the ossified base, are of clinical significance. METHODS: The relationships between radiopharmaceutical uptake in bone phase nuclear scintigraphy at the heels (palmar processes of the distal phalanx, including ossification of the cartilages of the foot), radiographic extent and type of ossification of the cartilages and clinical lameness were evaluated retrospectively in 21 Finnhorses (age > or = 4 years) in a total of 36 front feet. RESULTS: No significant relationship between height of the ossifications and radiopharmaceutical uptake at the ipsilateral heels existed. Clearly separate centres of ossification were not associated with increased uptake. Moderately increased uptake was suspected to be associated with ossification of the adjacent cartilage in only one foot. Intense uptake was present unilaterally in 4 horses, at one medial and 3 lateral heels. In 2 of these horses, a unilateral palmar digital nerve block relieved the mild lameness; 2 horses had no obvious lameness but had a history of being stiff or having locomotion problems during high speed trot. At 2 of the lateral heels, an incomplete fusion line was present between a large separate centre of ossification and the base, and the third horse had a high sidebone with bony protrusions, suggestive of chronic entheseopathy in a narrow foot. At the medial heel, an oblique radiograph revealed a faint radiolucent line at the base of the ossification. In all cartilages with intense radiopharmaceutical uptake at the heel and/or lameness, the ossified part of the cartilage was wider and more irregular compared to other ossifications of the front feet of the individual. CONCLUSIONS: Increased radiopharmaceutical uptake, associated with a different radiographic appearance from that of other ossifications of the front feet, was a conclusive sign of clinical significance. Obscure locomotion problems were more commonly associated with ossification of the cartilages than true lameness. POTENTIAL RELEVANCE: This information is useful in lameness and prepurchase examinations and is likely also to be applicable to other coldblooded breeds used for athletic purposes.

Animals↗
PubMed1986

Degradation of bovine articular cartilage proteoglycans in vitro. The effect of Bacteroides gingivalis.

The black-pigmented Bacteroides gingivalis has previously been isolated from periodontal pockets and been shown capable of inflicting advanced tissue damage. Its effect on the degradation of articular cartilage proteoglycans has not previously been known. In these experiments it was demonstrated that under aerobic conditions the anaerobic microbe B. gingivalis is very potent in degrading the proteoglycans of fresh articular cartilage. It is even more potent in the presence of fetal calf serum (FCS) than in its absence. When the cartilage has been frozen/thawed there is still a slight enhancement of the degradation by B. gingivalis, but when the cartilage has been devitalized and de-enzymed by heat, the cartilage-degrading capacity of B. gingivalis is totally abolished. However, addition to the cartilage cultures of filtered conditioned medium from B. gingivalis inhibits in some degree the degradation of articular cartilage proteoglycans. It is therefore suggested that the great cartilage-degrading ability of Bacteroides gingivalis shown in this culture system could be due to its ability to degrade proteinase inhibitors.

Animals↗
PubMed1993

Magnetic resonance imaging and morphometric quantitation of cartilage histology after chronic infusion of interleukin 1 in rabbit knees.

Cartilage pathology in rabbit knees was monitored by noninvasive magnetic resonance imaging (MRI) and evaluated using morphometric histologic measurements. Infusion of rabbit knees with the cytokine interleukin 1 induces cartilage degradation and inflammation. A miniosmotic pump was implanted subcutaneously to deliver interleukin 1 through a polyethylene catheter inserted into the rabbit knee. Rabbit knees were imaged using MRI and prepared for histologic examination at 5 and 12 days after chronic infusion of interleukin 1. MRI obtained 0.7-mm sections for three-dimensional reconstruction of cartilage image. Cartilage deterioration near the site of infusion was visible on MRI. MRI measurements indicated a reduction in cartilage thickness. Histology revealed a loss of staining of cartilage matrix proteoglycan, synovial hypertrophy, and perichondral bone resorption. Morphometric analysis of cartilage histology indicated a reduction in both cellularity (chondrocytes/m mu 2 area) and cell to matrix area ratio. These observations suggest that a loss of proteoglycan, an early event in cartilage degeneration, can be detected by MRI.

Animals↗
PubMed2005

Clinical and cost-effectiveness of autologous chondrocyte implantation for cartilage defects in knee joints: systematic review and economic evaluation.

OBJECTIVE: To support a review of the guidance issued by the National Institute for Health and Clinical Excellence (NICE) in December 2000 by examining the current clinical and cost-effectiveness evidence on autologous cartilage transplantation. DATA SOURCES: Electronic databases. REVIEW METHODS: Evidence on clinical effectiveness was obtained from randomised trials, supplemented by data from selected observational studies for longer term results, and for the natural history of chondral lesions. Because of a lack of long-term results on outcomes such as later osteoarthritis and knee replacement, only illustrative modelling was done, using a range of assumptions that seemed reasonable, but were not evidence based. RESULTS: Four randomised controlled trials were included, as well as observational data from case series. The trials studied a total of 266 patients and the observational studies up to 101 patients. Two studies compared autologous chondrocyte implantation (ACI) with mosaicplasty, the third compared ACI with microfracture, and the fourth compared matrix-guided ACI (MACI) with microfracture. Follow-up was 1 year in one study, and up to 3 years in the remaining three studies. The first trial of ACI versus mosaicplasty found that ACI gave better results than mosaicplasty at 1 year. Overall, 88% had excellent or good results with ACI versus 69% with mosaicplasty. About half of the biopsies after ACI showed hyaline cartilage. The second trial of ACI versus mosaicplasty found little difference in clinical outcomes at 2 years. Disappointingly, biopsies from the ACI group showed fibrocartilage rather than hyaline cartilage. The trial of ACI versus microfracture also found only small differences in outcomes at 2 years. Finally, the trial of MACI versus microfracture contained insufficient long-term results at present, but the study does show the feasibility of doing ACI by the MACI technique. It also suggested that after ACI, it takes 2 years for full-thickness cartilage to be produced. Reliable costs per quality-adjusted life-year (QALY) could not be calculated owing to the absence of necessary data. Simple short-term modelling suggests that the quality of life gain from ACI versus microfracture would have to be between 70 and 100% greater over 2 years for it to be more cost-effective within the 20,000--30,000 pounds sterling per QALY cost-effectiveness thresholds. However, if the quality of life gains could be maintained for a decade, increments relative to microfracture would only have to be 10--20% greater to justify additional treatment costs within the cost-effectiveness band indicated above. Follow-up from the trials so far has only been up to 2 years, with longer term outcomes being uncertain. CONCLUSIONS: There is insufficient evidence at present to say that ACI is cost-effective compared with microfracture or mosaicplasty. Longer term outcomes are required. Economic modelling using some assumptions about long-term outcomes that seem reasonable suggests that ACI would be cost-effective because it is more likely to produce hyaline cartilage, which is more likely to be durable and to prevent osteoarthritis in the longer term (e.g. 20 years). Further research is needed into earlier methods of predicting long-term results. Basic science research is also needed into factors that influence stem cells to become chondrocytes and to produce high-quality cartilage, as it may be possible to have more patients developing hyaline cartilage after microfracture. Study is also needed into cost-effective methods of rehabilitation and the effect of early mobilisation on cartilage growth.

Cartilage, Articular↗
PubMed1990

Changes in the hyaline articular cartilage after air exposure.

UNLABELLED: The changes of hyaline articular cartilage from rabbits after air exposure were evaluated. The knee joints were exposed to air for periods of thirty minutes to two hours. The animals were killed periodically, at three days, one week and three weeks postoperatively. After sacrifice, the cartilage was removed and prepared for study by light microscopy and electron microscopy. Exposure to room air for thirty minutes produced chondrocyte necrosis in the upper third of the cartilage, and exposure for 60 minutes or longer produced chondrocyte necrosis of the entire thickness of articular cartilage at three days after arthrotomy. But, three weeks after arthrotomy, we could not find any chondrocyte necrosis in any rabbits at varying periods of air exposure. There was no significant change in proteoglycan content between the aired and control cartilage. CLINICAL RELEVANCE: Exposing cartilage to air can cause transient and reversible cartilage damage. If these changes are not reversible, the orthopedic surgeon should consider avoiding the prolonged exposure of articular cartilage to air, since complete matrix disintegration is known to occur months after chondrocyte necrosis.

Air↗
PubMed1999

Spatiotemporal pattern of the mouse chondromodulin-I gene expression and its regulatory role in vascular invasion into cartilage during endochondral bone formation.

During endochondral bone formation, vascular invasion into cartilage initiates the replacement of cartilage by bone. Chondromodulin-I, a 25 kDa glycoprotein purified from bovine epiphyseal cartilage, was recently identified as a novel endothelial cell growth inhibitor. Here we cloned the mouse chondromodulin-I cDNA from a mouse whole embryo cDNA library. Northern blot analysis revealed that the chondromodulin-I transcripts were expressed in association with the formation of cartilage expressing type II collagen from days 11 to 17 of gestation in mouse embryos, at which time cartilaginous bone rudiments were gradually replaced by bone. Chondromodulin-I mRNA was also detected in the thymus and eyes at a lower level. In situ hybridization revealed significant expression in all cartilaginous tissues in the embryos at days 13.5 and 16 of gestation. However, the expression was completely abolished in the hypertrophic cartilage zone prior to calcification. Upon chondrogenic differentiation of mouse ATDC5 cells in vitro, the expression of chondromodulin-I transcripts was induced concomitantly with the formation of type II collagen-expressing chondrocytes. The expression of the transcripts then declined as type X collagen-expressing hypertrophic chondrocytes appeared in the culture. Purified chondromodulin-I protein inhibited the vascular invasion into cartilage ectopically induced by demineralized bone matrix in nude mice, leading to the suppression of bone formation in vivo. These results suggest that chondromodulin-I is involved in the anti-angiogenic property of cartilage, and that the withdrawal of its expression allows the vascular invasion which triggers the replacement of cartilage by bone during endochondral bone development.

Amino Acid Sequence↗
PubMed1999

Remobilization does not fully restore immobilization induced articular cartilage atrophy.

The recovery of articular cartilage from immobilization induced atrophy was studied. The right hind limbs of 29-week-old beagle dogs were immobilized for 11 weeks and then remobilized for 50 weeks. Cartilage from the immobilized knee was compared with tissue from age matched control animals. After the immobilization period, uncalcified articular cartilage glycosaminoglycan concentration was reduced by 20% to 23%, the reduction being largest (44%) in the superficial zone. The collagen fibril network showed no significant changes, but the amount of collagen crosslinks was reduced (13.5%) during immobilization. After remobilization, glycosaminoglycan concentration was restored at most sites, except for in the upper parts of uncalcified cartilage in the medial femoral and tibial condyles (9% to 17% less glycosaminoglycans than in controls). The incorporation of 35SO4 was not changed, and remobilization also did not alter the birefringence of collagen fibrils. Remobilization restored the proportion of collagen crosslinks to the control level. The changes induced by joint unloading were reversible at most sites investigated, but full restoration of articular cartilage glycosaminoglycan concentration was not obtained in all sites, even after remobilization for 50 weeks. This suggests that lengthy immobilization of a joint can cause long lasting articular cartilage proteoglycan alterations at the same time as collagen organization remains largely unchanged. Because proteoglycans exert strong influence on the biomechanical properties of cartilage, lengthy immobilization may jeopardize the well being of articular cartilage.

Amino Acids↗
PubMed2000

The role of chondrocyte-matrix interactions in maintaining and repairing articular cartilage.

Throughout life chondrocytes maintain the articular cartilage matrix by replacing degraded macromolecules and respond to focal cartilage injury or degeneration by increasing local synthesis activity. These observations suggest that mechanisms exist within articular cartilage that stimulate chondrocyte anabolic activity in response to matrix degradation or damage. An important cartilage anabolic factor, insulin-like growth factor I (IGF-I), appears to have a role in stimulating chondrocyte anabolic activity. Although IGF-I is ubiquitous, its bioavailability is controlled by a class of secreted proteins, IGF binding proteins (IGFPBs). Of the six known IGFPBs, IGFBP-3 is the most abundant in human articular cartilage. We recently found that with increasing age, articular chondrocytes increase their expression of IGFBP-3. This observation led us to investigate the potential role of IGFBP-3 in chondrocyte-matrix interactions. Using immunofluorescent staining and confocal microscopy we found that IGFBP-3 accumulates with increasing age in the chondrocyte territorial matrix where it co-localizes with fibronectin, but not with tenascin-C or type VI collagen. Using purified proteins we demonstrated that IGFBP-3 binds to fibronectin in a dose dependent manner, but not to tenascin-C. In vitro studies showed that IGFBP-3 alone inhibited chondrocyte synthetic activity while intact fibronectin alone significantly stimulated activity. When fibronectin and IGFBP-3 were combined we found that the inhibitory activity of low concentrations of IGFPB-3 was enhanced. These observations indicate that in mature articular cartilage IGF-I is stored in the chondrocyte territorial matrix through binding to a complex of IGFPB-3 and intact fibronectin. Storage of IGF-I of the territorial matrix may help maintain a relatively constant level of available IGF-I and the local increase in matrix synthesis following matrix damage may result from release of IGF-I. This mechanism may have an important role in maintaining and repairing articular cartilage and failure of this mechanism may lead to progressive articular cartilage degeneration.

Adaptation, Physiological↗
PubMed2000

[The possibility of isolation, culture and storage of articular cartilage cells].

Lesions of articular cartilage are a common problem and concern millions of people world-wide. A decrease in physical activity and pain symptoms among patients resulting from damage to articular cartilage have prompted research concerning new methods allowing cartilage regeneration. State-of-the-art treatment of articular damage depends very much on genetic engineering techniques. The aim of this paper was to determine the authors' own way of isolation, proliferation and storage of chondrocytes of articular cartilage. The material consisted of 30 rabbits, from which fragments of articular cartilage were taken. The study consisted of the following stages: isolation, chondrocyte proliferation, cell and matrix identification, storage and MTT tests. Matrix digestion was achieved using the following solutions: 0.1% type IA collagenase; 0.025% trypsin, a mixture of collagenase and trypsin. The greatest amount of cells were found after digestion of the basic matter of cartilage by 0.1% solution of type IA collagenase. When ascorbic acid was added to the medium, a 25% increase in cellularity was observed. A cumulation of procollagen mRNA was noted in the isolated cells. After about 21 days the isolated cells formed a multilayer structure, with the space between the cells filled with a substance that showed typical traits for cartilage matrix. Storing the isolated cells for less than 48 hours at room temperature gave a 90% survival rate. Most cells died after less than 12 hours when stored at 4 degrees C. The described method of chondrocyte isolation proved to be effective in preparing material for treatment of articular cartilage lesion.

Cartilage, Articular↗
PubMed1975

Cartilage fibrillation at the ankle joint in Liverpool necropsies.

The articular surfaces have been examined in 45 left ankle joints from a random series of adult necropsies in the city of Liverpool. Foci of overt fibrillation, with frank splitting of the articular cartilage surface, were extremely common in the ankle joint and were often already apparent in young adults. With increasing age overt fibrillation tended on the whole to become extensive, but this tendency was partly obscured by considerable variation between individuals. It initially and especially affected the periphery of the cartilage sheets and the boundaries between the central and malleolar articulation territories. Possible explanations for this peripheral susceptibility are discussed. One or more sites on the non-peripheral parts of the lateral and medial malleolar surfaces were next in order of susceptibility. The central territory of the articulation was the least susceptible to overt fibrillation. Minimal fibrillation, with a very superficial splitting of the cartilage surface, could occur at any site on the ankle joint surfaces. With increasing age, extensive involvement of the central territory by this minimal change was much more common than extensive overt fibrillation here. The surface markings of minimal fibrillation sometimes showed a macroscopially apparent orientation en face. In one sort these were parallel to flexion-extension movement and consistent with track markings from abrasive-adhesive wear. In a second sort they were parallel to the dominant en face orientation of the superficial cartilage collagen. The topography and natural history of cartilage fibrillation at the ankle joint is discussed with reference to Liverpool data from other joints. Some of the older ankles showed peripheral segments of fibrous tissue-covered cartilage loss. This feature was attributed to "ageing" rather than osteoarthrosis. Only 1 of 20 left ankles from subjects more than 70 years old showed any region of full-thickness uncalcified cartilage loss with abrasive wear of 'osteoarthritic' type. Thus it would seem that in the majority of the Lverpool population the articular cartilage of the normal ankle joint has a high resistance to the type of vertical wear found in clinically demonstrable osteoarthrosis. The practical implications of this conclusion are discussed.

Adult↗
PubMedDate not supplied

[Changes in biochemical characteristics of collagen and the cartilage water in osteoarthritis].

The stability of collagen molecules and moisture capacity of human normal and osteoarthrotic (OA) cartilage were studied before and after extraction of glycosaminoglycans (GAG) by 4M guanidinum chloride. The content and nature of water were determined by Fisher titration, DSC and analysis of sorbtion-desorbtion processes of water vapour in cartilage. The stability of collagen molecules was determined by the degree of enzymatic hydrolysis: collagenase, pronase and pepsin. It was found that weakening of bonds between main compounds of the cartilage matrix and decrease of GAG quantities in the OA cartilage were accompanied by structural disorganization of the collagen network, which is manifested by breakdowns of intramolecular bonds in telopeptides and intermolecular bonds in the spiral part of collagen molecules, these changes may contribute to increase of total water in OA cartilage. The correlation of free and bound water fractions in cartilage was increased from 5 to 44 in OA cartilage. These results can be used as a criterion of pathological condition of human articular cartilage.

Adult↗
PubMed2001

[An experimental study of tissue engineered autologous cartilage by using an injectable polymer].

OBJECTIVE: To investigate the proper cell density of tissue engineered autologous cartilage to indicate the clinical application. METHODS: The chondrocytes, isolated from mini swines' ears, were mixed with an injectable biocompatible matrix(Pluronic F127) to make the cell suspensions with the densities of 10,20, 30,40,50,60,70 x 10(6)/ml. The chondrocyte-polymer complex was injected into the subcutaneous tissue of the swines' abdomens. Each specimen was harvested and evaluated with body-mass, histological examination, and glycosaminoglycan content and type II collagen tests after 6 weeks in vivo. RESULTS: The histological examination had showed that the neo-cartilage was solid, homogenous cartilage when using 50 million chondrocytess/cc for 6 weeks. The samples with the 10 and 30 million chondrocytes/cc showed that the area of the cartilage was incomplete and separated by the remnant polymer. The mass of the samples was ranged from 30-110 mg after 6 weeks. The glycosaminoglycan content was lower from 5.8 to 9.0 percent, compared to the 9.2 percent of the normal auricular cartilage. Western-Blot had presented the type II collagen in all samples. CONCLUSION: This study has demonstrated that the qutologous cartilage could be generated by using tissue engineering technique, with the histological characteristics similar to natural cartilage. Fifty million chondrocytes per cc could yield the best quality cartilage in 6 weeks.

Animals↗
PubMed2002

The effect of the small and unstable autologous osteochondral graft on repairing the full-thickness large articular cartilage defect in a rabbit model.

We have investigated the effect of the insufficient autologous osteochondral graft on healing of the large articular cartilage defect using a rabbit model. An osteochondral defect, 7 mm in diameter, was made on the patellar groove of the femoral condyle and repaired with two surgical procedures: Group I, the osteochondral fragment as half as the defect was grafted. The graft was unstable and the size of the graft was smaller than the defect. This is a model of the insufficient autologous osteochondral graft to the large articular cartilage defect; Group II, the defect was left empty. At 2, 4, 12, and 24 weeks after the surgery, the specimens were analyzed macroscopically and histologically. To evaluate the microscopic morphology, a histologic grading scale composed of 5 categories was used. In Group I, although the graft sank a little, a grafted cartilage survived and the reparative fibrous tissue filled the defect covering implanted cartilage. In contrast, in Group II, the defect was only partially covered by fibrocartilaginous tissue with a faintly staining matrix. Throughout the entire observed periods, the scores of the repaired cartilage in Group I are significantly higher than those in Group II. Even the half size of osteochondral graft has an effect to reduce the size of the cartilage defect such as the spacer and leads to better healing compared to the cartilage defect untreated. In case that it is hard to transplant an optimal osteochondral graft because of large cartilage lesion, even the small and unstable osteochondral plug should be transplanted.

Animals↗

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