PURPOSE: To evaluate the effect of the chitosan-TGF-beta1 conjugate on articular cartilage defects of rabbits' knees MATERIALS AND METHODS: Full thickness cartilage defect(6mm, round shape) was made at both knees of 20 rabbits and, after the lapse of 3 days, chitosan-TGF-beta1(15ng/ml, 1ml) was injected into one side(experimental group) of knees and PBS(1ml) was injected into the other side(control group). 5 rabbits were sacrificed 6 weeks after the injection and the rest of 15 rabbits 12 weeks later. Then, gross morphology and histological evaluation(Mendelson scoring) was conducted. RESULTS: No arthritic findings was observed and histological results in the experimental group at 6(Ave. 11.3+/-1.5) and 12(Ave. 4.5+/-1.9) weeks postoperatively were superior to those in the control group at 6(Ave. 14.6+/-1.7) and 12(Ave. 9.8+/-2.2) weeks. Especially at 12 weeks, the experimental group was superior to the control group statistically in results of 5 subgroups except for filling of defects. The difference of two groups at 12 weeks was more remarkable than those at 6 weeks. CONCLUSION: Regeneration of something very close to normal cartilage was observed in the experimental group. It shows that the biological activity of TGF-beta1 is sustained by the action of conjugate with chitosan, through prolonged half life of TGF-beta1.
Cartilage ; Cartilage, Articular* ; Chitosan ; Half-Life ; Knee* ; Rabbits ; Regeneration ; Transforming Growth Factor beta1

OBJECTIVETo study the effect of gradually induced occlusal disorders on the expression of basic fibroblast growth factor (bFGF) of condylar cartilage in rat.

METHODSThe model of gradually induced occlusal disorders was established in rat. The expression of bFGF was examined by SABC technique of immunohistochemistry. The expression of bFGF was analyzed by amount of positive cells.

RESULTSbFGF was expressed positively in the proliferative cell layer, maturative layer and hypertrophical cell layer in the rat mandibular condyle cartilage. In control group, expression of bFGF increased from 2-week-old to 6-week-old, then it had a decrease during experiment. Compared with the control group, bFGF of experiment group was increasing at 2 week, 6 week and 8 week during experiment. But there was decreaseing at 4 week. There was no difference between young experiment group and the adult experiment group.

CONCLUSIONThe gradually induced occlusal disorders may lead to significant increase of expressiong of bFGF in condyle cartilage, which suggests that the bFGF may be involve in the procedure of repairing process of articular cartilage.

Culture media supplemented with animal serum e.g. fetal bovine serum; FBS is commonly used for human culture expansion. However, for clinical application, FBS is restricted as its carry a risk of viral or prion transmission. Engineering autologous cartilage with autologous human serum supplementation is seen as a better solution to reduce the risk of transmitting infectious diseases and immune rejection during cartilage transplantation. The purpose of this study is to establish and compare the effects of 10% autologous human serum (AHS) and 10% FBS on the growth of chondrocytes and the formation of tissue engineered human articular cartilage.
Cartilage, Articular/growth & development ; Cartilage, Articular/*transplantation ; Cell Count ; Cell Division/physiology ; Chondrocytes/*cytology ; Culture Media ; *Serum ; *Tissue Engineering

Platelet-derived growth factor(PDGF) is known to accelerate soft tissue fracture and periodontal bone healing, but little information is available for characterizing the healing of articualr cartilage. This study was designed to demonstrate the regeneration potential of pasteurized autogeneous osteochondral graft when PDFG was applied locally in vivo. Eighteen rabbits in two groups were used in the experiment. The free osteochondral fragment(1x1x1 cm) were taken from distal femur. The fragment were pasteurized in 65degrees C for 5 minutes. In experimental group(group II), the fragment were soaked in 0.25 mg/ml of recombinant human PDGF mixed 5 ml normal saline and reimplanted to the resected site, and followed with local administration of 0.25 mg/ml PDGF to knee joint. In control group(group I), the pasteurized fragment were reimplanted in the resected site without any treatments. The histologic characteristics of the transplanted autografts for three rabbits in each group were observed at 3, 5 and 7 weeks postoperatively. The results were as follows; Group II revealed the more favorable regeneration of articular cartilage, less arthritic changes and more mature arrangement of chondrocytes than group I. Even thought the cartilage is avascular and the regeneration capacity of pasteurized cartilage is severely limited, the regeneration of grafted articular cartilage is thought to be accellerated by increased newly formed blood vessels and soft tissues due to the diffusion of PDGF on grafted cartilage, and probably also by differentiation of mesenchymal cells in the initial stage of experiment. The results of this study suggest that local administration of PDGF could be used for the treatment of posttraumatic or degenerative arthritis and various cartilage damages.
Autografts ; Blood Vessels ; Cartilage ; Cartilage, Articular ; Chondrocytes ; Diffusion ; Femur ; Humans ; Knee Joint ; Osteoarthritis ; Platelet-Derived Growth Factor* ; Rabbits* ; Regeneration* ; Transplants*

PURPOSE: The aim of this study was to evaluate the expression of type II collagen, aggrecan, VEGF-A and PEDF mRNAs in the human chondrocytes derived from the articular cartilage of the femoral heads with avacular necrosis (AVN). MATERIALS AND METHODS: We cultured human chondrocytes that were primarily derived from the articular cartilage of femoral heads with AVN. We evaluated the mRNA expression of type II collagen, aggrecan, VEGF-A and PEDF. RESULTS: The chondrocytes of the AVN group showed decreased expressions of type II collagen mRNA and aggrecan mRNA (p<0.05). The expression of VEGF-A mRNA and PEDF mRNA in the AVN group was the same as that of the normal group (p>0.05). CONCLUSION: The cartilage matrix's formation ability was found to be decreased in the chondrocytes of the femoral heads affected by AVN.
Aggrecans ; Cartilage ; Cartilage, Articular ; Chondrocytes ; Collagen Type II ; Extracellular Matrix ; Head ; Humans ; Necrosis ; RNA, Messenger ; Vascular Endothelial Growth Factor A

OBJECTIVE: To explore whether the growth hormone is effective in the treatment of degenerative cartilage of knee in rabbits. METHOD: Thirty New Zealand white rabbits were administered intra-articular injection with monosodium iodoacetate (Sigma, St. Louis, USA) 2.5 mg and divided into 3 groups. Each group was administered with hyaluronic acid (Hyruan plus(R), LG life science, Seoul, Korea)(group A) 0.6 ml, growth hormone (Declage(R), LG life science, Seoul, Korea) (group B) or saline (group C) 0.6 ml intra-articulary once a week for 4 weeks, beginning 4 weeks after the degeneration induction. All rabbits were killed 9 weeks after degeneration induction. The histologic morphology was observed by optical microscope with knee cartilage. RESULTS: Mankin score was 2.4+/-1.3 in group A, 3.9+/-1.7 in group B, 7.4+/-0.8 in group C. Yoshimi score was 1.5+/-0.7 in group A, 2.2+/-0.9 in group B, 4.4+/-0.6 in group C. Gross and microscopic morphologic findings showed that group C represented the more severe than group A & B (p<0.01), also group A was better than group B (p<0.05). CONCLUSION: Growth hormone is effective on degenerative knee cartilage in rabbit model, but less than the hyaluronic acid.
Biological Science Disciplines ; Cartilage ; Growth Hormone ; Hyaluronic Acid ; Injections, Intra-Articular ; Knee ; Rabbits

The transforming growth factor-beta 1 was known as having the most important influence on chondrocytes among various growth factors, being abundant in articular chondrocytes and osteocytes. We performed in vitro monolayer cultures of human articular chondrocytes from normal and osteoarthritic patients and studied the transforming growth factor-beta 1 responsiveness of those chondrocytes. The cell-growth curve indicated that the primary osteoarthritic chondrocyte culture with transforming growth factor-beta 1 showed a more rapid growth pattern than normal chondrocytes with or without TGF-beta 1 and osteoarthritic chondrocytes without TGF-beta 1. The osteoarthritic group showed a sharp decline in growth pattern with subsequent culture. The shape of osteoarthritic chondrocytes was bigger and more bizarre compared to those of normal chondrocytes. With subsequent culture, this change became prominent. The transforming growth factor-beta 1 increased the [3H]-TdR uptake in each group. The phenotypes of chondrocytes were more clearly expressed in the normal group. The chondrocytes lost their phenotype (production of collagen type II) following subculture in each group. The transforming growth factor-beta 1 could not inhibit or delay the dedifferentiation process (loss of phenotype).
Cartilage, Articular/drug effects* ; Cartilage, Articular/cytology ; Cell Division/drug effects ; Cells, Cultured ; Human ; Osteoarthritis/pathology ; Reference Values ; Transforming Growth Factor beta/pharmacology*

Transforming growth factor-beta1(TGF-beta1) has been suggested to be a useful growth facto. that could maintain the phenotypic characteristics of cultured chondrocytes. We performed this study to investigate the dose-dependent effects of TGF-beta1 on cell proliferation and matrix synthesis in relation to the degree of chondrocyte dedifferentiation in monolayer culture. Chondrocytes were isolated from the articular cartilage of distal femur of neonatal Sprague-Dawley rats and were cultured in monolayer. When the cell population reached 70-80% of confluence, the cells were subcultured successively for 6 weeks for the following studies. Every weak, the dose dependent effects of rhTGF-beta1 (0ng/ml ,1ng/ml, 5ng/ml, 10ng/ml, 20ng/m1) on DNA synthesis, proteoglycan synthesis and collagen synthesis were evaluated by 3H-thymidine incorporation, 35S-sulfate incorporation and 3H-proline incorporation respectively. The DNA synthesis decreased with time of culture. The DNA synthesis was significantly decreased by the addition of rhTGF-beta1 at all concentrations. The dose-dependent inhibitory action was most prominent at initial 3 weeks. Proteoglycan synthesis was in the highest level at the second week and markedly decreased after 2 weeks. At 2 weeks, TGF-beta1 treatment increased the proteoglycan synthesis at all concentrations and this stimulatory effect was prominent at the concentrations of 5ng/ml and 10ng/ml. There was no significant difference in the level of collagen synthesis during the whole experimental period. TGF- beta1 treatment increased collagen synthesis at all concentrations and this stimulatory effect was prominent at the concentrations at 5ng/ml and 10ng/ml. The results of this study suggest that if the cultured chondrocytes treated by TGF-beta 1 are used for transplantation, the time for TGF-beta1 treatment and transplantation to be recommended is before 3 weeks and the beneficial concentration of TGF-beta1 is 5ng/ml to 10 ng/ml for the maintenance of the phenotypic properties.
Cartilage, Articular ; Cell Proliferation* ; Chondrocytes* ; Collagen ; DNA ; Femur ; Proteoglycans ; Rats, Sprague-Dawley ; Transforming Growth Factor beta ; Transforming Growth Factor beta1

After the articular cartilage injury, the metabolic level is increased during the progressive degeneration, the chondrocytes secrete a variety of inflammatory factors, and the original cell phenotype is gradually changed. For a long time, a large number of researchers have done a lot of researches to promote anabolism of chondrocytes and to maintain the stability of chondrocyte phenotype. There are many molecular signaling pathways involved in the process of promoting cartilage repair. This review focuses on the key signaling molecules in articular cartilage repair, such as transforming growth factor-beta and bone morphogenetic protein, and reveals their roles in the process of cartilage injury and repair, so that researchers in related fields can understand the molecular mechanism of cartilage injury and repair widely and deeply. Based on this, they may find promising targets and biological methods for the treatment of cartilage injury.
Bone Morphogenetic Proteins ; physiology ; Cartilage, Articular ; growth & development ; injuries ; Chondrocytes ; physiology ; Humans ; Regeneration ; Signal Transduction ; Transforming Growth Factor beta ; physiology

Recent advance in the transplantation of human organs are widely applied in many fields, despite little progress was made in orthopedic surgery in the bone and joint transplantation. Experimental studies on bone or joint transplantation have been reported enormously with variable results. Many authors used only small part of cartilage, epiphyseal plate or osteochondral graft and some authors studied the fate of massive autogenous and homogenous bone graft including articular surfaces, but few workers have reported on transplantation of whole bone including articular cartilage, epiphyseal plate, cancellous and cortical bone, and compared the result with autograft and fresh and frozen homograft. This expermient was undertaken for the study of autogenous, and fresh and deep-freezed homogenous transplantation of distal portion of femur including articular cartilage and epiphyseal plate in rabbits. The distal femur was exposed and completely freed of its soft tissue attachment and osteotomized at a one and half centimeter above the epiphyseal plate. Eighty young rabbits were divided into three groups: thirty for autograft, thirty for fresh homograft and twenty for deepfreezed homograft. The distal femur was replaced in situ in autograft and exchanged between two animals in fresh homograft. In group of deep-freezed homograft, the distal femur which was stored at −20 degrees centigrade for two weeks before it was replaced in a rabbit of similar weight. These animals were sacrificed at intervals varying from one to twelve weeks and longitudinal section of distal half of femurs were prepared for histological examination, and the results were observed as followe.1. In the autograft, the articular cartilage retained normal appearance except for reduced stainability of the chondrocytes until eight weeks, and early fibrillary degeneration appeared in the periphery in twelve weeks. In the fresh and deep-freezed homograft, almost similar findings were observed, which suggest the articular cartilage were rather resistive to immune reaction. 2. The epiphyseal plate continued normal growth in early stages in all groups, but in fresh homograft, the germinal cell layer underwent necrosis in four weeks and eventually fused in twelve weeks, In deep-freezed homograft, normal growth continued until eight weeks and partially fused in twelve weeks, which findings are not much different from autograft. 3. In autograft, solid bony union at grafted site was obtained in eight weeks, and in fresh homograft, satisfactory union process continued until four weeks and then gradually delayed in healing with some necrosis at twelve weeks. In deep-freezed homograft, very little difference in the timing and character of the union was noted from autograft. 4. The satisfactory result in the growth at epiphyseal plate and in fracture healing in deep-freezed homograft are suggestive of deep-freezing may destroy the antigenicity of bone homograft.
Allografts ; Animals ; Autografts ; Cartilage, Articular ; Chondrocytes ; Epiphyses ; Femur ; Fracture Healing ; Growth Plate ; Humans ; Joints ; Necrosis ; Orthopedics ; Rabbits ; Transplants