Cartilage tissue engineering, an effective way to repair cartilage defects, requires an ideal scaffold to promote the regeneration performance of stem cells. Cartilage extracellular matrix (CECM) can imitate the living environment of cartilage cells to the greatest extent. CECM not only exhibits good biocompatibility with chondrocytes and stem cells, which can meet the basic requirements of scaffolds, but also promotes chondrocytes to secrete matrix and induce stem cells to differentiate into chondrocytes; as such, this matrix is a better scaffold and has more advantages than existing ones. The promotion and induction effects could be related to various cartilage-related proteins inside. However, the practical application of this technique is hindered by problems, such as poor mechanical properties and insufficient cell penetration of CECM. Association with other materials can compensate for these inadequacies to a certain degree, and finding a combination mode with optimized performance is the application trend of CECM. This review focuses on research of CECM materials in cartilage tissue engineering.
Cartilage ; cytology ; Chondrocytes ; Extracellular Matrix ; Tissue Engineering ; Tissue Scaffolds

OBJECTIVETo explore the feasibility of constructing tissue-engineered cartilage with human dermal fibroblasts (HDFs) in vitro.

METHODSPorcine articular chondrocytes and HDFs were isolated and in vitro expanded respectively. Then they were mixed at the ratio of 1:1 (chondrocytes: fibroblasts) . The mixed cells were seeded onto polyglycolic acid (PGA) scaffold at the ultimate concentration of 5.0 x 10(7)/ml as co-culture group. Chondrocytes and HDFs at the same ultimate concentration were seeded respectively onto the scaffold as chondrocyte group ( positive control group) and fibroblast group ( negative control group). The specimens were collected after in vitro culture for 8 weeks. Gross observation, histology and immunohistochemistry were used to evaluate the results.

RESULTSIn chondrocyte group, the cell-scaffold constructs could maintain the original size and shape during in vitro culture. The new formed cartilage-like tissue had typical histological structure and extracellular matrix staining similar to normal cartilage. In co-culture group the constructs shrunk slightly at 8 weeks, cartilage-like tissue formed and GAG could be detected for strong expression by Safranin O staining. Furthermore, using the specific identification, a few HDFs derived cells were found to form lacuna structure at the peripheral area of cartilage-like tissue. In fibroblast group, the constructs deformed and shrunk gradually without mature cartilage lacuna in histology.

CONCLUSIONThe 3D-co-culture system can effectively induce the differentiation of HDFs to chondrocytes. The tissue-engineered cartilage can be constructed in vitro with the 3D-co-culture system.

Animals ; Cartilage ; cytology ; Cells, Cultured ; Chondrocytes ; cytology ; Coculture Techniques ; Dermis ; cytology ; Fibroblasts ; cytology ; Humans ; Swine ; Tissue Engineering ; methods ; Tissue Scaffolds

OBJECTIVETo obtain large amount of differentiated chondrocytes in vitro, examine and compare the biological characterization of rabbits' articular chondrocyte cultured in different density in vitvo.

METHODSFrom November 2001 to June 2004, articulate tissues were obtained from the joints of the adult rabbits. Chondrocytes were isolated from the cartilage tissue with type II collagenase digestion and cultured in DMEM/F-12 supplemented with 20% fetal bovine serum (FBS). The chondrocytes were cultured with low density of monolayer culture and high density of confluent culture respectively. The differentiated phenotype was evaluated by histochemistry or immunohistochemistry.

RESULTSWhen chondrocytes cultured in monolayer and in low density, it proliferated rapidly during the three generations, but with the same time, dedifferentiation was also rapid. After the third passage, most of the passage cells lost the phenotype, and the proliferation also stagnated. While chondrocytes cultured in high density, dedifferentiation slowed down. And even the phenotypes of the dedifferentiated chondrocyte which were cultured in low density could reduced partly by followed high density culture.

CONCLUSIONSCulture chondrocytes by high density in vitro can effectively maintain the differentiated phenotype of chondrocyte. It also keeps the proliferation character as monolayer culture. The dedifferentiated chondrocyte caused by many passages could redifferentiate partly. So it is indicated that confluent culture of original or expanded chondrocytes in high density is a better culture methods than culture in low density.

Animals ; Cartilage, Articular ; cytology ; Cell Culture Techniques ; methods ; Cells, Cultured ; Chondrocytes ; cytology ; Female ; Male ; Rabbits

OBJECTIVETo explore the chondrogenetic effect of induce media containing different concentrations of fetal bovine serum (FBS) on BMSCs differentiation in vitro and provide technical parameters for cartilage engineering in vitro.

METHODSPassage 2 BMSCs of swine were seeded at the density of 5 x 10(7) cells/cm3 to disc-shaped PGA scaffolds with a diameter of 5mm and a thickness of 2mm. After 7days, the scaffolds were induced in media with TGF-beta1, IGF-I, dexamethasone, and different concentrations of FBS: 0% in A group, 5% in B group, and 10% in C group. Specimens were collected after 8 weeks for gross observation, size evaluation, wet weight, glycosaminoglycan (GAG) content, histology assessment, and immunohistology of type II collagen.

RESULTSThe compound of C group showed china-white color, hard and fine texture, no obvious change in size and shape, typical lacuna structures, cartilage specific ECM, and significantly higher wet weight and GAG content. The compound of B group showed reduced size, fewer lacuna structures and some cartilage specific ECM. And the compound of A group showed greatly reduced size, soft and loose texture, and no typical lacuna structure or cartilage specific ECM.

CONCLUSIONSFBS was indispensable to chondrogenetic media for in-vitro tissue engineering of cartilage with BMSCs.

Animals ; Bone Marrow Cells ; cytology ; Cartilage ; cytology ; Cattle ; Cell Culture Techniques ; Cell Differentiation ; Serum ; Stromal Cells ; cytology ; Swine ; Tissue Engineering

BACKGROUNDChondrocytes' phenotype and biosynthesis of matrix are dependent on having an intact cytoskeletal structure. Microfilaments, microtubules, and intermediate filaments are three important components of the cytoskeletal structure of chondrocytes. The aims of this study were to determine and compare the effects of the disruption of these three cytoskeletal elements on the apoptosis and matrix synthesis by rabbit knee chondrocytes in vitro.

METHODSChondrocytes were isolated from full-thickness knee cartilage of two-month-old rabbits using enzymatic methods (n = 24). The isolated cells were stabilized for three days and then exposed to low, medium, and high doses of chemical agents that disrupt the three principal cytoskeletal elements of interest: colchicine for microtubules, acrylamide for intermediate filaments, and cytochalasin D for actin microfilaments. A group of control cells were treated with carrier. Early apoptosis was assessed using the Annexin-FITC binding assay by flow cytometry on days 1 and 2 after exposure to the disrupting chemical agents. The components and distribution of the cytoskeleton within the cells were analyzed by laser scanning confocal microscopy (LSCM) with immunofluorescence staining on day 3. The mRNA levels of aggrecan (AGG) and type II collagen (Col-2) and their levels in culture medium were analyzed using real-time PCR and enzyme-linked immunosorbent serologic assay (ELISA) on days 3, 6, and 9.

RESULTSIn the initial drug-dose-response study, there was no significant difference in the vitality of cells treated with 0.1 µmol/L colchicine, 2.5 mmol/L acrylamide, and 10 µg/L cytochalasin D for two days when compared with the control group of cells. The concentrations of colchicine and acrylamide treatment selected above significantly decreased the number of viable cells over the nine-day culture and disrupted significantly more cell nuclei. Real-time PCR and ELISA results showed that the mRNA levels and medium concentrations of AGG and Col-2 were significantly decreased for cultures treated with colchicine and acrylamide when compared with untreated cells at three, six, and nine days, and this inhibition was correlated with higher matrix metalloprotease-13 expression in these cells. Cellular proliferation, monolayer morphology, and matrix metabolism were unaffected in cytochalasin D-treated cells when compared with control cells over the nine-day culture period.

CONCLUSIONSThe disruption of the microtubulin and intermediate filaments induced chondrocyte apoptosis, increased matrix metalloprotease expression, and decreased AGG and Col-2 expression in rabbit knee chondrocyte cultures. Our findings suggest that microtubulin and intermediate filaments play a critical role in the synthesis of cartilage matrix by rabbit knee chondrocytes.

Animals ; Cartilage, Articular ; cytology ; metabolism ; Chondrocytes ; cytology ; Collagen ; metabolism ; Cytoskeleton ; metabolism ; Knee Joint ; cytology ; metabolism ; Microscopy, Confocal ; Rabbits

OBJECTIVETo explore and identify the method for IL-1beta induced New Zealand rabbit knee chondrocyte degeneration, thus providing experimental bases for Chinese medical research on osteoarthritis from in vitro cultured chondrocytes.

METHODSUnder aseptic conditions, bilateral knee joint cartilage was collected from 4-week old New Zealand rabbits. Chondrocytes were separated by type II collagenase digestion and mechanical blowing method. They were randomly divided into two groups when passaged to the 2nd generation, the normal control group (group Z) and the IL-1beta induced model group (group M). No intervention was given to those in group Z. 10% FBS culture media containing 10 ng/mL IL-1beta was added to group M. All cells were passaged to the 3rd generation. They were compared using morphological observation, toluidine blue staining, type II collagen immunohistochemical staining, and flow cytometry.

RESULTSUnder inverted microscope, the second and the 3rd generation chondrocytes' phenotype of group Z was stable with good proliferation. Most cells turned into fusiform and slabstone shaped. In group M, most cells turned into long spindle shape or irregular shape. Results of toluidine blue staining and immunohistochemistry showed that the positive expression of chondrocytes after staining in group Z was superior to that in group M. Results of flow cytometry showed that there was statistical difference in the apoptosis rate of the second generation chondrocytes between group M and group Z (P < 0.01).

CONCLUSIONIt was obviously seen that chondrocytes in IL-1beta induced New Zealand rabbit knee chondrocyte model obviously degenerated, which could be used in related experimental researches on osteoarthritis.

Animals ; Cartilage ; cytology ; drug effects ; Cells, Cultured ; Chondrocytes ; cytology ; drug effects ; Interleukin-1beta ; pharmacology ; Knee Joint ; cytology ; drug effects ; Rabbits

In recent years, there has been a growing emphasis on use of human adipose-derived stem cells (hADSCs) for cartilage tissue engineering owing to their ability to differentiate into chondrocytes, which is mainly induced by growth factors (GFs). In general, GFs for chondrogenic induction come from the transforming growth factor beta (TGF-beta) superfamily. To date, the most commonly used GFs for chondrogenes is TGF-beta1/3. However, the response of hADSCs to GFs may differ significantly from that of human bone marrow stem cells (hBMSCs). It has been reported that bone morphogenetic protein-6 (BMP-6) treatment induced TGF-beta receptor-I expression of hADSCs. It seems that these two cell populations varied strongly in their potency to undergo chondrogenesis in the same medium conditions. Here, we provide a concise review on various GFs used in chondrogenic differentiation of hADSCs in vitro.
Adipocytes ; cytology ; Cartilage ; Cell Differentiation ; Chondrocytes ; cytology ; Chondrogenesis ; Humans ; Stem Cells ; cytology ; TGF-beta Superfamily Proteins ; Tissue Engineering

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

Treatment of articular cartilage lesions remains a clinical challenge. The uses of prosthetic joint replace allograft and/or autograft transplant carry a risk of complications due to infection, loosening of its component, immunological rejection and morbidity at the donor site. There has been an increasing interest in the management of cartilage damages, owing to the introduction of new therapeutic options. Tissue engineering as a method for tissue restoration begins to provide a potential alternative therapy for autologous grafts transplantations. We aimed to evaluate how well a tissue engineered neocartilage implant, consist of human articular chondrocytes cultured with the presence of autologous serum and mixed in a fresh fibrin derived from patient, would perform in subcutaneous implantation in athymic mice.
Biomechanics ; Cartilage, Articular/injuries ; Cartilage, Articular/physiology ; Cartilage, Articular/*transplantation ; Chondrocytes/*cytology ; Culture Media ; Mice, Nude ; *Orthopedic Procedures ; Serum ; *Tissue Engineering

OBJECTIVETo compare the tissue engineered cartilage constructed with chondrocytes derived from auricular and articular cartilage.

METHODSChondrocytes were isolated from porcine auricular and articular cartilage, and BMSCs were obtained from bone marrow aspirate and cultured. Each kind of chondrocytes were resuspended alone or mixed with BMSCs at a ratio of 1:1, and seeded onto PGA/PLA scaffolds to construct tissue engineered cartilage (n = 4). The constructs were cultured for 8 weeks in vitro and then subcutaneously implanted into nude mice for 6 weeks. The differences between chondrocytes monoculture from articular and auricular cartilage or between each of them co-cultured with BMSCs were evaluated by gross view, measurement of thickness and wet weight, histological examinations including H&E, Safranin O, type II collagen, and Ponceau's & Victoria blue staining, and gene expression analysis of cartilage related genes.

RESULTSNo obvious differences were found histologically among the complexes constructed in vitro 8 weeks except for few elastic fibers secreted in the auricular chondrocytes + BMSCs co-culture group. Neo-cartilage is thicker in the groups of articular chondrocytes (38. 1% than the group of auricular chondrocytes, P < 0.05) and articular chondrocytes + BMSCs co-culture (19.3% than the group of auricular chondrocytes + BMSCs, P < 0.05). However, after 6 weeks in vivo the elastic fibers were found positive in the complexes constructed by auricular chondrocytes, and its staining was even stronger and more homogenous in the group of auricular chondrocytes + BMSCs co-culture. The tissues generated by articular chondrocytes alone and co-cultured with BMSCs both formed the characteristic features of three-layer structure of hyaline cartilage and ossified in vivo with significant up-regulation of COL10A1 and MMP-13. To summarize, auricular chondrocytes formed the elastic cartilage while articular chondrocytes formed the hyaline cartilage during the development of tissue engineered cartilage either by monoculture or the co-culture with BMSCs.

CONCLUSIONSThe chondrogenic response of chondrocytes from different cartilage origins demonstrates that an initial chondrocyte and cartilage type recapitulates the same in later tissue-engineered development.

Animals ; Bone Marrow Cells ; cytology ; Cartilage, Articular ; cytology ; Cells, Cultured ; Chondrocytes ; Coculture Techniques ; Ear Auricle ; cytology ; Mesenchymal Stromal Cells ; cytology ; Mice, Nude ; Swine ; Tissue Engineering ; methods ; Tissue Scaffolds