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 isolate and cultivate human periodontal ligament stem cells (PDLSC) and to investigate the feasibility of PDLSC in vitro differentiation into chondrogenic phenotype.

METHODSPeriodontal tissue was obtained from healthy young human teeth extracted for orthodontic purposes. PDLSCs were isolated by single-colony selection and cultivated. PDLSC of passage 3 was plated at density of 1 x 10(7) cells/cm3 and induced with chondrogenic induction medium of DMEM containing TGF-beta1 (10 microg/L), IGF-1 (50 microg/L), dexamethasone (40 microg/L) and 10% FBS. In control group, the constructs were maintained in DMEM medium + 10% FBS. After 21 days induction, the results were evaluated by histology, histochemistry, immunohistochemistry and RT-PCR.

RESULTSThe constructs in experimental group were smooth and relatively firm in texture after 3 weeks of culture. Toluidine blue staining showed the formation of distinct lacuna structure. Positive staining of type II collagen was also detected by immunohistochemistry and it was confirmed by RT-PCR. In contrast, in the control group, the constructs collapsed gradually, lacuna was barely detected in histology and type II collagen expression negative.

CONCLUSIONSPeriodontal ligament contain stem cells can be isolated and cultivated. PDLSC have the potential of chondrogenic differentiation.

Adolescent ; Adult Stem Cells ; cytology ; Cell Differentiation ; Cells, Cultured ; Child ; Chondrocytes ; cytology ; Humans ; Periodontal Ligament ; cytology

OBJECTIVETo investigate the capacity of human endometrial stromal stem cells for differentiation into osteoblasts and chondroblasts and their potential as seeding cells in bone tissue engineering.

METHODSHuman endometrial stromal stem cells were obtained from hysterectomy tissues from 15 women during normal menstrual cycles and induced to differentiate into osteoblasts and chondroblasts. The differentiated cells were examined with cytochemistry.

RESULTSA population of endometrial stromal stem cells was successfully isolated from human endometrial tissue and showed stable proliferation in vitro. After treatment with osteoblast and chondroblast revulsant, the endometrial stromal stem cells differentiated towards osteoblasts were verified by positive staining with alizarin red and towards chondroblasts by positive staining with Alcian blue.

CONCLUSIONEndometrial stromal stem cells obtained from human endometrial tissue with multilineage potential can differentiate into osteoblasts and chondroblasts in vitro, and may serve as candidate autogenous seeding cells for bone tissue engineering.

Adult ; Cell Differentiation ; Cells, Cultured ; Chondrocytes ; cytology ; Endometrium ; cytology ; Female ; Humans ; Middle Aged ; Osteoblasts ; cytology ; Stromal Cells ; cytology

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

Samples of healthy and full-term human umbilical cord blood samples were obtained asceptically. Mesenchymal stem cells (MSCs) were isolated by lymphocyte separation medium, and were characterized morphologically by fluorescence-activated cell sorting analysis. Differentiation of chondroblast and osteoblast was induced by 10 ng/ml TGF-beta, 100 ng/ml insulin and 10(-7) mol/L decaesadril, 6.25 microg/ml siderophilin, 10 mmol/L beta-sodium glycerophosphate, 50 microg/ml antiscorbic acid, respectirely; the aim was to investigate the potentiality of differentiation. Umbilical cord blood-derived MSCs were stained positive for MSCs marker CD13, CD90, CD166, CD73, CD44 and HLA-AB, but were negative for hematopoietic stem cell marker CD45, CD34 and HLA-DR. After 21 days induction, Toluidine Blue staining and von-Kossa staining were positive. Immunocytochemistry showed that Collagen II expressed in the induced cells. The results demonstrated that mesenchymal stem cells can be isolated from human umbilical cord blood and differentiated into chondroblasts and osteoblasts in vitro.
Cell Differentiation ; Cell Separation ; Cells, Cultured ; Chondrocytes ; cytology ; Fetal Blood ; cytology ; Humans ; Mesenchymal Stromal Cells ; cytology ; Osteoblasts ; chemistry

OBJECTIVETo investigate a method that constructing a tissue-engineered tendon with a continuous and heterogeneous transition region.

METHODSFibroblasts derived from rabbit epithelial tissue were cultured in vitro and collagen gel was prepared. The experimental groups were scaffold only group, fibroblasts+ chondrocytes group (Fb+ CC group), fibroblasts+ osteoblasts group (Fb+ OB group), fibroblasts+ chondrocytes+ osteoblasts group (Fb+ CC+ OB group). Heterogeneous cell populations(fibroblasts, chondrocytes and osteoblasts) with collagen gel were seeded within three predesigned specific regions (fibrogenesis, chondrogenesis, and osteogenesis) of decellularized rabbit achilles tendons to fabricate a stratified scaffold containing three biofunctional regions supporting fibrogenesis, chondrogenesis, and osteogenesis. The tests of morphology, architecture and cytocompatibility of the scaffolds were performed. Gradient tissue-specific matrix formation was analysed within the predesignated regions via histological staining and immunofluorescence assays.

RESULTSThe HE staining and scanning electron microscopy analysis demonstrated that no major cell fragments or nuclear material was evident, and increased intra-fascicular and inter-fascicular spaces were found, the cytocompatibility of the scaffolds showed that the numbers of viable cells on the scaffold surfaces increase steadily, no significant differences were found between the scaffold only containing ordinary culture medium and scaffold containing gel groups. Histological staining and immunofluorescence assays demonstrated that the cartilage-related markers (GAG, COL2A1) were found only in the chondrogenesis region, but bone-related proteins only in the osteogenesis region of bone tunnel, and fibrosis was remarkable for the fibrogenesis region in the joint cavity. The transitional architecture with ligament-fibrocartilage-bone was constructed in the ligament-bone tunnel interface.

CONCLUSIONSA transitional interface (fiber-fiberocartilage-bone) could be replicated in a decellularized tendon through stratified tissue integration in vitro. The cell-tendon complex offers the advantages of a multi-tissue transition involving controlled cellular interactions and matrix heterogeneity.

Animals ; Bone and Bones ; Cells, Cultured ; Chondrocytes ; cytology ; Collagen ; Fibroblasts ; cytology ; Ligaments ; Osteoblasts ; cytology ; Rabbits ; Tendons ; Tissue Engineering ; methods

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

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

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