ABSTRACT
OBJECTIVE@#To review the research progress in the construction strategy and application of bone/cartilage immunomodulating hydrogels.@*METHODS@#The literature related to bone/cartilage immunomodulating hydrogels at home and abroad in recent years was reviewed and summarized from the immune response mechanism of different immune cells, the construction strategy of immunomodulating hydrogels, and their practical applications.@*RESULTS@#According to the immune response mechanism of different immune cells, the biological materials with immunoregulatory effect is designed, which can regulate the immune response of the body and thus promote the regeneration of bone/cartilage tissue. Immunomodulating hydrogels have good biocompatibility, adjustability, and multifunctionality. By regulating the physical and chemical properties of hydrogel and loading factors or cells, the immune system of the body can be purposively regulated, thus forming an immune microenvironment conducive to osteochondral regeneration.@*CONCLUSION@#Immunomodulating hydrogels can promote osteochondral repair by affecting the immunomodulation process of host organs or cells. It has shown a wide application prospect in the repair of osteochondral defects. However, more data support from basic and clinical experiments is needed for this material to further advance its clinical translation process.
Subject(s)
Hydrogels , Cartilage , Bone and Bones , Tissue Engineering/methodsABSTRACT
BACKGROUND: With the development of cartilage tissue engineering, affinity peptides have attracted some attention because of their special affinity to some key factors of cartilage tissue engineering. OBJECTIVE: To review the screening and identification of various affinity peptides and their application in cartilage tissue engineering. METHODS: The articles related to affinity peptides in CNKI, Wanfang, and PubMed were searched by computer from January 2000 to May 2020. “Affinity peptides, cartilage tissue engineering, mesenchymal stem cell, scaffold” in English and Chinese were used as key words. Finally, 66 articles were included for analysis. RESULTS AND CONCLUSION: Many polypeptides with specific amino acid sequence can bind with some cells, factors and molecules, and have affinity. According to different targets, they can be divided into cell affinity peptide, factor affinity peptide and extracellular matrix molecular affinity peptide. Affinity peptides have been used in cartilage tissue engineering through screening and identification to enhance the repair effect of tissue engineering by adhering fine cells, recruitment factors and molecules. In many strategies of biomimetic cartilage multilayer scaffolds, affinity peptides that interact with specific molecules play an important role in simulating the environment of normal cartilage. At the same time, with the development of cartilage tissue engineering technology, especially the application of computer-aided technology, it provides a new strategy for the use of affinity peptides. However, the residence time, degradation rate and degradation pathway of affinity peptides in vivo are relatively few, which need to be further understood.
ABSTRACT
@#Presently, there is no specific federal legislation governing articular cartilage tissue engineering (ACTE) experimentation practices in Malaysia. However, there are related regulations and guidelines provided by government agencies to oversee and guide such practices. The rules and regulations provided in the documents have the essential aim of safeguarding public health through ensuring that non-clinical studies reach a certain quality, efficient and safe for human use. There are themes identified when scrutinising relevant documents which includes, the need for authorised personnel and the establishment of facilities in conducting such experiments, the aspect of cell-scaffold construct development, the use of human materials, the aspect of biosafety, animal care and use during the experiments, and considerations on the impact on the environment. The individual laboratory or facility shall adopt and adapt these standards as deemed appropriate by the ACTE researchers to ensure that non-clinical studies are conducted in a proper and ethical manner.
ABSTRACT
BACKGROUND: Clinical studies have shown that sodium hyaluronate at different molecular weights exhibits therapeutic effects on osteoarthritis. OBJECTIVE: To investigate the changes in interleukin-1 beta, tumor necrosis factor-alpha, and matrix metalloproteinase-3 in synovial fluid of osteoarthritis rabbits after treatment with different molecular weights of sodium hyaluronate injection. METHODS: Forty rabbits (purchased from Qinghai Experimental Animal Center, China) were randomly divided into normal, model, macromolecule, and small molecule groups, with 10 rabbits in each group. The control group did not undergo any treatment. Rabbits in the remaining three groups were injected with papain via the right knee joint cavity to establish rabbit models of osteoarthritis. At 7 days after successful modeling, the right knee joint cavity of rabbits in the macromolecule and small molecule groups were injected with 0.3 mL of (1.5-2.5)x106 Da and (0.8-1.5)x106 Da sodium hyaluronate injection. Rabbits in the model group were injected with equal amounts of physiological saline, once a week, for 5 successive weeks. At 7 days after the last injection, the right knee joint cavity was examined by MRI, cartilage tissue was stained with hematoxylin-eosin, the level of inflammatory factors in the washing fluid was determined, and proteoglycan and collagen gene expression was detected. This study was approved by the Medical Ethics Committee of Qinghai Red Cross Hospital, China (No. 201802065). RESULTS AND CONCLUSION: MR imaging: There were joint effusion and incomplete cartilage surface in the model group. In the macromolecule group, cartilage surface was rough and cartilage layer became thinner compared with the model group. Hematoxyin-eosin staining: Obvious cartilage injury was observed in the model, macromolecule, and small molecule groups, but the injury in the macromolecule, and small molecule groups was milder than that in the model group. The injury in the small molecular group was milder than that in the macromolecule group. Measurement of inflammatory factors: Compared with the control group, the levels of interleukin-1 beta, tumor necrosis factor-alpha and matrix metalloproteinase-3 increased in the model group (P < 0.05). Compared with the model group, the levels of interleukin-1 beta, tumor necrosis factor-alpha and matrix metalloproteinase-3 decreased in the macromolecule and small molecule groups (P < 0.05). The levels of interleukin-1 beta and matrix metalloproteinase-3 in the small molecule group were lower than those in the macromolecule group. There was no significant difference in the level of tumor necrosis factor-alpha between small molecule and macromolecule groups. Gene detection: Proteoglycan and collagen gene expression levels were significantly lower in the model group than in the control, macromolecule and small molecule groups (P < 0.05). Proteoglycan and collagen gene expression levels were significantly lower in the macromolecule group than in the small molecule group (P < 0.05). These results suggest that compared with large molecular weight of sodium hyaluronate, small molecular weight of sodium hyaluronate can promote the repair of cartilage tissue in osteoarthritis and alleviate synovitis inflammation.
ABSTRACT
The CRISPR/Cas9 system, consisting of Cas9 nuclease and single guide RNA (sgRNA), is an emerging gene editing technology that can perform gene reprogramming operations such as deletion, insertion, and point mutation on DNA sequences targeted by sgRNA. In addition, CRISPR/dCas9 (a mutant that loses Cas9 nuclease activity) still retains the ability of sgRNA to target DNA. The fusion of dCas9 protein with transcriptional activator (CRISPRa) can activate the expression of the target gene, and fusion transcriptional repressors (CRISPRi) can also be used to suppress target gene expression. Efficient delivery of the CRISPR/Cas9 system is one of the main problems limiting its wide clinical application. Viral vectors are widely used to efficiently deliver CRISPR/Cas9 elements, but non-viral vector research is more attractive in terms of safety, simplicity, and flexibility. In this review, we summarize the principles and research advances of CRISPR technology, including CRISPR/ Cas9 delivery vectors, delivery methods, and obstacles to the delivery, and review the progress of CRISPR-based research in bone and cartilage tissue engineering. Finally, the challenges and future applications of CRISPR technology in bone and cartilage tissue engineering are discussed.
Subject(s)
CRISPR-Cas Systems , Cartilage , Clustered Regularly Interspaced Short Palindromic Repeats , Tissue EngineeringABSTRACT
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.
Subject(s)
Cartilage , Cell Biology , Chondrocytes , Extracellular Matrix , Tissue Engineering , Tissue ScaffoldsABSTRACT
OBJECTIVE@#This study aimed to optimize the preparation of carboxymethyl chitosan/sodium alginate (CMCS/OSA) compound hydrogels. This study also aimed to investigate the applicability of the hydrogels in cartilage tissue engi-neering.@*METHODS@#Three groups of CMCS/OSA composite hydrogels with amino-to-aldehyde ratios of 2∶1, 1∶1 and 1∶2 were prepared. The microstructure, physical properties, and cell biocompatibility of the three groups of CMCS/OSA com-posite hydrogels were evaluated. Samples were subjected to scanning electron microscopy, rheological test, adhesion tension test, swelling rate test, and cell experiments to identify the CMCS/OSA composite hydrogel with the cross-linking degree that can meet the requirements for scaffolds in cartilage tissue engineering.@*RESULTS@#The experimental results showed that the CMCS/OSA hydrogel with a amine-to-aldhyde ratio of 1∶1 had good porosity, suitable gelling time, strong adhesive force, stable swelling rate, and good cellular biocompatibility.@*CONCLUSIONS@#The CMCS/OSA compound hydrogel prepared with a 1∶1 ratio of amino and aldehyde groups has potential applications in cartilage tissue engineering.
Subject(s)
Alginates , Cartilage , Chitosan , Hydrogels , Tissue EngineeringABSTRACT
BACKGROUND: Cartilage tissue engineering (CTE) aims to obtain a structure mimicking native cartilage tissue through the combination of relevant cells, three-dimensional scaffolds, and extraneous signals. Implantation of ‘matured’ constructs is thus expected to provide solution for treating large injury of articular cartilage. Type I collagen is widely used as scaffolds for CTE products undergoing clinical trial, owing to its ubiquitous biocompatibility and vast clinical approval. However, the long-term performance of pure type I collagen scaffolds would suffer from its limited chondrogenic capacity and inferior mechanical properties. This paper aims to provide insights necessary for advancing type I collagen scaffolds in the CTE applications. METHODS: Initially, the interactions of type I/II collagen with CTE-relevant cells [i.e., articular chondrocytes (ACs) and mesenchymal stem cells (MSCs)] are discussed. Next, the physical features and chemical composition of the scaffolds crucial to support chondrogenic activities of AC and MSC are highlighted. Attempts to optimize the collagen scaffolds by blending with natural/synthetic polymers are described. Hybrid strategy in which collagen and structural polymers are combined in non-blending manner is detailed. RESULTS: Type I collagen is sufficient to support cellular activities of ACs and MSCs; however it shows limited chondrogenic performance than type II collagen. Nonetheless, type I collagen is the clinically feasible option since type II collagen shows arthritogenic potency. Physical features of scaffolds such as internal structure, pore size, stiffness, etc. are shown to be crucial in influencing the differentiation fate and secreting extracellular matrixes from ACs and MSCs. Collagen can be blended with native or synthetic polymer to improve the mechanical and bioactivities of final composites. However, the versatility of blending strategy is limited due to denaturation of type I collagen at harsh processing condition. Hybrid strategy is successful in maximizing bioactivity of collagen scaffolds and mechanical robustness of structural polymer. CONCLUSION: Considering the previous improvements of physical and compositional properties of collagen scaffolds and recent manufacturing developments of structural polymer, it is concluded that hybrid strategy is a promising approach to advance further collagen-based scaffolds in CTE.
Subject(s)
Cartilage , Cartilage, Articular , Chondrocytes , Collagen Type I , Collagen Type II , Collagen , Extracellular Matrix , Mesenchymal Stem Cells , Polymers , Tissue EngineeringABSTRACT
Objective: To review the progress of cell sheet technology and its application in bone and cartilage engineering.
ABSTRACT
Results: The scaffolds in 3 groups were all showed a cross-linked and pore interconnected with pore size of 400-500 μm, porosity of 56%, and fiber orientation of 0°/90°. For dopamine modification, the scaffolds in groups B and C were dark brown while in group A was white. Similarly, water static contact angle was from 76° of group A to 0° of groups B and C. After cultured for 24 hours, the cell adhesion rate of groups A, B, and C was 34.3%±3.5%, 48.3%±1.5%, and 57.4%±2.5% respectively, showing significant differences between groups ( P<0.05). Live/Dead staining showed good cell activity of cells in 3 groups. MTT test showed that hBMSCs proliferated well in 3 groups and the absorbance ( A) value was increased with time. The A value in group C was significantly higher than that in groups B and A, and in group B than in group A after cultured for 4, 7, 14, and 21 days, all showing significant differences ( P<0.05). The mRNA relative expression of collagen type Ⅱ and Aggrecan increased gradually with time in 3 groups. The mRNA relative expression of collagen type Ⅱafter cultured for 7, 14, and 21 days, and the mRNA relative expression of Aggrecan after cultured for 14 and 21 days in group C were significantly higher than those in groups A and B, and in group B than in group A, all showing significant differences ( P<0.05).
ABSTRACT
Objective: To observe the feasibility of acellular cartilage extracellular matrix (ACECM) oriented scaffold combined with chondrocytes to construct tissue engineered cartilage.
ABSTRACT
Objective·To construct C-shaped cartilage rings by rabbit auricular cartilage-derived chondrocytes combing with both electrospun gelatin/ polycaprolactone(GT/PCL) nanofibrous membranes and 3D printed supporters for repairing tracheal cartilage defects.Methods·Primary chondrocytes were isolated from rabbit auricular cartilage with methods of trypsin enzyme digestion and collagenase enzyme digestion.After proliferation in vitro,the chondrocytes of passage 2 were harvested for further experiments.Ultrafine composite fibers of GT/PCL were fabricated via electrospinning.The electrospun GT/PCL membranes were tailored into rectangle shape,the length of which is 12 cm and the width is 2.5 cm.Chondrocytes were seeded on membrane at a density of 1 × 108 cells/mL.Then the membrane were rolled onto a 3D printed supporter of poly(DL-lactide-ε-caprolactone) (PLCL) material to construct a C-shaped cartilage-like complex.After 8 weeks of subcutaneous incubation in vivo,gross inspection and paraffin section staining were applied for evaluation.Results·After 8 weeks of culture in vivo,mature cartilage-like tissue were formed with open-cylindrical bellow appearance and pecific mechanical property.C-shaped rings arranged at regular intervals on the inner surface of tissue,which were similar to the normal structure of tracheal cartilages.Histological and immunohistological staining showed a large number of typical lacunar structures and extracellular matrix secretions.Conclusion·It is feasible to construct tissue engineered C-shaped cartilage tissue by combing chondrocytes with GT/PCL membrane and 3D printed PLCL supporter for tracheal cartilage repair.
ABSTRACT
Objective: To investigate the effect of cartilage tissue engineering scaffold PVA/ι-CA on the biological behavior of the ATDC-5 cells,and to evaluate its feasibility on constructing tissue engineering cartilage. Methods:The polyvinyl alcohol (PVA)and carrageenan were used to make the composite scaffold material PVA/ι-CA according to a certain proportion by physical blending technology and repeated freezing thawing method,and the porosity and pore size of PVA/ι-CA were detected.The ATDC-5 cells were seeded into the composite scaffold and its growth was observed; the expressions of collagen type Ⅱ in the ATDC-5 cells were tested by immunohistochemical staining and immunofluorescence staining; the morphology of the ATDC-5 cells was confirmed by Toluidine blue staining.The growth and secretion of extracellular matrix of the ATDC-5 cells were observed under scanning electron microscope (SEM);the proliferative rates of ATDC-5 cells in composite scaffold materials in negative control group (added with DMEM culture media)and experimental group (added with DMEM contain scaffold)were determined by MTT assay.The composite scaffolds were implanted subcutaneously in the SD rats.The histocompatibility and vascularization in vivo of the composite scaffolds were evaluated.Results:The average porosity of cartilage tissue engineering scaffold PVA/ι-CA was (86.88±3.88)%,and the average pore size was 20-40 μm.The HE staining results showed that the ATDC-5 cells grew well with the polygon and plumpness morphology. All the samples were stained positive for collagen type Ⅱ by immunohistochemistry and immunofluorescence staining,which verified the normal phenotype of chondrocytes on the scaffolds. All the sample were stained positive for toluidine blue staining,which verified ECM deposition of the ATDC-5 cells on the scaffolds.The number of the positive cells was significantly increased with the prolongation of time.After cultured for 7 d,few of the ATDC-5 cells presented polygonal;after cultured for 14 d,the ATDC-5 cells distributed more densely,and contacted with each other on the scaffold;after cultured for 21 - 28 d,the ATDC-5 cells filled the interconnected pores of the scaffolds,synthesizing a significant amount of neo-formed ECM.The proliferation of ATDC-5 cells in PVA/ι-CA grew fast during 7-14 d,and it became slow during 21-28 d;the difference was not statistically significant compared with control group (P >0.05).The subcutaneous implantation results showed the inflammatory reactions were slight at the early stage and eviated gradually,there was an increasing angiogenesis at the late stage,and the degradation and absorption of the meterial were slight.Conclusion:PVA/ι-CA composite material will be an ideal material for the cartilage tissue engineering.
ABSTRACT
In this paper we report the differentiating properties of platelet-rich plasma releasates (PRPr) on human chondrocytes within elastomeric polycaprolactone triol–citrate (PCLT–CA) porous scaffold. Human-derived chondrocyte cellular content of glycosaminoglycans (GAGs) and total collagen were determined after seeding into PCLT–CA scaffold enriched with PRPr cells. Immunostaining and real time PCR was applied to evaluate the expression levels of chondrogenic and extracellular gene markers. Seeding of chondrocytes into PCLT–CA scaffold enriched with PRPr showed significant increase in total collagen and GAGs production compared with chondrocytes grown within control scaffold without PRPr cells. The mRNA levels of collagen II and SOX9 increased significantly while the upregulation in Cartilage Oligomeric Matrix Protein (COMP) expression was statistically insignificant. We also report the reduction of the expression levels of collagen I and III in chondrocytes as a consequence of proximity to PRPr cells within the scaffold. Interestingly, the pre-loading of PRPr caused an increase of expression levels of following extracellular matrix (ECM) proteins: fibronectin, laminin and integrin β over the period of 3 days. Overall, our results introduce the PCLT–CA elastomeric scaffold as a new system for cartilage tissue engineering. The method of PRPr cells loading prior to chondrocyte culture could be considered as a potential environment for cartilage tissue engineering as the differentiation and ECM formation is enhanced significantly.
Subject(s)
Humans , Blood Platelets , Cartilage Oligomeric Matrix Protein , Cartilage , Chondrocytes , Collagen , Elastomers , Extracellular Matrix , Fibronectins , Glycosaminoglycans , Laminin , Methods , Phenotype , Platelet-Rich Plasma , Real-Time Polymerase Chain Reaction , RNA, Messenger , Tissue Engineering , Up-RegulationABSTRACT
For successful tissue engineering of articular cartilage, a scaffold with mechanical properties that match those of natural cartilage as closely as possible is needed. In the present study, we prepared a fibrous silk fibroin (SF)/poly(L-lactic acid) (PLLA) scaffold via electrospinning and investigated the morphological, mechanical, and degradation properties of the scaffolds fabricated using different electrospinning conditions, including collection distance, working voltage, and the SF:PLLA mass ratio. In addition, in vitro cell-scaffold interactions were evaluated in terms of chondrocyte adhesion to the scaffolds as well as the cytotoxicity and cytocompatibility of the scaffolds. The optimum electrospinning conditions for generating a fibrous SF/PLLA scaffold with the best surface morphology (ordered alignment and suitable diameter) and tensile strength (~1.5 MPa) were a collection distance of 20 cm, a working voltage of 15 kV, and a SF:PLLA mass ratio of S50P50. The degradation rate of the SF/PLLA scaffolds was found to be determined by the SF:PLLA mass ratio, and it could be increased by reducing the PLLA proportion. Furthermore, chondrocytes spread well on the fibrous SF/PLLA scaffolds and secreted extracellular matrix, indicating good adhesion to the scaffold. The cytotoxicity of SF/PLLA scaffold extract to chondrocytes over 24 and 48 h in culture was low, indicating that the SF/PLLA scaffolds are biocompatible. Chondrocytes grew well on the SF/PLLA scaffold after 1, 3, 5, and 7 days of direct contact, indicating the good cytocompatibility of the scaffold. These results demonstrate that the fibrous SF/PLLA scaffold represents a promising composite material for use in cartilage tissue engineering.
Subject(s)
Cartilage , Cartilage, Articular , Chondrocytes , Extracellular Matrix , Fibroins , In Vitro Techniques , Silk , Tensile Strength , Tissue EngineeringABSTRACT
PURPOSE: The purpose of this study was to investigate the effects of transplantation of an in vitro-generated, scaffold-free, tissue-engineered cartilage tissue analogue (CTA) using a suspension chondrocyte culture in a rabbit growth-arrest model. MATERIALS AND METHODS: We harvested cartilage cells from the articular cartilage of the joints of white rabbits and made a CTA using a suspension culture of 2x107 cells/mL. An animal growth plate defect model was made on the medial side of the proximal tibial growth plate of both tibias of 6-week-old New Zealand white rabbits (n=10). The allogenic CTA was then transplanted onto the right proximal tibial defect. As a control, no implantation was performed on the left-side defect. Plain radiographs and the medial proximal tibial angle were obtained at 1-week intervals for evaluation of bone bridge formation and the degree of angular deformity until postoperative week 6. We performed a histological evaluation using hematoxylin-eosin and Alcian blue staining at postoperative weeks 4 and 6. RESULTS: Radiologic study revealed a median medial proximal tibial angle of 59.0degrees in the control group and 80.0degrees in the CTA group at 6 weeks. In the control group, statistically significant angular deformities were seen 3 weeks after transplantation (p<0.05). On histological examination, the transplanted CTA was maintained in the CTA group at 4 and 6 weeks postoperative. Bone bridge formation was observed in the control group. CONCLUSION: In this study, CTA transplantation minimized deformity in the rabbit growth plate injury model, probably via the attenuation of bone bridge formation.
Subject(s)
Animals , Rabbits , Bone Transplantation , Cartilage/anatomy & histology , Cell Culture Techniques , Cells, Cultured , Chondrocytes/cytology , Growth Plate/anatomy & histology , Mesenchymal Stem Cell Transplantation , Tibia/surgery , Tissue Engineering , Transplantation, Autologous/methods , Transplantation, HomologousABSTRACT
<p><b>OBJECTIVE</b>To investigate the effect of electronspun PLGA/HAp/Zein scaffolds on the repair of cartilage defects.</p><p><b>METHODS</b>The PLGA/HAp/Zein composite scaffolds were fabricated by electrospinning method. The physiochemical properties and biocompatibility of the scaffolds were separately characterized by scanning electron microscope (SEM), transmission electron microscope (TEM), and fourier transform infrared spectroscopy (FTIR), human umbilical cord mesenchymal stem cells (hUC-MSCs) culture and animal experiments.</p><p><b>RESULTS</b>The prepared PLGA/HAp/Zein scaffolds showed fibrous structure with homogenous distribution. hUC-MSCs could attach to and grow well on PLGA/HAp/Zein scaffolds, and there was no significant difference between cell proliferation on scaffolds and that without scaffolds (P>0.05). The PLGA/HAp/Zein scaffolds possessed excellent ability to promote in vivo cartilage formation. Moreover, there was a large amount of immature chondrocytes and matrix with cartilage lacuna on PLGA/HAp/Zein scaffolds.</p><p><b>CONCLUSION</b>The data suggest that the PLGA/HAp/Zein scaffolds possess good biocompatibility, which are anticipated to be potentially applied in cartilage tissue engineering and reconstruction.</p>
Subject(s)
Animals , Female , Humans , Male , Young Adult , Biocompatible Materials , Bone Development , Physiology , Cartilage , Cells, Cultured , Durapatite , Chemistry , Lactic Acid , Chemistry , Mesenchymal Stem Cells , Physiology , Polyglycolic Acid , Chemistry , Regeneration , Physiology , Tissue Scaffolds , Chemistry , Zein , ChemistryABSTRACT
BACKGROUND:Insulin-like growth factor 1 is the key factor during cartilage development, which is involved in the growth and reconstruction of condylar cartilage. OBJECTIVE:To study the effect of insulin-like growth factor 1 on cel apoptosis and the apopotosis-associated factors of Bcl-2, Bax mRNA and protein expressions of rat condylar chondrocytes. METHODS:The 1-day-old and 28-day-old rat condylar chondrocytes were cultured and identified in vitro. The condylar chondrocytes with different ages were divided into experimental group and control group. After being starved for 24 hours, chondrocytes in the experimental group were incubated with 100μg/L recombined rat insulin-like growth factor 1 for 48 hours, while the chondrocytes in the control group were incubated normal y. RESULTS AND CONCLUSION:Compared with the control group, after being incubated with recombined insulin-like growth factor 1, the number of condylar chondrocytes was increased with high speed proliferation (Pproliferation and reduce cel apoptosis of newborn and adolescent rat condylar chondrocytes, which may be mediated by Bcl-2 and Bax.
ABSTRACT
BACKGROUND: Ischemia/reperfusion can induce degenerative alterations in articular cartilage. However, the precise mechanism remains poorly understood. OBJECTIVE: To observe the morphological changes and the apoptosis of articular cartilage of femoral head epiphyses with ischemia/reperfusion. METHODS: A total of 80 Sprague-Dawley rats were randomly assigned to two groups: ischemia/reperfusion (model of ischemia/reperfusion in hip joint) and sham-surgery (exposure of abdominal aorta for 5 minutes) groups, with 40 animals in each group. Articular cartilages of femoral head epiphysis were col ected in 6, 12, 24, and 48 hours, 5 days, and 2 and 4 weeks after operation. Morphology of articular cartilage of femoral head epiphyses was examined by light microscope, and cel apoptosis was detected by TUNEL method. RESULTS AND CONCLUSION: Light microscopy showed chondrocytes degeneration and reduction, as wel as fibrosis in matrix of cartilage in the ischemia/reperfusion group. Chondrocyte apoptosis was observed in both groups by TUNEL. Several apoptotic cells, less than five, were observed in the sham-surgery, while 10-30 apoptotic cells were found in ischemia/reperfusion group at 48 hours. Results indicated that ischemia/reperfusion can induce degenerative changes in articular cartilage of femoral head epiphyses, and cel apoptosis in developing hip joint may participate in damage of articular cartilage. Inhibition of chondrocyte apoptosis in articular cartilage may be useful for the prevention and cure of early osteoarthritis.
ABSTRACT
BACKGROUND: There are different methods to isolate and culture human nucleus pulposus cells, and the differences in digestive enzymes components and digestion time quite are significant. So how to rapidly and efficiently harvest human nucleus pulposus cells has become a research hotspot. OBJECTIVE: To optimize the digestive enzymes components and digestion methods for the preparation of human nucleus pulposus cells. METHODS: Nucleus pulposus tissue specimens were selected from three adult discs in the Department of Orthopedics, China-Japan Union Hospital of Jilin University. The acute traumatic disc tissues that outstanding to the spinal canal were taken under aseptic conditions, and then the peripheral white annulus and jel y-like nucleus pulposus in the center could be seen. According to different mixed enzyme concentration ratio, the samples were divided into two groups. The enzyme Ⅰ group was treated with 0.2% Ⅱ col agenase; and the mixed enzymeⅡ group was digested with 0.25% trypsin for 30 minutes, and then treated with 0.2% Ⅱ col agenase. According to digestion time, each group was divided into three subgroups: 2 hours group, 4 hours group, and overnight group. Final y, suspended cel volume was decided as 2 mL to count cells. Dulbecco’s modified Eagle’s medium containing fetal bovine serum was used for cel culture in vitro. Trypan blue staining was performed to count total cel number and ratio of living cells. Methylthiazolyldiphenyl-tetrazolium bromide assay was used to detect the growth curve of nucleus pulposus cells. RESULTS AND CONCLUSION: Based on the two digestion enzyme concentration, the number of digested cells in the enzyme Ⅰ group was larger than that in the enzyme Ⅱ group after digested for 2 and 4 hours, but the difference was not significant (P > 0.05). Overnight, cellsurvival rate was decreased in the enzyme Ⅰ group after digested for 2 and 4 hours when compared with the enzyme Ⅱ group, and the difference was significant (P < 0.05). After digested for 4 hours, tissue blocks disappeared, and the number of cells reached maximum. The results indicate that enzyme Ⅰgroup composite with Ⅱ col agenase is benefit for the separation of nucleus pulposus cells, and the digestion time is appropriate to 4 hours. This condition has the advantages of simple operation, high efficiency and low cost, and it considered that digestion of nucleus pulposus tissues with 0.2% Ⅱ col agenase for 4 hours is the best condition to obtain nucleus pulposus cells.