To investigate the pathologic characteristics of the articular cartilage and subchondral bone from osteoarthritic knees, and to compare the structural parameters of articular cartilage and subchondral bone between the medial and lateral tibial plateau, so as to determine the role of calcified zone and subchondral bone in the pathogenesis of osteoarthritis (OA). Methods The tibial plateaus were taken from 30 patients undergoing total knee arthroplasty between October 2009 and May 2011. The subjects included 11 males and 19 females with an average age of 65.1 years (range, 55-78years). The mean disease duration was 16.6 years (range, 10-25 years); the mean varus angle of the diseased knee was 9.3° (range, 1-23°). After gross observation, the cartilage-bone samples were taken out from the most weight-bearing regions in the internal areas of the medial and lateral plateaus. The decalcified paraffin-embedded sections were prepared and stained with HE and Safranin O/fast green for cartilage assessment (Mankin score), staging, and bone histomorphometry; the pathologic features of the cartilage and subchondral bone were also observed. The thickness of total articular cartilage (TAC), articular calcified cartilage (ACC), subchondral bone plate (SCP), and the trabecular bone volume (BV/TV) were measured by Image Pro Plus 6.0 imaging system, then the ratio of ACC/TAC was calculated. Results Macroscopic results showed that articular cartilage degeneration was more severe in the medial plateau than in the lateral plateau; Mankin score of the medial plateau (12.4 ± 1.1) was significantly higher than that of the lateral plateau (8.3 ± 1.6) (t=12.173, P=0.000). In the 60 samples, 14 samples were at stage I, characterisd by fissures within the superficial zone, dupl icated tidemark, and thickend subchondral bone; 19 samples were at stage II, characterisd by fissures extending into the deep zone, multiple subchondral bone resorption pits, and obviously thickend subchondral bone; and 27 samples were at stage III, characterisd by full-thickness cartilage defects, endochondral ossification, and eburnated subchondral bone. The bone histomorphometric study showed that TAC thickness of the medial plateau was significantly lower than that of the lateral plateau (P lt; 0.05); the ratios of ACC/TAC, BV/TV, and SCP thickness of the medial plateau were significantly higher than those of the lateral plateau (P lt; 0.05). However, there was no significantdifference in the ACC thickness between the medial and lateral plateaus (P gt; 0.05). Conclusion The calcified zone andsubchondral bone may play an important role in the initiation and progression of OA.
To investigate the feasibility of using the pedicled patella for repaire of the superior articular surface of the medial tibial condyle, 37 lower limbs were studied by perfusion. In this series, there were 34 obsolete specimens and 3 fresh specimens of lower legs. Firstly, the vessels which supply to patella were observed by the methods of anatomy, section and casting mould. Then, the form and area of the patellar and tibial medial conylar articular surface were measured in 30 cases. The results showed: (1) the arteries supplied to patella formed a prepatellar arterial ring around patella, and the ring gave branches to patella; (2) medial inferior genicular artery and inferior patellar branches of the descending genicular arterial articular branch merge and acceed++ to prepatellar ring at inferior medial part of patella; (3) the articular surface of patella is similar to the superior articular surface of the tibial medial condyle on shape and area. It was concluded that the pedicled patella can be transposed to medial tibial condyle for repaire of the defect of the superior articular surface. The function of the knee can be reserved by this method.
In order to investigate the effect of motion on repairing articular cartilage defect following autogenous periosteal graft, sixty adult rabbits were divided randomly into three groups: out-cage motion (OCM), in-cage motion (ICM) and immobilization (IMM). A defect of the articular cartilage, 1 cm x 0.5 cm in size, was made in the patellar-groove of femur of each hind limb. Free autogenous periosteal graft from the proximal tibia was sutured on the base of the left defect, while the right limb was served as control. The animals were sacrificed at 4, 8 and 12 weeks, respectively, after operation. The regeneration of the cartilage implanted was observed through gross, histology, histochemical assay and electronic microscope. The influence of different amount of motion on the chondrogenesis from the periosteal implant was also compared. The result showed that the hyaline cartilage produced from periosteal implant could be capable to repair full-thickness of articular cartilage. From statistical study, there was significant difference between OCM and ICM groups (P lt; 0.05), ICM and IMM (P lt; 0.05) as well as OCM and IMM (P lt; 0.01). It was suggested that the periosteal graft was effective in repair of defect of articular cartilage and the amount of motion was important for chondrogenesis.
In order to observe the effects of different facing directions of the germinal layer of periosteum on the cartilage regeneration, the human fibrin adhesive agent was used to adhere autogenous periosteum to repair the articular cartilage defect of rabbits. Twentyfour rabbits with 48 knee joints were divided randomly into two groups. A 0.6cm×1.2cm articular cartilage defect was created on the femoral trochlea until there was bleeding from the subchondral bone. A piece of periosteum, sized 0.75cm×1.5cm, was removed from the medial aspect of upper tibia. The periosteum was adhered to the defect by human fibrin adhesive agent. In Group 1 the germinal layer faced the subchondral bone and in Group 2 the germinal layer faced the joint cavity. The cartilage regeneration in both groups was observed by naked eyes and light microscope in 2nd and 6th weeks and by electron microscope after Safronin Ostained in 12th and 20th weeks. The results showed that before the 6th week, the cartilage regeneration was faster in Group 2 than that in Group 1. After that there was no significant difference in regeneration between the two groups. This suggested that the facing direction of the germinal layer was not a critical factor on cartilage regeneration. It was also found that the strength of the adhesive agent was not enough. The regenerated cartilage was proved to be hyaline cartilage.
ObjectiveTo observe and study the clinical effect of glucosamine in the treatment of patients with knee articular cartilage injury caused by rheumatoid arthritis. MethodsForty-six patients with knee articular cartilage injury caused by rheumatoid arthritis treated from January 2013 to June 2015 were selected as the research subjects, and they were randomly divided into control group (conventional treatment group, n=23) and observation group (conventional and glucosamine treatment group, n=23) . Then the Noyes classification and serum articular cartilage injury related indexes [cartilage oligomeric matrix protein (COMP), matrix metalloproteinase (MMP)-1, MMP-3 and mouse tissue inhibitors of metalloproteinase (TIMP)-1], inflammatory indexes [tumor necrosis factor (TNF)-α, interleukin (IL)- 17 and IL-33] of the two groups before and after treatment were compared. ResultsIn the observation group, after treatment for 4, 8 and 12 weeks, Noyes grade was better than that in the control group, but with no statistical significance (P ＞ 0.05) . In the observation group, after treatment for 4, 8 and 12 weeks, serum inflammatory markers serum COMP, MMP-1, MMP-3 and TIMP-1 and other related indicators of cartilage damage and serum TNF-α, IL-17 and IL-33 were all significantly lower than those in the control group (P ＜ 0.05) . ConclusionIn the treatment of patients with knee articular cartilage injury caused by rheumatoid arthritis, glucosamine has active role for the improvement of articular cartilage injury and inflammatory stress state of patients.
ObjectiveTo investigate the relationships between the expression of integrin β1 and activated cells in a partial-thickness articular cartilage injury model of adult rats. MethodForty-five male Sprague Dawley rats (aged 10 weeks and weighing 300-400 g) were randomly divided into operated group (n=15) , sham-operated group (n=15) , and control group (n=15) . Partial-thickness articular cartilage injury model was made by scarification in operated group, direct suture after opening of the knee joint was performed in sham-operated group, and no operation was done in control group. Five rats were sacrificed at 1, 7, and 14 days after operation respectively for macroscopic evaluation, HE staining, Safranin O staining, CD105, BrdU, CD105/integrin β1 immunofluorescence and double labeling staining. The histological score of HE staining, gray value of Safranin O staining and CD105-positive cells count were compared among groups at each time point. ResultsMacroscopic evaluation showed chondromalacia and cartilage fibrosis around the linear injury with aggravating tendency with time in operated group, but no chondromalacia and cartilage fibrosis in sham-operated and control groups. HE staining demonstrated a number of activated cells accumulating around the linear injury with nonuniform distribution in operated group, and uniform size and distribution in sham-operated and control groups. The histological scores at each time point in operated group were significantly higher than those in sham-operated group and control group (P<0.05) , but no significant difference was found between different time points in 3 groups (P>0.05) . Safranin O staining was nonuniform with hypochromasia around linear injury in operated group, but the staining was uniform in sham-operated group and control group. Gray value of Safranin O staining had no significant difference among groups and among different time points in the same group (P>0.05) . BrdU-positive and CD105-positive cells distributed unevenly around the linear injury in operated group, uniform distribution was observed in sham-operated group and control group. CD105-positive cells count in operated group was significantly higher than those in sham-operated group and control group at each time point (P<0.05) ; CD105-positive cells increased significantly with time in operated group (P<0.05) . CD105/integrinβ1-positive cells were observed around the linear injury in operated group, but was not observed in sham-operated group and control group. ConclusionsThe partial-thickness articular cartilage injury model is successfully established in rats, and cartilage injury could not be repaired completely in the model. The activated cells aggregation around the linear injury can be observed, but there is no obvious relationships between activated cells and cartilage matrix. These activated cells are in proliferation and could express both CD105 and integrin β1.
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.
Objective To manufacture a poly (lactic-co-glycolic acid) (PLGA) scaffold by low temperature deposition three-dimensional (3D) printing technology, prepare a PLGA/decellularized articular cartilage extracellular matrix (DACECM) cartilage tissue engineered scaffold by combining DACECM, and further investigate its physicochemical properties. Methods PLGA scaffolds were prepared by low temperature deposition 3D printing technology, and DACECM suspensions was prepared by modified physical and chemical decellularization methods. DACECM oriented scaffolds were prepared by using freeze-drying and physicochemical cross-linking techniques. PLGA/DACECM oriented scaffolds were prepared by combining DACECM slurry with PLGA scaffolds. The macroscopic and microscopic structures of the three kinds of scaffolds were observed by general observation and scanning electron microscope. The chemical composition of DACECM oriented scaffold was analyzed by histological and immunohistochemical stainings. The compression modulus of the three kinds of scaffolds were measured by biomechanical test. Three kinds of scaffolds were embedded subcutaneously in Sprague Dawley rats, and HE staining was used to observe immune response. The chondrocytes of New Zealand white rabbits were isolated and cultured, and the three kinds of cell-scaffold complexes were prepared. The growth adhesion of the cells on the scaffolds was observed by scanning electron microscope. Three kinds of scaffold extracts were cultured with L-929 cells, the cells were cultured in DMEM culture medium as control group, and cell counting kit 8 (CCK-8) was used to detect cell proliferation. Results General observation and scanning electron microscope showed that the PLGA scaffold had a smooth surface and large pores; the surface of the DACECM oriented scaffold was rough, which was a 3D structure with loose pores and interconnected; and the PLGA/DACECM oriented scaffold had a rough surface, and the large hole and the small hole were connected to each other to construct a vertical 3D structure. Histological and immunohistochemical qualitative analysis demonstrated that DACECM was completely decellularized, retaining the glycosaminoglycans and collagen typeⅡ. Biomechanical examination showed that the compression modulus of DACECM oriented scaffold was significantly lower than those of the other two scaffolds (P<0.05). There was no significant difference between PLGA scaffold and PLGA/DACECM oriented scaffold (P>0.05). Subcutaneously embedded HE staining of the three scaffolds showed that the immunological rejections of DACECM and PLGA/DACECM oriented scaffolds were significantly weaker than that of the PLGA scaffold. Scanning electron microscope observation of the cell-scaffold complex showed that chondrocytes did not obviously adhere to PLGA scaffold, and a large number of chondrocytes adhered and grew on PLGA/DACECM oriented scaffold and DACECM oriented scaffold. CCK-8 assay showed that with the extension of culture time, the number of cells cultured in the three kinds of scaffold extracts and the control group increased. There was no significant difference in the absorbance (A) value between the groups at each time point (P>0.05). Conclusion The PLGA/DACECM oriented scaffolds have no cytotoxicity, have excellent physicochemical properties, and may become a promising scaffold material of tissue engineered cartilage.
ObjectiveTo summarize the active changes of Wnt signaling pathway in osteoarthritis (OA) as well as the influence and mechanism of dual-targeted regulation on cartilage and subchondral bone and the role of crosstalk between them on OA process.MethodsThe relevant literature concerning the articular cartilage, subchondral bone, and crosstalk between them in OA and non-OA states by Wnt signaling pathway in vivo and vitro experimental studies and clinical studies in recent years was reviewed, and the mechanism was analyzed and summarized.ResultsWnt signaling can regulate the differentiation and function of chondrocytes and osteoblasts through the classic β-catenin-dependent or non-classical β-catenin-independent Wnt signaling pathway and its cross-linking with other signaling pathways, thereby affecting the cartilage and bone metabolism. Moreover, Wnt signaling pathway can activate the downstream protein Wnt1-inducible-signaling pathway protein 1 to regulate the progress of OA and it also can be established gap junctions between different cells in cartilage and subchondral bone to communicate molecules directly to regulate OA occurrence and development. Intra-articular injection of Wnt signaling inhibitor SM04690 can inhibit the progress of OA, and overexpression of Wnt signaling pathway inhibitor Dickkopf in osteoblasts can antagonize the role of vascular endothelial growth factor work on chondrocytes and inhibit the catabolism of its matrix.ConclusionThe regulation of metabolism and function of cartilage and subchondral bone and crosstalk between them is through interactions among Wnt signaling pathway and molecules of other signaling. Therefore, it plays an vital role in the occurrence and development of OA and is expected to become a new target of OA treatment through intervention and regulation of Wnt signaling pathway.