Superficial cartilage defect is an important factor that causes osteoarthritis. Therefore, it is very important to investigate the influence of superficial cartilage defects on its surface morphology and mechanical properties. In this study, the knee joint cartilage samples of adult pig were prepared, which were treated by enzymolysis with chymotrypsin and physical removal with electric friction pen, respectively. Normal cartilage and surface treated cartilage were divided into five groups: control group (normal cartilage group), chymotrypsin immersion group, chymotrypsin wiping group, removal 10% group with electric friction pen, and removal 20% group with electric friction pen. The surface morphology and structure of five groups of samples were characterized by laser spectrum confocal microscopy and environmental field scanning electron microscopy, and the mechanical properties of each group of samples were evaluated by tensile tests. The results show that the surface arithmetic mean height and fracture strength of the control group were the smallest, and the fracture strain was the largest. The surface arithmetic mean height and fracture strength of the removal 20% group with electric friction pen were the largest, and the fracture strain was the smallest. The surface arithmetic mean height, fracture strength and fracture strain values of the other three groups were all between the above two groups, but the surface arithmetic mean height and fracture strength of the removal 10% group with electric friction pen, the chymotrypsin wiping group and the chymotrypsin soaking group decreased successively, and the fracture strain increased successively. In addition, we carried out a study on the elastic modulus of different groups, and the results showed that the elastic modulus of the control group was the smallest, and the elastic modulus of the removal 20% group with electric friction pen was the largest. The above study revealed that the defect of the superficial area of cartilage changed its surface morphology and structure, and reduced its mechanical properties. The research results are of great significance for the prevention and repair of cartilage injury.
Objective To observe the long-term clinical results of repairing large articular cartilage defects of the hip and the knee with free autogeneous periosteum. Methods Based on the results of experimental studies, the authors used free autogeneous periosteum transplantation and postoperative continuous passive motion (CPM) to repair large articular cartilaginous defects in 52 patientsfrom February 1987 to August 1995. Of 37 patients with complete follow-up data, 16 had congenital dislocation of the hip, 6traumatic arthritis of hip, 1 femoral head destruction following mild infection, 2 ankylosing spondylitis, 6 intra-articular fracture of the knee, 4 arthritisof the knee and 2 stiff knee following joint infection. The patients with dislocation of hip were given relieving traction before operation. The cartilages of pathological changes were excised to bleeding bone. The defects were repairedwith periosteum removing from tibia. CPM were immediately applied for 4-6 weeksand no bearing was allowed 6 months after discharge. The silicon membrane was taken out in the 6th month. Results Thirty-seven patients (17 males, 20 females) were followed up 7-15 years with an average of 10.5 years. The functional evaluation referred to joint pain degree，joint mobile range，daily activity and X-ray findings. The results were excellence in 11 patients , good in 18 patients , poor in 8 patients. Conclusion The method to repair articular cartilage defect with free autogeneous -periosteum is effective and may be applied clinically.
Objective Platelet-rich plasma (PRP) can enhance the chondrocyte prol iferation and repair of cartilage defects. To explore the safety and efficacy of intra-knee-articular injection of PRP to treat knee articular cartilage degeneration by comparing with injecting sodium hyaluronate (SH). Methods Thirty consecutive patients (30 knees) with knee articular cartilage degeneration were selected between January 2010 and June 2010. According to different injections, 30 patients wererandomly divided into PRP group (test group, n=15) and SH group (control group, n=15). There was no significant difference in gender, age, body mass index, and Kellgren-Lawrence grade between 2 groups (P gt; 0.05). Test group received 3.5 mL of PRP intra-knee-articular injections while control group received 2 mL of SH during the same time period. Both treatments were administered in series of 3 intra-knee-articular injections at 3-week intervals. Then, adverse reactions were recorded. International Knee Documentation Committee (IKDC) score, Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) score, and Lequesne index were used for evaluation of treatment results. Results The patients of 2 groups were followed up 6 months. There were significant differences in IKDC score, WOMAC score, and Lequesne index between pre- and post-injection in 2 groups (P lt; 0.05); no significant difference was found between different time points (3, 4, and 6 months) in test group (P gt; 0.05), while significant differences were found between the postoperative 6th month and the postoperative 3rd and 4th months in control group (P lt; 0.05). There was no significant difference in IKDC score, WOMAC score, and Lequesne index between 2 groups within 4 months (P gt; 0.05), but the effectiveness of test group was significantly better than that of control group at 6 months after injection (P lt; 0.05). Adverse reactions occurred in 12 patients (31 injections) of test group and in 12 patients (30 injections) of control group. No significant difference in onset time, termination time, and duration of adverse reactions were found between 2 groups (P gt; 0.05). Conclusion Intra-knee-articular injection of PRP to treat knee articular cartilage degeneration is safe, which can alleviate symptoms of pain and swell ing and improve the qual ity of l ife of patients; however, further data of large samples and long-term follow-up are needed to confirm the safety and effectiveness.
Objective To establ ish a porcine model of articular full-thickness cartilage defect characterized byremaining cartilage calcified zone on femoral trochlea, so as to provide a considerable and comparative control group forinvestigating repair effects of tissue engineered scaffolds in articular cartilage defects with cartilage calcified zone remaining.Methods The full-thickness cartilage column defects (6 mm in diameter, 0.2-0.5 mm in depth) without damage on calcifiedcartilage zone were made on the femoral trochlea in 9 clean-grade 6-month-old Guizhou mini pigs by standard cartilage-defectmakingsuites. Microscopical observation was performed after modeling. Scanning were made by 3.0T MRI at 4 weeks. Thengeneral observation, stereomicroscope, and histological staining were used to observe cartilage repair. Results All animals wereal ive. No infection of incisions or patellar dislocations occurred; they were able to walk with partial weight-bearing immediatelyafter surgery and could move freely without limp at 1 week. Obvious signal discontinuity in trochlea and subchondral bone couldbe observed in MRI, without deep signal change in defects surrounding. Microscopical observation showed a few repair tissueand petechia at base of the defect with clear boundary. Nearly intact calcified zone of cartilage and zonal collapse of subchondralbone in defects could be observed with stereomicroscope. Under common microscope, no chondrocytes was found in defects,as well as negative staining of fast green-safranin O and alcian blue. Under polarized microscope, the bottom of defects werefilled with a l ittle of fibrous tissue presenting continuous and b l ight-refraction by sirius red staining. Conclusion Theanimal model of articular full-thickness cartilage defect on femoral trochlea by standard cartilage-defect-making suites can beapplied for the research of cartilage disease in early human osteoarthritis and function of calcified cartilage zone in pig.
Objective To investigate the possibility of sheep joint cartilage defect repair with tissue engineered cartilage constructed by using porous bioceramics as scaffold and TGF-β induced autologous bone marrow derived mesenchymal stem cells(MSCs) as seed cell. Methods In the experimental group(n=12), autologous MSCs were isolated and expanded in vitro and then implanted into the pre molded porous β-TCP; the cell β-TCP complex was implanted into sheep right humeral cartilage defect. The defects in β-TCP (n= 12) group were repaired by B-TCP only, while defects in the control group (n= 4) were left un-repaired. Samples were extracted 12 and 24 weeks after operation for histological, histochemical and immunohistochemical analysis. Results In the experimental group, cartilage-like tissue formation could be seen on the surface of the implants. Microscopic analysis demonstrated obvious degradation of B-TCP and extensive new cartilage formation 12 weeks after operation, containing rich extracellularmatrix. The cells were stained positively with type II collagen. The bioceramics had almo st completely been degraded and abundant cartilage formation could be seen in the whole defects 24 weeks later. In the B-TCP group, marginal cartilage ingrowth could be seen 12 weeks after operation and the number of chondrocytes increasedmarkedly after 24wee s. However, no cartilage can be found in the middle of the material. In the control group, only a small quantity of new cartilage formation could be seenalong the margin of defects. Conclusion It is feasible to generate tissue engineered cartilage with porous B-TCP and auto logousM SCs for cartilage defect repair.
It is very difficult to repair large articular cartilage defect of the hip. From May 1990 to April 1994, 47 hips in 42 patients of large articuler cartilage defects were repaired by allograft of skull periosteum. Among them, 14 cases, whose femoral heads were grade. IV necrosis, were given deep iliac circumflex artery pedicled iliac bone graft simultaneously. The skull periosteum had been treated by low tempreturel (-40 degrees C) before and kept in Nitrogen (-196 degrees C) till use. During the operation, the skull periosteum was sutured tightly to the femoral head and sticked to the accetabulum by medical ZT glue. Thirty eight hips in 34 patients were followed up for 2-6 years with an average of 3.4 years. According to the hip postoperative criteria of Wu Zhi-kang, 25 cases were excellent, 5 cases very good, 3 cases good and 1 case fair. The mean score increased from 6.4 before operation to 15.8 after operation. The results showed, in compare with autograft of periosteum for biological resurface of large articular defect, this method is free of donor-site morbidity. Skull periosteum allograft was effective for the treatment of large articular cartilage defects in hip.
Objective To investigate the influenceof insulin-like growth factor-I (IGF-I) on biological characteristics of articular chondrocytes cultured in vitro of rabbits. Methods Monolayer articular chondrocytes of 4week old rabbits were cultured in medium with IGF-I, at the concentrations of 3, 10, 30, 100, and300ng/ml. The DNA content in cells and glucuronic acid content in matrix were detected on the 2nd, 4th, 6th days after culture. Results The DNA content in cells and the glucuronic acid content in matrix in articular chondrocytes cultured in medium with IGF-I at concentrations of 3-300ng/ml were all significantly higher than those in control group (P＜0.01), which reached the peak at the concentrations of 30-100mg/ml on the 4th day. Conclusion IGF-I could obviously promote theproliferation of articular chondrocytes in vitro, and there exist time-dependent and dose-dependent effect.
Objective Melatonin (MLT) can increase the expression of cartilage-derived growth factor and stimulate the synthesis of cartilage matrix. To investigate the prevention and treatment effects of MLT on damaged cartilage through observing the expressions of bone morphogenetic protein 2 (BMP-2) and interleukin 1β (IL-1β) in articular cartilage of the rats with osteoarthritis (OA). Methods Forty SPF 4-week-old male SD rats (weighing 120-150 g) were randomly divided into 4 groups (n=10): normal control group (group A), OA group (group B), OA/pinealectomy group (group C), and OA/ pinealectomy/MLT group (group D). The rats of group A served as a control without treatment. The rats of groups B, C, andD underwent left knee joint injection of 0.2 mL 4% papain solution 1 time every other day for 2 weeks for establ ishing OAmodel. Two weeks after papain injection, the rats of groups C and D were exposed to continuous l ight for 24 hours (intensity of illumination: 500 lx) for creating pinealectomy models. And at the next day after pinealectomy model establ ishing, the rats of group D were treated with intra-articular injections of 0.2 mL 20 mg/mL MLT solution 4 times a week for 4 weeks. At 1 week after last MLT injection, the venous blood samples were taken in groups A, B, and C to test the level of serum MLT by ELISA, respectively, and then the specimens of left cartilage of femoral condyle were harvested for macroscopic, histological, and immunohistochemical examinations in 4 groups. Results The OA and pinealectomy models of rats were successfully establ ished, and all rats survived. There were significant differences in the serum MLT level among groups A, B, and C, and among different time points at the same group (P lt; 0.05). In group A, articular cartilage surface was smooth and elastic, and chondrocytes arranged regularly. In groups B and C, articular cartilage surface was rough, cartilage defects and subchondral bone exposure were observed in some areas, and chondrocytes arranged irregularly. In group D, cartilage surface was more smooth than that in groups B and C, and the degrees of cartilage defect and subchondral bone exposure decreased with regular arrangment of chondrocytes. There were significant differences in Mankin scores and integral absorbance values among 4 groups (P lt; 0.05). Conclusion Exposure to continuous l ight can accelerate degeneration process of articular cartilage of OA rats. Injections of 0.2 mL MLT solution (20 mg/mL) by intra-articular for 4 weeks can inhibit the progress of cartilage defects. Upregulationof anabol ic factor of BMP-2 as well as down-regulation of catabol ic factors of IL-1β is associated with cartilage repairin the pathological features of OA.
Objective To construct recombinant lentiviral expression vectors of porcine transforming growth factor β1 (TGF-β1) gene and transfect bone marrow mesenchymal stem cells (BMSCs) so as to provide TGF-β1 gene-modified BMSCs for bone and cartilage tissue engineering. Methods The TGF-β1 cDNA was extracted and packed into lentiviral vector, and positive clones were identified by PCR and gene sequencing, then the virus titer was determined. BMSCs were isolated frombone marrow of the 2-month-old Bama miniature pigs (weighing 15 kg), and the 2nd and 3rd generations of BMSCs wereharvested for experiments. BMSCs were then transfected by TGF-β1 recombinant lentiviral vectors (TGF-β1 vector group)respectively at multi pl icity of infection (MOI) of 10, 50, 70, 100, and 150; then the effects of transfection were detected bylaser confocal microscope and Western blot was used to determine the optimal value of MOI. BMSCs transfected by empty vector (empty vector group) and non-transfected BMSCs (non-transfection group) were used as control group. RT-PCR, immunocytochemistry, and ELISA were performed to detect the expressions of TGF-β1 mRNA, TGF-β1 protein, and collagen type II. Results Successful construction of recombinant lentiviral vectors of porcine TGF-β1 gene was identified by PCR and gene sequencing, and BMSCs were successfully transfected by TGF-β1 recombinant lentiviral vectors. Green fluorescence was observed by laser confocal microscope. Western blot showed the optimal value of MOI was 70. The expression of TGF-β1 mRNA was significantly higher in TGF-β1 vector group than in empty vector group and non-transfection group (P lt; 0.05). Immunocytochemistry results revealed positive expression of TGF-β1 protein and collagen type II in BMSCs of TGF-β1 vector group, but negative expression in empty vector group and non-transfection group. At 21 days after transfection, high expression of TGF-β1 protein still could be detected by ELISA in TGF-β1 vector group. Conclusion TGF-β1 gene can be successfully transfected into BMSCs via lentiviral vectors, and long-term stable expression of TGF-β1 protein can be observed, prompting BMSCs differentiation into chondrocytes.
OBJECTIVE To investigate possibility of cartilage cultured in centrifuge tube as graft materials. METHODS: Articular chondrocytes isolated from a 3-week-old rabbit formed cartilage after cultivation for 2 weeks. Articular cartilage of humeral head, growth plate of proximal tibia and meniscus were collected from a 6-week-old rabbit. The ultrastructure of chondrocytes and extracellular matrix in the three kinds of cartilages and cultured cartilage were observed by transmission electronic microscopy. RESULTS: Cartilage cultured in centrifuge tube possessed unique ultrastructure and was similar to articular cartilage and growth plate, but it was markedly different from meniscus. The four kinds of cartilages were characteristic of respectively different chondrocytes and extracellular matrix. Cultured cartilage showed typical apoptosis of chondrocytes and "dark chondrocytes" appeared in growth plate. Condrocyte apoptosis was not seen in articular cartilage and meniscus. CONCLUSION: Cartilage cultured in centrifuge tube has unique ultrastructure and may be used as graft materials for articular cartilage and growth plate.