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91.
《Annals of anatomy》2014,196(5):278-285
In osteoarthritis animal models the rat knee is one of the most frequently investigated joint. However, it is unknown whether topographical variations in articular cartilage and subchondral bone of the normal rat knee exist and how they are linked or influenced by growth and maturation. Detailed knowledge is needed in order to allow interpretation and facilitate comparability of published osteoarthritis studies. For the first time, the present study maps topographical variations in cartilage thickness, cartilage compressive properties and subchondral bone microarchitecture between the medial and lateral tibial compartment of normal growing rat knees (7 vs. 13 weeks). Thickness and compressive properties (aggregate modulus) of cartilage were determined and the subchondral bone was analyzed by micro-computed tomography. We found that articular cartilage thickness is initially homogenous in both compartments, but then differentiates during growth and maturation resulting in greater cartilage thickness in the medial compartment in the 13-week-old animals. Cartilage compressive properties did not vary between the two sites independently of age. In both age-groups, subchondral plate thickness as well as trabecular bone volume ratio and trabecular thickness were greater in the medial compartment. While a high porosity of subchondral bone plate with a high topographical variation (medial/lateral) could be observed in the 7-week-old animals, the porosity was reduced and was accompanied by a reversion in topographical variation when reaching maturity. Our findings highlight that there is a considerable topographical variation in articular cartilage and subchondral bone within the normal rat knee in relation to the developmental status.  相似文献   
92.
Objective:To investigate the effect of osteoporosis and intervertebral disc degeneration on the endplate cartilage injury in rats.Methods:A total of 48 female Sprague Dawley rats(3 months)were randomly divided into Groups A,B,C and D with 12 rats in each group.Osteoporosis and intervertebral disc degeneration composite model,simple degeneration model and simple osteoporosis model were prepared in Groups A,B and C respectively.After modeling,four rats of each group at 12th.18th and 24th week were sacrificed,Intervertebral height of cervical vertebra C6/C7 was measured.Micro-CT was used to image the endplate of cephalic and caudal cartilage at C6/C7 intervertebral disc.Abraded area rate of C6 caudal and C7 cephalic cartilage endplate was calculated,and then C6/C7 intervertebral disc was routinely embedded and sectioned.stained with safranin O to observe histological changes microscopically.Results:At 12,18 and24 weeks,intervertebral disc height of C6/C7 were(0.58±0.09)mm,(0.53±0.04)mm and(0.04±0.06)mm in Group A rats,(0.55±0.05)mm,(0.52±0.07)mm and(0.07±0.05)mm in Group B rats.At 24th week.intervertebral disc height of Group A rats was significantly lower than that of Group B rats(P0.05);intervertebral disc height of Groups A and B rats at each time point were significantly lower than that of Groups C and D(P0.05).There was no significantly statistical difference of intervertebral disc height between Groups C and D(P0.05).At 12 and 18 weeks,the abraded rate of C6 caudal and C7 cephalic cartilage endplate in Group A rats were significantly higher than that in Groups B.C and D rats(P0.05);the abraded rate in Group B was significantly higher than that in Groups C and D(P0.05).Microscopic observation of CT showed that ventral defects in C6caudal or C7 cephalic cartilage endplate in Groups A and B appeared after 12 weeks of modeling;obvious cracks were found in front of the C6 and C7 vertebral body,and cartilage defect shown the trend of"repairing"at 18 and 24 weeks after modeling.Conclusions:Intervertebral disc degeneration and osteoporosis can cause damage to the cartilage endplate.Co-existence of these two factors can induce more serious damage to the endplate.which has possitive correlation with intervertebral disc degeneration.Osteoporosis plays a certain role in intervertebral disc degeneration process,and accelerates the degeneration of intervertebral disc in a specific time window.  相似文献   
93.
94.
Dental-derived mesenchymal stem cells (MSCs) are promising candidates for cartilage regeneration, with a high capacity for chondrogenic differentiation. This property helps make dental MSCs an advantageous therapeutic option compared to current treatment modalities. The MSC delivery vehicle is the principal determinant for the success of MSC-mediated cartilage regeneration therapies. The objectives of this study were to: (1) develop a novel co-delivery system based on TGF-β1 loaded RGD-coupled alginate microspheres encapsulating periodontal ligament stem cells (PDLSCs) or gingival mesenchymal stem cells (GMSCs); and (2) investigate dental MSC viability and chondrogenic differentiation in alginate microspheres. The results revealed the sustained release of TGF-β1 from the alginate microspheres. After 4 weeks of chondrogenic differentiation in vitro, PDLSCs and GMSCs as well as human bone marrow mesenchymal stem cells (hBMMSCs) (as positive control) revealed chondrogenic gene expression markers (Col II and Sox-9) via qPCR, as well as matrix positively stained by Toluidine Blue and Safranin-O. In animal studies, ectopic cartilage tissue regeneration was observed inside and around the transplanted microspheres, confirmed by histochemical and immunofluorescent staining. Interestingly, PDLSCs showed more chondrogenesis than GMSCs and hBMMSCs (p < 0.05). Taken together, these results suggest that RGD-modified alginate microencapsulating dental MSCs make a promising candidate for cartilage regeneration. Our results highlight the vital role played by the microenvironment, as well as value of presenting inductive signals for viability and differentiation of MSCs.  相似文献   
95.
As a synthetic polypeptide water-soluble poly(l-glutamic acid) (PLGA) was designed to fabricate scaffolds for cartilage tissue engineering. Chitosan (CHI) has been employed as a physical cross-linking component in the construction of scaffolds. PLGA/CHI scaffolds act as sponges with a swelling ratio of 760 ± 45% (mass%), showing promising biocompatibility and biodegradation. Autologous adipose-derived stem cells (ASCs) were expanded and seeded on PLGA/CHI scaffolds, ASC/scaffold constructs were then subjected to chondrogenic induction in vitro for 2 weeks. The results showed that PLGA/CHI scaffolds could effectively support ASC adherence, proliferation and chondrogenic differentiation. The ASCs/scaffold constructs were then transplanted to repair full thickness articular cartilage defects (4 mm in diameter, to the depth of subchondral bone) created in rabbit femur trochlea. Histological observations found that articular defects were covered with newly formed cartilage 6 weeks post-implantation. After 12 weeks the regenerated cartilage had integrated well with the surrounding native cartilage and subchondral bone. Toluidine blue and immunohistochemical staining confirmed similar accumulation of glycosaminoglycans and type II collagen in engineered cartilage as in native cartilage 12 weeks post-implantation. The result was further supported by quantitative analysis of extracellular matrix deposition. The compressive modulus of the engineered cartilage increased significantly from 30% of that of normal cartilage at 6 weeks to 83% at 12 weeks. Cyto-nanoindentation also showed analogous biomechanical behavior of the engineered cartilage to that of native cartilage. The results of the present study thus demonstrate the potentiality of PLGA/CHI scaffolds in cartilage tissue engineering.  相似文献   
96.
New systematic approaches are necessary to determine and optimize the chemical and mechanical scaffold properties for hyaline cartilage generation using the limited cell numbers obtained from primary human sources. Peptide functionalized hydrogels possessing continuous variations in physico-chemical properties are an efficient three-dimensional platform for studying several properties simultaneously. Herein, we describe a polyethylene glycol dimethacrylate (PEGDM) hydrogel system possessing a gradient of arginine–glycine–aspartic acid peptide (RGD) concentrations from 0 mM to 10 mM. The system is used to correlate primary human osteoarthritic chondrocyte proliferation, phenotype maintenance and extracellular matrix (ECM) production to the gradient hydrogel properties. Cell number and chondrogenic phenotype (CD14:CD90 ratios) were found to decline in regions with higher RGD concentrations, while regions with lower RGD concentrations maintained cell number and phenotype. Over three weeks of culture, hydrogel regions containing lower RGD concentrations experience an increase in ECM content compared to regions with higher RGD concentrations. Variations in actin amounts and vinculin organization were observed within the RGD concentration gradients that contribute to the differences in chondrogenic phenotype maintenance and ECM expression.  相似文献   
97.
An optimal scaffold is crucial for osteochondral regeneration. Collagen and electrospun nanofibers have been demonstrated to facilitate cartilage and bone regeneration, respectively. However, the effect of combining collagen and electrospun nanofibers on osteochondral regeneration has yet to be evaluated. Here, we report that the combination of collagen and electrospun poly-l-lactic acid nanofibers synergistically promotes osteochondral regeneration. We first fabricated bi-layer microporous scaffold with collagen and electrospun poly-l-lactic acid nanofibers (COL-nanofiber). Mesenchymal stem cells were cultured on the bi-layer scaffold and their adhesion, proliferation and differentiation were examined. Moreover, osteochondral defects were created in rabbits and implanted with COL-nanofiber scaffold. Cartilage and subchondral bone regeneration were evaluated at 6 and 12 weeks after surgery. Compared with COL scaffold, cells on COL-nanofiber scaffold exhibited more robust osteogenic differentiation, indicated by higher expression levels of OCN and runx2 genes as well as the accumulation of calcium nodules. Furthermore, implantation of COL-nanofiber scaffold seeded with cells induced more rapid subchondral bone emergence, and better cartilage formation, which led to better functional repair of osteochondral defects as manifested by histological staining, biomechanical test and micro-computed tomography data. Our study underscores the potential of using the bi-layer microporous COL-nanofiber scaffold for the treatment of deep osteochondral defects.  相似文献   
98.
目的:了解正常膝关节软骨分布及股骨髁承重区的软骨厚度特点,为膝关节病变早期诊断和动态观察提供依据。方法:选取100名成人志愿者,男、女各50名,年龄20—30岁,平均25.3岁,膝关节均行MRI扫描。应用MIMICS软件对图像进行处理,在矢状位窗面上测量膝关节各部位软骨最大厚度。选择膝关节正常运动时的承重区,测量承重区域软骨的最大厚度并与其他区域进行比较。基于MRI图像行膝关节软骨三维重建,观察膝关节软骨的三维形态特征。结果:膝关节各部位的最大软骨厚度如下。胫骨外侧平台3.19mm,胫骨内侧平台3.07mm,股骨外侧髁2.93mm,股骨内侧髁3.19mm,股骨滑车软骨3.57mm,髌软骨3.75mm。不同性别与左右侧之间的软骨厚度差异无统计学意义(P〉0.05)。胫股关节承重区软骨厚度大于其他区域,有统计学差异(P〈0.05)。结论:成人正常膝关节各区域软骨厚度不同,胫股关节承重区软骨厚度大于非承重区域。基于MRI可以准确地测量膝关节各部软骨的厚度及重建膝关节软骨的三维形态。  相似文献   
99.
The effects of in vivo zinc deficiency and restricted food intake, on the in vitro synthesis of glycosaminoglycans of rib cartilage were studied in the rat. 35S-sulfate and 14C-glucosamine were used as precursors. The glycosaminoglycans were separated on microcolumns and specific radioactivities determined for the different fractions.

Chemical analyses showed that zinc deficiency or reduced food intake did not cause any qualitative or quantitative changes in the glycosaminoglycans. The radioassays indicated that zinc deficiency and reduced food intake, alone or combined, caused a somewhat lowered synthetic rate of chondroitin sulfate. In the discussion it is underlined that it seems difficult to determine conclusively the importance of zinc for the formation of the mucopolysaccharides through further in vivo deficiency studies, because of the difficulties to control and evaluate the inanition factor.  相似文献   
100.
Transforming growth factor-beta (TGF-β) plays an important part in the repair of cartilage in osteoarthritis. It has been hypothesised that intra-articular injection of TGF-β1 promotes repair of cartilage and protects the subchondral bone from damage in osteoarthritic temporomandibular joints (TMJs). We made bilateral partial perforations of the disc to induce osteoarthritic joints in 36 rabbits. TGF-β1 20, 40, or 80 ng were injected into the right joint, and vehicle alone was injected into the left joint. Four additional animals were used as normal controls. Microcomputed tomography was used to quantify the three-dimensional microarchitecture of subchondral bone, followed by assessment of the proteoglycan content. All joints treated with TGF-β1 were covered by a layer of well-organised fibrocartilage, and had increased proteoglycan content and normal microarchitectural properties, whereas the joint treated by vehicle alone had typical osteoarthritis-related degradation of cartilage and sclerosis of subchondral bone. These results suggested that TGF-β1 is an effective way of treating osteoarthritis of the TMJ.  相似文献   
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