• Applied Microscopy
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• v.21 no.2
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• pp.39-56
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• 1991

The development of notochordal cells of nucleus pulposus was studied with electron microscope in human fetuses ranging from 30 mm to 260 mm crown-rump length. At 30 mm fetus, primitive notochordal cells were large with central nucleus, few organelles, and their cytoplasm usually contained dense glycogen and fine filaments. Notochordal cells at all ages contained bundles of fine filaments of indeterminate nature. One unusual feature of fetal notochordal cells was the consistent presense of rough endoplasmic reticulum surrounding poorly developed mitochondria. At 50 mm fetus, notochordal cells formed dense masses with interdigitating cell membranes connected by a variety of cell to cell junctions. With increasing age, the cell connections became slender threaded cytoplamic extending from cell and enclosed large extracellular space. Chondrocyte-like cells appeared to be separated by large volumes of extracellular matrix. Viable notochordal and condrocyte-like cells existed in specimen from all age. The extracellular spaces were filled with fibrillar and granular material by 90 mm fetus. Necrotic cells were distinguished by loss of their membrane integrity, vacuolization of their organelles, and the presence of dense osmiophilic masses. In adult tissue, notochordal cells became rounded or irregular in shape and developed a pericellular matrix consisting of collagen fibrile, and dense particle. The structure of notochordal cells and their persistance in the nucleus pulposus after fetal life suggested that they may have a significant role in the formation and maintenance of the nucleus pulposus. The presence of Golgi complex and well-developed endoplasmic reticulum in chondrocyte-like cells suggested that they are capable of producing and maintaining the extracellular matrix.

• Journal of Animal Science and Technology
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• v.56 no.8
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• pp.33.1-33.8
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• 2014

Background: Sox 9 is a major marker of chondrocyte differentiation. When chondrocytes are cultured in vitro they progressively de-differentiate and this is associated with a decline in Sox 9 expression. The active form of vitamin D, 1, 25 $(OH)_2D_3$ has been shown to be protective of cartilage in both humans and animals. In this study equine articular chondrocytes were grown in culture and the effects of 1, 25 $(OH)_2D_3$ upon Sox 9 expression examined. The expression of the transient receptor potential vanilloid (TRPV) ion channels 5 and 6 in equine chondrocytes in vitro, we have previously shown, is inversely correlated with de-differentiation. The expression of these channels in response to 1, 25 $(OH)_2D_3$ administration was therefore also examined. Results: The active form of vitamin D (1, 25 $(OH)_2D_3$ when administered to cultured equine chondrocytes at two different concentrations significantly increased the expression of Sox 9 at both. In contrast 1, 25 $(OH)_2D_3$ had no significant effect upon the expression of either TRPV 5 or 6 at either the protein or the mRNA level. Conclusions: The increased expression of Sox 9, in equine articular chondrocytes in vitro, in response to the active form of vitamin D suggests that this compound could be utilized to inhibit the progressive de-differentiation that is normally observed in these cells. It is also supportive of previous studies indicating that $1{\alpha}$, 25-dihydroxyvitamin $D_3$ can have a protective effect upon cartilage in animals in vivo. The previously observed correlation between the degree of differentiation and the expression levels of TRPV 5/6 had suggested that these ion channels may have a direct involvement in, or be modulated by, the differentiation process in vitro. The data in the present study do not support this.

• Archives of Plastic Surgery
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• v.33 no.5
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• pp.616-620
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• 2006

Purpose: The isolated human chondrocytes for cartilage reconstruction and transplantation presents a major problem as these cells would change biologically in vitro. For more effective applications of these cells in the clinical field, it is necessary to get a large amount of cells in a short period without affecting their function and phenotype. Methods: This study reports the effects of placenta extract on chondrocytes in vitro. We initiated this study on the basis of the hypothesis that placenta extract can influence both the proliferation of chondrocytes and their biologic functions(for example, to express cell specific gene or to produce their own extracellular matrix). Chondrocytes in monolayer culture with or without placenta extract were collected and analyzed by MTT assay, ECM assay, and RT-PCR. Results: Placenta extract stimulated the proliferation of chondrocytes in monolayer culture. The phenotype of chondrocytes was well maintained during the expansion in monolayers. Chondrocytes expanded in the presence of placenta extract produced ECM, glycosaminoglycan, abundantly. Compared to chondrocyte expanded in culture medium only, chondrocytes expanded with placenta extract demonstrated higher COL2A1 expression that was biochemically comparable to primary chondrocytes. This study provides an evidence that placenta extract is helpful to expand chondrocytes during tissue cultivation, to maintain their differentiated phenotype and to promote their function. Conclusion: These results suggest that placenta extract during cultivation play an important role in controlling cell behaviors. Furthermore, these results provide a biologic basis for cartilage tissue engineering.

• The korean journal of orthodontics
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• v.21 no.1 s.33
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• pp.53-76
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• 1991

The study was designed to analyse the reorganization of the rabbit TMJ meniscus which was anteriorly displaced by surgery. The author compared the anteriorly displaced groups with control group. After surgical opening of the left rabbit TMJ space, cut the posterior attachment of the meniscus, and pushed it under the undercut area of the condyle head. Experimental groups were sacrificed by 1, 2, 4, 8 weeks after surgery. The samples were analysed with light microscope under T-B stain and electron microscope. The results were as follows: 1) The rabbit TMJ meniscus consisted of thick anterior and posterior band running different way, and comparative thin intermediate band runining antero-posteriorly. 2) Round oval shape chondrocyte-like cells were imbeded between the collagen fiber bundles and composed of proteoglycan granules, that showed metachromasia with toluidine blue, around the cell matrix. 3) Type II collagen fiber bundles in experimental group occured degenerative changes in organic patterns at 8 weeks, but those of type I collagen fiber bundles sustained longer, 4) The typical fibrocartilage of the rabbit TMJ meniscus was changed into fibrotic mode in process of time and showed the degenerative changes, which contained hyperplasia, calcification, resorption and hyalinization in the connective tissue. 5) The hyperplastic change of the synovial membrane in 4 week group and transitional change from fibrocyte to chondrocyte in cell type in 8 week group were observed. 6) The diameters of collagen fibers were diminished with the degenerative changes, the shape of the fibers became wavier and more nonorganic in running pattern and fiber bundle spaces widened.

• BMB Reports
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• v.51 no.10
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• pp.508-513
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• 2018

Fibronectin fragments found in the synovial fluid of patients with osteoarthritis (OA) induce the catabolic responses in cartilage. Nuclear high-mobility group protein Box 1 (HMGB1), a damage-associated molecular pattern, is responsible for the regulation of signaling pathways related to cell death and survival in response to various stimuli. In this study, we investigated whether changes induced by 29-kDa amino-terminal fibronectin fragment (29-kDa FN-f) in HMGB1 expression influences the pathogenesis of OA via an HMGB1-modulated autophagy signaling pathway. Human articular chondrocytes were enzymatically isolated from articular cartilage. The level of mRNA was measured by quantitative real-time PCR. The expression of proteins was examined by western blot analysis, immnunofluorescence assay, and enzyme-linked immunosorbent assay. Interaction of proteins was evaluated by immunoprecipitation. The HMGB1 level was significantly lower in human OA cartilage than in normal cartilage. Although 29-kDa FN-f significantly reduced the HMGB1 expression at the mRNA and protein levels 6 h after treatment, the cytoplasmic level of HMGB1 was increased in chondrocytes treated with 29-kDa FN-f, which significantly inhibited the interaction of HMGB1 with Beclin-1, increased the interaction of Bcl-2 with Beclin-1, and decreased the levels of Beclin-1 and phosphorylated Bcl-2. In addition, the level of microtubule-associated protein 1 light chain 3-II, an autophagy marker, was down-regulated in chondrocytes treated with 29-kDa FN-f, whereas the effect was antagonized by mTOR knockdown. Furthermore, prolonged treatment with 29-kDa FN-f significantly increased the release of HMGB1 into the culture medium. These results demonstrated that 29-kDa FN-f inhibits chondrocyte autophagy by modulating the HMGB1 signaling pathway.

• Nutrition Research and Practice
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• v.10 no.3
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• pp.265-273
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• 2016

BACKGROUND/OBJECTIVES: The inhibitory effect of Hijikia fusiforme (HF) extracts on degenerative osteoarthritis was examined in primary cultured rat cartilage cells and a monosodium iodoacetate (MIA)-induced osteoarthritis rat model. MATERIALS/METHODS: In vitro, cell survival and the expression of matrix metalloproteinases (MMPs), collagen type I, collagen type II, aggrecan, and tissue inhibitor of metalloproteinases (TIMPs) was measured after $H_2O_2$ ($800{\mu}M$, 2 hr) treatment in primary chondrocytes. In vivo animal study, osteoarthritis was induced by intra-articular injection of MIA into knee joints of rats, and then RH500, HFE250 and HFE500 were administered orally once a day for 28 days. To determine the anti-inflammatory effects of HFE, nitric oxide (NO), prostaglandin $E_2$ ($PGE_2$) expression were measured. In addition, real-time PCR was performed to measure the genetic expression of MMPs, collagen type I, collagen type II, aggrecan, and TIMPs. RESULTS: In the in vitro assay, cell survival after $H_2O_2$ treatment was increased by HFE extract (20% EtOH). In addition, anabolic factors (genetic expression of collagen type I, II, and aggrecan) were increased by HFE extract (20% EtOH). However, the genetic expression of MMP-3 and 7, known as catabolic factors were significantly inhibited by treatment with HFE extract (20% EtOH). In the in vivo assay, anabolic factors (genetic expression of collagen type I, II, aggrecan, and TIMPs) were increased by oral administration of HFE extract. However, the genetic expression of MMP-3 and 7, known as catabolic factors, and production of NO and $PGE_2$ were significantly inhibited by treatment with oral administration of HFE extract. CONCLUSION: HFE extract inhibited articular cartilage degeneration through preventing extracellular matrix degradation and chondrocyte injury.

• The Journal of Korean Medicine
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• v.28 no.4
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• pp.114-123
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• 2007

Osteoarthritis is characterized by cartilage degradation and chondrocytes death. Chondrocyte death is induced by the apotosis through special mechanisms including the activation of caspase-3. On the basis of this background, this study was designed to examine the cartilage protective and anti-apototic effects of Aralia Cordata in in vtro and in collagenase-induced arthritis rabbit model. To conduct in vitro study, chondrocytes culturedfrom rabbit knee joint were treated by 5 ng/ml IL-1a.For in vivo experiment, collagenase-induced arthritis (CIA) rabbit model was made via intraarticular injection with 0.25 ml of collagenase solution. Aralia cordata pharmacopuncture (ACP) was administrated on bilateral Dokbi acupoint (ST35) of rabbits at a dosage of 150 ${\mu}g/kg$ once a day for 28 days after the initiation of the CIA induction. In the study by using CIA rabbit model in vivo, ACP showed the inhibition of cartilage degradation in histological analysis. Aralia cordata also showed anti-apoptotic effect both in vitro and in vivo study. In chondrocytes treated by IL-1a, Aralia cordata inhibited caspase-3 activity and enhanced the proliferation of IL-1a-induced dedifferentiated chondrocytes. ACP showed the inhibition effect on the caspase-3 expression and activity from CIA rabbit model. This study indicates that ACP inhibits the cartilage destruction and the chondrocyte apotosis through downregulation of caspase-3 activity. These data suggest that ACP has a beneficial effect on preventing articular cartilage destruction in osteoarthrtis.

• Journal of Physiology & Pathology in Korean Medicine
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• v.19 no.3
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• pp.618-622
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• 2005

Articular cartilage is an important target for studying the arthritic diseases. To verify the therapeutic effects of bee venom herb-acupuncture in vivo, 3${\mu}$l of diluted solution of bee venom for herb-acupuncture were injected into articular cavity once a day during 3 months after making full-thickness defects in rat articular cartilage. Histological examination and immunohistochemistry indicated that the chondrocyte-like tissue was formed during the repair process of cartilage injury, and the expression of a cartilage-specific protein, collagen type II, were significantly activated. It means that the expression of the gene encoding type I collagen was down-regulated, whereas those of collagen type II were up-regulated. Histological examination by hematoxylin-eosin staining indicated that the cells regained their original round morphology. In addition, a homogeneous distribution of articular cartilage extracellular matrices was detected around the cells. These results suggested that bee venom herb-acupuncture was very effective on the recovery of articular chondrocyte phenotype.

• Maxillofacial Plastic and Reconstructive Surgery
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• v.14 no.1_2
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• pp.65-76
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• 1992

This study was designed to observe the adaptive changes of mandibular condyles to displacement of mandibular condyle in adult animals. In this study, 16 rabbits weighting about 3.5 kg was selected. Four rabbits were preserved for control group and 8 animals were divided into 3 groups, 2 weeks, 4 weeks and 8 weeks. The experimental animals were performed oblique osteotomy on both mandibular ramus and internal wiring at mandibular border. The experimental animals were sacrificed consecutively on the 2 weeks, 4 weeks and 8 weeks after oblique osteotomy and mandibular condyles were dissected out carefully to produced tissue specimen. The specimens were fixed with 10% N formaline solution for 24 hours and rinsed with phosphate buffer solution. It was decalcified with 5% nitric acid for 15 days. Thereafter the specimens were dehydrated in alcohol series and embedded paraffin as usual manner. The mebedded specimen were sectioned in $4-6{\mu}m$ microtome, stained with hematoxylin-eosin and azan stain and observed through light microscope. The following results were observed from this experiment. When there was postional change of condyle head after mandibular ramus oblique osteotomy in adult rabbit, 1. The density of chondrocyte was generally increased at condylar cartilage and the thickness of condylar cartilage was increased posterosuperior aspect of the mandibular condyle slightly. 2. The density of chondrocyte was increased at proliferative zone so fibrous articular zone, porliferative zone and hypertrophic zone was clearly distinguished. 3. Active endochondral bone formation was occurred at mandibular condyle.

• Macromolecular Research
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• v.16 no.6
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• pp.517-523
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• 2008

A RGD (Arg-Gly-Asp) conjugated chitosan hydrogel was used as a cell-supporting scaffold for articular cartilage regeneration. Thermosensitive chitosan-Pluronic (CP) has potential biomedical applications on account of its biocompatibility and injectability. A RGD-conjugated CP (RGD-CP) copolymer was prepared by coupling the carboxyl group in the peptide with the residual amine group in the CP copolymer. The chemical structure of RGD-CP was characterized by $^1H$ NMR and FT IR. The concentration of conjugated RGD was quantified by amino acid analysis (AAA) and rheology of the RGD-CP hydrogel was investigated. The amount of bound RGD was $0.135{\mu}g$ per 1 mg of CP copolymer. The viscoelastic parameters of RGD-CP hydrogel showed thermo-sensitivity and suitable mechanical strength at body temperature for cell scaffolds (a> 100 kPa storage modulus). The viability of the bovine chondrocyte and the amount of synthesized glycosaminoglycans (GAGs) on the RGD-CP hydrogels were evaluated together with the alginate hydrogels as a control over a 14 day period. Both results showed that the RGD-CP hydrogel was superior to the alginate hydrogel. These results show that conjugating RGD to CP hydro gels improves cell viability and proliferation, including extra cellular matrix (ECM) expression. Therefore, RGD conjugated CP hydrogels are quite suitable for a chondrocyte culture and have potential applications to the tissue engineering of articular cartilage tissue.