• Journal of Pharmaceutical Investigation
• /
• v.40 no.1
• /
• pp.45-49
• /
• 2010

Unlike human, with some exceptions, animals do not heal with excessive scar. The lack of suitable animal model has hindered the development of effective scar therapy. We previously reported that partial thickness rabbit ear wound model resembles human wound heal process. This study was designed to prepare a hypertropic scar wound model which can be employed for testing anti-scar therapy. Four wounds were created down to the bare cartilage on the anterior side of each rabbit ear using 8-mm dermal biopsy punch and histology analysis at post operation day (POD) 5, 28 and 48 were performed. As the outcome of scar formation is largely determined by the early inflammatory response to the wounding and the degree and the duration of occlusion, cephalodin(50 mg/kg) was injected daily and medical occlusive dressings were applied. Five micro wound and scar sections were stained with hematoxylin and eosin for quantification of epidermal regeneration and scar hypertrophy. Sections were also stained using Masson's trichrome and Sirius red to evaluate collagen organization and rete ridge formation. Wound closure process was assessed to 7wks post wounding. Complete removal of the epidermis, dermis and perichondrial layer caused delayed epithelialization, which results in hypertropic scarring. The inability of the wounds to contract and the delay in epithelialization in rabbit ear was likely due to cartilage and it created scar elevation. The results suggest that full thickness surgical punch wound model in rabbit ear could be employed as a reliable and reproducible scar wound model for testing anti-scar therapy.

• Proceedings of the PSK Conference
• /
• 2002.10a
• /
• pp.366.1-366.1
• /
• 2002

Emerging medical technologies for effective and lasting repair of articular cartilage include delivery of cells or cell-seeded scaffolds to a defective site to initiate de novo tissue regeneration. In this respect. the availability of an appropriate biomaterial scaffold is crucial to allow chondrocyte growth and cartilaginous matrix deposition in a three-dimensional geometry. Hyaluronic acid (HA) molecules are anchored to the chondrocyte membrane via receptors, such as CD44. (omitted)

• International Journal of Stem Cells
• /
• v.16 no.3
• /
• pp.326-341
• /
• 2023

Background and Objectives: Osteoarthritis (OA) is a degenerative disease that leads to the progressive destruction of articular cartilage. Current clinical therapeutic strategies are moderately effective at relieving OA-associated pain but cannot induce chondrocyte differentiation or achieve cartilage regeneration. We investigated the ability of wedelolactone, a biologically active natural product that occurs in Eclipta alba (false daisy), to promote chondrogenic differentiation. Methods and Results: Real-time reverse transcription-polymerase chain reaction, immunohistochemical staining, and immunofluorescence staining assays were used to evaluate the effects of wedelolactone on the chondrogenic differentiation of mesenchymal stem cells (MSCs). RNA sequencing, microRNA (miRNA) sequencing, and isobaric tags for relative and absolute quantitation analyses were performed to explore the mechanism by which wedelolactone promotes the chondrogenic differentiation of MSCs. We found that wedelolactone facilitates the chondrogenic differentiation of human induced pluripotent stem cell-derived MSCs and rat bone-marrow MSCs. Moreover, the forkhead box O (FOXO) signaling pathway was upregulated by wedelolactone during chondrogenic differentiation, and a FOXO1 inhibitor attenuated the effect of wedelolactone on chondrocyte differentiation. We determined that wedelolactone reduces enhancer of zeste homolog 2 (EZH2)-mediated histone H3 lysine 27 trimethylation of the promoter region of FOXO1 to upregulate its transcription. Additionally, we found that wedelolactone represses miR-1271-5p expression, and that miR-1271-5p post-transcriptionally suppresses the expression of FOXO1 that is dependent on the binding of miR-1271-5p to the FOXO1 3'-untranscribed region. Conclusions: These results indicate that wedelolactone suppresses the activity of EZH2 to facilitate the chondrogenic differentiation of MSCs by activating the FOXO1 signaling pathway. Wedelolactone may therefore improve cartilage regeneration in diseases characterized by inflammatory tissue destruction, such as OA.

• Fisheries and Aquatic Sciences
• /
• v.15 no.4
• /
• pp.299-303
• /
• 2012

Barbel structure and regenerated barbel length in the juvenile Chinese longsnout catfish Leiocassis longirostris (G$\ddot{u}$nther), were evaluated. The barbles consisted of an epidermis, a dermis, and a central rod. The epidermis harbored taste buds, granular cells and epidermal cells. The taste buds were basophilic and situated along the distal portion of the epidermis. The dermis was composed of loose connective tissue containing blood vessels pigment cells. The innermost central region was cartilage enclosed within layers of muscle layers. After 30 days, the regenerated barbel length measured $0.92{\pm}0.404mm$ at $15^{\circ}C$ (regenerated growth curve: y = 0.5085x + 4.0678, $r^2$ = 0.9654, where y is regenerated length and x is experimental period in days), $1.88{\pm}0.521mm$ at $20^{\circ}C$ (y = 0.1806x + 4.808, $r^2$ = 0.9822), and $6.44{\pm}0.751mm$ at $25^{\circ}C$ (y = 0.0914x + 4.9918, $r^2$ = 0.9944). Fifteen days after amputation, the regenerated length was significantly longer at $25^{\circ}C$ than at 15 or $20^{\circ}C$ (P < 0.05). The barbels of the Chinese longsnout catfish was the tender and flexible type, and our experimental findings provide evidence of temperature-dependent regeneration. Additional investigation of the behavior and physiology of the Chinese longsnout catfish is needed, particularly histological studies of regenerated barbels and the measurements of the numbers of taste buds per barbel under various environmental conditions.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
• /
• v.26 no.6
• /
• pp.613-619
• /
• 2000

The purpose of the present study was to investigate the effect of Bioactive glass on bone regeneration in the experimental mandibular bone defects. Five rabbits, weighing about 2.0kg, were used. Three artificial bone defects, $5{\times}5{\times}5mm$ in size, were made at the inferior border of the mandible. In the experimental group 1, the bone defect was grafted with $Biogran^{(R)}$ and covered with $Bio-Gide^{(R)}$ resorbable membrane. In the experimental group 2, $Biogran^{(R)}$ was grafted only. In the control group, the bone defect was filled with blood clot and was spontaneously healed. The animals were sacrificed at 1, 2, 4, and 8 weeks after the graft. Microscopic examination was performed. Results obtained were as follows: In the control group, the osteoid tissue was observed at week 1 and the bone trabeculi were connected each other and matured at week 2. The lamellar bone formation appeared at week 4, and the amount of bone tissue was increased at week 8. In the experimental group 1, the fibrous tissue was filled between the granules of Bioactive glass and the cartilage formation was found adjacent to the normal bone at week 1. The bone tissue was formed between the granules at week 2, while the amount of bone tissue increased and the lamellar bone formation was observed at week 4. The lamellar bone was increased at week 8. Histologic findings were Similar between the experimental groups 1 and 2, although the amount of Bioactive glass granules lost was increased in the latter. These results suggest that new bone formation is found around the Bioactive glass granules grafted into the bone defects, and the membrane plays a role in keeping the granules and preventing the fibrous tissue invasion.

• Maxillofacial Plastic and Reconstructive Surgery
• /
• v.11 no.1
• /
• pp.130-152
• /
• 1989

The purpose of this study was to observe the effect of intermaxillary fixation on the chondrocytes of the mandibular condyle under the light and the electron microscope. For this study, twenty rabbits were placed in maxillomandibular fixation, and two were used as a control group. The experimental group was subdivided into 3, 7, 14, 21 and 28 day group. After the experimental period of 3, 7, 14, 21 and 28 days, the animals were sacrificed with a vascular perfusion of 2.5% glutaraldehyde. The condylar processes were exenterated, and decalcified in 0.1M EDTA with 2.5% glutaraldehyde solution for two weeks. The specimens were rinsed with phosphate buffer solution and the post-fixation was carried out with 2% osmium tetroxide at $4^{\circ}C$ for two hours. Thereafter the specimens were dehydrated in alcohol series, cleared with propylene oxide and embedded in Epon 812 resin. Thin sections and ultra-thin sections were made, and the cellular structures of the condylar cartilages were observed with light and electron microscope. The results were as follows: 1. In the intermaxillary fixation group, the cartilaginous tissues of mandibular condyles showed a marked decrease in the thickness compared to the control group. 2. A remarkable change was noticed in the proliferating and the hypertrophic zone of the condylar cartilages in the experimental group. 3. An atrophic change of the condylar cartilage was appeared in the 3 day experimental group and degenerative change was observed in the 7 day experimental group, and recovery was seen in thereafter 14 day experimental group. 4. Calcification, degeneration and resorption of condylar cartilage were recognizable, and the cellular zone of the condylar cartilage was appeared indistinctly in 3 day and 7 day experimental group. The chondroblasts, however, were differentiated into chondrocytes and resumed mitosis, and then the cellular zones of the condylar cartilage were reorganized from the 14 day experimental group under the findings of light microscope. 5. Under the findings of electron microscope, atrophic changes and decrease in number of intracellular organelles, degenerative changes of cytoplasm, and pyknosis of nuclei were observed in early stage, however, a gradual regeneration and reorganization of the intracellular organelles were observed from 14 day experimental group.

• Journal of Veterinary Clinics
• /
• v.32 no.3
• /
• pp.224-230
• /
• 2015

This study was designed in the fabricated poly (L-Lactic-co-${\varepsilon}$-Caprolactone) (PLCL) scaffold using chitosan-alginate hydrogel, which would be more suitable to maintain the biological and physiological functions continuing three dimensional spatial organizations for chondrocytes. As a scaffold, hydrogels alone is weak at endure complex loading within the body. In this study, we made cell hybrid scaffold constructs with poly (L-Lactic-co-${\varepsilon}$-Caprolactone) (PLCL) scaffold and hydrogels to make a three-dimensional composition of cells and extracellular matrix, which would be a mimic of a native cartilage. Using a particle leaching technique with NaCl, we fabricated a highly-elastic scaffold from PLCL with 85% porosity and $300-500{\mu}m$ pore size. A mixture of bovine chondrocytes and chitosan-alginate gel was seeded and compared with alginate as a control on the PLCL scaffold. The cell maturation, proliferation, extracellular matrix synthesis, glycosaminoglycans (sGAG) production and collagen type-II expressions were better in chondrocytes seeded in chitosan-alginate hydrogel than in alginate only. These results indicate that chondrocytes with chitosan-alginate gel on PLCL scaffolds provide an appropriate biomimetic environment for cell proliferation and matrix synthesis, which could successfully be used for cartilage repair and regeneration.

• Proceedings of the PSK Conference
• /
• 2003.10b
• /
• pp.229.2-230
• /
• 2003

Extracellular matrix(ECM) is composed of the ground materials(proteoglycan) and nano size diameter fibrous proteins(ex. collagens) that together form a composite-like structure. In this study, fibrous scaffold with biomimetic architecture based on collagen nanofibers interpenetrated in PLGA/chitosan microfibrous matrix. Chitosan was selected for its structure similarity to glycosaminoglycan and neutralizing capacity for PLGA acidic metabolite. Collagen nanofiber were prepared by electrospinning. (omitted)

• Proceedings of the PSK Conference
• /
• 2003.10b
• /
• pp.237.3-238
• /
• 2003

Tissue engineering may be adequately defined as the science of persuading the body to regenerate or repair tissue that fail to regenerate or heal spontaneously. In the various techniques of cartilage tissue engineering, the use of 3-dimensional polymeric scaffolds implanted at a tissue defect site is usually involved. These scaffolds provided a framework for cells to attach, proliferate, and form extracellular matrix(ECM). The scaffolds may also serve as carriers for cells and/or growth factors. In the ideal case, scaffold absorb at a predefined rate so that the 3-dimensional space occupied by the initial scaffold is replaced by regenerated host tissue. (omitted)

• Proceedings of the KOR-BRONCHOESO Conference
• /
• 1982.05a
• /
• pp.10.3-11
• /
• 1982

Recently through the advancement of medical and surgical managements and the development of low pressure cuffed endotracheal tube, incidence of tracheal stenosis was decreased significantly. Though its incidence was decreased markedly, stenosis was developted unfortunately in the situations such as long term use of respirator, heavy infection, trauma of the trachea and long term intubation etc. Tracheal stenosis had been handled with various methods such as mechanical dilatation, tissue graft techniques, luminal augumentation and end to end anastomosis due to their individual advantages but their effects were not satisfactory. In 1959 Lester had been found the regenerated cartilage from the perichondrium of the rib incidentaly. Since then Skoog, Sohn and Ohlsen were reported chondrogenic potential of perichondrium through the animal experiments. Though many different materials have been tried to rebuild stenosis and gaping defect of trachea, tracheal reconstruction has been a perplexing clinical problems. We choose the perichondrium as the graft material because cartilage is the normal supporting matrix of that structure and it will be an obvious advantage to be able to position perichondrium over a defect and obtain new cartilage there. The young rabbits, which were selected as our experimental animals, were sacrified from two to eight weeks after surgery. The results of our experiment were as follows; 1) In control group, the defect site of trachea was covered with fibrosis and vessels but graft site was covered with hypertrophied perichondrium and vessels. 2) Respiratory mucosa was completely regenerated in defect sites both control and grafted groups. 3) The histologic changes of the grafted sites were as follows: 2 weeks- microvessel dilatation, inflammatory reaction, initiation of fibrosis 4 weeks- decreased microvessel engorgement, submucosal fibrosis, decreased inflammatory reaction immatured cartilage island was noted in the grafted perichondrium (one specimen) 6 weeks- mild degree vascular engorgement submucosal fibrosis. chronic inflamatory reaction cartilage island and endochondrial ossification was noted in the grafted perichondrium (Two specimens) 8 weeks- minute vascular engorgement dense submucosal fibrosis. loss of inflammatory reaction. cartilage island was noted in the grafted perichondrium (two specimens) 4) There was no significant differences in regeneration between active surface in and out groups. 5) We observed immatured cartilage islands and endochondrial ossification in the perichondrial grafted groups where as such findings were not noted in control groups except fibrosis. We concluded that perichondrium was the adequate material for the reconstruction of defected trachea but our results was not sufficient in the aspect of chondrogenic potential of perichondrium. So further research has indicated possibility of chondrogenic potential of perichondrium.