• Toxicological Research
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• 제35권3호
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• pp.287-294
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• 2019

The possibility of eye exposure for workers participating in manufacturing of nanoparticles or consumers using products containing nanoparticles has been reported, but toxicity studies on the eye are scarce. In this study, cytotoxicity of five nanoparticles including silver, ceria, silica, titanium and zinc were tested using Statens Seruminstitut Rabbit Cornea (SIRC) cells. When cells were treated with nanoparticles with concentrations of $1-100{\mu}g/mL$ for 24 hr, zinc oxide nanoparticles showed higher toxicity to cornea cells. $LC_{50}$ of zinc oxide nanoparticles was less than $25{\mu}g/mL$ but those of other nanoparticles could not be calculated in this test, which means more than $100{\mu}g/mL$. Generation of reactive oxygen species was observed, and expression of apoptosis related biomarkers including Bax and Bcl-2 were changed after treatment of zinc oxide nanoparticles, while no other significant toxicity-related changes were observed in cornea cells treated with Ag, $CeO_2$, $SiO_2$ and $TiO_2$ nanoparticles.

• 대한의용생체공학회:의공학회지
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• 제40권5호
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• pp.143-150
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• 2019

To evaluate the toxicity of ophthalmic drug, the Draize test and Bovine Corneal Opacity and Permeability (BCOP) test commonly used. In Draize test, experimental animals were under stress and pain due to long-term exposure of drug. In addition, regarding physiological functions, animal model is not perfectly reflected a human eye condition. Although some models such as $EpiOcular^{TM}$, HCE model, LabCyte Cornea-Model, and MCTT $HCE^{TM}$ were already presented advanced cornea ex-vivo model to replace animal test. In this sense, cornea tissue structure mimicked ex-vivo toxicity model was fabricated in this study. The corneal epithelial cells (CECs) and keratocytes (CKs) isolated from rabbit eyeball were seeded on non-patterned silk film (n-pSF) and patterned silk film (pSF) at $32,500cells/cm^2$ and $6,500cells/cm^2$. Sequentially, n-pSF and pSF were stacked to mimic a multi-layered stroma structure. The thickness of films was about $15.63{\mu}m$ and the distance of patterns was about $3{\mu}m$. H&E stain was performed to confirm the cell proliferation on silk film. F-actin of CKs was also stained with Phalloidin to observe the cytoskeletal alignment along with patterns of the pSF. In the results, CECs and CKs were shown the good cell attachment on the n-pSF and pSFs. Proliferated cells expressed the specific phenotype of cornea epithelium and stroma. In conclusion, we successfully established the ex-vivo cornea toxicity model to replace the eye irritation tests. In further study, we will set up the human ex-vivo cornea toxicity model and then will evaluate the drug screening efficacy.

• 한국임상수의학회지
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• 제27권4호
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• pp.411-414
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• 2010

Rabbit's cornea is the most common thing that used for researches in ophthalmology, so many experimentations have done. The purpose of this study was to survey the corneal pachymetry, tonometry and specular microscopy in New Zealand white rabbits. Three months old male rabbits ($2.9{\pm}0.2\;kg$) were examined with contact the specular microscope to evaluate the endothelial cell density, coefficiency of variation and the percentage of hexagonal cells in the central cornea. For the pachymetry, ultrasonic pachymeter was used for central cornea in each twenty rabbits, and tonometry was performed forty rabbit's eyes to evaluate the intraocular pressure. Corneal endothelial cell density in New Zealand white rabbit was $3304{\pm}354\;cell/mm^2$. Coefficiency of variation was $45.8{\pm}2$ and the percentage of hexagonal cells in the central cornea was $44.4{\pm}11%$. The pachymetry of cornea was $346.1{\pm}21\;{\mu}m$ and tonometry of eye was $14.3{\pm}2\;mmHg$. It is considered that normal New Zealand white rabbit's pachymetry, specular microscopy and tonometry were useful basic data of rabbit's cornea for research and clinic in veterinary ophthalmology.

• Molecules and Cells
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• 제26권1호
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• pp.67-73
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• 2008

Herpetic stromal keratitis (HSK) is an inflammatory disorder induced by HSV-1 infection and characterized by T cell-dependent destruction of corneal tissues. It is not known what triggers $CD4^+$ T cell migration into the stroma of HSV-1-infected corneas. The keratocyte is a fibroblast-like cell that can function as an antigen-presenting cell in the mouse cornea by expressing MHC class II and costimulatory molecules after HSV-1 infection. We hypothesized that chemokines produced by stromal keratocytes are involved in $CD4^+$ T cell infiltration into the cornea. We found that keratocytes produce several cytokines and chemokines, including MCP-1, RANTES, and T cell activation (TCA)-3. HSV-1 infection increased the production of MCP-1 and RANTES by keratocytes, and these acted as chemoattractants for HSV-1-primed $CD4^+$ T cells expressing CCR2 and CCR5. ExpreHerpetic stromal keratitis (HSK) is an inflammatory disorder induced by HSV-1 infection and characterized by T cell-dependent destruction of corneal tissues. It is not known what triggers $CD4^+$ T cell migration into the stroma of HSV-1-infected corneas. The keratocyte is a fibroblast-like cell that can function as an antigen-presenting cell in the mouse cornea by expressing MHC class II and costimulatory molecules after HSV-1 infection. We hypothesized that chemokines produced by stromal keratocytes are involved in $CD4^+$ T cell infiltration into the cornea. We found that keratocytes produce several cytokines and chemokines, including MCP-1, RANTES, and T cell activation (TCA)-3. HSV-1 infection increased the production of MCP-1 and RANTES by keratocytes, and these acted as chemoattractants for HSV-1-primed $CD4^+$ T cells expressing CCR2 and CCR5. Expression of MCP-1 in the corneal stroma was confirmed in vivo. Finally, when HSV-1-primed $CD4^+$ T cells were adoptively transferred into wild type and MCP-1-deficient mice that had been sublethally irradiated to minimize chemokine production from immune cells, infiltration of $CD4^+$ T cells was markedly reduced in the MCP-1-deficient mice, suggesting that it is the MCP-1 from HSV-1-infected keratocytes that attracts $CD4^+$ T cells into the cornea.

• 한국생물공학회:학술대회논문집
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• 한국생물공학회 2002년도 생물공학의 동향 (X)
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• pp.289-292
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• 2002

The corneal tissue consists of three layers : epithelium, stroma, and endothelium. Central cornea is a highly differentiated tissue whereas the limbus contains the epithelial stem cell. In the present study. we report the engineering of the three-dimensional reconstructed cornea derived from rabbit limbal epithelial and stromal cells. The differentiation degree of corneal stem cells were assessed in serum concentration and inoculation density of stromal cells. Optimal condition differentiation of corneal stem cells is achieved when 5% FBS was supplemented to culture medium and $1-2{\times}10^5$ cells/ml inoculation density of stromal cells.

• Applied Microscopy
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• 제24권4호
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• pp.98-106
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• 1994

The corneal formation of compound eye of Pieris rapae L., which was mostly made during pupal stage, was morphologically investigated with light microscope, scanning electron microscope and transmission electron microscope. The regeneration of the microvilli were found on the surface membranes of corneagen cells and retinular pigment cells of preommatidium after apolysis pupal cuticle. The microvilli were finally differentiated to corneal nipples of the ommatidium. The corneal cuticle was generated on the superficial layer of the preommatidium from corneagen cells and retinular pigment cells. The corneal process was also formed under the cuticular layer from the corneagen cells. The pore canal was appeared within the cuticular layer and connected with the retinular pigment cell as if the root of interommatidial hair was connected. The interommatidial hair was projected randomly among the ommatidial facets and cornal nipple was arrayed regular on the ommatidial facets. The cornea was convex lens and the refracting power by its convex shape was 4 diopter.

• Applied Microscopy
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• 제25권4호
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• pp.9-16
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• 1995

Ultrastructure of stemmata(larval eye) of 5th-instar larval in cabbage butterfly, Pieris rapae L, was morphologically investigated with light microscope, scanning electron microscope and transmission electron microscope Six stemmata are on each side of the head. Stemmata V and VI have a Y-shaped sulcus on the surface of their corneal lenses, the others have a columnar shaped process and smooth globular surface. The visual type of stemmata is resembled a single ommatidium of compound eye. The dioptric apparatus are a biconvex shaped cornea and crystalline cone. As a photoreceptor, each stemmata consists of 7 retinular cells arranged into 2 tiers. The first ceil tier of 3 distal retinular cells has formed a V-shaped cup rhabdome and the second cell tier of 4 basal retinular cells has formed a H-shaped fused rhabdome. Each retinular cell filled with pigment granules and contained multivesiclular bodies, coated vesicle and common organelles. The peripheral parts of retinular cells are enveloped by neuroglia cells and retinular cells are surrounded by 3 corneagenous cells. The distal portions of the 3 corneagenous cells contact each other, but the Y-shaped stemmata is separated from each other immediately under the cornea. The 7 axons from each stemma congregate into a bundle and each 7-axon group joins to form a stemmatal nerve, consisting of 42 retinular axons.

• Biotechnology and Bioprocess Engineering:BBE
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• 제10권3호
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• pp.262-269
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• 2005

Many researchers have employed cryopreserved amniotic membrane (CAM) in the treatment of a severely damaged cornea, using corneal epithelial cells cultured on an amniotic membrane (AM). In this study, two Teflon rings were made for culturing the cells on the LAM and CAM, and were then used to support the AM, which is referred to in this paper as an Ahn's AM supporter. The primary corneal epithelial cells were obtained from the limbus, using an ex-plantation method. The corneal epithelium could be reconstructed by culturing the third­passage corneal epithelial cells on the AM. A lyophilized amniotic membrane (LAM) has a higher rate of graft take, a longer shelf life, is easier to store, and safer, due to gamma irradiation, than a (AM. The corneal epithelium reconstructed on the LAM and (AM, supported by the two­Teflon rings, was similar to normal corneal epithelium. However, the advantages of the LAM over that of the (AM make the former more useful. The reconstruction model of the corneal epithelium, using AM, is considered as a good in vitro model for transplantation of cornel epithelium into patients with a severely damaged cornea.

• 한국안광학회지
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• 제13권4호
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• pp.161-169
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• 2008

목적: 알칼리 화상 후 초기 임상적 손상반응의 진행과 치료를 위한 각막 재생의 이해를 높이기 위하여, 화학적 손상 후 동반하는 다양한 인자에 대한 면역조직화학적 변화를 조사하였다. 방법: 알칼리 화상을 입은 각막의 자가치유과정을 면역형광염색법과 H-E 염색, 그리고 TUNEL assay를 통해 면역조직화학적 측면에서 관찰하였다. 결과: 화상 후 각막의 치유는 진행되었지만 각막기질(stroma)과 내피세포의 세포사는 지속적으로 관찰되었다. 각막가장자리의 혈관신생과 손상된 각막의 ${\alpha}$-SMA의 발현은 알칼리 화상 3일 후부터 나타났으며, 각막기질에서의 콜라젠 III(collagen III)의 형성과 콘드로이친황산(chondroitin sulfate)의 발현은 ${\alpha}$-smooth muscle actin(${\alpha}$-SMA)와 transforming growth factor-${\beta}$(TGF-${\beta}$)의 발현증가와 일치하는 결과를 얻었다. 결론: 각막혼탁을 막기 위해서는 알칼리 화상 후 3일 이내에 혈관신생, 콜라젠 및 콘드로이친황산의 형성을 억제하는데 주력하는 치료가 효과적일 것이라 사료된다. 이 연구는 알칼리 화상을 입은 각막의 치유과정에 있어서의 면역조직화학적 지식을 제공함으로써, 각막의 재생을 촉진하는 치료제의 개발과 이용에 초석이 되리라 사료된다.

• Molecules and Cells
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• 제19권2호
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• pp.232-238
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• 2005

Corneal endothelial cells play an important role in maintaining the transparency and ionic balance of the cornea. Inflammation causes many changes in the intracellular and extracellular environment of the cornea, including acidosis. We examined the relationship between changes in extracellular pH and expression of cyclooxygenase-2 in cultured bovine corneal endothelial cells. When extracellular pH ($[pH]_o$) was reduced to pH 6.4, COX-2 mRNA increased, with a peak at 2 h. This was blocked by pretreatment with actinomycin D and incubation with spermine NONOate (SPER/NO, a nitric oxide donor). Exposure to the $H^+$ ionophore, carbonyl cyanide m-chlorophenylhydrazone (CCCP), also raised COX-2 mRNA levels. CCCP-induced COX-2 mRNA expression was also reduced by SPER/NO. These results were confirmed immuno-cytochemically. These data demonstrate that COX-2 expression is stimulated by the lowering of extracellular pH that could result from bacterial infection, and that this is countered by over-production of nitric oxide, which could also result from bacterial infection.