Distribution Patterns of Involucrin in the Stratum Corneum of the Normal and Psoriatic Artificial Skins / 대한해부학회지

Cornified envelope is highly insoluble structure formed beneath the plasma membrane during terminal differentiation of keratinocytes and is stabilized by cross linking of various proteins, including involucrin, loricrin, and cornifin. Psoriasis is a chronic skin disease characterizing inflammatory reaction and hyperproliferation of keratinocyte. There are some differences in involucrin immunolabelling in stratum corneum between normal and psoriasis epidermis. Labelling was convergent to cornified envelope in psoriasis skin but throughout cytoplasm in normal skin. To compare terminal differentiation patterns of normal and psoriasis keratinocytes, we reconstructed normal and psoriatic artificial skin by using primary cultured keratinocytes from normal and psoriasis skin and then performed immunogold labelling for involucrin in stratum corneum. Psoriatic artificial skin had thin and poorly organized corneal layer. Immunogold labelling for involucrin revealed same pattern of that in vivo by showing throughout cytoplasm in lower layer but convergent cornified envelope in upper layer. Compared with psoriatic artificial skin, normal artificial skin had well organized and thick stratum corneum. Involucrin labelling was throughout cytoplasm in most of corneal layer but convergent to cornified envelope in some uppermost cells. Even though some cells show convergent pattern in normal artificial skin, absolute number of this pattern was no lesser than in artificial psoriatic skin because of normal artificial skin had thick stratum corneum. This result showed there was no difference in involucrin distribution in terminal differentiation of normal and psoriasis keratinocytes in organotypic culture model. It is concluded that although well organized multiple corneal layers are formed in normal artificial skin, they can not reach to full maturation of cornified envelope, and difference of involucrin localization in cornified envelope of psoriasis epidermis is related with not peculiarities of the cells but rapid growing in vivo.

Osteogenesis of Recombinant BMP-7 Adenovirus-transduced Human Dermal Fibroblasts in Collagen Sponge / 대한해부학회지

As a preceding study to apply recombinant BMP-7 gene to the human, we investigated bone formation in immunodeficient mice by using tissue engineering and gene transplatation. Human dermal fibroblasts were transduced with AdBMP-7 and cultured with type I collagen solution to form collagen sponge. The collagen sponge containing AdBMP-7 transduced fibroblasts was transplanted into hypodermis of the mice and osteogenesis in the spongy was investigated by histochemical, electronmicroscopic, and radiologic methods at 1, 2, 4, 6, and 8 weeks. At one week after transplantation, there were fluent cells infiltration around the collagen sponge and capsular structure was formed with fibers arranged in concentric circles. New vessel formation was observed in the capsule and subcapsular area of the sponge, but there were nucleus condensation and obscure cell boundary in the cells of the central region. Lacuna containing eosinophilic structures were observed in the capsular structure at two weeks. This structures were enlarged with time and were confirmed to be bone tissue by showing positive reaction for Von Kossa stain. Cartilaginous structure was not observed in light microscopic level, but a few chondroblasts were observed in pericapsular area in electron microscopic observation. After 6 weeks, radiopaque shadows were observed at the region of transplantation. Cortical bone was formed in periphery of the sponge while marrow like structure was observed in central region; some trabecula bone, adipocytes, and well developed vessels. The percentage of bone formation in transplanted sponge at 1, 2, 4, 6, and 8 weeks were 0, 63, 88, 100, and 100% (n = 8), respectively. From these results, bone formation by BMP-7 transduced human dermal fibroblasts using collagen sponge scaffolds in immunodeficient mouse shows another potential way of human gene transplantation using recombinant BMP-7 adenovirus.

Role of Cardiac Transcription Factor Nkx2.5 on Cardiomyoplasty Model in vitro / 대한해부학회지

Despite therapeutic advance, the prevalence of ischemic heart disease continues to increase. Recently, cell transplantation of stem cell has been proposed as a strategy for cardiac repair following myocardial damage. However, low differentiation efficiency into cardiomyocyte and poor cell viability associated with transplantation have limited the reparative capacity of these cell. In this study, we engineered P19 embryonal carcinoma cells using plasmid vector to overexpress the transcription factor MEF2c, Nkx2.5 involved in cardiomyogenesis. We investigated 1) formation of intercellular junction of P19 in mono-culture and co-culture with cardiomyocyte for functional and structural synchronous contraction after transplantation, 2) differentiation into cardiomyocyte, 3) resistance to hypoxic condition. An P19 embryonal carcinoma cell line expressing GFP, MEF2c, Nkx2.5 was generated by gene transfection and clonal selection. Nkx2.5 overexpression induced connexin43 expression level decrease. Electron microscopy revealed myofibril organization and immunostaining with cTnT showed positive staining in P19-Nkx2.5, consistent with early stage cardiomyocyte. Connexin43 and N-cadherin was expressed between P19-MEF2c and cardiomyocyte, P19- Nkx2.5 and cardiomyocyte in co-culture. And beating rate of cardiomyocyte co-cultured with P19-Nkx2.5 increased much more than other group, even if P19-Nkx2.5 did not have synchronous contraction with cardiomyocyte. Additionally, P19-Nkx2.5 had a resistance against hypoxia. These result suggest that overexpression of Nkx2.5 induced differentiation of P19 into cardiomyocyte and would be electro-mechanical coupling with cardiomyocyte after transplantation. Futhermore, Nkx2.5 overexpression had protection potential to hypoxic injury. Therefore, P19 cell overexpressed Nkx2.5 would be promising cell source for further study of new therapy of myocardial disease and building up in vitro model.

In vitro Model for Ischemia-Reperfusion Injury of Cultured Kupffer Cells / 대한해부학회지

The aims of this study were to describe a reproducible method for the isolation, purification and primary culture of rat Kupffer cells, and were to develop in vitro system which could provide a tool for the study of ischemia-reperfusion injury. Kupffer cells were isolated following sequential collagenase digestion of the liver by perfusion and enrichment of a nonparenchymal cell fraction by a double-densities gradient centrifugation step using Percoll and were selected by allowing them to adhere to culture vessel for 2 h at 37 degrees C under 5% CO2. The purity of obtained Kupffer cell was about 90% assessed by the phagocytosis of 3 micrometer latex beads. This method for Kupffer cell isolation resulted in yields of 1~5 x10(7) Kupffer cells per liver and Kupffer cells were preserved in maintenance cultures for 10 days. The phagocytic capacity of cultured Kupffer cells was measured according to the amount of latex beads incorporated into the cytoplasm. Larger round Kupffer cells in the culture had higher phagocytic capacity compared with smaller round or irregular shaped Kupffer cells. The different phagocytic capacity of Kupffer cells which was dependent on size and shape in vivo was well preserved during culture. The experimental group of Kupffer cells in culture were sequentially treated with ischemia and reperfusion at 1h and 30 min. The ratio of Kupffer cells having latex beads in their cytoplasm was significantly increased compared with control (p<0.01). This result was able to explain the Kupffer cells' activation after ischemia-reperfusion injury in vivo. In conclusion, Kupffer cells in this culture well resembled the cells in vivo and this in vitro model could provide a valuable tool for the study of Kupffer cells with a key role in pathophysiology of ischemia-reperfusion injury.

Formation of Intercellular Junction between Cardiomyocyte and H9c2 Cell Line in Co-Culture / 체질인류학회지

Recently, new treatments for human heart disease such as ischemia, infarction, cardiomyopathy, coronary heart disease have been developed. transplantation various kinds of cells from skeletal muscle, endothelium, mesenchyme, hemopoietic tissue to injured area after infarction were challenged. It's so called 'Cell Transplantation'. This therapeutic strategy already adopted and got a good result in clinical trial. But several limitations are still remained, including ethics, donor cell numbers, side effects, therapeutic efficiency. In this research, we investigated the formation of intercellular junction and synchronous contraction between cardiomyocyte and H9c2 cell line in co-culture to establish experimental model in vitro for cell transplantation. For this purpose, two kinds of cells, primary cultured cardiomyocyte and H9c2 (cardiomyoblast cell line) were used. Cultured cardiomyocytes had repetitive contraction-relaxation pattern along longitudinal axis both in single and coculture. But their contractions were slower, less regular, less strong in co-culture than in cardiomyocyte culture only. H9c2 cells did not contracted actively themselves, but moved toward cardiomyocyte passively coincided with contraction. In contact region between two kinds of cells, there was no signal after immunocytochemical staining labeled with connexin43 (gap junction), desmoplakin (desmosome), N-cadherin (adherent junction) even though they had membrane contact. Moreover, F-actin and striation were less developed. These results suggested that co-culture system interfere with remodelling of contractile apparatus, intercellular junction formation as well as contraction-relaxation. Furthermore cardiomyocyte could not induce H9c2 cells differentiation into cardiomyocyte. Therefore, much more research would be essential for clinical application of cell transplantation and this study would be the basic source for further study of new therapy of myocardial disease and building up in vitro model.

Change in Expression of Keratin and Proto-oncogene Induced by Beta-propiolactone in HaCaT Cell / 대한해부학회지

To investigate the relationship between the morphologic changes and the expression of keratin and proto-oncogene induced by Beta-propiolactone (BPL), we assessed on the expression of keratins (K8, K10, K13) and proto-oncogenes (c-fos, c-jun, c-myc) in human HaCaT cell line. The cells were treated with 0, 0.1, 1 microgram/ml BPL for 2 or 6 hours. Morphologic studies revealed that BPL changed the cells into fibrocyte-shaped, caused highly lobulated nuclei and reduced desmosomes in their number. Findings of immunofluorescence and Northern blotting indicated that BPL consistently decrease expression of K10 representing a normal differentiation marker of keratinocytes, while increasing expression of K8 and K13 associated with a pathologic differentiation. This reagent also up-regulated expression of c-fos and c-jun, and down-regulated expression of c-myc. Together with staining for each keratin or proto-oncogene and DNA content in flow cytometry, BPL increased K8 expression dramatically at S-G2-M phase. The induction of c-Fos at S-G2-M phase appeared within 2 hours, and c-Jun gradually occurred. However, c-Myc was inhibited regardless of phases of cell cycle. In conclusion, these changes caused by BPL demonstrate a close relationship between the morphologic evidence and the altered expression of each keratin and proto-oncogene.

The Effect of Green Tea Catechin on Epithelial Cancer Cell Lines / 대한해부학회지

Catechin is main component of polyphenol extracts from green tea, it is associated with prevention of hypertension and atherosclerosis, anti-diabetic effect, antioxidant, antitumor. The purpose of this research is to investigate the effect and its mechanism of green tea catechin on epithelial cancer cell lines in various concentrations and durations. For this study, epithelial cancer cell lines, A549 (lung cancer), EATC (Ehrlich-Lettre ascites tumor cell) were used. Inverted, light, confocal and electron microscopes were applied to find morphological changes. MTT assay, flowcytometric analysis, gel electrophoresis were used to compare severity of cellular damages to control after exposure to 1, 10, 100 and 500 microgram/ml catechin for 48 hours. In the A549 cells, after 1 microgram/ml and 10 microgram/ml catechin treatments, there was no notable changes. However, exposure to 100 microgram/ml catechin induced increase of cytoplasmic granules, destruction of lamellar body, inhibition of cell cycle, especially G0/G1. In the early phase of 500 microgram/ml catechin administration, decrease of cell population, severe destruction of lamellar bodies and mitochondria, derangement of cell cycle were shown. In the EATC, such as those effects occurred after exposure to lower concentration of catechin than in that of A549 cells. After exposure of 10 microgram/ml catechin, rounded-up cells and necrotic cells were found. Whereas, most of cells were under apoptotic changes-cytoplasmic condensation, nuclear fragmentation, cellular shrinkage, ladder pattern in the electrophoresis, when administrated 100 microgram/ml catechin. These results suggested that exposure of catechin induced severe cellular damage and growth inhibition in dose- and time-dependent manner. And we confirmed that these effects of catechin were involved with apoptosis, necrosis and cell cycle arrest and were quite different according to cancer type. Therefore, much more research would be demanded before clinical application of catechin to human cancer therapy and this study would be the basic source for further study of green tea.

The Measurement of Double Staining for Senescence Associated-beta-Galactosidase Activity and Keratin 10 or Involucrin in Monolayer and Organotypic Cultured Keratinocytes / 대한해부학회지

This experiment developed the methodology of double staining for senescence associated-beta-galactosidase (SA-beta-gal) activity and keratin 10 (K10) or involucrin. To prove the usefulness of the double staining, the author investigated the relationship between senescence and differentiation in monolayer and organotypic cultured keratinocytes. The results were as follows: K10 and involcrin together with SA-beta-gal were doubly stained in most of monolayer cultured keratinocyte. This fact indicated that the senescence and differentiation had simultaneously occurred in the same keratinocyte. In spite of the advantages to preserving structures, the paraffin specimen was not suitable for double staining because of the limitation of SA-beta-gal reactivity. Although the cryosectioned specimen did not have the morphology as good as the paraffin specimen, it was suitable for double staining due to the goodness of SA-beta-gal reactivity. Double staining well reflected the disturbances of senescence and differentiation which could be caused by deranged organizations of the organotypic cultured skin. The organotypic cultured skin which showed deranged organizations such as stratified basal layer, no typical cell features in each epdermal layer, and wide intercellular spaces had SA-beta-gal activity in epidermis and K10 or involucrin reaction in basal cell. But the skin which showed well arranged organizations resembling in vivo skin had no SA-beta-gal activity and no K10 or involucrin reaction in basal cells. In conclusion, it might be suggested that the double staining for SA-beta-gal activity and K10 or involucrin could be used for detecting the extent of senescence and differentiation in the same cell.

Replicative Senescence and Differentiation Properties of Reconstituted Skin and Monolayer Human Keratinocytes in Vitro / 대한해부학회지

This experiment tried to elucidate the characteristics of senescence and differentiation in the reconstituted skin and the monolayer cultured human keratinocytes in vitro, respectively. While the keratinocytes were cultivated from undifferentiated state to completely senescent and differentiated, the monolayer cultured cells of every passage were doubly stained with SA-beta-gal initially, then keratins or involucrin. We also performed the SA-beta-gal enzyme staining and the immuno-reaction such as keratins or involucrin in the reconstituted skin. The results were as follows: Lack of reactivity against SA-beta-gal in the reconstituted skin indicated that there was no senescence occurred. The reconstituted skin showed decreased expression of K10 and preceded expression of involucrin compare to in vivo skin. Nevertheless, the reconstituted skin which did not express the K10 or involucrin in the basal cell maintained the differentiation system similar to that of in vivo skin. On the other hand, the monolayer cultured keratinocytes showed a thoroughly different pattern in the senescent and differentiating process. SA-beta-gal was colocalized with K10 or involucrin in the cells of high percentage ratio by the double staining method, and this indicated that the senescence and differentiation in the kratinocytes were simultaneously progressed. Reaching the nearer stage leading to the cell death, the cells choosed the one of senescence or differentiation pathway. It was supported by the fact that the percentage index of double staining together with SA-beta-gal and involucrin was lower at passage 5 than passage 1~4. The SA-beta-gal's reactivity was maximally reached at passage 4 and the involucrin maximally reached at passage 5. These trends suggested that the senescence was preceded by the differentiation. In conclusion, the reconstituted skin maintained only the differentiation system without the cell senescent process similar to the in vivo while the senescent and differentiating events were simultaneously processed in the monolayer cultured keratinocytes.

Effect of Paclitaxel on the beta-actin, Fibronectin, Laminin and Fine Structure in HeLa and L929 Cells / 대한해부학회지

The aim of this investigation was to elucidate the changes in the cytoplasmic distribution of beta-actin, fibronectin, and laminin through mainly the morphological changes occurring in HeLa and L929 cancer cell treated with paclitaxel. Whether or not paclitaxel regulates cell proliferation was assessed with MTT assay. Possible influence on the distribution of beta-actin, fibronectin, and laminin in these cells was confirmed with immunocytochemistry and analySIS Auto software program. The changes in cell morphology were observed under inverted and electron microscope. The MTT assay showed that 1 micrometer and 10 micrometer concentrations of paclitaxel inhibited HeLa cell growth approximately by 20% to 80% and L929 cell by 27% to 44% in a dose- and time-dependent manner. The distribution of these proteins was changed from the condensed around nucleus and strong reaction to the weak throughout cytoplasm. The morphological changes indicated that paclitaxel changes the location or number of protein synthesis apparatus: damages of RERs, Golgi complex, and increase of heterochromatin. These data suggest that the growth inhibition and morphological changes of tumor cells induced by paclitaxel might be modulated by the rearrangement and decreased production of beta-actin, fibronectin, and laminin in cytoplasm.

Skin Pigmentation and its Regulation: Role of Keratinocyte and Ovarian Hormones on Human Melanocytes in Vitro / 대한해부학회지

Estrogen and progesterone are thought to be responsible for the pigmentary changes in pregnancy and also melasma. To investigate the action mechanism of estrogen and progesterone on the facultative skin pigmentation, Human melanocytes and keratinocytes were cultivated in the forms of pure melanocyte culture, co-culture (melanocytes and keratinocytes were cultivated together in a vessel but they were separated with membrane) or mixed culture (melanocytes and keratinocytes were cultivated together in a vessel in mixed form). After 2 days of cultivation in the presence of hormones (estrogen, progesterone and melanocyte stimulating hormone), the author studied the cell proliferation, the cellular features (the number of dendrites, perimeter and area), and the tyrosinase activity of melanocytes. Progesterone or melanocyte stimulating hormone increased in both the cell growth and the tyrosinase activity in pure melanocyte culture but estrogen did not. However, mixed culture treated with estrogen lead to increases in the tyrosinase activity. Pure melanocyte culture treated with estrogen or progesterone increased in the cell perimeter and the area but not in the number of dendrites. Co-cultured melanocytes without hormones revealed more increases in the perimeter (p.0.01) and the area (p.0.01) even in the number of dendrites (p.0.01) compared to the pure cultured melanocytes treated with the hormones. It was postulated with these results that estrogen, progesterone and keratinocyte possibly induced hyperpigmentation of the skin via the keratinocytes stimulated by estrogen, via the proliferation of melanocytes induced by progesterone, and via the cellular features altered by keratinocytes.

Measurement of Replicative Senescence in Long Term Cultured Human Keratinocytes / 대한해부학회지

The keratinocyte culture has been used for the reconstruction of artificial skin or as in vitro skin model. For these purpose, keratinocytes should be cultured for long time (usually 10 cumulative population doublings) and it is important to evaluate the state of replicative senescence or cell senescence during this time. This study was undertaken to investigate senescence associated beta-galactosidase (SA-beta-gal) activity for the senescent cell and keratin 19 immunohistochemistry for the skin stem cell in keratinocytes on ten times serial subculture (referred to 10 cumulative population doublings). Keratinocytes were isolated from foreskin of a 2 day old child, and cultured in KSFM and then in DMEM/F-12. In both keratinocytes cultured in KSFM and DMEM/F-12, lysosomal beta-galactosidase activity, which is detected at pH 4.0, was present in all cells regardless of their replicative age. In contrast, SA-beta-gal activity, which is detected at pH 6.0, was present in a few cells (from 0.1% to 3%) during whole subcultures. These data suggest that most of keratinocytes did not undergo replicative senescence in this culture. Furthermore, in keratin 19 skin stem cell staining, a lot of keratinocytes (13.8%) showed strong positive reaction on the 10th subculture. Together with the results of beta-galactosidase activity, the persistence of high proportion of keratin 19 positive skin stem cells implies further increment of keratinocyte populations by continued subcultures.

Effect of Lectin on Fine Structure and Extracellular Matrix Protein of Cancer Cell Lines / 대한해부학회지

Lectins are glycoproteins that bind specifically to carbohydrates. Considerable interests in the lectins were encouraged by several reports that certain members of the family bind to the extracellular matrix proteins (ECM), such as fibronectin and laminin. However, the relations between lectin and ECM protein remain unclear. To elucidate the relations of lectin-matrix-cell, we treated three cancer cell lines, HeLa, L929, and EATC with ConA and PHA-P at low dose (4 microgram/ml) and high dose (20 microgram/ml) for 1, 3, 5 days. 1. Whether or not lectins significantly regulate the cell proliferation was evaluated by MTT assays. 2. Whether the amount of fibronectin and laminin which of cancer cells can be influenced by lectins was confirmed by immunocytochemical staining. 3. Whether, in turn, the lectins which can change the morphology were observed under inverted and electron microscopes. ConA and PHA-P inhibited cell proliferation rate of all cell lines in a dose- and time- dependent manner. The amount of fibronectin and laminin considerably reduced in the three cell lines after the lectins treatment in a dose- and time-dependent manner. The cancer cell lines showed various morphological changes such as cell aggregation, irregular-shaped cellular processes, rounded cells, cytoplasmic vacuolation, swollen RERs, dilation of mitochondria, margination of chromatin and cell death. In conclusion, our results showed ConA and PHA-P caused damages of the three cancer cell lines, but the effect of PHA-P was much stronger than ConA. Taken together, the present data strongly indicate that ConA and PHA-P influence the cell proliferation rate, reduce the amount of fibronectin and laminin and induce cell injuries of HeLa, L929, and EATC cell lines. Our results also suggest that the cancer cell proliferation and the morphological changes might be modulated by the specific interaction between lectins and ECM proteins associated with the cell surface.

Anti-tumor Effect of Green Tea Catechin on Cancer Cell Lines / 대한해부학회지

In this research, the author investigated antitumor effects of green tea catechin on cancer cell lines in various concentrations and durations. Additionally, antitumor mechanism of catechin associated with apoptosis and necrosis, especially their onset and duration were invesigated. Cancer cell lines, L1210 (lymphocytic leukemia), L929 (fibrosarcoma), HepG2 (hepatoblastoma) were used. In each group, intensity of morphological changes and cell damage was observed under inverted, light, confocal and electron microscopes, and MTT and flowcytometric analysis, gel electrophoresis were used to elucidate the effects of catechin after exposure to 1, 10, 100 and 500 microgram/ml catechin until 72 hours. In all cancer cell lines, catechin induced cellular injury and inhibition of proliferation in concentration- and duration-dependent manner. The effects of catechin were the strongestt in L1210 cells and L929 and HepG2 cells in order. Dual phenomena, of apoptosis and necrosis, were shown after catechin treatment. In necrotic cells, cellular swelling, cell organelles destruction, nuclear disintegration and random DNA fragmentation were observed. In apoptotic cells, apoptotic bodies, nuclear and cytoplasmic condensations, periodic DNA fragmentation were seen. In L1210 cells, necrotic and apoptotic cells were co-existed earlier, after exposure to catechin 100 microgram/ml and then apoptosis predom-inated later. In the same concentration, catechin induced apoptosis of L929 cells. but after exposure to 500 microgram/ml catechin, They were involved with apoptosis and necrosis simultaneously. On the other hand, HepG2 cells were damaged less than other cell lines but were involved with necrosis and inhibition of G2/M phase after treatment with 500 microgram/ml catechin. These results suggested that anti-tumor mechanism of catechin, associated with apoptosis, necrosis and cell cycle arrest, were quite different according to cancer type, concentration and duration of catechin treatment. Therefore, much more research would be essential for clinical application of catechin and this study would be the basic source for further study of green tea.

Effects of Ischemic Preconditioning on Hypoxia-Reoxygenation Injury of Cardiac Myocyte in Culture / 대한해부학회지

Short period of ischemia and reperfusion protect heart against subsequent prolonged ischemia-reperfusion injury. This phenomenon was first described by Murry et al in 1986, who demonstrated that four 5-minute coronary artery occlusions followed by equal period of reflow at each time before a subsequent prolonged occlusion resulted in a reduction of infarct size in dog. Although the precise mechanism of preconditioning remains unknown, this phenome-non is present among different species of mammals, including dogs, rats, pigs, rabbits, and human. The objects of present study was to investigate effect of ischemic preconditioning on cell viability, structural changes and apoptosis during 60 min hypoxia and 60 min reoxygenation of the cell. In present study we investigated through cell culture system using myocyte of three days old neonatal rat cultured for three days. During hypoxia and reoxygenation, differences between preconditioned and nonpreconditioned of beating counts, morphological and structural changes are investigated through inverted phase contrast microscope and transmis-sion electron microscope. To detection of apoptotic cell, TUNEL (TdT-mediated dUTP-biotin nick end labeling) stain was accomplished, and through which we invesigate the effects of preconditioning on apoptosis. Viabiliy of each cell and it's mitochondria were measured quantitatively by MTT assay. After 60 min of hypoxia and 60 min of reoxygenation, beating rate decreased remarkably. But at the time of 60 min of reoxygenation, there was marked increase in beating count in pre-conditioned cell. Swollen mitochondria with amorphous granules in inner membrane, destroyed mitochondrial cristae, indented nuclear envelope, chromatin condensation, contracture of myofibril, fragmentation of myofilaments, cytoplasmic shrinkage were observed in both preconditioned cell and nonpreconditioned cell. But it is much less in pre-conditioned cell than in nonpreconditioned cell. MTT activity decreased in both experimental groups in compared with normal group, but in preconditioned group, MTT activity increased markedly in compared with nonpreconditioned group. And apoptosis is decreased by precontitioning in TUNEL staining. These results suggest that cardioprotective effects of ischemic preconditioning is mediated by attenuating structural destroy, increasing cell viability, decreasing apoptosis.

Effect of beta-amyloid Peptide on Fine Structure of Cardiac Myocytes in Culture / 대한해부학회지

Several predetermined concentrations of beta-amyloid peptide, (betaA) were administered to the rat cardiac myocyte cultures for three days to determine the effects of betaA. Stainings with congo red and crystal violet were used to evaluate the deposition of betaA in the cardiac myocytes and MTT assay was used to elucidate the cytotoxic effects of betaA by anlaysis of cell viability. Beating rates and morphological changes were investigated with inverted microscope and TEM was used to study the fine structures. Administration of 0.5 microgram/ml of betaA to cardiac myocytes induced the reduction of beating rate, however, it did neither affect the viability nor fine structures. No significant differences in cell viability or fine structures were noted in the experimental groups which were exposed to 5 microgram/ml or higher concentration of betaA. Deposition of betaA was confirmed in the cytoplasm of betaA treated cardiac myocytes with congo red and crystal violet amyloid stains. The viability of cardiac myocytes exposed to betaA was found to be reduced significantly (19%) compared to control cultures with the MTT assay. Cardiac myocytes treated with betaA presented a reduced cytoplasmic area that appeared very condensed under inverted microscope. Mitochondrial abnormalities in betaA treated cardiac myocytes included their significant enlargement, vacuolization, disorganization or paucity of cristae, paracrystalline inclusion, and accumulation of amorphous material in mitochondrial space. Mitochondrial abnormalities were present sometimes in betaA treated cardiac myocytes without disorganization of myofibils or degeneration of other cell organelles. To understand the mechanism involved in amyloid deposit and its role in pathogenesis of the diseases such as Alzheimer and inclusion body myositis (IBM), a need for in vitro model is imperative. This model of betaA treated cultured cardiac myocytes represent a amyloidosis model, and it offers several advantages for future studies of betaA to help elucidate the pathogenesis of amyloid diseases. For example, cardiac myocytes can be easily accessible, and since cardiac myocytes can be cultured for quite a long time, it is possible to study morphological and physiological changes consequent to amyloid deposits.

The Investigation of the Melanocytes in a Cultured Skin Equivalent Model / 대한해부학회지

Melanocytes grown in the pure monolayer culture lack the three-dimentional organization and the cellular interactions that exist in vivo. These can be partially overcome by growing melanocytes together with other epidermal cells in cultured skin equivalent models. In this study, skin equivalents were prepared by seeding mixtures of cultured human keratinocytes and melanocytes in ratio 10 : 1 onto artificially constructed dermis. They were cultured in DMEM/F12 (1 : 1) for 4 days and then lifted to the air-liquid interface and maintained in DMEM/F12 (3 : 1) for 10 days. Histological and electronmicroscopic examinations of the cultured skin equivalants revealed a structure that closely resembled human interfollicular epidermis; 1. Melanocytes, were identified by positive staining with melanoma-specific antibodies (NKI/C3 and S-100 protein) and prominent cytoplasm with rich cell organelles, were located in the basal layer. 2. Melanocytes contained predominently early stage melanosomes and prominent Golgi apparatus. Mature melanins, were usually abundant in normal skin, were hardly seen both in melanocytes and in neighbouring keratinocytes. 3. Melanocytes were surrounded by keratinocytes but did not form intercellular junctions with them. 4. Keratinocytes were charaterized by microfilament bundles and intercellular junctions such as desmosomes and hemidesmosomes with neighbouring keratinocytes and artificial dermis. The melanocyte in the above skin equivalents had a strong resemblance to the one of normal human skin and therefore this model can be used as artificial skin for the transplantation and in the investigation of melanocytes' role to the UV stimuli.