Mesenchymal Stem Cells Decrease Oxidative Stress in the Bowels of Interleukin-10 Knockout Mice

Background/Aims@#Inflammatory bowel disease (IBD) is an autoimmune disease characterized by chronic inflammation mainly in the large intestine. The interleukin-10 knockout (IL-10 KO) mouse is a well-known animal model of IBD that develops spontaneous intestinal inflammation resembling Crohn’s disease. Oxidative stress is considered to be the leading cause of cell and tissue damage. Reactive oxygen species (ROS) can cause direct cell injury and/or indirect cell injury by inducing the secretion of cytokines from damaged cells. This study evaluated the effects of mesenchymal stem cell (MSC) on the progression of IBD. @*Methods@#In this study, human bone marrow-derived MSCs were injected into IL-10 KO mice (MSC). Oxidative stress and inflammation levels were evaluated in the large intestine and compared with those in control IL-10 KO mice (CON) and normal wild-type control mice (Wild). @*Results@#The levels of ROS (superoxide and hydrogen peroxidase) and a secondary end-product of lipid peroxidation (malondialdehyde) were considerably higher in the CON, while superoxide dismutase and catalase levels were lower in the MSC. Inflammation-related marker (interferon-γ, tumor necrosis factor-α, IL-4, and CD8) expression and inflammatory histological changes were much less pronounced in MSC than in CON. @*Conclusions@#MSCs affect the redox balance, leading to the suppression of IBD.

An Effective Isolation of the Vascular Endothelial and Smooth Muscle Cells from the Mouse Aorta / 대한해부학회지

The mechanism of the disease such as artherosclerosis is easily elucidated by the comparison among cells isolated from each aorta of knockout mouse and wild type mouse, respectively. This study was aimed at effectively harvesting the endothelial and smooth muscle cells from 4~6 weeks old wild type C57BL/6J mouse aorta. The tunica adventitia was completely removed to get the aortic tissues only consisting of the tunica intima and the tunica media under the stereoscope. These aortic tissues were treated with type I collagenase or type II collagenase solution, respectively, and then the endothelial or smooth muscle cell was isolated. CD31 marker of the endothelial cell and alphasmooth muscle actin marker of the smooth muscle cell were identified with confocal microscope. The percentages of the labelled cells by each marker represented the extent of purification of endothelial or smooth muscle cells, respectively, for harvested cells according to the collagenase solutions. 70~80% of culture vessel was covered with the endothelial cells 10 days after the treatment of the type I collagenase solution, while 40~50% of culture vessel covering with the cells after the treatment of the type II collagenase solution. 70~80% of culture vessel was covered with the smooth muscle cell regardless of the type of the collagenase solution on the 13th day. Percentages of the CD31 positive cells after the treatment with the type I or the type II collagenase solution was 91.1+/-.865%** and 86.4+/-.641%, respectively (**p <0.05, n=5). Percentages of the alphasmooth muscle actin labelled cells after the treatment with the type I or the type II collagenase solution were 87.9+/-.713% and 86.6+/-.778%, respectively, and these values were not significantly different. Taken together, the aortic tissues using the type I collagenase solution comparing with using the type II collagenase solution were much more effective in the isolation of the endothelial cells

Effect of Propofol on Kupffer Cell Superoxide Dismutase Activities and Cytoprotections during Hypoxia-Reoxygenation / 대한해부학회지

The aims of this study were to verify the hypoxia-reoxygenation injury of primary cultured Kupffer cells and the effect of propofol against the hypoxia-reoxygenation injury through quantitating lactate dehydrogenase (LDH) release and superoxide dismutase (SOD) activity.The sequential treatments with hypoxia and reoxygenation induced significant increasement of LDH release (P.0.01) and decresement of SOD activity(P.0.05) in primary cultured Kupffer cell. The level of LDH release and SOD activity after sequential treatments with hypoxia and reoxygenation were restored to the control level by the propofol treatment in the concentration of 0.5 and 5 microgram/mL. Propofol in concentration of 50 microgram/mL induced significant increasement of LDH release (P.0.01) on both normal culture and hypoxia-reoxygenation culture of the Kupffer cell. As hypoxia and reoxygenation procedures and propofol treatment were concurrently added to the cultured Kupffer cell, propofol treatment in the concentration of 50 microgram/mL decreased significantly the SOD activity (P.0.01). In conclusion, propofol in this hypoxia-reoxygenation model could provide a valuable clue for the study of liver transplantation and of propofol.

The Effects of Keratinocyte-derived Factors Involved in Transforming the Morphologies of Melanocyte and in Translocating Melanosomes to Keratinocyte / 대한해부학회지

Keratinocyte-derived factors are involved in regulating the proliferation, differentiation or melanogenesis of melanocytes. To investigate the effects of keratinocyte-derived factors on the skin pigmentation, human melanocytes and keratinocytes were cultivated in the forms of pure melanocyte or keratinocyte culture system, co-culture system (melanocytes and keratinocytes were cultivated together in a vessel but they were separated with semipermeable membrane) or mixed culture system (melanocytes and keratinocytes were cultivated together in a vessel in mixed form). The authors studied the cellular features (dendritogenesis and area) and the tyrosinase activities and observed the electron microscopic structures for melanosome transfer. Melanocyte in co-culture system increased in the area (p.0.05) but not in the dendritogenesis compared with the melanocyte in pure culture system. The tyrosinase activities of co-culture system on the 2nd and 4th day revealed higher compared with the ones of the pure and mixed culture system (p.0.05). In the co-culture system, the tyrosinase activities were gradually decreased with the lapse of time and vice versa in the pure and mixed culture system. On the 6th day culture, all of the three melanocyte culture systems showed the same tyrosinase activities. In spite of high tyrosinase activities in the medium, there were no tyrosinase activities in keratinocytes with the co-culture system. In transmission electron microscopic findings, there were scant of melanosomes in keratinocytes with the co-culture and mixed culture systems. In conclusion, keratinocyte-derived factors modulate the activities and melanogenesis of melanocytes but there were no effects on melanosome transfer to keratinocytes.

Effects of Dexamethasone Withdrawal on Proliferation and Differentiation of Mesenchymal Stem Cells / 대한해부학회지

With potential of differentiation into many different lineages, mesenchymal stem cells have been candidate on cell therapy for recovery of injured body. Dexamethasone plays important role in mesenchymal stem cells differentiation and can derived into osteoblast, chondrocytes, adipocytes, and fibroblasts in vitro. There has been many studies on effect of dexamethasone for differentiation of MSCs with continuous exposure, but little work on the effect for deprivation during this progress. This result will be an important guild line for evaluation of transplanted MSCs after pretreatment with dexamethasone. In this study, dexamethasone was deprived by weekly withdrawal schedule in the process of differentiation induction by dexamethasone. During this period, expression of APase was evaluated as mark of osteoblast differentiation and number of BrdU incorporated cells were counted as index of proliferation. APase level of one or two week exposure groups decreased immediately after deprivation of dexamethasone and approached to control level at 4~5 week but three or four week exposure groups reached peak level at 3th week then decreased but still remained higher level than other groups. Dexamethasone exposure groups showed the trend of decreased in mitotic activity compared to control, but there were significant increase in mitosis after deprivation of dexamethasone. This pattern prominent in 6, 9, 12, 15 day exposure groups. These results showed that the effect of dexamethasone derived MSCs differentiation into osteoblasts is faint without full enough exposure and the period should be more than three weeks.

Morphological Study for Osteoinduction by Human Fibroblasts Transduced with rhBMP-7 Adenovirus / 대한해부학회지

To evaluate availability of the BMP-7 adenovirus (AdBMP-7) as a gene therapy for osteoinduction, we investigated in morphological aspect at 1, 2, 4, 6 weeks after cells injection. Primary cultured human dermal fibroblasts, transduced with AdBMP-7, were injected into gastrocnemius muscle of the nude mice. One week after fibroblasts transplantation new tissue was observed in the muscle. Majority of new tissue was evaluated as cartilage and calcification in the matrix was confirmed by Von Kossa stain as well as electron microscopy. Two weeks after transplantation, spongy bone was built up and adipocytes were observed in intertrabecular spaces. Osteoblasts and osteoclasts were observed in the bony tissue surface. In the result of Von Kossa-Van Gieson stain, osteolysis was dominant in bony trabeculae. Bone marrow was established in 4th weeks with intertrabecular space filled up by hematopoietic cells. At the 6th weeks, the number of trabeculae decreased and thickness of the cortical bone was increased. A great part of bone matrix has laminar structure which run paralleled to surface and which included osteocytes and canaliculi. These data demonstrate that cell mediated AdBMP-7 for gene therapy initiate development of cartilage and calcification of matrix within 1 week and complete bone and bone marrow formation within 4 weeks, so then, could be made practical application for promotion of osteoinduction.

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.

Change in the Beating Rate and Intercellular Adhesion Molecule of Cardiomyocytes in Culture / 대한해부학회지

This experiment was designed for the elucidation of relationships between the cell adhesion molecules and synchronous beating rates of cardiomyocytes isolated from ventricles of 3-day-old rats. These cells were grown on the culture vessel coated or non-coated with cardiogel for 1, 3, 5, and 7 days. The synchronous beating rate and morphologic changes of cells were investigated under the inverted microscope. Those changes of cardiomyocytes were observed by transmission elcectron microscopy (TEM). Connexin43, pan-cadherin, and alpha-sarcomeric actin were stained by indirect immunofluorescent (IF) technique. Western blotting were used for identifying unique bands of connexin43 and pan-cadherin in the regions of specific size. The synchronous beating numbers of cardiomyocytes in each group on the dish coated or non-coated with cardiogel were significantly different for 3, 5, and 7 days in culture. The maximum values of synchronized beating in the cells appeared on the day 5. The beating numbers of cells grown on coated dish comparing with non-coated dish were significantly increased on the day 5 and day 7. The proliferation of cardiomyocytes increased markedly in the cardiogel-coated dish on the day 5, while the number of fibroblasts in non-coated dish were obviously increased on the day 7. In indirect IF studies, a normal redistribution of connexin43, pan-cadherin, and alpha-sarcomeric actin of the cells was expressed in day 3 throughout day 5. The reaction intensity of those proteins were increased or decreased in the proportion to the beating numbers. The lack of reaction was appeared in the fibroblasts consisting of monolayer on the day 7. Unique bands of connexin43 and pan-cadherin having a specific size were marked on Western Blotting. The structures such as gap junction, fascia adherence and desmosome compatible with intercellular adhesion in cardiac muscle were abundant on day 3 to 7. In conclusion, the amount or reaction intensity of connexin43 and pan-cadherin in cardiomyocytes were stronger simultaneously with the increase of synchronous beating numbers, particularly for 3 and 5 days. The maximum beating rates of cardiomyocytes reached on the day 5, while the maximum beating rates of them were markedly decreased owing to the proliferation of fibroblasts on day 7. TEM findings consisting of intercalated discs might be explained regardless of coating with cardiogel on why the close relationships between the beating rates and the connexin43 and pan-cadherin of those cells in culture exist.

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.

The Effects of Propofol on Kupffer Cells in the Rat Liver / 대한마취과학회지

BACKGROUND: Propofol has an antioxidant capacity and can be used for ischemia-reperfusion injury of the liver. However, the effects of propofol on the Kupffer cells have not been established. METHODS: Kupffer cells were isolated and cultured from male Sprague-Dawley rats. The effects of propofol on the Kupffer cells were evaluated by a phagocytosis assay, TNF-alpha gene expression, TNF-alpha production, and superoxide anion release after administering propofol in different concentrations on the cultured Kupffer cells. RESULTS: The latex bead phagocytosis by the Kupffer cells was suppressed when the Kupffer cells were exposed to propofol irrespective of concentrations. Higher propofol concentrations decreased the loss of Kupffer cells after latex bead phagocytosis. Propofol induced TNF-alpha mRNA expression in the Kupffer cells, but the mRNA expression level after 50microgram/ml of propofol decreased. The pattern of TNF-alpha mRNA expression induced by propofol was different to that induced by LPS: TNF-alpha mRNA was expressed continuously in the propofol-treated cells until 16 hours after exposure to propofol, whereas the level of TNF-alpha mRNA expression induced by LPS was evident after 2 hours and was not found thereafter. TNF-alpha production after propofol treatment was not higher than that of the control. Formazan precipitation did not show any qualitative differences between cells untreated or treated with propofol concentrations of 0.5, 5.0, and 50microgram/ml. CONCLUSIONS: These results showed that propofol might inhibit Kupffer cells. This suggests that propofol can be used for patients with ischemia-reperfusion injury of the liver.

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.

Diffusion-Weighted MR Imaging in Animal Model with Acute Ischemic Brain Infarction: Evaluation of Reversible Brain Injury

PURPOSE: To determine whether the analysis of abnormally high signal intensities in ischemic tissue, as revealed by diffusion-weighted MR imaging (DWI) can be used to evaluate reversible brain lesions in a cat model of acute ischemia. MATERIALS AND METHODS: Ten cats were divided into two groups of five (Group I and Group II), and in all animals the middle cerebral artery was temporarily occluded. Group I underwent T2-DWI 30 minutes after occlusion, and Group II 120 minutes after occlusion. In both groups, DWI was performed one hour and 24 hours after reperfusion (at one hour, non-T2-weighted; at 24 hours, T2-weighted). Both occlusion and reperfusion were monitored by 99m TC-ECD brain perfusion SPECT. All animals were sacrificed 24 hours later and their brain tissue was stained with TTC. Signal intensity ratios (SIR, signifying average signal intensity within the region of interest divided by that in the contralateral, nonischemic, homologous region) of the two groups, as seen on DWI were compared. The percentage of hemispheric lesions occurring in the two groups was also compared. RESULTS: SIR after occlusion of the middle cerebral artery was 1.29 in Group I and 1.59 in Group II. Twenty-four hours after reperfusion, SIR in Group I was higher than in Group II (p<0.01). After occlusion and reperfusion, the percentage of hemispheric lesions in Group I was less than in Group II. For the latter, the percentage of these lesions revealed by TTC staining and T2-weighted imaging was 48% and 59%, respectively, findings distinctly different from those for Group I. In addition, in group I, infarction was revealed by neither TTC staining nor T2-weighted imaging (p<0.01). CONCLUSION: The use of DWI to evaluate signal intensity ratios can help determine whether or not brain injury after temporary cerebral ischemia is reversible.

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.