• Childhood Kidney Diseases
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• v.10 no.1
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• pp.8-17
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• 2006

Purpose : We describe the changes of rat glomerular epithelial cells when exposed to high levels of glucose and advanced glycosylation endproducts(AGE) in the in vitro diabetic condition. We expect morphological alteration of glomerular epithelial cells and permeability changes experimentally and we may correlate the results with a mechanism of proteinuria in DM. Methods : We made 0.2 M glucose-6-phsphate solution mixed with PBS(pH 7.4) containing 50 mg/mL BSA and pretense inhibitor for preparation of AGE. As control, we used BSA. We manufactured and symbolized five culture dishes as follows; B5 - normal glucose(5 mM) + BSA, B30 - high glucose(30 mM) + BSA, A5 - normal glucose(5 mM) + AGE, A30 - high glucose(30 mM) + AGE, A/B 25 - normal glucose(5 mM) + 25 mM of mannitol(osmotic control). After the incubation period of both two days and seven days, we measured the amount of heparan sulfate proteoglycan(HSPG) in each dish by ELISA and compared them with the B5 dish at 2nd and 7th incubation days. We observed the morphological changes of epithelial cells in each culture dish using scanning electron microscopy(SEM). We tried the permeability assay of glomerular epithelial cells using cellulose semi-permeable membrane measuring the amount of filtered BSA through the apical chamber for 2 hours by sandwich ELISA. Results : On the 2nd incubation day, there was no significant difference in the amount of HSPG between the 5 culture dishes. But on the 7th incubation day, the amount of HSPG increased by 10% compared with the B5 dish on the 2nd day except the A30 dish(P<0.05). Compared with the B5 dish on the 7th day the amount of HSPG in A30 and B30 dish decreased to 77.8% and 95.3% of baseline, respectively(P>0.05). In the osmotic control group (A/B 25) no significant correlation was observed. On the SEM, we could see the separated intercellular junction and fused microvilli of glomerular epithelial cells in the culture dishes where AGE was added. The permeability of BSA increased by 19% only in the A30 dish on the 7th day compared with B5 dish on the 7th day in the permeability assay(P<0.05). Conclusion: We observed not only the role of a high level of glucose and AGE in decreasing the production of HSPG of glomerular epithelial cells in vitro, but also their additive effect. However, the role of AGE is greater than that of glucose. These results seems to correlate with the defects in charge selective barrier. Morphological changes of the disruption of intercellular junction and fused microvilli of glomerular epithelial cells seem to correlate with the defects in size-selective barrier. Therefore, we can explain the increased permeability of glomerular epithelial units in the in vitro diabetic condition.

• Applied Microscopy
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• v.31 no.1
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• pp.71-83
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• 2001

Laminin, a kind of multidomain glycoproteins, is mainly localized in the basement membranes of various tissues. It is known that laminin plays an important part in mammalian lung morphogenesis. The authors have undertaken this study to investigate the changes in the distribution of laminin, and to find out cells which synthesize laminin during the organogenesis and differentiation of the lung. The fetal and neoantal rats (Sprague-Dawley strain) were used as experimental animals. The immunohisto-chemical methods were employed for detection of laminin within the developing lung tissue and the immunegold cytochemical methods were performed for detection of cells which synthesize laminin according to each stage of development. The results are as follows; 1. During fetal life, strong immunoreactivity for laminin is maintained in the basement membranes of the blood vessels and the bronchioles, the extracellular matrix of the mesenchyme, and basal lamina of the alveolar septum in the fetal rat lung. 2. After birth, laminin immunoreactivity at the alveolar septum is gradually reduced. 3. During fetal life, laminin is mainly detected within the cytoplasm of the mesenchymal cells, the endothelial cells of blood vessels and the fibroblasts in fetal rat lung. 4. According to the differentiation of type I and type II pneumocyte after birth, laminin is detected within cytoplasm of the type I pneumocytes, type II pneumocytes and fibroblasts. It is consequently suggested that laminin is largely expressed in the developing lung and laminin may be also synthesized by the type II pneumonocytes at early newborn stages.