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Original Articles
- Ultrastructural Changes of the Bile Canaliculi after Common Bile Duct Ligation.
- Kook Seon Yoo, Suk Hee Lee, Hee Kyung Park, Chang Ho Cho, Jong Min Chae
- Korean J Pathol. 1996;30(3):175-183.
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Abstract
PDF - The purpose of this study was to investigate the morphologic changes of the bile canaliculi and its associated structures of the liver induced by common bile duct ligation(CBDL) in the rat. The canalicular surface and lateral surface of the dry-fractured hepatocytes was studied with scanning electron microscopy at 1~6 weeks post ligation. The first week after CBDL, the bile canaliculi were dilated. The microvilli were increased in number and the lumens contained granular materials After 2 weeks or more, the bile canaliculi were dilated to a variable degree, and with irregularity, measuring from 1.5 to 5 micrometer in diameter, and in the advanced stage, the canaliculi showed blunting and the disappearance of microvilli. Some canaliculi had sprouting side branches. At 4~6 weeks post-ligation, the lateral surface of the hepatocytes also showed some irregularity and a tortuous appearance, and numerous small sized microvillous projections were formed. The tubular structures of the proliferated SER distributed adjacent to the lateral surface of the hepatocytes, and the direct connection of a tubular structure and the cytoplasmic membrane was observed. These results suggest that the deformity and loss of microvilli of bile canaliculi reflect the disturbance of bile secretion from the hepatocytes. And prolonged obstruction of bile flow may result in bile excretion via the lateral surface of hepatocytes.
- Ultrastructural Changes of Lead Acetate Induced Liver Injury in Rats.
- Eun Sook Chang, Jin Seok Oh
- Korean J Pathol. 1996;30(3):184-198.
- 1,866 View
- 36 Download
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Abstract
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- To evaluate the ultrastructural changes and the mechanism causing liver injury by lead, light and electron microscopic(LM and EM) examination using Timm sulphide silver method(TSM) was done. Sprague-Dawley rats were divided into a control and 3 experimental groups. The experimental groups were orally administered 0.5% lead acetate(LA). Group 1 received a one time dose of 10 ml of LA by gastric intubation. Groups 2 and 3 continuously received LA instead of drinking water. The control group was composed of 3 rats in each group which did not receive any treatment. Rats of group 1, 2 and 3 and control were sacrificed at 1/2, 1, 1 1/2 hours, 2 days, and at 1, 2, 4, 6 and 8 weeks later, except group 3. Before sacrifice, they were perfused with 0.1% sodium sulphide and 2.5% glutaraldehyde through the abdominal aorta for TSM. The liver was taken for LM and EM examinations. Blood lead concentration began to increase from the 2nd day up to 3.29 microgram/ml at 2nd week, and the urinary delta-ALA level showed a steady increase from the 2nd day. LM and EM examination of liver revealed that absorbed lead granules in group 1 were transported into sinusoidal spaces, Kupffer cells, and the hepatocytes within 1 hour and then disappeared 1/2 hour thereafter. In group 2 deposited lead was found in the hepatocytic cytosol bound to mitochondria. That in turn inhibited mitochondrial respiration with resultant mitochondrial swelling at the 1st week and thereafter at 6th week myelin figure formation and condensation of mitochondria, and peroxisomes were increased at 8th week. Based on these results it can be concluded that a transient intake of subletal dose of LA is biotransformed completely by periportal hepatocytes within 1 1/2 hours, but excessively accumulated lead can induce liver cell injury due to lipid peroxidation of membrane by direct toxic effect of lead and by products of lipid peroxidation. We postulate that lead acetate triggers presumably primarily mitochondrial membrane injury and then other organellar changes may play a role in disturbance of a network of interacting of key events capable of causing cell death.
- The Morphologic Changes of the Sinusoidal Endothelial Cells in N-diethylnitrosamine Induced Cirrhotic Rat Liver.
- Ok Ji Paik, Hee Kyung Park, Jong Min Chae, Jyung Sik Kwak, Tae Joong Sohn
- Korean J Pathol. 1996;30(7):604-615.
- 1,811 View
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Abstract
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- The purpose of this study is to investigate the morphologic changes of the sinusoidal endothelial cells and the associated structures of the cirrhotic rat liver induced by repeat intraperitoneal injections of N-diethylnitrosamine (DEN) (100 mg/kg/week). One day to 6 weeks later, rat livers were observed under the light, transmission and scanning electron microscopy, and immunostained with laminin antibody. Two weeks after DEN treatment, the fibrillar material in Disse's space was noted, and then a basement membrane-like structure was found at 4 weeks after treatment. Laminin was detected in perisinusoidal areas after 4 weeks. Laminin was strongly positive on the fibrous septum and in the sinusoidal wall of cirrhotic nodules after 6 weeks of treatment. The diameters and numbers of sinusoidal endothelial fenestrations did not change significantly until 2 weeks. They decreased within 4 weeks, and then the sinusoidal endothelium was poorly fenestrated at 6 weeks after DEN treatment. These results suggest that as fibrosis develops in cirrhosis, the deposit of extracellular matrix such as laminin within Disse's space is a major contributing factor in the structural alteration of sinusoidal endothelial cells, and the capillarization of the sinusoidal endothelial cells may be a contributor to impairment of the hepatic function in cirrhosis.
- PDGF-R alpha Expression in Preneoplastic and Neoplastic Hepatocellular Lesions: A Rat Model N-nitrosomorpholine Stop Experiment.
- Su Jin Kim, Kyoung Tae Kim, Jin Sook Jeong
- Korean J Pathol. 2006;40(5):354-360.
- 1,773 View
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Abstract
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- BACKGROUND
N-nitrosomorpholine (NNM) is a genotoxic hepatocarcinogenic agent. Preneoplastic and neoplastic hepatocyte lesions were induced in rats by oral exposure to NNM (200 mg/L) in a stop model experiment. Platelet-derived growth factor receptor (PDGF-R) is a tyrosine kinase receptor that works with PDGF, stimulating cellular growth and proliferation. The present study was designed to determine the role of PDGF-R alpha expression in hepatocellular neoplasms and precursors.
METHODS
Seventeen rats out of a starting number of 30 died. From the fifth week until the 24th week one or two rats were evaluated. Preneoplastic single cells or foci, foci of altered hepatocytes (FAH) hepatocellular adenomas (HCA) and hepatocellular carcinomas (HCC) were studied histologically, and the expressions of GSTp and PDGF-R alpha by immunohistochemistry.
RESULTS
At the fifth week, GSTp +single cells showed PDGF-R alpha expression (20.8+/-5.8%). At the sixth week, GSTp +single cells, located at periportal areas, co-expressed PDGF-R alpha (43.4+/-9.6%). Over the next several weeks periportal hepatocytes showed weaker PDGF-R alpha expression but no GSTp. GSTp+FAH, and all HCA, demonstrated no PDGF-R alpha expression. However, nine out of 10 (90%) HCC showed PDGF-R alpha expression.
CONCLUSIONS
These data showed that there were two peaks of PDGF-R alpha expression, and suggest that the earlier expression is related with the response to NNM-induced hepatocyte toxicity, and that the later response is associated to malignant transformation.
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