The cholestasis are defined as blockade or secretory distrubance of bile and appearance of bile in hepatocytes, Kupffer cells and biliary passages, usually associated with dilated bile canaliculi. Intra-and extraheptic cholestasis were induced by 17-ethinyl estradiol, or chlorpromazine hydrochloride and by ligation of bile duct to investigate the mechanism of the hepatic injury, ultrastructural changes of liver and alterations of liver function. The results obtained were as follows. 1) Functional and histological changes of intra-and extrahepatic cholestasis differed in various experimental groups. The liver weight is increased in 17-ethinyl estradiol treated group and ligation of bile duct group (5.6+/-0.15, P<0.001, 5.3+/-0.19 gm/100 gm body weight, P<0.001). The common features of intra-and extrahepatic cholestasis were double membrane bounded amorphous vesicular material infiltrations in the cytoplasm of hepatocyte, partial loss of microvilli of bile canaliculi, anf focal thickening of pericanalicular ectoplasm on electron microscopy. 2) Intrahepatic cholestasis induced by 17-ethinyl estradiol show significantly increased serum level of alkaline phosphatase and total bile aicd (134.0+/-16.82 IU/L, 29.5+/-4.68 umol/l). Kupffer cell proliferation and focal cytoplasmic degradation with myelin figures are characteristic features on electron microscopy. Chlorpromazine hydrochloride induced intrahepatic cholestasis show increased serum level of AST, ALT, Cholesterol and bilirubin (156.9+/-11.32, 49.0+/-2.83 IU/L, 59.3+/-6.73 mg/dl, 1.8+/-.043 mg/dl). Inflammatory cell infiltration, chiefly lymphocytes and esoinophils are seen in periportal area. Prominent vesiculation and vacuolations of smooth endoplasmic reticulum are characteristic feature on electron microscopy. 3) Extrahepatic cholestasis induced by ligation of bile duct show increase serum level of AST, ALT, GGT, cholesterol, total bile acid, and bilirubin (290.2+/-50.24, 171.5+/-47.17, 159.3+/-24.54, 33.7+/-1.47 IU/L, 86.6+/-9.18 mg/dl, 246.6+/-27.34 umol/l, 13.9+/-0.83 mg/dl). Light microscopically, morphologic alterations are feathery degeneration of hepatocytes, proliferation of bile ducts, bile infarct and prominent intracytoplasmic lipid droplets. Electron microscopically, electron dense acidophilic body, bile casts and complete loss of microvilli are seen in dilated bile canaliculi. Also noted are hypertrophy of cannalicular ectoplasm. Finely granular materials are infiltrated in degenerative cytoplasm.
Rats ; Animals

This study was performed to investigate the effect of endotoxin to the CCl4-induced liver injury. Twelve Sprague-Dawley rats were intraperitoneally injected 1.6 g/kg CCl4 as control group. Another 24 rats were orally administrated 300 mg/kg of neomycin at 16 and 3 hours prior to CCl4 injection as experimental group. Twelve among them were intraperitoneally infected 1.0 mg/kg of endotoxin(E-Coli, 0111:B4, No L-2630, lipopolysaccharide, Sigma, USA) and CCl4 simultaneously for offsetting neomycin effect. The rats were sacrificed at 1, 4, 10, and 24 hours after CCl4 injection. The liver tissues from all experimental groups were observed by light and electron microscopy. The results obtained were summarized as follows: In the CCl4 only group, the hepatocytes revealed sweling of ER and mitochondria with many lipid droplet in the cytoplasm. Focal cellular necrosis was seen at the later phase. The Kupffer cells were activated and showed many cytoplasmic processes, secondary lysosomes, and vaculoles. The endothelial cells were edematous. Several neutrophils, platelets, and microthrombi were scattered in the sinusoid. In the neomycin-CCl4-endotoxin administrated group, both hepatocytic destruction and intrasinusoidal microthrombi formation were more pronounced. In the neomycin pretreated group, the hepatocytes revealed mild cellular destruction without necrosis. There is no intrasinusoidal microthrombi. According to these results, it would be concluded that the small dosage of gastrointestinal tract-derived endotoxin affects to the liver injury caused by CCl4. The synergistic effects of CCl4 and gastrointestinal tract-derived endotoxin which can not be detoxified by damaged Kupffer cells, may be more important in the pathogenesis of CCl4-induced liver injury.
Rats ; Animals

Chronic deposition of uric acid in the kidney can lead to progressive tubulointerstitial injury with granuloma formation. We hypothesized that uric acid crystal deposition may induce granuloma formation by stimulating local expression of macrophage migration inhibitory factor(MIF), which is a known mediator of delayed type hypersensitivity(DTH). A model of acute uric acid nephropathy was induced in rats by the administration of oxonic acid (an inhibitor of uricase) together with uric acid supplements. Kidney tissue examined at 35 days showed widespread tubulointerstitial damage with intratubular uric acid crystals deposition and granuloma formation. Tubules within the areas of granuloma showed a six-fold increase in MIF mRNA compared to uninvolved areas by in situ hybridization. Moreover, the areas of increased MIF mRNA expression correlated with sites of dense accumulation of macrophages and T cells. Control rats fed a normal diet had no discernible evidence of renal disease by routine light microscopy and minimal tubular expression of MIF mRNA and protein. These data suggest that intrarenal granulomas in urate nephropathy may be the consequence of a crystal induced DTH-like reaction mediated by MIF.
Rats ; Animals

Potassium(K+) balance is achieved by the control of urinary K+ excretion and by the control of K+ absorption from the digestive tract. It has been established that chronic potassium depletion is associated with a remarkable hypertrophy of the outer medullary collecting duct of the kidney. But, there are no morphological studies regarding the intercalated cells during the chronic changes of potassium diet. Electron microscopy was performed to observe the morphological alterations of the intercalated cell of the entire collecting duct in response to chronic changes of potassium diet in rat kidney. By electron microscopy, the characteristic features of normal type A intercalated cell of the cortical collecting duct included numerous micro-projections of the apical plasma membrane, complicated basal infolding, apical cytoplasmic tubulovesicles, evenly distributed mitochondia, and centrally located nucleus. In potasium-depleted type A intercalated cell, microprojections of the apical plasma membrane were increased in length and number, basal infoldings were uncomplicated, tubulovesicles were almostly disappeared, and mitochondria were increased in number. Type A intercalated cell of potassium-loading after restriction was found to be almost normal except longer microprojections and increased mitochondria. The characteristic features of normal intercalated cell of the outer medullarycollecting duct(OMCD) included relatively short micro-projections of the apical plasma membrane, uncomplicated basal infoldings, apical cytoplasmic tubulovesicles, and apically distributed mitochondia. In comparison with normal, potassium-depleted intercalated cell of OMCD was hypertrophy, microprojections of the apical plasma membrane were increased in length and number, basal infoldings were complicated, tubulovesicles were almost disappeared, mitochondria were increased in number, and several lysosomes were appeared. Intercalated cell of OMCD of potassium-loading after restriction was found to be almost normal except increased cell size, longer microprojections, and increased mitochondria and lysosomes compared to control. The characteristic features of normal intercalated cell of the inner medullary collecting duct (IMCD) included very short and scant microprojections of the apical plasma membrane, uncomplicated basal infoldings,apica cytoplasmic tubulovesicles, evenly distributed mitochondia, and some lysosomes. In potasium-depleted intercalated cell of IMCD, cell size was prominently increased, microprojections of the apical plasma membrane were increased in length and number, basal infoldings were complicated, tubulovesicles were almostly disappeared, and mitochondria were increased in number. Intercalated cell of IMCD of potassium-loading after restriction was found to be almost normal except increased cell size and increased microprojections in number and length compared to control. These results suggest that intercalated cells adapt through morphological changes to preserve potassium balance during chronic changes of potassium diet.
Rats ; Animals

Diuretics are natriuretic agents which inhibit sodium reabsorption at their major site of action on the renal tubules and increase the excretion of sodium and combined anions. Increment of urine volume is the secondary to the natriuretic effects. Diuretic resistance occurs that threshold dose of diuretics is higher than that of other patients. It is frequently manifested among the edematous patients such as those with the nephrotic syndrome. Prolonged use of diuretics decreases the natriuretic effect of diuretics, which is called diuretic tolerance. This is important adaptations of distal nephron segment. To elucidate the mechanism of diuretic resistance, 1 mg of bumetanide was given to the nephrotic syndrome(NS) patients group and control group, respectively. The peak plasma concentration was delayed in NS patients. The proportion of urine free bumetanide for 24 hours was 73% in NS patients but 100% in control group. The ratio of urine volume and amount of Na+ and Cl - for 24 hours to the total and free urine bumetanide was decreased in NS patients. The study suggests that pharmacokinetic and pharmacodynamic changes of the diuretics induce the diuretic resistance. To determine the additive diuretic effect of albumin to the action of the furosemide, 160 mg of furosemide was administered intravenously with albumin in NS patients. Simultaneous infusion of albumin and furosemide did not enhance the diuretic effect of furosemide pharmacodynamically and pharmacokinetically. Albumin preinfusion 30 minutes before furosemide administration potentiates the diuresis, but natiuresis and pharmacokinetics were not changed. Semiquantitative immunoblotting of rat kidneys was carried out to investigate whether chronic diuretics adminstration induces changes in the abundance of Na+ transporters in distal nephron. Furosemide infusion increased cortical and outer medullary abundances of Na+-Cl- cotransporter(TSC) and all 3 subunits of the epithelial sodium channel(ENaC). Hydrochlorothiazide infusion increased abundances of some kinds of subunits of ENaC. These increases in the abundances of Na+ transporters may account for the generation of diuretic tolerance.These data suggest that to overcome the diuretic resistance or tolerance, diuretic dose increment over the threshold level and more frequent administration of the diuretics are recommended. Diuretic combinations are also proposed. Addition of albumin to augment the diuretics effect ought to be considered cautiously.
Rats ; Animals

No abstract available.
Animals ; Rats*

This study was carried out to investigate the mechanisms of interstitial pulmonary fibrosis of rats after the intratracheal administration of bleomycin. Both lungs after bleomycin injection were examined by light and electron microscopy. The results are as follows: Light microscopically, 1 or 2 weeks after bleomycin injection acute and chronic inflammatory infiltrates and edema in the interstitium and alveolar spaces were observed. Proliferation of alveolar type II pneumocytes was also found at 4 to 6 weeks after bleomycin injection, chronic inflammatory infiltrates with interstitial fibrous thickening were noted. Electron microscopically, the number of type II pneumocytes and irregular lamellar bodies were increased and blunted microvilli were noted at 2 weeks. 4 to 8 weeks, proliferation of fibroblasts with deposition of abundant collagen fibrils in the thickened interstitium revealing irregular or collapsed alveolar spaces were observed. Based on these findings, it can be concluded that bleomycin-induced interstitial pulmonary fibrosis is considered to pass from an early acute inflammation of the interstitium and alveolar spaces to an interstitial fibroblast proliferation and collagen deposition to the length of the period after injection.
Rats ; Animals

This study was performed to investigate the distribution of endotoxin in various organs after intraperitoneal injection of E. coli homogenator(0111:B4, 3X10(9)cells/200g of body weight). Sprague-Dawley rats were intraperitoneally injected with E. coli homogenator and sacrificed 1 and 3 hours after injection. The lung, liver, and kidney were immunohistochemically stained with avidin-biotin complex method and observed by light and electron microscopy. On the light microscopy, granular deposits of reaction products of immunohistochemical stain were found on the cytoplasmic membrane of endothelial cells and some of parenchymal cells of all organs observed. Electron microscopic study revealed finely granular reaction products on the surface of endothelial cells and some of parenchymal cells. The pinocytotic vesicles of endothelial cells demonstrated reaction products in the early phase of experiment. The distribution of reaction products were prominent in the liver among three organs. The Kupffer cells showed the most sensitive and strongest positive reaction. The hepatocytes and endothelial cells revealed weak positive reaction 3 hours later. The alveolar macrophages of the lung were also positive from the early phase of endotoxemia, while the pneumocytes and alveolar septa demonstrated weakly positive reaction in the later phase. The capillary endothelium of the kidney revealed positive reaction from the early phase. According to above results, it is concluded that the endotoxin entered into the systemic circulation was captured in the liver and lung. And both mononuclear phagocytic system and endothelial cells could be activated or damaged by endotoxin.
Rats ; Animals

PURPOSE: To determine whether febrile seizure enhances neuroexcitability by altering synaptic transmission and whether febrile seizure-induced hyperexcitability leads to long-lasting neuronal death. METHODS: We investigated the expression of synaptic and postsynaptic proteins and the apoptosis of neuronal cells in rat pup hippocampus after hyperthermic seizure using immunoblotting and confocal microscopy. RESULTS: Hyperthermic seizure enhanced the long-term expressions of presynaptic proteins such as syntaxin, VAMP, SNAP-25 and nSec1, whereas that of NSF was decreased. The expressions of postsynaptic NMDA receptors 1, 2a and 2b were up-regulated. The expression of postsynaptic AMPA glutamate receptors 1 month after hyperthermic seizures altered by way of increasing the ratio of GluR1 to GluR2 and decreasing NSF-GluR2 interaction, which leads to the formation of Ca2+permeable AMPA receptors and enhanced toxicity. However, in spite of enhanced neuroexcitability, there was a transient increase of neuronal death in hipocampus one week after hyperthermic seizure, but returned to baseline one month later. CONCLUSION: These results demonstrate both presynaptic and postsynaptic forms of long-term enhancement of glutamate synaptic transmission after hyperthermic seizure and support the idea that early-life febrile seizure might have persistent effects on neuronal excitability in the hippocampus.
Rats ; Animals

No abstract available.
Animals ; Rats*