OBJECTIVE: The acidic saline animal model of pain has been suggested to mimic fibromyalgia (FM). In this model, repeated intramuscular (IM) injections of acidic saline produce a widespread hyperalgesia that persists without evidence of significant peripheral tissue damage or inflammation, and is believed to be centrally maintained. We examined the changes of pain-related neurotransmitters in specific brain regions of this model after deep-sea water (DSW) drinking. METHODS: Rats were injected with 100microliter of acidic saline (pH 4.0) at days 0 and 5 into the left gastrocnemius muscle. Control rats received identical injections of physiological saline (pH 7.2) on the same schedule. Two acidic saline rats were given DSW from 1 week following the last IM injection to sacrifice. All rats were sacrificed on day 20. All regions of interest were examined for the changes of pain-related neurotransmitters with immunohistochemistry. RESULTS: Preliminary results showed that compared to controls, acid injected rats demonstrated strong expression of serotonin in red and raphe nucleus. Acid injected rats showed significant reductions of the serotonin expression in red and raphe nucleus after DSW drinking. CONCLUSION: IM acid injections increased the expression of serotonin in red and raphe nucleus of rats. The overwhelming reduction of serotonin expression in the nuclei after DSW drinking suggests DSW might be helpful for pain and anxiety. These preliminary data support the validity of acidic saline treatment as a model of FM, and provide a foundation for future analyses of specific brain regions that contribute to this syndrome.
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Diaphragm is though to play the most role in breathing and has a substantially greater proportion of slow oxidative and fast glycolytic fibers, and low proportion of fast oxidative fibers. The respiratory muscle, diaphragm, has the functional characteristics of slow speed of contraction, high resistance to fatigue and the ability to respond to intermittent ventilatory loads, for example of exercise. In the present study, the characteristics of the metabolism (depletion and repletion) of glycogen and the structural changes of diaphragm during depletion and repletion of glycogen were observed in rats. For comparison, the red gastrocnemius muscle which has a greater proportion of fast oxidative glycolytic (FOG) and slow oxidative (SO) fibers, and low proportion of fast glycolytic (FG) fiber, was also studied. The glycogen concentration of diaphragm in overnight fasted rats was 2.30+/-0.14mg/gm wet weight. The values of glycogen concentration at 60, 90 and 120minutes of treadmill exercise loaded rats was significantly decreased compared to that of the overnight fasted rats. There was no significant difference among the glycogen concentration of diaphragm at 60, 90 and 120minutes of exercises. The glycogen concentration of diaphragm was decreased to 1.12+/-0.17 from 2.30+/-0.14mg/gm wet weight by treadmill exercise. The glycogen depletion rats of diaphragm during exercise was faster than that of red gastrocnemius in both of the first 60minutes and 120minutes duration of exercise. The glycogen repletion of diaphragm after intragastric glucose administration by stomach tube was studied in control and exercise groups. The glycogen concentration was significantly increased after glucose administration in both of the control and exercise groups. All of the concentration of exercise group at 60, 120 and 180minutes after glucose administration was significantly higher than those of control group. In conclusion, one of the characterics of diaphragm in glycogen metabolism is fast glycogen depletion during exercise, and slowness of glycogen repletion after glucose ingestion in rats.
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Amiodarone, an antiarrhythmic drug, may exert pulmonary toxicity in some patients but the pathogenesis is not clear. This study was carried out to investigate the pathogenetic mechanism of pulmonary injury induced by amiodarone at dose of 100 mg/kg/day given to rats by intraperitoneal injection for 3 weeks. And the preventive effects of concomitantly injected steroid (10 mg/kg/day) on amiodarone induced pulmonary injury was also studied using bronchoalveolar lavage, light microscopy and transmission electron microscopy. The results obtained were summarized as follows: Mild lymphocytosis of bronchoalveolar lavage fluid was found in all experimental groups. Intracytoplasmic lamellar body formation was found in all types of pulmonary cells and type II pneumocytes revealed the earliest abnormal lamellar body formation. The capillary endothelial cells showed cellular swelling and detachment from underlying basement membrane at early phase of experiment and the edema of alveolar wall and interstitium were noted. Interstitial fibrosis and proliferation of type II pneumocytes were noted at late phase. The lungs of steroid injected groups revealed accumulation of lamellar bodies in all types of pulmonary cells but interstitial fibrosis was not occurred. These findings support the concept that amiodarone is responsible for a drug-induced phospholipidosis and directly toxic to pulmonary endothelial and epithelial cells. And steroid may regress the progression of amiodarone induced pulmonary injury.
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The purpose of this study was to investigate the inhibitory role of vitamin A with respect to activation of Ito cells in fibrosis of the rat liver induced by common bile duct ligation(CBDL). The liver was examined by immunohistochemical staining for a-smooth muscle actin,the known marker of activated Ito cells, and light and electron microscopy after CBDL andCBDL with intraperitoneal injection of retinoic acid (Sigma, USA) 1 mg/Kg in 3 times per week. The results were sumrrlerized as follows: After CBDL, the bile ductules were markedly proliferated in the periportal areas extending toterminal hepatic veins. Interstitial fibrosis and inflammatory cell infiltration appeared, however,cholestasis was minimal. Retinoic acid treatment with CBDL decreased bile ductular proliferationand interstitial fibrosis compared to CBDL only. After CBDL, proliferated and activated Ito ceIs showing positive reaction in smooth muscle actin were present in the periductular andperisinusoidal areas, and areas of increased interstitial fibrosis. Activated ito cells weredecreased in number after CBDL with vitamin A treatment. Electron microscopically,intracytoplasmic fat droplets and the cytoplasmic processes of Ito cells were decreased afterCBDL. Myofibroblasts were frequently appeared in the interstitial fibrosis after CBDL. But,intracytoplasmic fat droplets of Ito cells were well preserved, and myofibroblasts were found lessfrequently after CBDL with vitamin A treatment. The results suggest that vitamin A plays an inbitory role in the activation and fibrogenesis ofIto cells after CBDL.
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Ultrastructural study of the effects of amiodarone on the liver tissue was performed. Rats were fed with amiodarone containing diet and were sacrificerd at 1st, 3rd, 4th, 5th and 8th weeks of experiment. Charateristic lisosomal inclusion bodies were appeared form first week, which were more prominent and increased in size at the 5th and 8th week of experiment. These inclusion bodies were found in hepatocytes, Kupffer cells, bile duct epithelial cells and fibroblasts but most prominent in hepatocytes. The lysosomal inclusion bodies could be divided into four types; those characterized by (1) dense bodies with packed crystaloid contents, (2) multilamellated bodies, (3) irregular shaped bodies with varying electron density and 4. dense bodies containing stacks of fine membranous structures. All types were found in all experimental groups. But the type 1 and 2 were predominent at early stage, while type 3 and 4 were more prominent at later stage According to these findings, the formation of the lysosmal inclusion body was a characteristic change in derangement of phospholipid metabolism. And amiodarone could induce disturbance of phospholipid metabolism in all kinds of cells in liver tissue.
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The enhancing potential of anatoxin a (AFB1) and D-galactosamine (DGA) on development of preneoplastic glutathione S-transferase placental form positive (GST-P+) hepatic foci was examined using an in vivo mid-term assay system based on two-stage concept of hepatocarci-nogenesis. Rats were initially given a single dose (200 mg/kg) of diethylnitrosamine (DEN) intraperi-toneally, and thereafter. with an interval of 2 weeks, AFBl at a graded concentration (0.06, 0.012, 0.0024, 0.00048, and 0.000096 mg/kg i.g.) and DGA (100 mg/kg i.p.) were administered for 6 weeks and then sacrificed. All rats were subjected to a two-thirds partial hepatectomy to induce a potent growth stimulus to DEN-altered hepatocytes at the week 3. The modifying potential was scored by comparing the number and the area (mm2) per cm2 of GST-P+ foci in the liver with those of the corresponding control group given DEN alone. AFBl (at a graded concentration between 96 ng/kg and 60 microgram/kg) exerted a strong promoting effect oil induction of GST-P+ foci with both the number and the area. The logarithmic dose of AFBl and the potency to promote hepatocarcinogenesis were in dose-dependent relationship. DGA, a known necrogenic chemical to cause periportal necrosis and stimulate hepatocellular proliferation. also revealed the increase in the area of GST-P+ foci. although its enhancing potentia1 was 1ess profound than that of AFBl. The results suggest that DGA is also a useful proliferative stimulus m improve the medium-termdetection of unknown carcinogens.
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This study was carried out to investigate the light and electron microscopic findings of the livers of rats after an intraperitoneal injection of cadmium chloride. The Sprague-Dawley rats were intraperitoneally injected with cadmium chloride dissolved in water, once a day for three days. These animals were sacrificed at 1, 3, 8, and 24 hr after the last injection. Control groups of the rats were also sacrificed in the same manner. The liver was extirpated and examined by both light and electron microscopy. The results obtained are as follows: The parenchyma of the liver shows focal neutrophilic infiltration and spotty necrosis. The hepatocytes show fatty change, ballooning degeneration, swelling of the endoplasmic reticulum and mitochondria, increase numbers of secondary lysosomes and residual bodies. Focal patic venules and sinusoids of the liver are congested. The Kupffer cells are increase in number. Therefore, it can be concluded that the cadmium is directly acted to hepatocytes resulting in cellular injuries and deposits in the fat droplets of the cytoplasm of the hepatocytes, not Ito cells as previously suggeted.
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To investigate the microvascular changes in primary pulmonary hypertension, the lungs of 24 Sprague-Dawley rats were treated by an intraperitoneal injection of 2% monocrotaline(MCT) solution and then examined with scanning electron microscopy(SEM) after microvascular corrosion casting. Histologic examination revealed significant medial thickening in the small to medium-sized pulmonary arteries. Scanning electron microscopic findings of the normal lungs showed two kinds of microvascular structures. One showed a well-fortned three-dimensional basket structure of uniform flat-tubular alveolar capillaries, which were connected to each other in a T or Y shape or at right angles. The other revealed a two-dimensional reticular sheet of round tubular branches mainly in the bronchial artery-supplying regions. The MCT-treated groups(remodelling) showed apparent changes in both kinds of microvasculatures in comparison to the normal group but the more prominent change was found in Lbe bronchial artery microvasculature showing the dense thick encasement around large pulmonary arteries. Alveolar microvasculature of the pulmonary artery revealed individually enlarged angular appearance, with generally deformed alveolar architecture. Quantitatively, the significant enlargement of diameter and intercapillary distance appeared in both microvasculatures of MCT-induced rat lungs, but the density was increased only in the bronchial artery microvasculature. In conclusion, our three-dimensional microvascular study of the MCT-treated rat lungs demonstrates a new morphologic finding of vascular remodeling in primary puhnonary hypertension, which is thought to play an important vascular role in the pathogenesis in addition to interstitial fibrosis.
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To investigate the tubular major histocompatibility complex(MHC) expression and inflammatory phenotypes in tubulointerstitial nephritis, Lewis rats were inununized with azobenzen-earsonate-tyrosine in complete Freund adjuvant and challenged either foot pad or kidney, either by subcapsular injection or by ex vivo perfusion. The rats were sacrificed 2, 3, 5, 10 and 15 days after antigenic challenge. Foot pad swelling was significant at the antigenic challenge site (151.8 vs 6.8 x 10(-2) mm) at 24 hours. Tubulointerstitial nephritis was induced by both methods and the inflammatory infiltrate which first appeared on day 2, became prominent at day 5, then gradually subsided in ex vivo perfused rats, while inflannnation started on day 3 in subcapsular injected rats. The major site of inflammation was in the cortex and outer stripe of the outer medulla, with predominance of mononuclear cells throughout the course. The inflammatory cells showed mainly OX8 and ED1 positivity with OX19, W3/25 and CD5 positivity in minority. RT1B expression was diffuse in the cytoplasm of proximal tubules at day 2 and 5. These results suggest the involvement of cell mediated immunity in this experimental model, and the possibility that tubular epidielial cells process antigen and then become targets in immune injury.
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Although there have been many reports about the importance of the spleen's role in hepatic fibrogenesis, the exact mechanism is still uncertain. The author designed this study to evaluate splenic function on hepatic fibrogenesis. The degree of hepatic fibrosis and the population of splenocyte subsets were studied in the experimental animal model with fibrosis produced by injecting normal swine serum intra-peritoneally into Sprague-Dawley rats. The animals were divided into three groups; group A was subjected to injection of swine serum only, group B swine serum and complete Freund's adjuvant and group C swine serum and cyclosporin A. The experimental hepatic fibrogenesis by swine serum was augumented by coinjection with the adjuvant and inhibited by cyclosporin A. The study of the splenocyte subset revealed increased percentages of spienic B cell and CD4+ cell and a decreased percentage of CD8+ cell, and these changes of splenocyte subset were also augumented by the adjuvant and inhibited by cyclosporin A. The percent of monocytes was not significantly altered, although a tendancy of early decrease by the adjuvant was noted.
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