Effect of Dietary Nucleotides on Degree of Fibrosis and Steatosis Induced by Oral Intake of Thioacetamide

The administration of thioacetamide in ratsinduces nodular cirrhosis of the liver, characterized byfibrous septae, parenchymal nodules, proliferation ofthe bile ducts, and excessive deposition of connective tissue elements. Nodular cirrhosis is alsoassociated with changes in lipid metabolism, as shown bythe accumulation of lipid droplets in the hepatocytecytoplasm. Adequate nutritional support during cirrhosis is important to sustain liver function andpromote recovery after the lesions have been induced.Supplementation with nucleotides may increase cellularproliferation and thus optimize hepatic recovery. The aim of this study was to investigate theeffects of dietary nucleotide supplementation on thedegree of fibrosis and steatosis in rats with livercirrhosis induced by four months of oral intake ofthioacetamide. The use of dietary nucleotides afterthioacetamide administration was found to decrease thepercentage area of fibrous septae. In animals with livercirrhosis fed the nucleotidesupplemented diet for two weeks, the total area of fibrosis was reduced.Withdrawal of the hepatotoxic agent led to a decrease inthe degree of steatosis in cirrhotic animals, which wassignificant in rats given the nucleotide-supplemented diet during a two-week recovery period. Inconclusion, dietary nucleotides may be an importantfactor in the histological recovery of damaged liver inexperimental cirrhosis.     

Influence of administration of long-chain polyunsaturated fatty acids on process of histological recovery in liver cirrhosis produced by oral intake of thioacetamide

Patients with liver cirrhosis frequently show some degree of protein-energy malnutrition and obviously require nutritional support. In this study, the treatment of rats consisted of thead libitum oral intake of a 300 mg/liter thioacetamide solution, used as drinking water for four months. Thioacetamide treatment produced a severe alteration in the plasma fatty acid profile with significant decreases of these, which mimicked changes described in human cirrhosis. This hepatotoxic agent causes nodular cirrhosis, with loss of the normal architecture of the liver and disruption of the vascular pattern. The goal of the study was to evaluate the influence of n-3 and n-6 series long-chain polyunsaturated fatty acid dietary supplementation in experimental animals and to assess the effects of those dietary components on structural recovery in the liver. Significant increases of saturated and monounsaturated fatty acids as well as n-6 polyunsaturated fatty acids were seen only in the animals given the n-6 polyunsaturated fatty acid supplemented diet. However, only rats given the standard diet exhibited some degree of histological regeneration.     

Chronic liver injury by thioacetamide and promotion of hepatic carcinogenesis

Summary To verify whether a mild, but prolonged liver injury by chemicals needing bioactivation causes both hepatic cirrhosis and the appearance of hepatocyte nodules and tumors (providing the liver has been exposed previously to initiating stimuli), diethylnitrosamine-initiated and uninitiated rats were administered thioacetamide at low dose (250 mg/l drinking water) for 6 months. Hepatocyte nodule incidence as well as changes in the drug-metabolizing system were followed at monthly intervals. In the uninitiated rats a micronodular liver cirrhosis slowly developed upon thioacetamide chronic administration; a few hepatocyte focal lesions of small size were seen from the 3rd month onward. By contrast in the diethylnitrosamine-initiated thioacetamide-treated rats the liver was macronodular because of the appearance and growth of many hepatocyte nodules; some hepatomas were also seen. During thioacetamide administration both uninitiated and diethylnitrosamine-initiated rats underwent a progressive decrease of the cytochrome P-450 liver content as well as of the activity of aminopyrine N-demethylase, ethoxycoumarin O-deethylase and ethoxyresorufin O-deethylase. On the other hand, most components of the phase II of the drug-metabolizing system were markedly enhanced. In conclusion, chronic administration of thioacetamide at low doses provided strong promoting stimuli for previously initiated hepatocytes.     

Steatosis and Collagen Content in Experimental Liver Cirrhosis Are Affected by Dietary Monounsaturated and Polyunsaturated Fatty Acids

Background and Methods: We used thioacetamide administered orally to induce cirrhosis in rats, and after these had recovered for 1 and 2 weeks we examined the effects of dietary supplementation with monounsaturated and n-3 polyunsaturated fatty acids, or with a combination of n-3 and n-6 polyunsaturated fatty acids, on the extent of steatosis and collagen content in the liver. Results: Nodular cirrhosis, increased collagen content, and lipid accumulation were established after 4 months of treatment with thioacetamide. When the animals were fed a diet rich in oleic acid for 2 weeks, the steatosis and fibrosis decreased. Supplementation with n-3 polyunsaturated fatty acids favored reductions in collagen content but did not reduce the fat accumulation. With a diet supplemented with a mixture of n-3 and n-6 fatty acids we found no reduction in either lipid accumulation or collagen content. Conclusions: Fibrosis and steatosis may be influenced by dietary fat, and monounsaturated fat appears to influence favorably the histologic recovery of the damaged liver.     

Nucleoside-nucleotide free diet protects rat colonic mucosa from damage induced by trinitrobenzene sulphonic acid.

BACKGROUND: Growing evidence suggests that intestinal recovery from injury induced by radiation, endotoxin, and protein deficiency is improved by the ingestion of nucleosides and nucleotides. AIM: This study examined the effect of dietary nucleosides and nucleotides supplementation on trinitrobenzene sulphonic acid induced colonic damage in experimental colitis. METHODS: Sprague-Dawley rats were randomised into two groups and fed nucleic acid free 20% casein diet (control) or this diet supplemented with 0.5% nucleoside-nucleotide mixture for four weeks. On the second week, colonic inflammation was induced in rats by intracolonic administration of 0.25 ml of 50% ethanol containing 25 mg of trinitrobenzene sulphonic acid. Additionally, other sets of rats were treated with 0.25 ml of 50% ethanol, 25 mg of trinitrobenzene sulphonic acid in 0.25 ml saline, or 0.25 ml of 0.9% saline. RESULTS: After two weeks, colon weight, macroscopic and microscopic damage scores, were significantly greater (p < 0.05) in the nucleoside-nucleotide supplemented group compared with the non-supplemented control groups. The same variables seen in the trinitrobenzene sulphonic acid-ethanol group fed nucleoside-nucleotide free diet were greater (p < 0.05) than in the rest of the groups fed nucleoside-nucleotide free diet and treated with ethanol, trinitrobenzene sulphonic acid in saline, or saline. Histologically, segmental ulceration and inflammation associated with significantly increased infiltration of polymorphonuclear leucocytes, macrophages, lymphocytes, fibroblasts were observed in the supplemented group compared with the controls. In the nucleoside-nucleotide supplemented group the epithelial damage, mucosal erosion, oedema, and coagulative necrosis of the muscularis propria was more extensive in comparison to the non-supplemented control groups. CONCLUSIONS: This study suggests that dietary nucleosides and nucleotides may aggravate colonic damage and inflammation in chemically induced experimental colitis in rats; and that nucleoside-nucleotide free diet combined with other pharmacological agents may offer a better response.     

Reproducible production of thioacetamide-induced macronodular cirrhosis in the rat with no mortality

BACKGROUND/AIMS: Hepatotoxin-induced rat models of liver cirrhosis are limited by the wide heterogeneity of cirrhosis produced. The present study developed a modified, reliable, and reproducible technique by which hepatic and systemic responses to thioacetamide during induction of cirrhosis were monitored by weekly weight changes. METHODS: Male Wistar rats (200-230 g) were divided into three groups. Group 1 (n=20) received continuous administration of 0.03% (w/v) thioacetamide in the drinking water for 12 weeks. Group 2 (n=20) received the same concentration of 0.03% thioacetamide as an initial concentration that was modified according to weekly weight changes in response to thioacetamide during the induction of cirrhosis. Group 3 (n=6) received normal water and served as controls. RESULTS: Mortality of Group 1 was 30% and the production of cirrhosis was only 45%. In contrast, there were no deaths in Group 2 and well-developed macronodular cirrhosis was found in 90% of the rats which was associated with significant portal hypertension, as indicated by increased portal venous pressure (13.6+/-0.4 vs. 9.1+/-0.3 mmHg, cirrhotic vs. control, respectively, P<0.01, Student's unpaired t-test). CONCLUSIONS: Variations in responses to thioacetamide can be easily monitored by weekly weight changes to reduce mortality to zero and simultaneously increase the production and quality of cirrhosis induced in rats.     

Increase in hepatocyte and nuclear volume and decrease in the population of binucleated cells in preneoplastic foci of rat liver: a stereological study using the nucleator method

Gamma-glutamyltranspeptidase-positive hepatocyte foci were produced in female rats given a single dose of diethylnitrosamine neonatally after birth and, after weaning, a diet containing phenobarbitone for 30 wk. The nucleator method, a new stereological approach, provided an efficient, unbiased estimate of mean cell volume in focal lesions and extrafocal areas. It also provided an unbiased sample of cells to estimate hepatocyte nuclear volume and the percentage of binucleated cells. The results showed an increase in the mean volume of mononucleated cells--from 4,700 micron3 in extrafocal areas to 12,700 micron2 in foci--and of binucleated cells--from 6,900 micron3 to 25,000 micron3. This demonstrated the hypertrophic effect of the carcinogenic treatment in focal lesions. A striking reduction in the proportion of binucleated cells was also observed in the preneoplastic lesions. Nuclear volume measurements from mononucleated and binucleated hepatocytes were used to assess ploidy. An apparent increase in nuclear ploidy, with no change in cellular ploidy, was noted in focal tissue when compared with nonfocal tissue. This appeared to be caused by an increase in mononucleated tetraploid cells and a reduction in binucleated cells with two diploid nuclei, indicating an altered mitotic mechanism in focal lesions. The significance of these changes in cell volume, apparent ploidy levels and binuclearity in preneoplastic foci is discussed in relation to the hepatocarcinogenic process.     

[18F]FDG accumulation in an experimental model of multistage progression of cholangiocarcinoma

Aim: The diagnosis of cholangiocarcinoma (CCA) is difficult, and due to the insidious course of the disease, most cases present at a relatively late stage. Positron emission tomography (PET), using [(18)F]fluoro-2-deoxyglucose ([(18)F]FDG) as a tracer is one the most powerful molecular imaging techniques available. We hypothesized that [(18)F]FDG accumulates at sites of early CCA development and that FDG-PET may be of value for the early diagnosis of CCA. Methods: We added 300 mg/L thioacetamide to the drinking water of rats who went on to develop CCA within 20 weeks. From eight weeks onwards, groups of three rats were injected with [(18)F]FDG, subsequently the liver was perfused, dissected and subjected to quantitative autoradiography using a phosphor imaging system. The liver sections were stained for histology, and glutathione S-transferase (GST) enzyme activity was determined. We correlated [(18)F]FDG uptake with pathological liver changes. Results: The experiments demonstrate that thioacetamide causes atypical bile ducts and invasive CCA. Rat livers harvested early after the start of administration of thioacetamide contained only cirrhosis and/or atypical bile ducts, but CCA and FDG accumulation were absent. At 20 weeks, all rats had developed CCA and all, except two animals with a very small carcinoma, had strongly elevated focal FDG uptake. Quantitative autoradiography revealed tumor-to-normal-liver ratios as high as 5:4. In all rats with a carcinoma, there was a backdrop of cirrhosis, and interestingly cirrhotic areas did not show elevated FDG accumulation. Conclusion: [(18)F]FDG accumulates in CCA, is able to distinguish CCA from liver cirrhosis, but is probably unsuitable to detect very early CCA lesions.     

低Se低VE诱导肝细胞凋亡及相关基因所起的作用

目的 研究低硒（Ｓｅ）低维生素Ｅ（ＶＥ）能否诱导大鼠肝细胞凋亡及相关基因ｐ５３、ｂｃｌ－２和ｃ－ｍｙｃ所起的作用。方法 以天然的和人工半合成的低Ｓｅ低ＶＥ饲料喂养大鼠１７周,采用末端脱氧核苷酸转移酶介导的缺口末端标记（ＴＵＮＥＬ）检测肝细胞凋亡,采用免疫组化法检测肝细胞ｐ５３、ｂｃｌ－２和ｃ－ｍｙｃ蛋白。结果 与补Ｓｅ和ＶＥ组大鼠相比,低Ｓｅ低ＶＥ组大鼠肝细胞凋亡显著增加;ｐ５３和ｃ－ｍｙｃ蛋白增     

Effect of dietary nucleotides on small intestinal repair after diarrhoea. Histological and ultrastructural changes.

The effects of specific nutrients on intestinal maturation and repair after injury are practically unknown. The purpose of this work was to study the effects of dietary nucleotides on the repair of the intestinal mucosa after chronic diarrhoea induced by a lactose enriched diet in the weanling rat. One group of weanling rats was fed with a standard semipurified diet (control group), and another group was fed with the same diet containing lactose as the only soluble carbohydrate (lactose group). After 14 days the lactose group was allowed to recover for four weeks with the control diet (lactose-control group) or with the control diet supplemented with AMP, GMP, IMP, CMP, and UMP 50 mg/100 g each (lactose-nucleotide group). The control group was divided into two subgroups, which were fed with the control diet and the nucleotide supplemented diet for the same period (control-control group and control-nucleotide group). The lactose diet induced diarrhoea after 24 hours of feeding. Two weeks later there were changes in intestinal structure with loss of enterocyte microvillar surface, significant lymphocyte infiltration, supranuclear cytoplasmic vesiculation, decreased number of goblet cells, and enlarged mitochondria with low density and few cristae. After recovery from diarrhoea, animals fed the nucleotide enriched diet showed an intestinal histology and ultrastructure closer to that of the normal control group. Mitochondrial ultrastructure was closer to normal in comparison with the lactose-control diet group. In this second group the number of goblet cells as well as the villous height/crypt depth ratio was reduced and the number of intraepithelial lymphocytes increased compared with the nucleotide supplemented group. These results suggest that dietary nucleotides may be important nutrients for intestinal repair.     

Effect of granulocyte-macrophage colony-stimulating factor on hepatic regeneration after 70% hepatectomy in normal and cirrhotic rats

BackgroundPost-hepatectomy liver insufficiency is one of the most serious postoperative problems and its prevention is important after major hepatic resection, especially in the cirrhotic liver. Some growth factors and cytokines appear to play important roles in liver regeneration. In the present study we have investigated the effects of granulocyte-macrophage colony-stimulating factor (GM-CSF) on hepatic regeneration after 70% partial hepatectomy (PH) in cirrhotic and non-cirrhotic rats.MethodsA rat model of liver cirrhosis was prepared using thioacetamide (TAA) (a dose of 20 mg/100 g body w, intra-peritoneally) on three days a week for 12 weeks. Adult male rats were divided into four groups:Group 1 (n=10) no cirrhosis and no GM-CSF; Group 2 (n=10) no cirrhosis and GM-CSF; Group 3 (n=10) cirrhosis and no GM-CSF; and Group 4 (n=10) cirrhosis and GM-CSF. All the rats underwent a 70% hepatectomy, and GM-CSF was administrated immediately after operation in Groups 2 and 4. On postoperative days 2 and 7, fresh samples from the remnant liver were obtained to evaluate its regenerative capacity.The liver regenerative process was estimated by DNA synthesis, using flow cytometry.ResultsProliferation index (PI) of hepatocytes at 48 h was higher in Group 4 rats than Group 3 rats (p<0.05). On postoperative day 7, PI was elevated in Group 3 rats compared with Group 4 rats, but this difference was not statistically significant. In non-cirrhotic rats given GM-CSF, PI was increased compared with Group 1 rats at day 2 (p<0.05), but not at day 7.ConclusionsThe findings suggest that the proliferative capacity of liver cells is impaired and delayed after 70% PH in cirrhotic rat liver. GM-CSF administration might enhance the liver PI in both normal and TAA-induced cirrhotic rats.     

Esophageal Varices in Rat Models of Liver Cirrhosis

Animal models resembling the human situation arevery useful to investigate human disease. However, therehas been no evidence of esophageal varices in rats withliver cirrhosis. In the present study, to determine whether intrahepatic portalhypertension produced by liver cirrhosis inducesesophageal varices in rats, the esophagus was examinedendoscopically in rat models of liver cirrhosis. Allrats given carbon tetrachloride or thioacetamide and sixof seven rats given a choline-deficient diet hadesophageal varices or venous dilatation after 16 weeksof treatment, although the varices in one rat given carbon tetrachloride and in two rats given acholine-deficient diet were reduced from weeks 16 to 18.These findings suggest that timing is important whenstudying esophageal varices in rat models of liver cirrhosis. It is concluded that certain modelsof liver cirrhosis in rats could be used as models ofesophageal varices due to intrahepatic portalhypertension.     

Intimal hyperplasia following carotid endarterectomy in an insulin-resistant rat model

Hyperhomocysteinemia, a known risk factor for cardiovascular disease, results in an elevation of intimal hyperplasia (IH) following a carotid endarterectomy (CEA) in a rat model. An exaggerated IH response following CEA has been observed in rats with dietary induced hyperhomocysteinemia. Type 2 diabetics often present with hyperhomocysteinemia and are at higher risk for developing vascular blockage following surgical procedures. To determine if insulin resistance increases IH risks following endarterectomy, the 3 goals of this study were: (1) to establish plasma homocysteine concentrations in dietary induced insulin-resistant rats and their controls, (2) to investigate whether a positive correlation of IH and plasma homocysteine response occurs following CEA in the insulin-resistant rat model, and (3) if so, to attempt to decrease IH by supplementation with folic acid, a known enzymatic cofactor in the homocysteine metabolic pathway. To achieve these aims, male rats (275 to 300 g) were fed 1 of 4 diets for a 4-month period: (1) high-fat sucrose (HFS), (2) low-fat complex carbohydrate (LFCC), (3) HFS + 25 mg/kg folic acid (HFS+F), or (4) LFCC + 25 mg/kg folic acid (LFCC+F). At the end of the 4-month period the rats underwent an open (non-balloon) unilateral CEA. Two weeks post-endarterectomy, blood, liver and carotid tissue were removed to measure plasma insulin, folic acid, and homocysteine, 2 key enzymes of homocysteine metabolism-methylenetetrahydrofolate reductase (MTHFR) and cystathionine beta-synthase (CBS)-and percent lumenal stenosis (IH%). Computer-assisted morphometric analysis was used to measure the percentage of IH in the carotid artery. Plasma homocysteine was significantly higher in the HFS group when compared with the LFCC group (11.3+/-1.3 micromol/L v 7.4+/-0.6 mircomol/L, P=.008) as was post-endarterectomy IH producing lumenal stenosis (30.7%+/-4.2% v 14.0%+/-4.3%, P=.008). Plasma insulin in the HFS group was higher than the LFCC (control) group and was significant (36.3+/-3.0 microU/mL v 21.1+/-0.8 microU/mL, P=.0004). Folic acid supplementation in the HFS group resulted in reductions of plasma homocysteine (HFS v HFS+F, 11.3+/-1.3 micromol/L v 7.95+/-1.0 micromol/L, P=.02) and post-endarterectomy IH (HFS v HFS+F, 30.7%+/-4.2 % v 10.4%+/-1.6%, P=.0001). The control or LFCC group was not statistically different from the HFS+F group in homocysteine or IH. Folate supplementation did not decrease insulin concentrations in the HFS+F group compared to the LFCC group. We conclude that the HFS diet produced an insulin-resistant state with an elevated plasma homocysteine and an exaggerated IH response following carotid endarterectomy in this rat model. Dietary folate supplementation reduced plasma homocysteine concentrations in the HFS diet, which implicates hyperhomocysteinemia as an etiologic factor in the development of post-CEA IH in this insulin-resistant rat model.     

Modulation of rat gastric mucosal prostaglandin E2 release by dietary linoleic acid: effects on gastric acid secretion and stress-induced mucosal damage

We studied chronic intake of diets deficient in or supplemented with linoleic acid to determine whether it affects gastric acid secretion, release of prostaglandin E2, and stress-induced lesions. For 8-10 wk rats were fed three dietary regimens supplying 3.5% (control group), 0.3%, and 10% of total calories as linoleic acid. We found that diets deficient in linoleic acid (0.3%) reduced release of prostaglandin E2 into the gastric lumen (-77%) and increased basal (+133%) and pentagastrin-stimulated acid secretion (+93%) and the area of cold restraint-induced gastric mucosal lesions (+280%), when compared with the control group. Diets supplemented with linoleic acid (10%) increased prostaglandin E2 release into the gastric lumen (+106%) and reduced basal (-44%) and pentagastrin-stimulated acid secretion (-78%) and the area of cold restraint-induced mucosal.lesions (-80%). Prevention of these lesions by the 10% linoleic acid diet was confirmed by quantitative histology. Pretreatment with indomethacin (8 mg/kg intraperitoneally) abolished the effects of the 10% linoleic acid diet on prostaglandin formation, acid secretion, and mucosal injury. We conclude that in rats chronic intake of dietary linoleic acid reduces acid secretion and prevents cold restraint-induced mucosal lesions, possibly because of augmented synthesis of endogenous prostaglandins in the gastric mucosa.     

Protective effects of dietary enrichment with docosahexaenoic acid plus protein in 5-fluorouracil-induced intestinal injury in the rat

OBJECTIVE: The intestinal side effects of anti-tumoural therapy can be so severe as to preclude its clinical efficacy, although the use of selected nutrients and growth factors may ameliorate the noxious effects. This study examines whether dietary supplementation with the polyunsaturated fatty acid docosahexaenoic acid (DHA) potentiates the protective action of growth hormone in the intestine and whether a synergetic effect occurs with dietary protein and DHA enrichment and growth hormone treatment. METHODS: Male Wistar rats were divided into nine groups and received a standard diet, or a diet supplemented with protein, or a diet supplemented with DHA, or a diet supplemented with both protein and DHA. Three days later, the rats were given 5-fluorouracil (5-FU) and treated with either growth hormone or placebo. A further group of animals fed a standard diet was not treated and served as a control group. Intestinal morphometry, proliferation and apoptosis were determined. RESULTS: Supplementing the diet with DHA prevented the negative action of 5-FU on mucosal morphometry, but protein supplementation was necessary to prevent the increased apoptosis. When growth hormone was also given with the dietary supplementation, the hypoproliferative effect of 5-FU was also prevented. CONCLUSION: Enriching the diet with DHA protects against intestinal lesions produced by the anti-tumoural drug 5-FU but requires the joint administration of supplementary protein and growth hormone to reduce the noxious effects of 5-FU.     

Role of insulin in the stimulation of renal 25-hydroxyvitamin D3-1 alpha-hydroxylase by phosphorus deprivation in rats

The increase in serum 1,25(OH)2D concentration in response to dietary phosphorus (P) depreviation is dependent on the presence of insulin in rats. The present study was undertaken to clarify whether insulin exerts its effects by affecting the renal production of 1,25(OH)2D. The 25(OH)D-1 alpha-hydroxylase activity in kidney homogenates was markedly stimulated by P deprivation in control rats (0.20 +/- 0.06 pmol/g tissue/min in the rats on a normal P diet v 1.3 +/- 0.15 pmol/g/min in the rats on a low P diet; 6.5-fold increase). In contrast, in streptozotocin-diabetic rats, the increase in the renal 1 alpha-hydroxylase activity in response to P deprivation (0.25 +/- 0.01 pmol/g/min; 3.6-fold increase) as well as the enzyme activity in the rats on a normal P diet (0.07 +/- 0.01 pmol/g/min) was markedly suppressed. Furthermore, all the changes in the renal 1 alpha-hydroxylase activity in insulin-deficient rats disappeared by insulin replacement (0.16 +/- 0.01 pmol/g/min in the rats on a normal P diet v 1.3 +/- 0.01 pmol/g/min in the rats on a low P diet; eightfold increase). These results demonstrate that the stimulation of 1 alpha-hydroxylase in response to dietary P deprivation is blunted by insulin deficiency and is fully restored by insulin replacement. It is suggested that insulin, in addition to its direct stimulatory effect on 1 alpha-hydroxylase, alters the responsiveness of renal 1 alpha-hydroxylase to P deprivation. These effects of insulin on 1 alpha-hydroxylase may be responsible for the change in serum 1,25(OH)2D concentration in response to dietary P deprivation, although the possibility cannot be ruled out that insulin also affects the metabolic clearance of 1,25(OH)2D.     

Fermented mushroom milk-supplemented dietary fibre prevents the onset of obesity and hypertriglyceridaemia in Otsuka Long-Evans Tokushima fatty rats

AIM: Fermented milk product containing edible mushroom water extracts (mushroom yogurt; MY) has been reported to have glycaemic control and triglyceride-lowering effects in streptozotocin (STZ)-induced diabetic rats and Zucker diabetic fatty (ZDF) rats. Here, we investigated how MY-supplemented dietary fibre (10 and 20%, v/w) influences the onset of obesity and hypertriglyceridaemia in Otsuka Long-Evans Tokushima fatty (OLETF) rats. METHODS: The OLETF rats were fed a powdered chow diet supplemented with MY at the levels of 10 (v/w) and 20% for 6 weeks from 10 weeks of age, but the OLETF control rats were not supplemented. Their weight, fat distribution and lipid profile have been determined. RESULTS: The body weights in MY-fed rats were reduced compared with the control rats. The perirenal fat was decreased in both MY groups, but the visceral and epididymal fats reduced only in the MY 20% group. The concentrations of serum triglyceride and non-esterified fatty acid in MY-fed rats were decreased in a dose-dependent manner. However, the levels of other serum lipid profiles [total cholesterol, low-density lipoprotein cholesterol, and high-density lipoprotein cholesterol] were comparable among all rats. CONCLUSION: Anti-obesity and triglyceride lowering by MY-supplemented dietary fibre in OLETF rats might have resulted from the synergistic effect of components in the fermented mushroom-milk product.     

Expression of growth hormone receptor and its mRNA in hepatic cirrhosis

AIM: To investigate the expression of growth hormone receptor (GHR) and mRNA of GHR in cirrhotic livers of rats with the intension to find the basis for application of recombinant human growth hormone (rhGH) to patients with liver cirrhosis.METHODS: Hepatic cirrhosis was induced in SpragueDawley rats by administration of thioacetamide intraperitoneally for 9-12 weeks. Collagenase Ⅳ was perfused in situ for isolation of hepatocytes. The expression of GHR and its mRNA in cirrhotic livers was studied with radio-ligand binding assay, RT-PCR and digital image analysis.RESULTS: One class of specific growth hormone-binding site, GHR, was detected in hepatocytes and hepatic tissue of cirrhotic livers. The binding capacity of GHR (RT, fmol/mg protein) in rat cirrhotic liver tissue (30.8±1.9) was significantly lower than that in normal control (74.9±3.9) at the time point of the ninth week after initiation of induction of cirrhosis (n=10, P＜0.05), and it decreased gradually along with the accumulation of collagen in the process of formation and development of liver cirrhosis (P＜0.05). The number of binding sites (×10 4/cell) of GHR on rat cirrhotic hepatocytes (0.86±0.16) was significantly lower than that (1.28±0.24)in control (n= 10, P＜0.05). The binding affinity of GHR among liver tissue, hepatocytes of various groups had no significant difference (P＞0.05). The expression of GHR mRNA (riOD,pixel) in rat cirrhotic hepatic tissues (23.3±3.1) was also significantly lower than that (29.3±3.4) in normal control (n=10, P＜0.05).CONCLUSION: The growth hormone receptor was expressed in a reduced level in liver tissue of cirrhotic rats,and lesser expression of growth hormone receptors was found in a later stage of cirrhosis. The reduced expression of growth hormone receptor was partly due to its decreased expression on cirrhotic hepatocytes and the reduced expression of its mRNA in cirrhotic liver tissue.     

Different effects of short- and long-term dietary choline-deficiency on hepatic microsomal phospholipids and drug oxidation

Prolonged administration of a choline-deficient diet to male rats results in the development of hepatic cirrhosis and alterations in oxidative drug metabolism. The present study was designed to assess whether the changes in drug metabolism were related to the development of cirrhosis or merely to the effects of choline-deficiency on hepatic microsomal lipid composition. Male rats were given a synthetic choline-deficient diet for either 1 week (short-term) or 30 weeks (long-term), and results at each time were compared with age-matched control rats given the same diet but with supplementary choline.
After both 1 week and 30 weeks of the choline-deficient dietary regimen, the proportion of microsomal phospholipid present as phosphatidylcholine was significantly decreased, and that present as phosphatidylethanolamine was significantly increased, compared with appropriate controls. However, microsomal cholesterol content (per mg of microsomal protein) was not significantly changed at either time. Cytochrome P-450 levels and the turnover of ethylmorphine N -demethylase (enzyme activity/nmol cytochrome P-450) were significantly reduced in the cirrhotic (30 week) model whereas short-term intake of the diet did not alter the levels of cither enzyme. These findings suggest that the effects of changes in phosphatidylcholine and phosphatidylethanolamine levels in choline-deficiency cirrhosis have minimal importance with respect to changes in drug oxidation. Instead, altered regulation of specific cytochrome P-450 isozymes appears to be the principal cause of impaired oxidation.