Effects of gomisin A on hepatocarcinogenesis by 3'-methyl-4-dimethylaminoazobenzene in rats.

We examined the effects of gomisin A on tumor promotion in the liver after a short-term feeding of 3'-methyl-4-dimethylaminoazobenzene (3'-MeDAB) to rats, compared with the effects of phenobarbital. Male Donryu rats were fed ad libitum a diet containing 0.06% 3'-MeDAB and 0.03% or 0.01% gomisin A or water containing 0.05% phenobarbital. Gomisin A and phenobarbital did not cause any proliferative and neoplastic lesions by themselves in 40 weeks of feeding. Altered foci in the liver increased with a peak at 12 weeks after the rats were fed 3'-MeDAB. Gomisin A decreased the number of hepatic altered foci such as the clear cell and basophilic cell type foci in the early stages. Phenobarbital enhanced neoplastic alterations so that the number and size of the foci were much larger in the phenobarbital-combined group than in the 3'-MeDAB-control group. Thus, phenobarbital acted as a promoter of cells initiated by 3'-MeDAB; on the other hand, gomisin A showed a weak suppressive effect on tumor promotion.     

The effect of gomisin A on immunologic liver injury in mice

The hepatoprotective effect of Gomisin A (TJN-101), which is a lignan compound isolated from Schizandra fruits, was studied on three immunologic liver injury models in mice. The first liver injury model was produced by the injection of anti-basic liver protein (BLP) antibody into DBA/2 mice which had been previously immunized with rabbit IgG (RGG). Other models were effected by injection of anti-liver specific protein (LSP) antibody into DBA/2 mice or by the injection of bacterial lipopolysaccharide (LPS) into ddY mice pretreated with Corynebacterium parvum (C. parvum). TJN-101 inhibited the elevation of transaminase (GOT and GPT) activities and showed the tendency to inhibit the histopathological changes of the liver in all models. Moreover, TJN-101 inhibited deoxycholic acid-induced release of transaminase from cultured rat hepatocytes in vitro, but did not affect the formation of hemolytic plaque forming cells in immunized mice spleens and hemolytic activity of guinea pig complement in immunohemolysis reaction. These results, therefore, suggested that the hepatoprotective effect of TJN-101 could be related to the protecting effect of hepatocyte plasma membrane rather than the inhibiting effects of the antibody formation and complement activity.     

Protective effect of verapamil on multiple hepatotoxic factors-induced liver fibrosis in rats.

The purpose of the present work was to investigate the effect of verapamil on liver fibrosis induced by multiple hepatotoxic factors in rats. Male Wistar rats were divided into a normal control group, a liver fibrosis model control group, and verapamil groups with different dosages. Multiple hepatotoxic factors including carbon tetrachloride (CCl(4)), ethanol and high cholesterol were used to make the animal model of liver fibrosis. The parameters of serum l-alanine aminotransferase (ALT), liver malondialdehyde and hydroxyproline contents were measured. Samples of the liver obtained by biopsy were subjected to histological and immunohistochemical studies for the expressions of alpha-smooth muscle actin (alpha-SMA) and transforming growth factor-beta(1) (TGF-beta(1)). Results showed that verapamil induced a dose-dependent decrease of serum ALT, liver malondialdehyde and hydroxyproline compared with liver fibrosis model control. Verapamil reduced hepatocyte degeneration and necrosis, and delayed the formation of liver fibrosis. The levels of expression of alpha-SMA and TGF-beta(1) in the hepatic tissue of three of the verapamil-treated groups were significantly less than those of the liver fibrosis model control group. The results showed that verapamil acts against the formation of liver fibrosis, the mechanism might be due to a protective effect for hepatocytes and through decreasing TGF-beta(1) to block the activation of hepatic stellate cells (HSCs) and collagen gene expression.     

Effects of gomisin A on vascular contraction in rat aortic rings

Gomisin A (GA) is an active ingredient of the fruits of Schisandra chinensis which has been widely used as a tonic in traditional Korean medicine. GA induces not only endothelium-dependent but also endothelium-independent relaxation in an isolated rat's thoracic aorta. This study was aimed to investigate the molecular mechanism by which GA induces endothelium-independent vasorelaxation. Rat aortic rings were denuded of endothelium, mounted in organ baths, and subjected to contraction or relaxation. We measured the amount of GTP RhoA as well as the phosphorylation level of 20 kDa myosin light chains (MLC??), myosin phosphatase-targeting subunit 1 (MYPT1) and protein kinase C-potentiated inhibitory protein for heterotrimeric myosin light-chain phosphatase of 17 kDa (CPI17). Pretreatment with GA dose-dependently inhibited the concentration-response curves in response to sodium fluoride (NaF) or thromboxane A(2) agonist U46619, but not to phorbol 12, 13-dibutyrate (PDBu). GA decreased the activation of RhoA as well as the phosphorylation level of MLC??, MYPT1(Thr???), and CPI17 induced by 8.0 mM NaF or 30 nM U46619. However, K+ channel blockers such as glibenclamide, apamin, or charybdotoxin did not affect the vascular relaxation induced by GA. Furthermore, GA did not affect the level of phosphorylation of CPI17 induced by PDBu. GA reduces vascular contraction through inhibition of RhoA/Rho-kinase pathway in endothelium-denuded rat aorta.     

Effects of gomisin A, a lignan component of Schizandra fruits, on experimental liver injuries and liver microsomal drug-metabolizing enzymes

Effects of oral administration of gomisin A, one of the components isolated from Schizandra fruits, on liver injuries induced by CCl4, d-galactosamine and dl-ethionine and on liver microsomal drug-metabolizing enzyme activities were investigated. Gomisin A suppressed the increase of serum transaminase activities and the appearances of histological changes such as degeneration and necrosis of hepatocyte, inflammatory cell infiltration and fatty deposition in each type of liver injury. The repeated administration of gomisin A (30 or 100 mg/kg, p.o., daily for 4 days) induced an apparent increase of liver weight in liver-injured and normal rats. Gomisin A decreased serum triglyceride and lipid contents of the liver in biochemical studies. Increases of microsomal cytochrome b5 and P-450, elevations of NADPH cytochrome C reductase, aminopyrine N-demethylase and 7-ethoxycoumarin O-deethylase activities and decrease of 3,4-benzo(a)pyrene hydroxylase activity per cytochrome P-450 were observed after the administration of gomisin A. In addition, gomisin A was found to enhance the incorporation of 14C-phenylalanine into liver protein and to shorten the hexobarbital-induced sleeping time. These changes caused by gomisin A were similar to those by phenobarbital. However, gomisin A is distinctly different from phenobarbital in the finding that phenobarbital lessened the survival ratio of CCl4-intoxicated mice, but gomisin A did not. Our observation suggest that gomisin A shows an antihepatotoxic action by oral application and also has hypolipidemic (mainly triglyceridemic) and liver protein synthesis-facilitating actions and that the enlargement of the liver seen with gomisin A is the adaptive hypertrophy which is due to the induction of drug-metabolizing enzymes.     

吲哚-3-原醇对复合因素所致肝纤维化大鼠的治疗作用及部分机制研究

目的观察吲哚-3-原醇(I3C)对复合因素诱导肝纤维化大鼠的治疗作用并探讨其可能机制。方法采用复合因素(CCl4、酒精、高脂低蛋白饲料)制备大鼠肝纤维化模型,用I3C治疗10 d后,检测大鼠肝组织的羟脯氨酸(Hyp)、超氧化物歧化酶(SOD)、丙二醛(MDA)的含量;通过HE及Mas-son三色染色,观察肝脏病理学改变及胶原含量改变;免疫组化法观察肝脏中α-平滑肌肌动蛋白(α-SMA)的表达;West-ern blot检测肝组织中基质金属蛋白-2(MMP-2)的表达。结果与模型对照组比较,I3C治疗组肝组织Hyp含量降低,SOD活性升高,以大剂量(12 mg.kg-1)组明显(P<0.01),MMP-2蛋白表达升高;病理学改变尤其是胶原纤维的沉积明显减轻(P<0.05),α-SMA表达也降低。结论 I3C可促进复合因素所致大鼠肝纤维化模型的恢复,其机制与降低肝组织氧化应激、减少活化HSC数量以及促进基质胶原降解有关。     

Effects of calcium channel blocking agents on calcium and centrilobular necrosis in the liver of rats treated with hepatotoxic agents

Carbon tetrachloride, chloroform, dimethylnitrosamine, thioacetamide or acetaminophen was each administered to rats in a single hepatotoxic dose. Nifedipine, verapamil or chlorpromazine was administered in association with the hepatotoxic agents to determine if calcium channel blocking agents would prevent an increase in liver cell calcium associated with hepatotoxicity and to determine if these agents would protect against the development of centrilobular necrosis. Following a latent period different for each toxic agent, a 4- to 18-fold increase in liver cell calcium content had occurred by 24 hr. The calcium increase and the centrilobular necrosis (mean histologic score) were correlated. A relatively high calcium to necrosis ratio was obtained with dimethylnitrosamine, thioacetamide and acetaminophen. A lesser calcium to necrosis ratio was obtained with chloroform and carbon tetrachloride, the two toxic agents that destroyed the intracellular calcium sequestration activity of the liver endoplasmic reticulum. Nifedipine or chlorpromazine, administered prior to and 7 hr after the toxic agent, completely prevented the centrilobular necrosis caused by thioacetamide, carbon tetrachloride and acetaminophen; almost completely prevented necrosis with dimethylnitrosamine; and provided partial protection against chloroform toxicity. Two doses of verapamil provided partial protection against necrosis when carbon tetrachloride was the toxic agent and provided almost complete protection with dimethylnitrosamine. A reduction in liver cell calcium was associated with the protective action of the three calcium channel blocking agents. These findings are compared with earlier studies of the protective effects of calcium channel blocking agents in cardiac ischemia.     

Effect of gomisin A (TJN-101), a lignan compound isolated from Schisandra fruits, on liver function in rats

TJN-101 [+)-(6S, 7S, R-biar)-5,6,7,8-tetrahydro-1,2,3,12-tetramethoxy- 6,7-dimethyl-10,11-methylenedioxy-6-dibenzo [a, c] cyclooctenol) is one of the lignan compounds isolated from Schisandra fruits. When TJN-101 was administered orally at the doses of 3-100 mg/kg/day for 4 days, bile secretion, hepatic excretion of dye or hepatic hemodynamics 24 hr after the last dose was investigated in comparison with the phenobarbital (100 mg/kg/day)-treated group. Bile flow was dose-dependently increased; in contrast, biliary concentration of bile acids was decreased in TJN-101 (30 and 100 mg/kg/day)-treated groups. Similar changes were also observed in the phenobarbital-treated group. These results suggested that the enhancement of bile secretion caused by TJN-101 or phenobarbital was due to an increase of a bile acid-independent fraction. In the bromosulfophthalein (BSP) clearance test for liver function, both TJN-101 (30 and 100 mg/kg/day) and phenobarbital accelerated the disappearance from the blood and biliary excretion of BSP. Hepatic hemodynamics was examined by the hydrogen clearance method and measurement of liver wet and dry weight. Liver blood flow tended to increase in the TJN-101 (10-100 mg/kg/day) or phenobarbital-treated group. On the other hand, TJN-101 (3-100 mg/kg/day) or phenobarbital hardly altered the water content of the liver. These results suggested that the liver enlargement caused by both compounds was not accompanied with hepatic edema and that the enhancement of bile secretion or hepatic excretion of BSP might be related to an increase of liver blood flow.     

Investigations into the effects of various hepatotoxic compounds on urinary and liver taurine levels in rats

The effect of various hepatotoxicants on urinary taurine and urinary creatine has been studied in the rat. Several hepatotoxic agents, carbon tetrachloride, thioacetamide, galactosamine and allyl alcohol which all caused hepatic necrosis (sometimes accompanied by steatosis), resulted in a rise in urinary taurine and in some cases creatine, when administered to rats. Ethionine and hydrazine also raised urinary taurine but caused only steatosis and did not raise urinary creatine. Therefore urinary taurine and possibly creatine may be useful markers of liver injury and dysfunction. Liver taurine levels were also affected by some of the hepatotoxicants but in those cases where there was a rise in urinary taurine this could not be accounted for by the loss in liver taurine. It is suggested that the increase in urinary taurine is partly due to changes in protein synthesis and hence in sulphur amino acid metabolism caused by hepatotoxic agents. However, bromobenzene did not increase urinary taurine and-naphthylisothiocyanate and lithocholate caused reduced levels. It is suggested that this lack of increase in urinary taurine may be due to depletion of glutathione or interference with the biliary system.     

The role of liver antioxidant system in predisposition of rats to hepatotoxic effect of ethanol

A new methodological approach capable of revealing factors responsible for the susceptibility of rat liver to ethanol hepatotoxicity has been developed. Using the correlation, dispersion, iteration, multifactor regression, and canonical analyses, a relation was established between the initial state of the liver antioxidant system and the character and degree of the subsequent ethanol-induced damage. In particular, it was found that intact animals with initially low level of reduced glutathione and retinols in the liver, as well as those with enzymopathy of cytosol HDNB-glutathione-8-transferase, are more susceptible to the ethanol liver damage.     

内南五味子木脂素戈米辛J对肝线粒体膜脂质过氧化和超氧阴？…

目的　研究来自内南五味子的戈米辛J对脂质过氧化的影响和清除超氧阴离子自由基 (O·2 )的能力。方法　采用离体大鼠肝线粒体膜的脂质过氧化模型和黄嘌呤氧化酶 鲁米诺化学发光法。结果　戈米辛J象VitE一样能剂量依赖性抑制Fe2 VitC和ADP/NADPH所致的脂质过氧化 ;戈米辛J的IC50 分别为 5 75 ( 95 %可信限 :5 42～ 6 11)和0 95 ( 0 14～ 6 5 4) μmol·L-1。VitE的IC50 分别为 74 8( 30 2～ 185 3)和 6 5 1( 0 13～ 319) μmol·L-1。戈米辛J抑制Fe2 VitC和ADP/NADPH所致的脂质过氧化的作用比VitE的作用分别强 13倍和 6 8倍。戈米辛J也剂量依赖地抑制黄嘌呤 黄嘌呤氧化酶 鲁米诺化学发光 ,其抑制发光强度 5 0 %的浓度 (IC50 )为 2 18 2 2 μmol·L-1。结论　戈米辛J具有抑制OH·诱导的脂质过氧化和清除O·2 的作用     

Limited hepatotoxic potential of acrylonitrile in rats

The possible hepatotoxicity of acrylonitrile (ACN) was investigated based on reports of decreased hepatic glutathione in rats and liver abnormalities in man after exposure to ACN. Male and female rats pretreated po daily for 3 days with sodium phenobarbital (400 μmol/kg) or with Aroclor 1254 (300 μmol/kg) were given ACN (50, 75, 100, or 150 mg/kg) po for 1, 2, or 3 days, or 100 or 500 ppm ACN in drinking water for 21 days. Rats were killed 30 min or 24 hr after one dose of ACN or on Day 22 in the subacute study. Hepatic nonprotein sulfhydryl (NP-SH) concentration and the activities in serum of sorbitol dehydrogenase (SDH) and transminase (GPT) were measured. The liver was examined grossly and microscopically. Hepatic NP-SH decreased significantly (39, 60, 74, and 81%) at 30 min after 50, 75, 100, or 150 mg ACN, respectively. In some experiments serum SDH was significantly elevated (approximately fourfold) 24 hr after 150/mg/kg ACN. Pretreatment with phenobarbital and Aroclor 1254 resulted in only a slight enhancement of the ACN-induced elevation in serum SDH or GPT activities. Serum SDH increased 60% in rats given 500 ppm ACN in drinking water. Focal superficial necrosis of the liver associated (p < 0.001) with hemorrhagic gastritis of a distended forestomach was found in rats necropsied 24 hr after administration of 150 mg/kg ACN. Other than this superficial necrosis, light microscopy revealed only minor changes in liver tissue. Electron microscopy disclosed no changes in the organelles of hepatocytes of rats treated for 21 days with ACN.     

Effects of acrolein on macrophage functions in rats

Male Sprague-Dawley rats were exposed to 0.1, 1.0 or 3.0 ppm acrolein or filtered air 6 h/day, 5 days/week for 3 weeks. Rats were tested one day following the last exposure and exhibited no change in pulmonary clearance of inhaled 35S-labeled Klebsiella pneumoniae at any acrolein concentration. Decreased numbers of peritoneal cells were obtained from exposed rats while the number of cells lavaged from the lungs was unchanged. Macrophages of acrolein-exposed rats had altered phagocytic and enzymatic patterns as compared to macrophages from animals breathing filtered air. However, these changes had no apparent effect on macrophage killing of inhaled bacteria and were therefore probably not indicative of extreme chemical toxicity.     

内南五味子木脂素戈米辛J对肝线粒体膜脂质过氧化和超氧阴离子自由基的作用

目的　研究来自内南五味子的戈米辛J对脂质过氧化的影响和清除超氧阴离子自由基 (O·2 )的能力。方法　采用离体大鼠肝线粒体膜的脂质过氧化模型和黄嘌呤氧化酶 鲁米诺化学发光法。结果　戈米辛J象VitE一样能剂量依赖性抑制Fe2 + VitC和ADP/NADPH所致的脂质过氧化 ;戈米辛J的IC50 分别为 5 75 ( 95 %可信限 :5 42～ 6 11)和0 95 ( 0 14～ 6 5 4) μmol·L-1。VitE的IC50 分别为 74 8( 30 2～ 185 3)和 6 5 1( 0 13～ 319) μmol·L-1。戈米辛J抑制Fe2 + VitC和ADP/NADPH所致的脂质过氧化的作用比VitE的作用分别强 13倍和 6 8倍。戈米辛J也剂量依赖地抑制黄嘌呤 黄嘌呤氧化酶 鲁米诺化学发光 ,其抑制发光强度 5 0 %的浓度 (IC50 )为 2 18 2 2 μmol·L-1。结论　戈米辛J具有抑制OH·诱导的脂质过氧化和清除O·2 的作用     

实验性急性胆管梗阻对大鼠肝功能的影响

目的　观察急性胆管梗阻早期大鼠肝功能的变化 ,为临床治疗胆管梗阻提供依据。　方法　利用Wistar大鼠制成胆管梗阻模型 ,于胆管梗阻前及梗阻术后 0 .5、1及 2小时测定血清丙氨酸转氨酶 (ALT)、γ 谷氨酰转肽酶 (GGT)、碱性磷酸酶 (ALP)、总胆汁酸 (TBA)、总胆红素 (TBIL)、直接胆红素 (DBIL)及δ 胆红素 (δ BIL)的含量。　结果　胆管梗阻后0 .5小时大鼠血清中ALT、GGT、TBA、TBIL、DBIL及δ BIL水平即明显升高 (P <0 .0 1) ,并与梗阻时间的长短相关 (P <0 .0 5 ) ,而ALP 2小时后才升高。　结论　急性胆管梗阻半小时即可出现肝功能的变化 ,提示梗阻早期即可出现肝脏的损害     

实验性急性胆管梗阻对大鼠肝功能的影响

目的观察急性胆管梗阻早期大鼠肝功能的变化,为临床治疗胆管梗阻提供依据.方法利用Wistar大鼠制成胆管梗阻模型,于胆管梗阻前及梗阻术后0.5、1及2小时测定血清丙氨酸转氨酶(ALT)、γ-谷氨酰转肽酶(GGT)、碱性磷酸酶(ALP)、总胆汁酸(TBA)、总胆红素(TBIL)、直接胆红素(DBIL)及δ-胆红素(δ-BIL)的含量.结果胆管梗阻后0.5小时大鼠血清中ALT、GGT、TBA、TBIL、DBIL及δ-BIL水平即明显升高(P＜0.01),并与梗阻时间的长短相关(P＜0.05),而ALP 2小时后才升高.结论急性胆管梗阻半小时即可出现肝功能的变化,提示梗阻早期即可出现肝脏的损害.     

Effects of bisphenol A given neonatally on reproductive functions of male rats

Male Sprague-Dawley rats (Crj:CD (IGS) were treated neonatally with bisphenol A (BPA) to evaluate effects on reproductive parameters. Animals were given BPA subcutaneously in corn oil to dosages of 0.002-97 mg/kg body weight, or 0.9 mg/kg 17beta-estradiol (E2) once a day from postnatal day (PND) 0 to PND 9. Preputial separation, copulatory rate, fertility rate, sperm analysis, serum testosterone levels, and gene expression in the testis were assessed. Males in the E2 group showed a decrease in testis weight and alterations of estrogen-mediated gene expression in the testis on PND 10, and by PND 150 incomplete preputial separation, decreases in the copulatory rate, testicular and accessory organ weights and number of sperm. In contrast, males in all BPA groups showed normal reproductive parameters. These results indicate that in male rats, BPA given during the neonatal period neither affected reproductive function nor evoked estrogen-mediated gene responses in the testis.     

Studies on the metabolic fate of gomisin A (TJN-101). I. Absorption in rats]

Gomisin A (TJN-101) is one of the lignan components isolated from Schisandra Fruits and expected to have some efficacies in clinical treatment of hepatitis. The serum concentrations of TJN-101 and Met. B, which was identified as a demethylenated substance and one of the major metabolites of TJN-101 in rats, were investigated. After intravenous administration at doses of 1.6, 4.0 and 10 mg/kg of body weight, the serum concentration of TJN-101 decreased biphasically, and the terminal elimination half-life at each dose was about 70 min. Dose-dependency was observed for the area under the concentration-time curve (AUC). On the other hand, the serum concentration of TJN-101 increased rapidly and reached maximum within 15 to 30 min when administered orally. This result was supported by the in situ roop method. The Cmax and the AUC values were not exactly dose-dependent, but the values increased with a dose-up of TJN-101. The biotransformation of TJN-101 to Met. B, was very rapid in both intravenous and oral administrations. The AUC value of Met. B after oral administration of TJN-101 at a dose of 1.6 mg/kg was relatively larger than any other dosages. It suggested that TJN-101 was extensively underwent the first pass effect in rats. More than 80% of TJN-101 was bound with rat serum protein in vitro and in vivo. Therefore, it seems to be necessary to pay attention when it was administered concurrently with high protein binding drugs.