Effect of ursodeoxycholic acid on in vivo and in vitro toxic liver injury in rats

Chronic administration of ursodeoxycholic acid decreases portal pressure in rats with biliary cirrhosis

Liver cirrhosis is characterized by increased IHR (intrahepatic resistance) and lipid peroxidation, and decreased antioxidative defence. The present study investigates the effects of administration for 1 month of the antioxidant UDCA (ursodeoxycholic acid) in BDL (bile-duct-ligated) cirrhotic rats. Splanchnic haemodynamics, IHR, hepatic levels of TBARS (thiobarbituric acid-reacting substances), GSH (glutathione), SOD (superoxide dismutase) activity, nitrite, PIIINP (N-terminal propeptide of type III procollagen) and collagen deposition, histological examination of liver, mRNA expression of PIIIP-alpha1 (type III procollagen) and TGF-beta1 (transforming growth factor-beta1), protein expression of TXS (thromboxane synthase) and iNOS (inducible NO synthase), and TXA2 (thromboxane A2) production in liver perfusates were measured. The results showed that portal pressure and IHR, hepatic levels of PIIINP, hepatic collagen deposition, mRNA expression of PIIIP-alpha1 and TGF-beta1, protein expression of iNOS and TXS, and production of TXA2 in liver perfusates were significantly decreased in UDCA-treated BDL rats. The increased levels of hepatic GSH and SOD activity and decreased levels of TBARS and nitrite were also observed in UDCA-treated BDL rats. In UDCA-treated BDL rats, the reduction in portal pressure resulted from a decrease in IHR, which mostly acted through the suppression of hepatic TXA2 production and lipid peroxidation, and an increase in antioxidative defence, leading to the prevention of hepatic fibrosis.

Liver delivery of NO by NCX-1000 protects against acute liver failure and mitochondrial dysfunction induced by APAP in mice

1. NCX-1000, (3alpha, 5beta, 7beta)-3,7-dihydroxycholan-24oic acid[2-methoxy-4-[3-[4-(nitroxy)butoxy]-3-oxo-1-propenyl]phenyl ester, is a nitric oxide (NO)-derivative of ursodeoxyxholic acid (UDCA) that selectively release NO in the liver. 2. Here, we demonstrated that administering mice with 40 micromol kg(-1) NCX-1000, but not UDCA, improves liver histopathology and reduces mortality caused by 330 micromol kg(-1) APAP from 60 to 25% (P<0.01). Administration of NCX-1000, in a therapeutic manner, that is, 2 h after acetaminophen (APAP) intoxication reduced mortality, improved liver histopathology and prevented liver IFN-gamma, TNF-alpha, Fas/Fas ligand and inducible nitric oxide synthase (iNOS) mRNA accumulation caused by APAP. 3. In vitro exposure of primary cultures of mouse hepatocytes to APAP, 6.6 mm, resulted in apoptosis followed by necrosis. Loss of cell viability correlates with early mitochondrial membrane potential (Deltapsi(m)) hyperpolarization followed by depolarization and cytochrome c translocation from mitochondria to cytosol. APAP-induced apoptosis associated with procaspase-3 and -9 cleavage, appearance of truncated Bid and activation of poly(ADP-ribose) polymerase (PARP). 4. Treating primary culture of hepatocytes with 5 microm cyclosporine and 10 microm trifluoperazine for eight resulted in significant reduction of apoptosis induced by APAP suggesting that loss of Deltapsim was mechanistically involved in apoptosis induced by APAP in vitro. 5. NCX-1000, but not UDCA, concentration-dependently (ED(50)=16 microm) protected against Deltapsi(m) depolarization and reduced transition from apoptosis to necrosis caused by 6.6 mm APAP. 6. Treating primary cultures of hepatocytes with the NO-donor DETA-NO, 100 microm, reduced apoptosis induced by APAP and prevented caspase activation. 7. In conclusion, NCX-1000 is effective in protecting against APAP-induced hepatotoxicity when administered in a therapeutic manner. This protection may involve the inhibition of apoptosis and the maintenance of mitochondrial integrity.

Gene therapy for gastric cancer: A review

Gastric cancer is common in China, and its early diagnosis and treatment are difficult. In recent years great progress has been achieved in gene therapy, and a wide array of gene therapy systems for gastric cancer has been investigated. The present article deals with the general principles of gene therapy and then focuses on how these principles may be applied to gastric cancer.

Effect of ursodeoxycholic acid on prostaglandin metabolism and microsomal membranes in alcoholic fatty liver

The aim of the present study was to evaluate the effect of ursodeoxycholic acid (UDCA) on prostaglandin and fatty acid metabolism and the possible relation of these substances to the development of alcoholic fatty liver in rats. The effects of UDCA (40 mg/kg/day, 30 days) were studied in rats pair-fed a high-fat diet (52% of calories as fat) with daily ethanol (4 g/kg/day, 30 days) intragastric intubation. The livers of ethanol-treated animals were characterized by fatty dystrophy. Liver triglyceride and cholesterol ester contents and the activities of serum marker enzymes, alanine aminotransferase and gamma-glutamyltransferase, were significantly increased. Ethanol enhanced phosphoinositol and sphingomyelin content in liver microsomes and lowered prostaglandin E(2) (PGE(2)) concentration in the liver. An increase in the percentage of monoenoic fatty acids and a decrease in the n-6 acid family in liver phospholipids, linoleoyl-CoA desaturase, and PGE(2) synthase activities in liver microsomes were observed in ethanol-treated rats. Treatment with UDCA improved liver morphologic characteristics, decreased triglyceride and cholesterol ester contents, increased the PGE(2) level, and normalized linoleoyl-CoA desaturase and PGE(2) synthase activities, as well as phospholipid and fatty acid patterns in the liver. The activities of the serum marker enzymes were decreased in the ethanol- and UDCA-treated group. Ursodeoxycholic acid lowered the viscosity of the microsomal membrane, as assessed by both fluorescence probe techniques and the saturated/unsaturated fatty acid ratio. We propose that the hepatoprotective effect of UDCA in alcoholic fatty liver is related to the stabilization of microsomal membranes, the prevention of a decrease in essential fatty acids and PGE(2) in the liver, and, probably, an improvement in biochemical processes controlled by PGE(2).

Effect of ursodeoxycholic acid on biochemical parameters, hepatocyte proliferation and liver histology in galactosamine hepatitis in the rat

The effect of oral administration of ursodeoxycholic acid (UDCA) on biochemical parameters, liver histology and liver cell proliferation was investigated in rats with galactosamine hepatitis. Treatment with UDCA led to a decrease of aminotransferases, but did not show any significant changes in liver histology or liver cell proliferation. The improvement of liver enzymes without change of histology in this animal model of hepatitis following treatment with UDCA is in agreement with results obtained from clinical trials with UDCA in patients with chronic viral hepatitis.