thromboxane-b2 and Fatty-Liver

Steatosis accentuates the severity of hepatic ischemia-reperfusion injury (IRI). 3-Hydroxy-3-methylglutaryl-coenzyme A reductase inhibitors ("statins") protect the heart and brain against post-ischemic injury, without necessarily lowering serum cholesterol. We tested whether 10-day or 1-day atorvastatin administration protects livers with fatty change or non-alcoholic steatohepatitis (NASH) against IRI.. Mice with dietary or genetic simple steatosis (SS) or NASH were subjected to 60 min of partial hepatic ischemia/24-h reperfusion, with/without atorvastatin administered with food (5 mg/kg body weight) for 10 days, or injected intravenously (5 mg/kg) 24 h before ischemia. Liver injury, Toll-like receptor-4 (TLR4), cytokines/chemokines, endothelial nitric oxide synthase (eNOS), activation and thromboxane B2 production were determined.. Atorvastatin conferred 70-90% hepatic protection against IRI in obese animals with SS or NASH, in which IRI was accentuated twofold to fivefold. IRI markedly upregulated TLR4 and activated nuclear factor-κB (NF-κB); atorvastatin abrogated these effects, as well as activating eNOS. Atorvastatin dampened the post-ischemic induction of thromboxane B2, macrophage inflammatory protein-1a, monocyte chemotactic protein-1, tumor necrosis factor-α, interleukin (IL)-12 p40, γ-interferon, IL-6, and adhesion molecules (vascular cell adhesion molecule-1, E-selectin, vascular endothelial-cadherin), and reduced macrophage and neutrophil recruitment. There was no reduction in serum cholesterol that could explain these effects, and hepatic cholesterol was normal in these mice. A single 24-h injection of atorvastatin conferred equivalent hepatoprotection.. Statins exert major hepatoprotection against IRI in lean, fatty, and NASH livers that is not due to cholesterol removal. Rather, statins downregulate TLR4 to prevent NF-κB activation, with resultant suppression of adhesion molecules, chemokines/cytokines, and thromboxane B2 production. Short-term statin treatment is an effective, readily-available preventive agent against hepatic IRI, irrespective of obesity and fatty liver disease.

Topics: Administration, Oral; Animals; Atorvastatin; Cell Adhesion Molecules; Cytokines; Cytoprotection; Disease Models, Animal; Down-Regulation; Drug Administration Schedule; Enzyme Activation; Fatty Liver; Heptanoic Acids; Hydroxymethylglutaryl-CoA Reductase Inhibitors; Injections, Intravenous; Liver; Male; Mice; Mice, Obese; NF-kappa B; Nitric Oxide Synthase Type III; Non-alcoholic Fatty Liver Disease; Obesity; Pyrroles; Reperfusion Injury; RNA, Messenger; Thromboxane B2; Time Factors; Toll-Like Receptor 4

To investigate the dynamic changes of plasma levels of prostacycline (PGI2) and thromboxane A2 (TXA2) and their relationship with the severity of hepatic injury in rats with nonalcoholic fatty liver disease (NAFLD).. We established a NAFLD model, with a fat-rich diet consisting of 10% lard oil + 2% cholesterol, which was given to Sprague-Dawley rats (n=48) for a period of 8, 12, 16 and 24 weeks. The other rats were fed standard diets and were used as normal controls (n=24). At sacrifice, liver pathology scores were evaluated and plasma levels of PGI2, its stable metabolic product 6-keto-PGF1 alpha and TXA2, and TXB2 were determined by radioimmunoassay.. Simple fatty livers were observed in the model group at 8 weeks. From 12 weeks to 24 weeks, the livers gradually progressed from simple steatohepatitis to liver fibrosis. Plasma levels of TXB2 in the model group increased higher than in the control group after 8 weeks [(52.4+/-3.15) ng/L vs (41.1+/-1.45) ng/L] and continued to increase over time, with the highest levels at 24 weeks [(117.7+/-7.47) ng/L]. A strong positive correlation (r=0.537) was seen between plasma TXB2 levels and the severity of liver injury. Plasma 6-keto-PGF1 alpha concentrations decreased in the model group in comparison with the control group after 8 weeks [(31.1+/-1.62) ng/L vs (36.5+/-1.68) ng/L] and continued to decrease over time, with the lowest concentrations at 24 weeks [(3.4+/-2.43) ng/L t=3.77]. A negative correlation was shown between the 6-keto-PGF1 alpha level and the severity of the liver injury.. A rat model of NAFLD was established successfully by feeding a fat-rich diet for 24 weeks. In this model, the imbalance of plasma PGI2 and TXA2 levels (increased TXB2 and decreased 6-keto-PGF1 alpha levels) may play a role in the pathogenesis of experimental NAFLD.

Topics: 6-Ketoprostaglandin F1 alpha; Animals; Epoprostenol; Fatty Liver; Liver; Male; Rats; Rats, Sprague-Dawley; Thromboxane A2; Thromboxane B2