| Budget Amount *help |
¥4,010,000 (Direct Cost: ¥3,500,000、Indirect Cost: ¥510,000)
Fiscal Year 2007: ¥2,210,000 (Direct Cost: ¥1,700,000、Indirect Cost: ¥510,000)
Fiscal Year 2006: ¥1,800,000 (Direct Cost: ¥1,800,000)
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| Research Abstract |
We generated a hepatocyte-specific null mutation of Pten in mice (Pten KO mice) and established these mice as a model of human NASH.
In vitro experiment, we added hydrogen peroxide to overnight cultured Pten KO hepatocytes. Although hepatocytes viability decreased to 20% 1h after exposure to hydrogen peroxide, preincubation of NAC improved hepatocytes viability to about 80%. Although ROS level of hepatocytes increased about 3 times over compared to that of hydrogen peroxide-unexposured group 1h after exposure to hydrogen peroxide, preincubation of NAC decreased ROS to the same level as that of hydrogen peroxide-unexposured group. Moreover mitochondrial injury were suppressed after addition of NAC.
In vivo experiments, to test whether N-acetyl-cystein (NAC), eicosapentaenoic acid (EPA), Ursodeoxycholic acid (UDCA), agents for improving lipid metabolism or for anti oxygen are effective for NASH, we have administered them to Pten-deficient mice for 70 weeks just after weaning. At 40 and 70
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weeks, improvement of steatohepatitis and hepatic tumor were observed by macroscopic and microscopic findings. At 10 and 40 weeks, biochemical analysis, the quantitative analysis of lipids and fatty acids composition contained in the liver, serum reactive oxygen species (ROS) and the hepatic expression of molecules related with lipogenesis or elimination of ROS such as SREBP1c were examined. Moreover phosphorylation of ERK and Akt were performed by Western blot analysis.
NAC improved hepatitis by reducing ROS. EPA and UDCA improved steatosis by decreasing expression of SREBP1c. Moreover they reduced onset of hepatic tumor by inactivating ERK and change of the ratio of stearic acid to oleic acid. EPA and UDCA also reduced hepatitis by elimination of ROS. Moreover EPA controls expression of SREBP1c by increasing of AMPK α 1.
We concluded the effects of NAC, EPA, UDCA are all related with ROS elimination however the effective points are different. Accordingly, we propose mixed therapy of these agents are effective of human NASH. Less
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