Objective To investigate the involvement of sirtuin 1（SIRT1）-uncoupling protein 2（UCP2） pathway in the development of non-alcoholic fatty liver disease and whether berberine exerts its effects by regulating this pathway. Methods Male SD rats were divided into three groups： normal control group, high-fat diet group, and berberine supplement group. The rats in the normal control group were given normal diet while the rats in the other two groups were fed with high-fat diet. Rats in the berberine supplement group were concurrently given berberine（100 mg/kg body weight） once daily. After 16 weeks, the levels of serum, liver lipids, and serum aminotransferase were measured using an automatic biochemical analyzer. Superoxide dismutase（SOD） activity and malondialdehyde（MDA） content in the liver were measured using commercial kits. Histopathological changes of liver tissues were observed by hematoxylin and eosin（HE） staining and Oil Red O staining. The hepatic m RNA and protein levels of SIRT1 and UCP2 were assayed by reverse transcription polymerase chain reaction（RT-PCR） or Western blotting. Results Berberine supplement could significantly decrease the serum and liver lipid contents in rats fed with high-fat diet. Meanwhile, SOD level was significantly elevated, but MDA level was reduced in the liver. The results of HE and Oil Red O staining showed that the hepatic steatosis was alleviated in berberine supplement group. Furthermore, berberine induced an increase in SIRT1 expression but a decrease in UCP2 expression. Conclusion The regulation of hepatic SIRT1-UCP2 pathway may be an important mechanism by which berberine exerts the beneficial effects in NAFLD rats.
OBJECTIVE:To investigate effects of the extracts from soothing-liver and invigorating-spleen formulas on the injury due to oxidative stress,mediated by the Nuclear factor-like 2(Nrf2)-Antioxidant response element(ARE) pathway,in the hepatocytes of rats with non-alcoholic fatty liver disease(NAFLD) induced by high-fat diet.METHODS:Soothing-liver and invigorating-spleen formula mixtures were prepared for five groups:normal,model,soothing-liver formula group(SLG),invigorating-spleen formula group(ISG),integrated formula group(IG).The rat model of NAFLD was induced by feeding rats a high-fat diet(HFD).After 16 weeks,the hepatic tissue was examined following Haematoxylin-Eosin(H&E) staining and with Transmission electron microscopy(TEM).Levels of hepatic lipids,serum lipids and hepatic functions were measured using a biochemical analyser.Hepatocytes were isolated from the livers of rats and were identified by cellar immunohistochemistry,cellular immunofluorescence and flow cytometry.The expression levels of Nrf2,Kelch-like epichlorohydrin-associated protein 1(Keap-1),haeme oxygenase-1(HO-1) and NAD(P)H:quinone oxidoreductase 1(NQO1) m RNAs were assessed by real-time fluorescence quantitative PCR.Nrf2,Keap-1,HO-1 and NQO1 proteins were measured by Western blotting.Finally,the levels of oxidative stress factors Superoxide Dismutase(SOD),malonaldehyde(MDA) and Glutathione peroxidase(GSH-Px) in hepatocytes were measured by WST-1,TBA and colorimetry.RESULTS:The H & E and TEM results showed that the NAFLD model rats successfully reproduced typical pathogenetic and histopathological features.The liver function and levels of hepatic lipids and serum lipids from the model rats were dramatically increased.Compared with the model group,the levels of hepatic lipids,serum lipids and hepatic function in the treatment groups were ameliorated to different degrees.The yields of purified hepatocytes in each rat were 4-5 × 108.The viability of the isolated hepatocytes was higher than 95%,with a purity over 93.2%.Cellular immunohistoche
