Effects Of Berberine On The Expression Of MRNA And Protein Related To Nrf2-ARE Signal Pathway In Hepatic Tissue Of NAFLD Rats

Objective:To observe the effects of berberine on the expression of m RNA and protein related to Nrf2-ARE signal pathway in hepatic tissue of non-alcoholic fatty liver disease(NAFLD) rats which were made by feeding with high-fat diet. To discuss the mechanism that how berberine treat NAFLD.Methods:24 SPF SD male rats were divided randomly into 3 groups according to their weights,which were called the normal group, the model group and the treating group. The normal group was given basic feed while the other two groups were fed with high-fat diet. Besides, rats in the treating group were fed with berberine by 100mg/kg. 8 weeks later, AST, ALT, TC, TG, LDL-C and HDL-C in blood serum or liver tissue were detected. GSH-Px and NO in blood serum and liver tissue were analyzed by ELISA, while pathological changes of liver tissue were observed through HE and Oil red O staining. The expression levels of Nrf2, Keap1, HO-1, NQO1 m RNA and proteins were measured by Fluorescence quantitative PCR or Western blot.Results:1. Liver histopathologyHE staining: Liver tissue of rats in the normal group was in good structure, with clear lobular structure and normal hepatic sinus structure. Hepatic cords and sinusoids were substantially radially arranged around the central vein. Liver cells structure was of integrity with a little small fat cavitation. In contrast, hepatocytes of rats in the model group indicated severe fatty degeneration and hepatocytes swelling. Compared with the model group, fatty liver degeneration in the treating group had different degrees of improvement.Pathological sections stained with oil red O presented hepatocytes in the model group were swelling and suffused with red lipid droplets of different sizes or even fused into a chain while hepatocytes of the normal group were in neat rows with cytoplasm occasionally scattered red dye lipid drops. Lipid droplets in the treating group were significantly reduced than in model group.2. Determination of serum lipidsSerum lipids: The levels of serum TC, TG and LDL-C were significantly higher in model group while the HDL-C was lower than that in the normal group(P<0.01,P<0.05). Compared with the model group, TC, TG, HDL-C and LDL-C in the treating group improved significantly(P<0.05). The results show that there is lipid metabolism disorder in NAFLD rats and the berberine can improve it.3. Determination of ALT and AST contentIn the model group, the level of AST and AST/ ALT was higher than that in the normal group(P<0.05) while ALT increased not that obviously(P>0.05). Compared with the model group, the level of AST, AST/ ALT and ALT decreased not that significantly in the treating group(P>0.05). The elevated levels of AST and AST/ ALT demonstrated that long-term lipid metabolic disturbance could result in the damages of hepatocytes.4. Determination of oxidative stress factorThe level of GSH-Px in serum and hepatic tissue decreased outstandingly in the model group than that in the normal group(P<0.05). Compared with the model group, the level of GSH-Px increased significantly in the treating group(P<0.05). This suggests that the activation of GSH-Px were low in NAFLD rats. The level of NO in serum and hepatic tissue were higher in model group than that in the normal group(P<0.05). Compared with the model group, the level of NO reduced significantly in the treating group(P<0.05). This indicated that the berberine can protect liver by cutting the expression of NO.5.The expression levels of Nrf2、keap1、HO-1、NQO1 m RNA and proteinThe expression levels of Nrf2, NQO1, HO-1 m RNA and protein in the model group were significantly higher than that in the normal group(P<0.05). Compared with the model group, the expression levels of Nrf2, NQO1, HO-1 m RNA increased obviously in the treating group(P<0.05). However, there were no significant differences among all these groups as to the expression levels of Keap1 m RNA and protein. The results show that the berberine can up regulate the expression levels of Nrf2, NQO1, HO-1 m RNA and protein in hepatic tissue.Conclusions:1. NAFLD rats could be replicated by high-fat diet intervention for 8 weeks.2. The disorder of lipid metabolism and fatty liver degeneration exist in NAFLD rats. So does the activation of Nrf2-ARE signal pathway in hepatic tissue.3. Bererine could alleviate fatty liver degeneration and oxidative stress in NAFLD rats probably by regulating Nrf2-ARE signal pathway and oxidative stress factors. As a result, related m RNA and proteins of Nrf2-ARE signal pathway as well as oxidative stress factors may be the targets in the treatment of NASH by berberine.