| The NF-E2-related Factor 2 (Nrf2) was shown to protect from ROS-and toxin-induced tissue damage through its capacity to induce the expression of antioxidant proteins and detoxifying enzymes.A central role in the defence against oxidative stress is attributed to Nrf2 through reducing durg-induce hepatotoxicity, liver fibrosis and inflammation,inhibiting the chemical carcinogenesis,and has related to hepatocellular apoptosis.Therefore, the further study on the change of expression of Nrf2 at different phase of nonalcoholic fatty liver disease(NAFLD) in this experiment offer a new clue for preventing and treating NAFLD.Objective The mice model of NAFLD for studying was set up by feeding female km mice with high-cholesterin and high-fat diet, then observing the difference of expression of Nrf-2 and blood plasma 8-iso-prostaglandinF2a between the mice model group and the control group, to investigate the role of Nrf2 in liver inflammatory damage induced by oxidative stress, and to offer a new clue for preventing and treating NAFLD.Methods1. Establishment of the fatty liver model of mice:twenty-six healthy female KM mice were randomly divided into two groups:control group(n=10)was fed with normal diet; model group(n=16)was fed with high-fat diet after the mice were fed one week normally.All mice were free to drink, eat and feed in coops in animal experimental lab,where temperature was 20～25℃,light and dark were equally 12 hours.2. Histopathology detected by HE staining:Five of control-group's mice and eight of model-group's mice were sacrificed at the end of 8w and 12w.Fasting during the previous night, the mice were anesthetized by celio-injection of 10% cholral hydrate solution(0.3ml/100g weight).The liver were picked off and weighed, then the liver was fixed by 10% formalin solution for the purpose of pathologic slices for light microscope.3. Liver fuction detected by serum:The blood were got from the pericardium,and the samples of serum were isolated to test the level of serum alanine aminotransferase (ALT),triglyceride(TG), cholesterol (CHOI), total bilirubin (TBIL), glucose(GLU) by7170-AHITAC.4. The level of 8-iso-prostaglandinF2a:the level of 8-iso-prostaglandinF2a was detect by ELISA.5. The expression of Nrf2:the expression of Nrf2 was detected by immunohistochemistry.Results1.Histopathology studied by microscope:In the control group, constitution of hepatic tissue was clear and Integrity, constitution of hepatic lobules was normal, central veins was big and had thin paries.Hepatic cells were polygon which were arranged in hepatic cord, which were distributed as radial around central veins. As for the mice in 8W model group,they have unclear edge of hepatic lobules and disordered arrangement of hepatic cord; major part of the hepatic sinus disappeared; majority of the hepatic cells appeared fatty degeneration,lipid droplet vacuoles(fatty degeneration)in different sizes and numbers were visible inside the cytoplasm,specially in the area around the lobules. As for the mice in 12W,the hepatic cells became extremely swollen and formed round shape; lipid droplet vacuoles(fatty degeneration)in different sizes and numbers were visible inside the cytoplasm, and sometimes the lipid droplets merged together and squeezed the nucleus to the cell side, which made it look very similar with fatty cells; the rest of the hepatic cells had focal necrosis and hepatic interstitials had no fibrosis changes.2 Compared with control group:in 8W and 12W group, the liver wet weight, liver index, serum alanine aminotransferase,cholesterol, glucose increased obviously(P<0.01), serum triglycerid, total bilirubin exhibited no difference. 3. In the normal hepatic cells of control group, the expression of Nrf2 was lower in few hepatic cell cytoplasm.The expression of Nrf2 was higher in damaged hepatic cell cytoplasm in 8w model group, and was hyperexpress in 12w model group. Compared with control group, model group induced an obvious up-regulation of Nrf2 both in 8w and 12w(p<0.05).Furthermore, Compared with 8w model group, the expression of Nrf2 was statistically higher in 12w model group(P<0.05).4. Compared with control group, the level of 8-iso-prostaglandinF2a was statistically higher both in 8w and 12w model group. (P＜0.05).Conlusionl.By feeding with high lipid food, NAFLD model were made in mice successfully. The method of making model is convenient and easily succeed, so it is an ideal method.2. Simple fatty liver and steatohepatitis were observed in model group that was fed with high-fed diet, the development of NAFLD was intimate associated with metabolic disturbance of glucolipid, inflammation damage and oxidative stress. The level of 8-iso-prostaglandinF2a increased and the expression of Nrf2 up-regulated, indicate that it may protect liver from inflammation damage induced by oxidative stress with the development of NAFLD.
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