Cai Yue-Qin, Zhang Li-Zong, Wang De-Jun, Chen Fang-Ming, Chen Zhi-Yun, Zhu Ke-Yan, Li Jian-Shuang, Yan Mao-Xiang
Zhejiang Chinese Medical University, Hangzhou, China.
Zhongguo Ying Yong Sheng Li Xue Za Zhi. 2014 Sep;30(5):465-70.
To explore the role of NF-E2-related factor 2(Nrf2) and its related factors in the progression of nonalcoholi steatohepatitis (NASH) by investigating the alterations of lipid metabolism and liver histopathology as well as the changes of mRNA and protein expression levels of Nrf2 and its related factors in rats during NASH progression.
Male SD rats were randomly divided into normal group and model group, which were administrated with high fat diet to establish nonalcoholic steatohepatitis model. The rats from both groups were randomly killed at the end of 4, 12 weeks respectively. The levels of alanine aminotransferase (ALT), aspartate aminotransferase (AST), total cholesterol (TC), triglyceride (TG), high density lipoprotein cholesterol (HDL-C), low density lipoprotein cholesterol (LDL-C) were detected in the serum and liver tissue; Changes in fat deposition in liver tissue were determined by oil red O staining. HE staining were used to observe the pathological changes of liver tissue and to calculate nonalcoholic fatty liver disease (NAFLD) activity score (hepatic steatosis, inflammation and ballooning degeneration of liver cells). The expression of Nrf2 in liver was detected by immunohistochemical staining. The mRNA and protein levels of Nrf2 and related factors in liver were determined by Realtime PCR and Western blot, respectively.
After 4 weeks of high fat diet, the levels of ALT, AST, TC in rat serum and TC, TG, LDL-C in liver were significantly increased compared with that of the normal group (P < 0.01, P < 0.05). After 4 weeks of high fat diet, the levels of ALT, AST, TC, TG in serum and TC, TG, LDL- C in liver increased further (P < 0.01, P < 0.05). Until the 12th week, the content of HDL-C in liver was significantly lower than that of the normal group (P < 0.05). At the end of the 4th or the 12th week, lipid droplets in the model rat liver cells were heavily dyed red and hepatic steatosis increased severely, with ballooning degeneration of liver cells. With the extension of high fat diet feeding time, fat deposition in the liver tissue, hepatic steatosis, NAFLD score, Nrl2 expression were significantly increased (P < 0.01). Expression levels of mRNA and protein of Nrf2, heme oxyenase 1(HO1), NADPH quinone oxidoreductase 1(NQO1), γ-glutamylcysteine synthethase (γ-GCS), glutathione S-transferase (GST) in the model rats increased or decreased at the end of the 4th or the 12th week differentially, (P < 0.01, P < 0.05) with the more significant changes at the end of the 4th week than the 12th week.
Nrf2 and its related factors may be involved in the occurrence and development of nonalcoholic fatty liver disease, which may play an important role in the process of NASH formation.
通过研究非酒精性脂肪性肝炎（NASH）进展过程中大鼠脂质代谢、肝脏组织病理学变化以及Nrf2及其相关因子mRNA和蛋白表达水平的变化，探讨NF-E2相关因子2（Nrf2）及其相关因子在非酒精性脂肪性肝炎进展中的作用。
将雄性SD大鼠随机分为正常组和模型组，给予高脂饮食建立非酒精性脂肪性肝炎模型。分别在4周、12周结束时随机处死两组大鼠。检测血清和肝组织中丙氨酸氨基转移酶（ALT）、天冬氨酸氨基转移酶（AST）、总胆固醇（TC）、甘油三酯（TG）、高密度脂蛋白胆固醇（HDL-C）、低密度脂蛋白胆固醇（LDL-C）水平；采用油红O染色法测定肝组织脂肪沉积变化。用苏木精-伊红（HE）染色观察肝组织病理变化并计算非酒精性脂肪性肝病（NAFLD）活动评分（肝脂肪变性、炎症及肝细胞气球样变性）。采用免疫组织化学染色法检测肝脏中Nrf2的表达。分别用实时荧光定量PCR和蛋白质免疫印迹法测定肝脏中Nrf2及其相关因子的mRNA和蛋白水平。
高脂饮食4周后，大鼠血清中ALT、AST、TC水平及肝脏中TC、TG、LDL-C水平较正常组显著升高（P<0.01，P<0.05）。高脂饮食4周后，血清中ALT、AST、TC、TG水平及肝脏中TC、TG、LDL-C水平进一步升高（P<0.01，P<0.05）。至12周时，肝脏中HDL-C含量显著低于正常组（P<0.05）。在第4周或第12周结束时，模型大鼠肝细胞内脂滴被重度染成红色，肝脂肪变性严重加重，伴有肝细胞气球样变性。随着高脂饮食喂养时间延长，肝组织脂肪沉积、肝脂肪变性、NAFLD评分、Nrl2表达显著增加（P<0.01）。模型大鼠在第4周或第12周结束时，Nrf2、血红素加氧酶1（HO1）、NADPH醌氧化还原酶1（NQO1）、γ-谷氨酰半胱氨酸合成酶（γ-GCS）、谷胱甘肽S-转移酶（GST）的mRNA和蛋白表达水平有不同程度的升高或降低（P<0.01，P<0.05），第4周结束时变化较第12周更显著。
Nrf2及其相关因子可能参与非酒精性脂肪性肝病的发生发展，在NASH形成过程中可能起重要作用。
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