动态观察非酒精性脂肪肝大鼠肝脏ChREBP的表达

Expression of carbohydrate response element binding protein in livers of rats with non-alcoholic fatty liver disease

目的观察非酒精性脂肪性肝病(NAFLD)模型大鼠肝脏糖类应答元件结合蛋白(ChREBP)mRNA的动态表达情况,探讨ChREBP在大鼠NAFLD发病中的作用。方法随机将48只大鼠分为正常对照组(C组)和模型组(M组),分别给予普通饲料和高脂饮食喂养,于第4,8和12周末,测定大鼠血清肿瘤坏死因子α(TNF-α)、游离脂肪酸(FFA)、甘油三酯(TG)、总胆固醇(TC)以及肝组织匀浆TG,测定空腹血糖(FBG)、空腹胰岛素(FINS),并计算胰岛素敏感指数(ISI)。应用半定量RT-PCR检测各个时点大鼠肝组织ChREBP mRNA的表达。结果第4,8和12周末M组大鼠肝组织ChREBP mRNA表达量显著高于C组(P<0.01),且随造模时间延长表达量显著增加(P<0.05);M组大鼠血清FFA、TG、TC和TNF-α及肝组织匀浆TG较同期C组均显著升高(P<0.01),ISI显著降低(P<0.01);相关分析显示,在第8和12周末,M组大鼠肝组织ChREBP mRNA表达量与血清TNF-α水平呈正相关(r=0.754,P<0.05;r=0.845,P<0.01),在第12周末ChREBP mRNA表达量与肝脏炎症活动度计分呈正相关(r=0.711,P<0.05),在第8和12周末ChREBP mRNA表达量与ISI呈负相关(r=-0.773,P<0.05;r=-0.820,P<0.05)。结论高脂饮食诱导的NAFLD模型大鼠随造模时间的延长,肝脏ChREBP基因表达增加,ChREBP可能通过参与胰岛素抵抗的调控而在NAFLD的发生发展过程中发挥作用。

Objective To investigate the expression of carbohydrate response element binding protein（ChREBP） mRNA in the livers of rats with non-alcoholic fatty liver disease（NAFLD） ,and to explore its role in the pathogenesis of NAFLD. Methods Forty-eight male Wistar rats were randomly divided into control group and model group. The rats were fed with standard diets and high-fat diets in control group and model group, respectively. At the end of week 4,8,12, the rats were sacrificed for detecting the levels of tumor necrosis faetor-α （ TNF-α）, free fatty acids, triglyeeride, total cholesterol in serum, triglyceride in liver tissue, fasting blood glucose, fasting insulin, and calculating insulin resistance index. The expression of ChREBP mRNA was detected with RT-PCR. Results The expression of ChREBP mRNA in liver in model group was significantly higher than in control group after 4 weeks, and the expression of ChREBP in- creased gradually in model group after fed with high-fat（ P 〈 0.05 ）. The levels of free fatty acids, triglyceride, total cholesterol and TNF-α were significantly higher in model group than those in control group（ P 〈 0.01 ）, but the level of insulin sensitivity index was signifi- candy lower（ P 〈 O. O1 ）. A positive correlation was found between the expression of ChREBP mRNA and serum TNF-α level in model group at the end of week 8 and 12 （r = 0.754, P 〈 0.05;r = 0. 845, P 〈 0.01 ）. ChREBP mRNA level was positively correlated with he- patic inflammation score at the end of week 12 （r = 0. 711, P 〈 0.05 ）, but negatively correlated with ISI at the end of week 8 and 12 （ r = - 0.773, P 〈 0.05 ; r = - 0. 820, P 〈 0.05 ）. Conclusion The expression of ChREBP mRNA is up-regulated in liver of NAFLD rats. ChREBP may participate in the development of NAFLD through regulating insulin resistance.