大鼠肝组织核因子-κB活性变化与过氧化物酶体增殖物激活受体γ表达的关系

目的 观察不同病因所致的脂肪性肝病大鼠肝组织核因子-κB(NF-κB)的活性变化,过氧化物酶体增殖物激活受体γ(PPAR γ)的表达,及其相互关系在脂肪性肝病炎症反应中的作用。方法40只Wistar 大鼠随机分为正常对照组、酒精组、高脂组和酒精加高脂4组,每组10只大鼠,16周断头处死,用HE、苏丹Ⅳ、Masson三色染色观察肝组织光镜下的病理改变和超微结构的变化。用电泳迁移率分析、逆转录聚合酶链反应观察各组大鼠肝组织NF-κB的活性变化与PPAR γ mRNA的表达、各生物化学指标间的相互关系。 结果 模型组大鼠肝组织均表现有不同程度的脂肪变性、炎症、坏死和纤维化,以酒精加高脂组病理损害最重。酒精组和酒精加高脂组的NF-κB活性(142±16.32,238±19.14)明显高于正常对照组(73±9.24,F值分别为6.36、17.93,P值均<0.01)和单纯高脂组(84±10.38,F值分别为5.96、16.20,P值均<0.01),酒精加高脂组的NF-κB活性显著高于酒精组(F=6.23,P<0.01),而高脂组和正常对照组比较差异无统计学意义。酒精组、高脂组和酒精加高脂组大鼠肝组织PPAR γmRNA的表达(0.2530±0.069,0.3647±0.082,0.1226±0.054)均较正常对照组(0.8097±0.094)有不同程度的减弱(F值分别为15.43、7.24、21.45,P值均<0.01)。相关分析显示:酒精组和酒精加高

Relationship between NF-kappa B binding activity and expression of PPAR gamma-mRNA in the livers of rats with fatty liver disease

OBJECTIVE: To investigate the changes of NF-kappa B binding activity, the expression of PPARr and their correlation in the liver of rats with fatty liver disease (FLD) induced by different pathogenic factors and to investigate the molecular mechanism of the inflammation in FLD. METHODS: 40 Wistar rats were randomly divided into 4 groups of ten each: normal group, alcohol group, fat-rich diet group, alcohol adding fat-rich diet group. The rats were sacrificed at the end of the 16th week from the starting day of the experiment. Serum and liver specimens were collected. Histological specimens were stained with HE, SudanIV, and Masson and then studied microscopically. The ultrastructural changes were also checked under an electron microscope. NF-kappa B binding activity and the expression of PPARr mRNA were determined by electrophoretic mobility shift assay (EMSA) and RT-PCR respectively. The correlations between NF-kappa B binding activity and the expression of PPARr and the biochemical indexes were analyzed. RESULTS: Steatosis, inflammation, necrosis and fibrosis were present in livers of the rats of all the experimental groups, and were most severe in the alcohol adding fat-rich diet group. NF-kappa B binding activity was markedly increased in the livers of the alcohol group (142+/-16.32) and of the alcohol adding fat-rich diet group (238+/-19.14) in comparison to the livers of the normal (73+/-9.24, F = 6.36, 17.93) and those of the fat-rich diet group (84+/-10.38, F = 5.96, 16.20). Binding activity was higher in the alcohol adding fat-rich diet group than that in the simple alcohol group, but there was no difference between those of the fat-rich diet and normal groups. The level of PPARr mRNA was lower in the livers of the alcohol, fat-rich diet, alcohol adding fat-rich diet groups (0.2530+/-0.069, 0.3647+/-0.082, 0.1226+/-0.054) than that of the controls (0.8097+/-0.094) (F = 15.43, 7.24, 21.45). NF-kappa B binding activity was correlated positively with the level of serum TNF alpha (r = 0.527, 0.639) and the content of MDA in the liver homogenates (r = 0.723, 0.537), but negatively with the expression of PPARr in the livers of the alcohol and the alcohol adding fat-rich diet groups (r = -0.568, -0.891). CONCLUSION: The enhanced nuclear factors NF-kappa B binding activity and decreased expression of PPARr play a pivotal role in the inflammatory response of FLD induced by alcohol and fat-rich diet. It may provide a new idea for treating FLD effectively.