Fas/FasL信号传导通路对NAFLD大鼠肝细胞凋亡的影响  

Effects of death receptor-mediated pathways on hepatocyte apoptosis in nonalcoholic fatty liver disease rats

作　　者：康敏[1] 钟德君[1] 李鹏[2] 李郁[3] 

机构地区：[1]泸州医学院附属医院消化内科,四川泸州646000 [2]四川省绵阳市中心医院消化内科,621000 [3]四川省绵阳市中心医院心内科,621000

出　　处：《重庆医学》2011年第7期633-635,I0001,I0002,共5页Chongqing medicine

基　　金：泸州医学院基金资助项目(07087)

摘　　要：目的通过研究肝细胞凋亡及死亡受体信号转导通路在大鼠非酒精性脂肪性肝病(NAFLD)形成中的作用,探讨NAFLD的发病机制。方法将30只雄性SD大鼠随机分为对照组和高脂饲料(4、8、12周)组;HE染色观察肝组织光镜下的病理改变;电镜观察肝细胞超微结构变化;流式细胞仪检测肝细胞凋亡百分数;免疫组化法检测Fas、FasL在肝组织中的蛋白表达;实时荧光定量PCR法检测半胱天冬酶-8(Caspase-8)mRNA表达。结果 HE染色结果显示,对照组大鼠肝脏无异常发现,高脂组大鼠肝脏4周出现脂肪变,8周出现轻度脂肪肝,12周出现中、重度脂肪肝;电镜下观察高脂组大鼠肝细胞线粒体肿胀,嵴变短、减少甚至消失,粗面内质网减少,核型欠规则;流式细胞仪检测显示,与对照组比较,高脂组大鼠肝细胞凋亡百分数增加,随造模时间延长凋亡率增加更明显;免疫组化染色显示随着肝脏脂肪变加重,Fas、FasL蛋白染色加深,阳性细胞数增加;实时荧光定量PCR法显示Caspase-8 mRNA表达量在高脂组中显著高于对照组,且随肝脏脂肪变及炎症加重呈进行性上升。结论 NAFLD大鼠模型中,肝细胞凋亡促进NAFLD大鼠病情进展;肝细胞凋亡以及Fas、FasL、Caspase-8 mRNA相关调控蛋白的活化是引起NAFLD脂肪变性、炎症及纤维化的重要因素。Objective To investigate the roles of death receptor-mediated pathways in hepatocye apoptosis on nonalcoholic fatty liver disease（NAFLD） rats and to probe into the pathogenesis of NAFLD.Methods Hepatocyte apoptosis index（AI） was detected by flow cytometry（FCM）.The expressions of Fas and FasL were detected by immunohistochemistry method.Meanwhile,the expressions of Caspase-8 was detected by real-time flurescent quantitive polymerase chain reaction.Results HE staining revealed that fatty degeneration at 4 week,mild fatty liver at 8 w,moderate to severe fatty liver at 12 week in high-fat diet group,and electron microscopy showed ultrastructural changes in hepatocytes high-fat diet group（12 week）,including swelling of hepatic mitochondria,shortened or even disappearance of crests,decrease of rough surfaced endoplasmic reticulum,and nuclear shape was irregular.AI of nonalcoholic steatosis rat model of 4-12 weeks was significantly higher than that of normal.The percentage of hepatocyte apoptosis increased significantly as the time going.Immunohistochemical staining showed that Fas and FasL expression in high-fat diet group,the degree of fatty changes and inflammatory staining depened and expanded,the number of positive cells increased,showed a diffuse positive.Real-time quantitative PCR assay showed that the relative expression quantity of Caspase-8 mRNA in model group was significant higher than the control group at the same time.There was also a significant difference in model group of different time point.Conclusion In rat model of NAFLD,the degree of hepatocyte apoptosis is closely related to the degree of liver injury.Pathological hepatocyte apoptosis promotes the progress of NAFLD.The severity of hepatocyte apoptosis is consistent with the Fas,FasL protein expression,the increase degree of Caspase-8 mRNA expression in the development of NAFLD.

关 键 词：脂肪肝 细胞凋亡 半胱氨酸天冬氨酸蛋白酶 Fas Fas配体蛋白质 大鼠 

分 类 号：R575[医药卫生—消化系统]