Thy1.1阳性肝脏卵圆细胞在大鼠肝硬化形成与消减过程中的动态表达

The dynamic expression of Thy1.1 positive hepatic oval ceils during the shaping and reducing processes of liver cirrhosis induced by dimethylnitrosamine in rats

目的肝脏卵圆细胞(HOC)在二甲基亚硝胺(DMN)致大鼠肝硬化形成与消减过程中表达的动态变化,探讨其病理生理意义。方法应用DMN腹腔注射(4周12次)制备大鼠肝硬化模型,分别于造模后3d、2、4周及终止造模后2,4周处死大鼠取肝组织,进行常规组织学观察,透射电镜下观察HOC 超微结构,免疫组织化学和western blot方法检测Thy1.1的表达变化,应用图像分析法对所标记的HOC进行半定量测定以及光镜下计数细胞数量。结果DMN造模4周大鼠已形成典型的肝硬化;终止造模后2周时肝组织病变较造模4周时有所减轻,终止造模后4周时炎症明显减轻并以不完全纤维间隔为主。Thy1.1 阳性染色细胞正常大鼠肝组织未见到,造模后3 d时可见微量表达,2周时呈散在分布,4周时明显增多,见于纤维间隔周围,终止造模后2周、即第6周时阳性染色显著强于造模4周,大量出现于汇管区,8周时较6周有所减少,表达量基本与4周时相等。阳性染色图像分析、光镜下阳染细胞计数及western blot三者的结果呈一致性。Western blot结果与免疫组织化学观察结果也具一致性。电镜下显示HOC具有形态小,核以卵圆型为主,高的核/浆比例等特点。结论Thy1.1阳性的HOC可能与肝硬化的消减或逆转有关。

Objectives To study the dynamic change of hepatic oval cells （HOC） in the process of rat liver cirrhosis formation induced by dimethylnitrosamine （DMN）, and to explore its pathophysiology significance. Methods A rat cirrhosis model was established by using DMN. Microscopical and electronmicroscopical changes of HOC were examined. Thy1.l was detected by immunohistochemical method at different times. The ratio of HOC was checked using image pattern analysis and Western blot. The number of HOC was counted microscopically. Results At the 4th week after DMN administration, the liver fibrosis was at its peak, with false lobules formation combined with large areas of hemorrhage and necrosis. The fibrosis started to minimize at the 6th week, and also the inflammatory changes at the 8th week. Thy1.1 positive stained cells dispersed at the 2nd week; increased at the 4th week around fiber septa; reached its peak at the 6th week, then decreased at the 8th week. The results of image pattern analysis, cell counting under light microscope and Western blot were constant, with the highest cell numbers at the 6th week, and dropped at the 8th week. The ultrastructure of HOC was characterized by their small sized, oval nuclei, and higher nucleus/plasma ratio. Conclusions During the formation and reduction of rat cirrhosis caused by DMN, Thyl.l stained HOC showed notable dynamic change, which may play an important role in the cirrhotic process.