大鼠肝组织中卵圆细胞定向迁移的机制研究

Study on the mechanism of directional migration of hepatic oval cells in rats

目的探讨细胞间黏附分子-1(intercellular adhesion molecule-1,ICAM-1)对大鼠肝卵圆细胞(ovalcells,OVCs)在损伤肝组织中迁移的介导作用。方法致癌剂3'-甲基-4-二甲基胺偶氮苯(3'-methyl-dimethy-laminoazo benzene,3'-Me-DAB)饲喂Wistar大鼠,分别于第2,4,6,8,10,12周取肝组织标本行HE染色和ICAM-1免疫组化检测;第4、6、8、10周取肝组织标本,透射电镜观察OVCs和纤维的生长情况;4周时用Percoll密度梯度离心法分离、纯化OVCs,透射电镜观察OVCs超微结构,ICAM-1免疫细胞化学检测OVCs对ICAM-1的表达。结果透射电镜下观察到OVCs超微结构的改变为核大,核/浆比大,核仁小,胞浆内细胞器少,可见少量内质网和小线粒体,整个细胞呈幼稚、未分化状态;ICAM-1免疫细胞化学检测阳性;损伤肝组织HE染色和ICAM-1免疫组化检测显示,肝损伤初期,Hering管周围OVCs增生并且ICAM-1阳性表达,随着肝损伤的加重,OVCs继续增生,并且,OVCs沿增生的肝纤维向肝小叶迁移,同时,ICAM-1阳性表达也继续增多,并逐渐向肝小叶弥散分布;透射电镜下观察到,肝损伤初期,OVCs在Hering管周围增生,肝纤维随之增生,增生的OVCs与肝纤维黏附生长。结论肝损伤不同时期ICAM-1表达的分布与OVCs分布一致,ICAM-1在肝硬化和原发性肝细胞癌(hepatocellular carcinoma,HCC)的发生、发展过程中可能起到介导OVCs在肝内定向迁移的作用。

Objective To investigate the induction of intercellular adhesion molecule-1 （ICAM-1） for OVCs directional migration in liver tissue. Methods Wistar rats were fed with 0.6 g/kg 3＇-methyl-dimethylaminoa-zobenzene （3＇-Me-DAB） in feedstuff for a week. Then liver tissue specimens were gathered in the 2nd, 4th, 6th, 8th, 10th, 12th week, and paraffin sections were stained with HE, immunochemistry and transmission electromicroscope were used to observed the distribution of OVCs and ICAM-1. OVCs were isolated by density ladder centrifugation in the 4th week, and then OVC＇s morphology was observed under transmission electromicroscrope and immunocytochemistry were performed to detect the expression of ICAM-1. Results Observing OVC＇s morphology under transmission electromicroscrope showed that OVC was infantile and undifferentiated with big nucleus, clear nucleolus, large nucleoplasm-ratio, small mitochondria, and little endoplast. In initial stage of damaged liver, OVCs and the expression of ICAM-1 mostly distributed around Hering duct, and then gradually increased and expanded toward hepatic lobule, shown by staining paraffin sections with HE, immunochemistry and transmission electromicroscrope. Immunocytochemistry indicated that ICAM-1 expression on OVCs was positive. Conclusion The expression of ICAM-1 is in accord with distribution of hepatic oval cells, and ICAM-1 is likely to guide OVCs directional migration in the course of the occurrence and development of liver cirrhosis and HCC.