慢性肝损伤时肝内干细胞的增殖

The proliferation of hepatic stem cells in chronic liver injury

目的：采用免疫组织化学的方法研究慢性肝损伤时肝干细胞在肝脏内的分布和增值,初步探讨肝脏的损伤修复与肿瘤发生的细胞生物学机制。方法：3,-me-DAB喂食大鼠四周,建立应激模型刺激大鼠肝内干细胞的迅速增殖,取材、固定制成石蜡切片,ABC法检测肝干细胞特异性的表面标记蛋白CD34、C-11、CK19、OV6和神经前体细胞的特异性表面标记Nestin在大鼠肝脏内的表达。结果：大鼠肝实质结构改变显著,汇管区内结缔组织细胞大量增生,浸润周围肝组织形成假小叶。靠近界板处断续的排列着卵圆样细胞分别表达CD34、CK19、OV6和Nestin,阳性细胞的形态和分布特点相似,而且具有典型的干细胞的特点。此外,肝实质内可见大量的单个核样干细胞分别表达OV6、CD34、Nestin和CK19。这些细胞类似造血系统来源的单核细胞分布在肝索、肝血窦、肝内血管、增生的小叶间胆管和胆管之间,多见于汇管区的结缔组织内。结论：3’-me-DAB作用后,肝内存在着多种干细胞,而且具有空间分布的规律性。增生的干细胞在损伤应激下继续增殖分化为肝实质细胞,参与肝脏的组织修复,同时成为引发肝脏肿瘤的可能原因之一,具体机制还需要进一步的深入研究。

Objective:In this study,we introduce an immunohistochemical method to label the stem cells during chronic liver damage with the purpose of investigating the mechanism of liver damage and repair and the develop- ment of carcinoma in the liver.Methods:SD rats were fed with 3'-me-DAB for 1 month to induce the proliferation of stem cells in the liver.CD34,C-11,CK19,OV6,which were proved to be the markers of the hepatic stem cells in our previous studies,were identified with ABC staining.The neuroepithelial stem cell expressing protein nestin was also stained to identify the progenitor cells in the rat livers.Results:The structure of the rat liver was markedly changed.The connective tissue cells in the portal areas proliferated and infiltrated into the liver paren- chyma to form artificial lobules.The stem cells expressing CD34,C-11,CK19,OV6 and nestin respectively were found to line intermittently near the limiting plate,having the similiar distributional changes and morphological features.Furthermore,there were some mononuclear cells,which were positive for OV6 and CD34,nestin, CK19,dispersing in the hepatic cords and sinusoids,especially in the mesenchymal tissue of the portal area.Con- clusion:3'-me-DAB would induce the proliferation of the intrahepatic stem cells.These cells have regular spatial distributions,and they continue to proliferate and differentiate into the liver parenchyma cells which participate in the liver repair and become a potential pathogenetic cause of carcinoma of the liver.Further studies are necessary to elucidate the mechanism.