Small hepatocytes (SH) have been identified in regenerative organs and have been proposed to be hepatocyte progenitor cells. Their characteristic presence in birds, and their maturation into functional and mature hepatocytes, have not yet been elucidated. We previously demonstrated the appearance of chicken SH, which express CD44, in a model of chicken hepatopathy treated with bile duct ligation (BDL). We expanded on our previous research and performed a detailed study of the ultrastructure of chicken SH. Four weeks after BDL, we observed chicken SH with high electron density cytoplasm and with colony formation. In the chicken SH, electron microscopical analysis found no formation of tight junctions and no glycogen. Ultrastructural analysis also revealed the existence of various types of chicken SH with characteristics lying between those of chicken SH with colony formation and mature hepatocytes. The analysis of immunoelectron microscopy showed CD44 expressed on the surface of the extensive SH-like cells in the hepatic lamina. These results suggest that the expression of CD44 changes according to the differentiated stage of SH in a chicken BDL model.

已在再生器官中鉴定出小肝细胞 (SH)，并提出其为肝细胞祖细胞。它们在鸟类中的特征存在以及它们成熟为功能性和成熟的肝细胞，尚未阐明。我们之前在用胆管结扎术 (BDL) 治疗的鸡肝病模型中展示了表达 CD44 的鸡 SH 的出现。我们扩展了我们之前的研究，并对鸡 SH 的超微结构进行了详细研究。BDL 后 4 周，我们观察到具有高电子密度细胞质和集落形成的鸡 SH。在鸡 SH 中，电子显微镜分析没有发现紧密连接的形成，也没有糖原。超微结构分析还揭示了各种类型的鸡SH的存在，其特征介于具有集落形成和成熟肝细胞的鸡SH之间。免疫电镜分析显示CD44表达于肝膜内广泛的SH样细胞表面。这些结果表明 CD44 的表达根据鸡 BDL 模型中 SH 的分化阶段而变化。