大白鼠胎肝细胞GERL的超微结构和电镜细胞化学观察

GERL IN FETAL HEPATOCYTES: AN ULTRASTRUCTURE AND ELECTRON MICROSCOPIC HISTOCHEMISTRY STUDY ON THE RAT FETUSES

本文采用透射电镜和电镜细胞化学方法,对12、15、17、19和21天大白鼠胚胎肝细胞内的GERL进行了观察。超微结构显示:1.胚胎12天,胎肝细胞GERL由刚性膜板(RL)和短管状结构组成。RL以相对挺直的细管为特征,位于高尔基复合体的成熟面。2.胚胎15和19天,肝细胞GERL由管囊状的RL和一些小泡、短粗管和圆形致密小体组成;并常见GERL与有衣小泡、初级和次级溶酶体相连。3.胚胎17和21天,胎肝细胞的结构处于分化、更新阶段,GERL解体,在超薄切片上不易辨认。酸性磷酸酶电镜细胞化学结果显示:胎肝细胞的GERL和溶酶体呈酸性磷酸酶阳性反应,而高尔基体为阴性反应,还可显示出GERL的网状形式和退化解体的形式,这两种形式在常规超薄切片上均未见到。上述结果提示,在胎肝细胞中存在GERL;GERL的形成与胎肝细胞的分化以及溶酶体的形成和功能有关。由于GERL具有独特的超微结构、酶学特征和功能特点,可以认为它是一种单独的细胞器。

GERL in fetal hepatocytes of 12, 15, 17, 19 and 21 days Wistar rat fetuses was investigated by means of transmission electron microscopy and ultracytochemistry. The ultrastructural study showed that: on the day 12 fetuses, GERL of fetal hepatoeytes was consisted of rigid lamellae and short tubules. Rigid lamellae were characterized by the relatively rigid, thin tubules and located at the maturation face of Golgi apparatus. On the day 15 and 19 fetuses, GERL was composed of tubulevacuole-like rigid lamellae, some vesicles, short or thick tubules and round dence bodies. GERL was often found tobe contiuned with lysosomes, including coated vesicle, primary and secondary lysosomes. On the day 17 and 21 fetuses, when the structure of fetal hepatocytes was at the stage of differentiation and renewal, GERL degenerated and could notbe identified. Acid phosphatase ultraeytochemieal results showed that the enzyme reaction product was seen in all parts of GERL and lysosomes, however, no portion of the Golgi stack showed AcP activity. AcP reaction product could also demons trated in the network form and degenerated form of GERL. As mentioned above, our study suggested: (1) there was indeed GERL in fetal hepatocytes of rat fetuses; (2) the formation of GERL was related to the differentiation of fetal hepatocytes as well as the formation and function of lysosomes; (3) according to the unique ultrastructure, enzymological and functional features, it be a preference to the view that the GERL might be a distinct cytoplasmic organelle.