四塩化炭素頻回吸入マウス肝におけるセロイド色素並びに血鉄素ないしフェリチン生成の電顕的研究

Abstract

Mice were made to inhale carbon tetrachloride (CCl4) vapor 5 to 103 times (at a rate of three times a week); the liver was collected from the mice after completion of inhalation, and prepared chiefly into Epon sections without electron staining; and these sections were examined under the electron microscope for the yellow-brown pigment made up of ceroid and hemosiderin that appeared in the Kupffer cells. It was found that osmiophilic bodies occurring in the phagolysosomes in the Kupffer cells increased in number as well as in size, and were fused with each other as the experimental period was prolonged, the giant phagolysosomes being filled with ceroid granules made up of clusters of osmiophilic multivacuolar structures and osmiophilic fingerprint-like structures at the end of the experiment over a longer period.The ferritin-like particles appeared scatte red or as clusters or in the shape of siderosomes in the cytoplasmic matrix. The clusters were also seen protruding out of the limiting membrane of phagolysosomes in such a way as if budding, and thus being pushed out of the phagolysosomes. Subsequently the ferritin-like particles or hemosiderin granules mentioned above were identified by their disappearance following the dithionite desiderization method (the tissue piece method) applicable to the ultrastructural level.On the other hand, the participation of erythrocytes in ceroid formation could be confirmed by the fact that erythrocytes engulfed by Kupffer cells are frequently found in the giant phagolysosomes where ferritin-like particles or hemosiderin granules are coexistent with ceroid granules. These findings are thought to support the view of Maeda et al. that erythrocgtes may becoine common origin of ceroid and hemosiderin.In the carbon tetrachloride inhalation experiment ov er a long period, the Kupffer cell came to include numerous large phagolysosomes filled with ceroid granules, while ferritinlike particles or hemosiderin granules were hardly found except in the rim of phagolysosomes in the same cell. This finding suggests that with the process of the CCl4 inhalation experiment, ceroid granules greatly accumulate in the cytoplasm, while hemosiderin granules in the cytoplasm decrease gradually through lysosornal discharge (“reverse pinocytosis”) into the cytoplasmic matrix in the shape of ferritin particles.