Ultrastructural alterations of the cortical epithelial cells of the irradiated and recovering rat thymus.
To understand the roles of cortical thymic epithelial cells (CTECs) in T-lymphocyte development, we analyzed rat thymi recovering from irradiation (6Gy), at the ultrastructural level. The morphological alterations in the CTECs were most prominent during the third to fifth day of recovery, when proliferating thymocytes were observed in the vicinity of the CTECs. The most striking finding among the alterations in the CTECs after irradiation was a cytoplasmic vacuolization with an increased amount of granular and membranous content. The granular content was observed as loosely aggregated structures or finely dispersed granules and dense bodies. The membranous content appeared in various forms including vesicular, tubular, and irregular membranous structures and myelin figures. The above features are characteristic of the hyperfunctional state of CTECs with increased secretion activities, which suggests their important roles in the repopulation and maturation of the cortical thymocytes during recovery after irradiation.
Arudchelvan
Yamini
Y
Department of Human Science, Yamaguchi University School of Medicine, Ube, Japan. yarudchelvan@yahoo.com
Tokuda
Nobuko
N
Adachi
Yasuhiro
Y
Sawada
Tomoo
T
Fukumoto
Tetsuo
T
D000818:Animals; D049109:Cell Proliferation / Q000528:radiation effects; D004847:Epithelial Cells / Q000378:metabolism / Q000528:radiation effects / Q000648:ultrastructure*; D005260:Female; D008854:Microscopy, Electron; D051381:Rats; D013950:Thymus Gland / Q000378:metabolism / Q000528:radiation effects* / Q000648:ultrastructure*