Molecular mechanism of damage and repair of mouse thymus lymphocytes induced by radiation.
OBJECTIVE
To investigate the role of apoptosis in radiation-induced mouse thymus lymphocyte damage and repair and provide the basis for understanding the molecular mechanism of radiation-induced lymphocyte damage and repair as well as the prevention and treatment of acute radiation sickness.


METHODS
We studied the dynamic changes of apoptosis of mouse thymus lymphocytes and the expression of bax and bcl-2 gene products after 2, 4, 6 and 8 Gy of whole body gamma-irradiation using in situ terminal labeling, DNA electrophoresis and immunohistochemical techniques.


RESULTS
At the early stage after irradiation, the percentage of apoptotic lymphocytes increased rapidly in accordance with the increasing of radiation doses, while the counts of the thymus and peripheral lymphocytes decreased sharply, showing an opposite change to lymphocyte apoptosis. After 6 Gy gamma-irradiation, typical morphological characteristics of thymus apoptotic lymphocytes in early, middle and late stages were found by transmission electron microscopy. The thymus lymphocytes displayed characteristic DNA ladders 4 hr and 8 hr after 2-6 Gy gamma-irradiation,using DNA gel electrophoresis techniques. Abnormal expression of bcl-2 and bax gene products were shown in irradiated lymphocytes.


CONCLUSIONS
Apoptosis plays an important role in the process of radiation-induced mouse thymus lymphocyte damage and repair. Bcl-2 and Bax proteins may regulate the process of lymphocyte apoptosis.
Cui
Yufang
Y
Department of Experimental Pathology, Institute of Radiation Medicine, Beijing 100850, China. gaoyb@nic.bmi.ac.cn
Yang
Hong
H
Wu
Shuxia
S
Gao
Linlu
L
Gao
Yabing
Y
Peng
Ruiyun
R
Cui
Xuemei
X
Xiong
Chengqi
C
Hu
Wenhua
W
Wang
Dewen
D
D000818:Animals; D017209:Apoptosis / Q000528:radiation effects*; D004307:Dose-Response Relationship, Radiation; D005720:Gamma Rays; D008214:Lymphocytes / Q000502:physiology / Q000528:radiation effects*; D008297:Male; D051379:Mice; D011518:Proto-Oncogene Proteins / Q000032:analysis; D019253:Proto-Oncogene Proteins c-bcl-2 / Q000032:analysis; D013950:Thymus Gland / Q000473:pathology / Q000528:radiation effects; D013997:Time Factors; D051028:bcl-2-Associated X Protein
C494827:Bax protein, mouse; D011518:Proto-Oncogene Proteins; D019253:Proto-Oncogene Proteins c-bcl-2; D051028:bcl-2-Associated X Protein