[The effects of acute large dose of gamma-irradiation on immune function of mice].
OBJECTIVE
To observe the effects of large dose of gamma-irradiation on immune function of mice.


METHODS
225 cleaning-grad C57 mice, weighing(20+/-2.0) g, were randomly divided into 6 groups, and treated with 0, 6, 9, 12, 15 and 20 Gy gamma-irradiation. At different times after irradiation, lymphocytes were collected and lymphocytic apoptosis and T cell subsets were analyzed by TUNEL, May-Grunwald Giemsa (MGG) staining and flow cytometry.


RESULTS
(1)At early stage(1-14) d after radiation, the apoptotic rate of peripheral blood lymphocytes increased significantly and 12 Gy radiation resulted in the highest apoptotic rate. The number of T lymphocytes and T cell subsets decreased continuously in a dose-dependent manner. CD8(+) T cells were the most sensitive in T cell subsets to irradiation. These results suggested that early severe injury might be one of the important features of immune injury caused by acute radiation. (2) One month after radiation, the apoptotic rate of lymphocytes began to decrease and T lymphocytes and their subsets recovered gradually. However, neither the lymphocytic apoptotic rate nor the number of CD3(+) T cells and CD8(+) T cells, recovered to normal level, indicating that large dose of radiation had severe remote effects on immune function.


CONCLUSIONS
Apoptosis of a large number of peripheral blood lymphocytes in early stage after radiation may result in sharp reduction of T cell number and late immune function depression.
Cui
Yu-fang
YF
Department of Immunology, Institute of Radiation Medicine, AMMS, Beijing 100850, China. yufangc@vip.sina.com
Ding
Yan-qing
YQ
Xu
Han
H
Liu
Xiao-lan
XL
Jin
Wei
W
Mao
Jian-ping
JP
Mao
Bing-zhi
BZ
D000818:Animals; D017209:Apoptosis / Q000528:radiation effects*; D015496:CD4-Positive T-Lymphocytes / Q000166:cytology / Q000528:radiation effects; D018414:CD8-Positive T-Lymphocytes / Q000166:cytology / Q000528:radiation effects; D003037:Cobalt Radioisotopes; D005260:Female; D008214:Lymphocytes / Q000166:cytology / Q000528:radiation effects*; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D011829:Radiation Dosage; D014916:Whole-Body Irradiation
D003037:Cobalt Radioisotopes