Title: [Relationship between apoptosis of mouse thymic lymphocytes and expressions of bax, bcl-2 and bcl-XL after gamma-ray radiation with lethal dose].
Abstract: AIM To observe the relationship between apoptosis of mouse thymic lymphocytes and the expressions of bax, bcl-2 and bcl-X(L) after gamma-ray radiation with lethal dose and provide the basis for treatment of acute severe radiation sickness. METHODS 250 cleaning-grade C57 mice were randomly divided into 6 groups and treated with 0, 6, 9, 12, 15 and 20 Gy of whole body single gamma-irradiation, respectivety. The mice were killed by dislocation and then the thymus and peripheral blood samples were taken at 1-28 days and 3-12 months after irradiation. The lymphocytic apoptosis was analyzed by TUNEL. The expressions of bax, bcl-2 and bcl-X(L) were detected by in situ hybridization and immunohistochemical staining. RESULTS (1)Mouse peripheral leucocytes showed a transient elevation at 6 h after radiation and then decreased rapidly. The leucocyte's number reduced to minimal level at day 7 after 6 Gy gamma-irradiation and returned to basic normal value until one month after radiation. (2)24 h after irradiation the apoptotic rate of thymic lymphocytes increased swiftly, and apoptotic rate was positively correlated with radiation dose in the range of 6-12 Gy. There was no such a correlation after >/=15 Gy irradiation. (3)24 h after 6 Gy irradiation the apoptotic rate of thymic lymphocytes reached the maximal level. Afterwards it began to decrease, but still higher than that of control group even after 12 months. (4)3 h after 6 Gy radiation the expression of Bax protein in thymic lymphocytes increased immediately, and reached the highest value at 24 h. On the other hand, the expressions of Bcl-2 and Bcl-X(L) proteins reduced evidently at 3 h after radiation, reaching the lowest level at 24 h. Analysis of bax and bcl-2 mRNAs was concordant with the protein expression results. CONCLUSION After 6-12 Gy gamma-ray irradiation, the apoptotic rate of thymic lymphocytes is positively correlated with the radiation doses, suggesting that apoptosis is a major way of thymic lymphocyte death after </=12 Gy radiation. Increased Bax and decreased Bcl-X(L) expressions in lymphocyte suggest that both of them play an important role in thymic lymphocyte apoptosis caused by lethal dose radiation.
Publication Year: 2004
Publication Date: 2004-11-01
Language: en
Type: article
Indexed In: ['pubmed']
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Cited By Count: 2
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