低剂量辐射诱导小鼠胸腺细胞DNA裂解适应性反应的剂量率效应  

Dose-rate effects of adaptive response of thymocyte DNA lysis induced by low dose ionizing radiation in mice

作　　者：刘淑春[1] 吕喆[1] 王珍琦[1] 刘扬[1] 刘光伟[1] 龚守良[1] 

机构地区：[1]吉林大学公共卫生学院卫生部放射生物学重点实验室,吉林长春130021

出　　处：《吉林大学学报（医学版）》2004年第5期675-677,共3页Journal of Jilin University：Medicine Edition

基　　金：国家自然科学基金资助课题 (39170 2 75 )

摘　　要：目的 :观察低剂量辐射诱导胸腺细胞 DNA裂解适应性反应的剂量率效应。方法 :用 X射线照射Kunming雄性小鼠 ,其诱导剂量 (D1)及其后攻击剂量 (D2 )分别是 75 m Gy和 1.5 Gy,D1剂量率为 6 .2 5、 12 .5、2 5、 5 0、 10 0和 2 0 0 m Gy· min- 1 ,D2剂量率为 2 87m Gy· m in- 1 ,D1和 D2间隔 6 h。通过荧光分光光度计检测DNA裂解断片的变化。结果 :D2组胸腺细胞 DNA裂解率明显高于假照组 (P<0 .0 0 1) ;当 D1剂量率为 6 .2 5、12 .5和 2 5 m Gy· min- 1 ,D1+D2组 DNA裂解率明显低于 D2组 (P<0 .0 5或 P<0 .0 1)。结论 :当 D1在 75 m Gy,剂量率为 6 .2 5～ 2 5 m Gy· min- 1 ;D2为 1.5 Gy,剂量率为 2 87m Gy· min- 1 ;D1和 D2间隔 6 h,可在全身照射条件下诱导小鼠胸腺细胞 DNA裂解的适应性反应。Objective To observe the dose-rate effects of adaptive response of thymocyte DNA lysis induced by low dose radiation. Methods Kunming male mice were irradiated with the inductive dose (D1: 75 mGy; dose rate: 6.25, 12.5, 25, 50, 100, and 200 mGy·min -1 ) and the challenging dose (D2: 1.5 Gy; dose rate: 287 mGy·min -1 ) , the interval between D1 and D2 was 6 hours. The DNA lytic fragmentation was measured with fluorospectrophotometry. Results The DNA lytic rate in the D2 group was significantly higher than that in sham-irradiation group; when the dose rates were 6.25, 12.5 and 25 mGy·min -1 ,the DNA lytic rates in D1+D2 groups were significantly lower than those in the D2 group (P<0.05 or P<0.01). Conclusion When the mice are irradiated with 75 mGy (D1: 6.25~25 mGy·min -1 ) 6 hours before 1.5 Gy (D2: 287 mGy·min -1 ) exposure, the adaptive response of thymocyte apoptosis can be induced under the condition of whole-body irradiation.

关 键 词：辐射 电离 辐射剂量 DNA裂解 适应性反应 

分 类 号：Q691[生物学—生物物理学]