^(147)Pm诱导血红细胞系对^(60)Coγ射线辐射的适应性反应

Adaptive Response to ^(60)Co γ-radiation Induced by ^(147)Pm Internal Exposure to the Peripheral Erythrocytes of Mice

目的 研究低剂量１４７Ｐｍ 内照射能否改变相继高剂量６０Ｃｏγ射线引起的ＲＢＣ 损伤的适应性效应。方法 应用外周血ＲＢＣ计数、网织红细胞（ＲＣ）计数、正常染红细胞（ＮＣＥ） 微核和嗜多染红细胞（ＰＣＥ） 微核检测，观察低剂量１４７Ｐｍ 内污染诱导小鼠ＲＢＣ系统的适应性反应。结果 剂量为２ ．０Ｇｙ 的６０Ｃｏ γ射线外照射可引起明显的血ＲＢＣ 系统损伤，与正常对照组比较，ＲＢＣ和ＲＣ计数显著降低（ Ｐ＜ ０．０１） ；ＮＣＥ和ＰＣＥ微核细胞率明显增高（Ｐ＜ ０．０１） 。预先用０．３７、３ ．７ 和３７Ｂｑ／ｇ 体重的１４７Ｐｍ 内污染预处理动物，３ 天后再予２．０Ｇｙ 的高剂量６０Ｃｏ γ射线外照射，ＲＢＣ和ＲＣ计数则显著增高，ＮＣＥ和ＰＣＥ微核细胞率显著降低，与单纯高剂量６０Ｃｏ γ射线外照射组比较有非常显著性差异（Ｐ＜ ０．０１）；并且某些指标与正常对照组比较已无显著性差异（ Ｐ＞ ０．０５） 。结论 预先用低剂量１４７Ｐｍ β射线内照射动物， 可诱导血ＲＢＣ 系统的放射适应性反应，使血ＲＢＣ系统对相继高剂量６０Ｃｏ γ射线外照射引起的损伤效应有了明显的抵抗力。提示外周血ＲＢＣ

Objective To explore whether low doses of internally deposited 147 Pm could change the damaged adaptive effects of subsequent high dose of 60 Co γ-radiation to the erythrocytes from the peripheral blood of mice. Method Kunming male mice were injected through tail vein with 147 Pm(NO 3) 3 at low doses of 0, 0.37, 3.7 and 37 Bq/g by body weight. Three days later the mice were irradiated with 60 Co γ-ray at a high dose of 2.0 Gy. the counts of peripheral red blood cels(RBC) 、 reticulocytes(RC)、micronucleated normochromatic erythrocytes(mn-NCE) and micronucleated polychromatic erythrocytes(mn-PCE) were determined 24h after a high dose of γ-radiation. Results The counts of the RBC and RC were significantly decresed , the frequency of mn-NCE and mn-PCE was significantly increased compared with the controls ( P< 0.01) . However, when exposing to the radiation of 147 Pm in vivo at doses from 0.37 to 37 Bq/g by body weight before 60 Co radiation the number of RBC and RC was significantly increased, and the frequency of mn-NCE and mn-PCE was significantly decreased ( P <0.05～0.01), as compared with that in the group in which solely high doses of the 60 Co radiation. Conclusion Low dose β-radiation in vivo with 147 Pm can induce an adaptive response of the erythroblasts, the radioadaptive cells have a obvious resistance to the genetic damages induced by subsequent high dose of 60 Co external radiation. The erythrocyte system of peripheral blood might be one of the more sensitive biological indexes to low doses of ionizing radiation.